Traditional perforated screens of india by Pavitra Sanath Kumar

TRADITIONAL PERFORATED SCREENS OF INDIA (Study of its origin, purposes and behavior)

AA E+E Environment & Energy Studies Program Architectural Association School of Architecture Graduate School

MSc Sustainable Environmental Design Dissertation Priject 2013-14

Pavitra Sanath Kumar September 2014

Authorship Declaration Form Environment &Energy Studies Programme ARCHITECTURAL ASSOCIATION GRADUATE SCHOOL PROGRAMME

MSc SUSTAINABLE ENVIRONMENTAL DESIGN 2013-14

SUBMISSION

DISSERTATION PAPER

TITLE TRADITIONAL PERFORATED SCREENS OF INDIA (Study of its origin, purpose and behavior)

NUMBER OF WORDS (Excluding footnotes and references) 14,550 words

STUDENT NAME

PAVITRA SANATH KUMAR

DECLARATION “I certify that the contents of this document are entirely my own work and that any quotation or paraphrase from the published or unpublished work of others is duly acknowledged.”

SIGNATURE

DATE

19/09/2014

TRADITIONAL PERFORATED SCREENS OF INDIA

AUTHORSHIP DECLARATION FORM TABLE OF CONTENTS ACKNOWLEDGEMENTS ABSTRACT CHAPTER 1. INTRODUCTION

1.1 JAALI 1.2 CLIMATIC CHALLENGES 1.3 RESEARCH OUTLINE

1.3.1 CLIMATIC INFLUENCE 1.3.2 EXTENT OF STUDY 1.3.3 DESIGN DECISIONS

CHAPTER 2. ORIGIN OF JAALI

CHAPTER 3. CLIMATE STUDY

CHAPTER 4. THEORITICAL BACKGROUND

CHAPTER 5. FIELDWORK

CHAPTER 6. QUANTIFYING THE SCREENS

CHAPTER 7. DESIGN APPLICATION

CHAPTER 8. CONCLUSIONS

CHAPTER 9. REFERENCES

CHAPTER 10. APPENDIX

2.1 POPULAR EXAMPLES FROM HISTORY 2.2 PRESENT EXAMPLES

3.1 CLASSIFICATION 3.2 CLIMATES IN INDIA 3.3 COMFORT

4.1 FUNDAMENTALS OF JAALI 4.2 PREVIOUS RESEARCH 4.3 ADVANTAGES AND DISADVANTAGES

5.1 CHOICE OF THE PRECEDENTS 5.2 METHOD OF STUDY 5.3 JAIPUR / HOT SEMI-ARID CLIMATE 5.4 NAGARCOIL / TROPICAL MONSOON CLIMATE 5.5 AGRA / HUMID SUB-TROPICAL CLIMATE 5.6 PERFORMANCE TABLE 5.7 CONCLUSIONS

6.1PERFORATION PERCENTAGE 6.2PERFORATION SIZE 6.3 THICKNESS 6.4 DAY LIGHTING

7.1 HOT SEMI ARID CLIMATE 7.2 HUMID SUBTROPICAL CLIMATE 7.3 TROPICAL MONSOON CLIMATE

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

Acknowledgements First and foremost I would like to thank my course director and my tutor Professor Simos Yannas for his invaluable guidance, support and encouragement that helped me stay on the right track in this research. I would also like to thank the entire SED staff, especially Jorge Rodriguez, Paula Cadima and Herman Calleja for their very useful advice and feedback for this research. I also express my gratitude to friends Karthikeya Rajput, Megha Nanaiya, Kimmy El Dash, Mariyam Zakiya and Bala Murugan for helping me and supporting me with this research. Very special thanks to closest friends Jorge Ramirez, Ganesh Sivakumar, Adriana Comi Pretelin and Praew Sirichanchuan for their constant support and for sharing very memorable and cherishing moments with me. I would like to thank my cousin Ajay Gautham for accompanying and helping me with my fieldwork. Most important of all, I am very grateful my parents, sister and my whole family for believing in me, supporting and encouraging me throughout this course.

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

Abstract Fixed perforated screens act as a good envelope in hot climates, providing adequate amount of ventilation, day light and solar radiation. The vernacular buildings in hot climates are the living proof of this. As the historic examples show different climatic conditions having given birth to different kinds of Perforated Screens, to learn from such selected precedents would be useful. Intensive fieldwork was undertaken over a period of 2 days each at 3 sub climates within the hot climates of India. The measures from the data loggers, concurrent spot measurements and questionnaires help in analyzing the performance of the screen. The fieldwork results are processed with a understanding of its performance with respect to the architecture of the space and the demands posed by the climate. As a result, various charts are drawn about each screen tested with respect to the amount of heat, light and air it allows in. Based on these results and understanding of the Jaali, space and the climate, co-relations are drawn between important parameters. Then the research is taken forward by testing physical models and giving a basic guide to design a Jaali based on the internal requirements. While discussing where it can be used, the paper suggests the possible adaptive strategies that can be coupled with this element.

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

CHAPTER 1 INTRODUCTION

TRADITIONAL PERFORATED SCREENS OF INDIA

Traditional architecture has always provided simple solutions for tough challenges posed by the climate and the environment. The simple solutions as we call it have evolved over hundreds of years, changing and adapting to the requirement of the gradual changes that the lifestyle goes through. Hence it can be said that it will always be evolving, getting better and better. The architectural styles, practices and traditions fall out of use when a convenient solution is found. In the present day, the simpler solution is the usage of HVAC appliances, which results in an independent building that is uninfluenced and unaware of its context. Since the introduction of this luxury, this prototypical style of architecture has started spreading even in places that cannot afford to use energy. This brings a necessity for looking back at the broken link of the traditional architecture and borrowing some of its elements after understanding its complete potential. In doing so, an element that is found to be used beyond geographic borders and in recent times beyond climatic restrictions is the perforated screens that are known as â&#x20AC;&#x153;Jaaliâ&#x20AC;? in India. Jaali has formed an identity in the traditional architecture in Hot Climates. It is a traditional architectural element that is found across the world in different forms and materials catering to different needs. It provides privacy due to difference in light levels from outdoor to indoor, so Jaali in the present times is more popular for this quality. The figure 1.1.1 shows the difference when viewed from outside to inside and the other way round through the Jaali in Cairo, Egypt. The non-obvious fact being that it has a greater potential than providing privacy and security. This research aims to explore the intricacies and complete potential of this element and exploit its abilities in order to adapt it in the present context.

1.1 JAALI: What is the capacity of a perforated screen? Can the differentiation in the form from one place to another tell us the climatic factors that shaped it? In that case, how and where can we utilize the screens in the current context? Can comfort be achieved with this? These are the vital questions that shaped the topic. Examples of Jaali in the traditional architecture is found invariably only in hot climates. It is more popular for its aesthetical beauty and workmanship, especially the ones found in the desert regions. What is hidden by the aesthetic beauty is its potential to deal with challenges posed by the hot climates. Low energy building design for hot climates will have to deal with 3 main targets, they are a) appropriate ventilation, b) good shading and c) adequate day lighting. The primary function of a perforated screen is to cut-down the amount of heat and excess light, but also provide adequate ventilation into the spaces, while keeping the view, privacy, security and aesthetic beauty. The figure 1.1.2 is the exterior and the interior view of the Jaali in Jaisalmer, India showing the aesthetic qualities. There are some studies that have been carried out by Sherif et al (2010) about the Jaali for hot climates based on orientation and its specific climatic requirements. These recent research about the Jaali was done to test its performance as a solar screen in front of a window or a glazed surface and it was proved to be beneficial in saving up to 30% of the cooling loads in the desert climate. But other qualities of the screen were not put under test. Hence out of all the functions that the Jaali is capable of, there can be a balance achieved by pri2

JAALI | INTRODUCTION

1.1.1.a

1.1.1.b Figure 1.1.1 Wooden Jaali (Mashrabiya) found in Egypt, a)Interior view, b) Outside view (source:www.flickr.com)

1.1.2.a 1.1.2.b Figure 1.1.2 Stone Jaali in Jaisalmer, India; a) Interior view, b) exterior view (source: www.flickr.com) ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

oritizing a particular quality depending on the function of the space.

1.2 CLIMATIC CHALLENGES

Hot climates provide challenges like maintaining right amount of ventilation, humidity, and light to achieve comfort. Hence low energy buildings in hot climates will have to prevent direct solar radiation within the space, but at the same time maintain good amount of light and provide adequate ventilation. The regular glazed windows cannot facilitate ventilation while keeping the rain out and in addition is known to cause uncomfortable glare, especially in tropical climates (Givoni 1998). In the current context, it is easy to find perforated screens in the hot climatic regions but only in the transitional spaces (see Fig 1.2.1). But there are examples from the past that show the use of such screens in living rooms and bedrooms alike, without compromising on privacy. The domination of glass has taken away the traditional perforated screens from the context and has left us with specific examples for remembrance. Perforated screen is one of the important solutions presented by the history of hot climates, to beat the heat and keep the spaces comfortable. The design of the each of the screen in these places depended on the local climatic and functional requirements and available resources and materials. Hence one can see a wide range of screen designs through the world and the ones that are common within the sub-climate. As the climate played the essential factor in shaping this element, the climatic conditions are analyzed to understand the requirements and necessities. The hot climate shows a basic requirement of shading, in order to prevent direct sunlight indoors. When the hot climates are broken down into hot dry and hot humid climates, there is a distinct requirement of the amount of wind inside to provide comfort. This would be the important factor in the design of the Jaali.

1.3 RESEARCH OUTLINE This research starts with tracing the evolution of perforated screens through history, its uses, adaptations and development in all the varied hot climates. In most of the historic context, houses had simpler designs, while palaces had special and intricate designs. So this element was explioted for its aesthetic beauty. 1.3.1 CLIMATIC INFLUENCE Perforated screens in India are found in a large number. Experiencing hot climate thorugh out the year, most of the traditional buildings have Jaali that is personalized to a particular function and the local climate. According to Koppen Classification, India has a majority of hot and few regions of cold climate. The hot climates are further classified into five sub climates that range from dry to humid conditions, they are as follows: • • • • •

Hot Dry Hot Semi-Arid Humid Subtropical Tropical Monsoon Tropical Savanna

The literature provides evidence of the Jaali being a luxurious and a favoured element and its potential to save energy. Thus Jaali of particular climates are chosen to study. To investigate the screens, intensive fieldwork was carried out in the 3 different climates in India. Starting with understanding of the local climate, the function of the space with the Jaali, the level of comfort in the space is evaluvated. The built precedents are chosen based on the locally recurring and popular screen. A period of 2-3 days was spent in each example, measuring each as4

CLIMATIC CHALLENGES | INTRODUCTION

1.2.1 a)

1.2.1 b) Figure 1.2.1 Jaali found in the present context; a)Perforated blocks, b) Brick Jaali, Kerala. (source: www.flickr.com)

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

pect of comfort (like temperature, humidity and air flow) in the space due to the Jaali. It involved placing data loggers, taking concurrent spot measurements and questioning the people who spent more time in the spaces with the Jaali. This research moves into detailed analysis and documentation of the performance of the screens in particular climatic conditions. The study and analysis synthesized to give a clear understanding of the Jaali from the fieldwork. 1.3.2 EXTENT OF STUDY Performance of the perforated screen is accessed here through a comparative analysis. The amount of heat that the screen allows inside, the amount of light and air allowed inside was compared with the same measurements outside the Jaali. Repetitive spot measurements inside and outside were taken to access them and it resulted in giving a relationship between the design of the Jaali and the level of comfort that is achieved inside interms of ventilation, daylight, and shading. The preliminary analysis of the measurements shows that there was a clear understanding of the performance of the screens during that period. Precedent 1: The first study was done in Jaipur, Hot semi-arid condition, the screens are oriented towards the direction of the summer predominant wind direction. The Figure 1.3.1 shows the space and the Jaali that was measured. As it happens to be West, the perforation percentage is so less that there is no direct sunlight within the spaces. Thus this Jaali is able to prevent direct solar radiation and brings in small amount of wind indoors. Precedent 2: The second study was done in Agra, humid subtropical condition, in a prayer space (see Fig 1.3.2) that the screens are found on all the four directions of the building, but the perforation percentage on the North is found to be much higher than the ones on the other 3 sides. As it was a public space, it did not have any adaptive option to increase or decrease the air flow. The building has the overhung shading elements on all sides and hence the Jaali had bigger perforations. Precedent 3: The last study was done in Nagarcoil, a tropical monsoon climate that had a high amount of humidity throughout the year. The Jaali measured is in the Kingâ&#x20AC;&#x2122;s court shown in Fig 1.3.3. The Jaali in the building fulfilled 3 important objectives, to prevent rain inside, prevent glare from the high angle of the sun, and provided maximum wind flow to tackle humidity (see Fig 1.3.2 (iii)). 1.3.3 DESIGN DECISIONS In the next stage the measurements from the precedents are synthesized and a performance chart of the different comparable Jaali is drawn with respect to perforations, material and all the climatic factors. This gives a co-relation between the type of the Jaali to the internal comfort it provides, with respect to quality of light, solar shading and the velocity of wind received inside. In addition to the field work, the relationship of design of Jaali to its performance is further refined with respect to a hot dry and hot humid climate in India. At the end, the two main targets of blocking direct sun indoor and receiving the right amount of wind, is established. The importance of making a fixed Jaali adaptable is realized from the fieldwork. Hence adaptable design options for three hot climates from the fieldwork are presented at the end of the research and proving its performance through the design guidelines obtained from this research.

RESEARCH OUTLINE | INTRODUCTION

1.3 (i) a)

1.3 (i) b) Figure 1.3.2 (i) Hawa Mahal, Jaipur; a) Jaali b) The Queen’s chambers with the Jaali

1.3 (ii) a)

1.3 (ii) b) Figure 1.3.2 (ii) Tomb of Salim Chisti, Agra; a) Jaali b) The tomb with the Jaali

1.3 (iii) a)

1.3 (iii) b) Figure 1.3.2 (iii) Padmanabhapuram Palace, Nagarcoil; a) Jaali b) The King’s court with the Jaali

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

CHAPTER 2 ORIGIN OF JAALI

TRADITIONAL PERFORATED SCREENS OF INDIA

Tracing the journey of Jaali through time and the way it was adapted to a particular function and climate. The range of functions the Jaali is capable of and also how it fell out of practice can tell us the advantages and the disadvantages of using a Jaali. This is accomplished with the help of books, historic accounts and papers that have regarded the Jaali as an aesthetic or functional element. Jaali that is used in the current context are in the buildings that depend completely on HVAC systems to run them. They are used in front of glass, in hot climates to provide solar shading , in cold climates to provide appropriate daylight and in some cases for pure aesthetics. The complete potential and other functions of the Jaali can be explored further with a thorough knowledge of the fundamentals of the Jaali. Hence the growth/transformation of Jaali over time is traced, until present conditions. Fig 2.1 Map showing the locations where the perforated screens were extensively found in the history “ Window openings normally serve three functions: let in direct or indirect sun light, to let in air and to provide a view. In hot-arid climates it is rarely possible or desirable to combine these three functions in a single architectural solution.” - Hassan Fathy

2.1 POPULAR EXAMPLES FROM HISTORY 2.1.1 Mashrabiya : 12th Century Most examples found in Cairo, Egypt (26°3N, 30°5E) and in regions of Saudi Arabia, Morocco, Egypt, Malta, and Bagdad in Hot Semi-Arid climate. Mashrabiya is directly translated as ‘place to drink’ and it is interpreted as “place to cool the drinking water”. The traditional Mashrabiya is wooden screen with intricate floral patterns. Figure 2.1.1 shows the interior and the exterior of mashrabiya. It is made of wooden lattice of cylinders connected with spherical joints (E.Aljofi, 2005). Mashrabiya is used between rooms for cross ventilation like in some houses in Jeddah, Saudi Arabia. Hassan Fathy observes that the closely formed wooden Mashrabiya, absorbs the moisture from the air in the night and in the morning evaporates sending in the cooler air. 2.1.2 Jaali/Jali, Jaipur, India : 14th Century Thar desert of Rajasthan has the most recurring examples of the perforated screens. The state’s capital Jaipur which is located at 26°9N,75°8E. It is categorised under Hot Semi-Arid Climate. Jaali/Jali literally translates to net. Earliest perforated screens are known to have prevailed in 14th century buildings of houses, palaces and public buildings alike in the Indian deserts. Jaali are fixed screens, in some cases have an opening to the centre like a window. Figure 2.1.2 shows the interior and the exterior of the Jaali that is found in Jaisalmer, Rajasthan, India. Indian history maps out the relocation of two popular clans into the Thar or Indian desert in the North West of India, to avoid being invaded by the neighboring kingdoms or robbed by the local bandits. The desert climate gave them 10

POPULAR EXAMPLES | ORIGIN OF JAALI

Figure 2.1 Map showing the locations where the perforated screens were found in the history

2.1.1 a)

Figure 2.1.1 Bayt Al Suhaymi, Caira, Egypt

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

a distinct style of architecture, among which the primary feature is the extensive use of Jaali. The windows don’t have moveable shutters but the fixed Jaali that is intricately carved from the local material. Not just the windows but the entire wall is found to have thin Jaali that protects the internal space form the strong sunlight and provides the slightest breeze (Rajput Palaces). The perforations are flower patterns with intricate details. In public buildings, this element is found in all orientations as a veranda or balcony cover (see Fig 3.2). In houses it is found mostly towards the street, as a perforated window or door. 2.1.3 Azhi, Kerala, India : 15th Century It is found in Kerala, India at 8.5°N, 76.9°E. Kerala is a Southern state in the tip of the Indian sub-continent. It is cut-off from the rest of India, as the linear state is wedged between Arabian Sea and long stretch of Western Ghats. It has a different weather and hence different architectural traditions from the rest of the country. It has Warm - Humid climate and as a result has thick vegetation. Hence the traditional constructions is mostly of wood. Azhi is a local name for the perforated screens that covers the balcony/veranda space in a house (Varanasi, 2004). (See figure 2.1.3 shows the interio and the exterior of Azhi). It is a series of horizontal wooden strips that are sloping downwards, with a railing of vertical wooden strips in the balcony of a typical Kerala house. It is always seen to be fixed with completely openable parts (like seen in figure 2.1.3) and in all orientations. As evaporative cooling is the main target in warm-humid climates, all activities of the occupants happen in the semi-open like spaces (with roof and verandas) (Koch – Nielsen, 2002). In addition to avoid rain and glare, these screens were used in common spaces of the house. 2.1.4 Capiz Shell Windows, Philippines : 17th Century This screen is a traditional architectural element of Philippines that is located at 14°3N, 120°5E. Capiz shell windows are traditional sliding windows found in Philippines. (See Figure 2.1.4 interior and the exterior of the capiz shell windows) These windows are perforated wooden windows, in which the perforations are filled with Capiz shells, just like the modern day window with glass (Oliver, Paul,1997). Hence these perforations help only the admission of light and not ventilation. Philippines has a Humid Sub-tropical climate, where humidity is a problem. To deal with humidity, a regulated flow of air is required. As the windows were not perforated for ventilation, the windows are kept completely open and there is always a continuous inflow of warm air. This was later controlled by adding “Jalousie” on the inside of the window (Oliver, Paul, 1997). Jalousie is a traditional name for louvers. It is said to have its origin in Hawaii, which has a tropical semi-arid climate. In warm humid climates, openness should be the dominant character and solid walls should be as minimal as possible. Walls can take the form of adjustable shading device (Koch – Nielsen, 2002). That is exactly seen here, but there was either a condition of good ventilation and uncomfortable glare (windows open) or no ventilation and adequate lighting (windows closed).

POPULAR EXAMPLES | ORIGIN OF JAALI

2.1.2 a)

2.1.2 b)

2.1.2 c) Figure 2.1.2 Jaali in North India; a) Jaipur Palace, b) Mehrangarh Fort c) Jaisalmer Palace, Rajasthan, India

2.1.3 a)

2.1.3 b) Figure 2.1.3 Kuthiramalika, Kerala, India; a) Interior, b) Exterior

2.1.4 a)

2.1.4 b) Figure 2.1.4 Spanish Colonial House, Philippines; a) Interior, b) Exterior ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

2.1.5 Perforated walls in Malay Houses : 18th Century This Perforated walls is found in Malaysia located at 5°5N, 100°3E. Malay houses are traditional dwellings constructed by the indigenous ethnic Malay of the Malay Peninsula, Sumatra and Borneo. Using renewable natural materials including timber and bamboo, the dwellings are often built without the use of metal including nails. The traditional houses are normally on stilts for reasons like flood, termite protection and improve ventilation. (See Figure 2.1.5 that shows the interior and the exterior of the Malay houses). Malaysia has a hot humid climate, and the walls all around a typical traditional house is perforated to provide a steady flow of ventilation. The walls have different range of openings from fixed to adjustable perforations. The feature of raising the building on stilts provides better exposure to prevailing wind and in the process allows air to be cooled as it passes over the vegetation below the building and therefore cools the floor (Oliver, Paul, 1997).

2.2 PRESENT USE 2.2.1 Cobogo, Brazil : 19th Century Manaus in Brazil is located at 3°1S, 60°0W, has only two seasons, summer and winter and rain is a common factor through-out the year (Koenigsberger, 1974). Being categorized under warm-humid climate, humidity is a problem and mostly has partially cloudy sky. Cobogo/Combogo is a perforated block generally made of terracotta, ceramic or a mix of sand and concrete. In Brazil, it was initially used for privacy in service spaces (corridors, kitchens and laundry) in both residential and non-residential buildings (Bittencourt, 1993) (See Figure 2.2.1 that shows (i)cobogo used in classroom space in India, (ii) cobogo used in the balcony space in Brazil). It is mostly the double skin in the building, and is used only where very high rate of ventilation is required (more than what a window can provide). 2.2.2 Brick Jaali, Kerala, India : 20th Century “Kerala has a hot, wet, humid, tropical climate, so the roof pitch is steep and the eaves come down low to protect the walls from the heavy rains and at other times of the year from the hot sun. Rooms in the houses were mainly used for storage and for brief periods of privacy and were therefore small, while deep, shady, cool verandahs were used for living purposes. There was very little difference between urban and rural buildings” Laurie Baker. The local predominant construction materials are wood and brick (See Figure 2.2.2 are the examples of Laurie Baker’s design with the locally significant architectural feature of brick jaali). Like seen in some of the cases above, the perforated screens were used as another skin before the walls, providing the complete privacy and good ventilation. In some cases the space between the brick jaali and the walls created the space like living and other common activities. 2.2.3 Examples of Jaali in 21st Century (i) Arab World Institute, Paris by Jean Nouvel

POPULAR EXAMPLES | ORIGIN OF JAALI

2.1.5 a)

2.1.5 b) Figure 2.1.5 Malay House, Kedah, Malaysia a) Interios, b) exterior

2.1.5 a)

2.1.5 b) Figure 2.2.1 a)Lucio Costa Arch, Laranjeiras, Brazil, b)DPS Kindergarten school, Bangalore

2.1.6 a)

2.1.6 b) Figure 2.2.2 a&b Projects by Laurie Baker, Kerala, India

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

Function of Jaali : Lighting, Aesthetics The 10 storey building has a glass facade, behind which is visible a metalic jaali. (see Fig. 2.2.3 (i)). It is made of 240 photo sensitive motor controlled apertures, that automatically opens and closes to control the amount of light and heat entering the building from the sun (www.imarabe.org). (ii) The Velodrome, London, Hopkins Architects Function of Jaali : Ventilation The indoor cycling center, that has horizontal slits on all sides, that open under the sitting space to provide subtle but effective natural ventilation (Brunelli, 2014) (see Fig. 2.2.3 (ii)).

CONCLUSIONS: The earliest two examples are from arid conditions. The amount of air it admits is very critical. These spaces with the Jaali show a subtle way of keeping the space ventilated and has small windows that will be used only when more ventilation is required. Hence the opening percentage goes from the least possible to a minimum number. But in the later 3 cases, they are all from humid climates, having more open conditions compared to the first 2 cases. They all have shading elements as well. If the shading element could prevent direct sun and if the climate demanded open envelops, then why was the Jaali introduced? The humid climates that occur close to the equator, experiances severe glare. The Jaali here was designed to prevent glare and maintain privacy. From the above study it is understood that the perforated screens through history was mainly used in Hot climates. It performs 3 main functions that are as follows: 1) Ventilation 2) Shading 3) Day - Lighting As the functions of the perforated screens are well explained, the other factors that also go with it is the fact that it is aesthetically pleasing, provides privacy due to the difference in the amount of light from inside to outside and offers privacy and security. These factors can encourage to be used in other (non-hot) climatic conditions too. Out of the functions of ventilation, shading and day-lighting. Shading will not be necessary in the cold weather conditions, so ventilation and day-lighting can be optimized by the usage of perforated screens.

21ST CENTURY | ORIGIN OF JAALI

Figure 2.2.3 (ii) Dilating faรงade of Institute du Monde Arabe, Paris

Figure 2.2.3 (i) Natural Ventilation in the Velodrome, London

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

CHAPTER 3

CLIMATE STUDY

TRADITIONAL PERFORATED SCREENS OF INDIA

3.1 CLIMATE CLASSIFICATION

30 N Tropic of Cancer 15 N

Hot Dry

EQUATOR

Warm Humid

15 S Tropic of Capricon

Hot Dry

30 S

The occurrence of the Jaali through the history is as much due to the climate, as due to the cultural requirements. Hence the climatic conditions will tell the environment in which the Jaali was invented and later adapted. G A Atkinson in 1953 has given a climatic classification, where he describes the occurrence of hot humid and hot dry conditions with respect to the equator (see fig 3.1.1). It is observed that the hot climate occurs 30° of North and South of the equator, out of which humid conditions occur 15° North and South of the equator and beyond that is the Arid conditions. Koenigsberger (1974) suggests that Air temperature and Humidity are the two main factors that control our comfort and hence the hot climates are studied based on that. Widely dividing the 2 climates as Hot Dry and Hot Humid climates, both the conditions have high solar radiation throughtout the year, and humid climates experiance lower sunangles as it closer to the equator. This also shows that there is very little variations within the length of the day throughout the year. The basic charecters are analysed with the help of the climatic data of a place from the hot dry region and hot humid region (see Fig. 3.1.2). The Dry condition is charecterised by a large diurnal variation where as the humid climate has a no variations. The analysed climatic data is presented in Table 4.1.3. Table 4.1.4 lists the cliamatic requirement poses by the climate to achieve comfort. 20

Figure 3.1.1 Atkinson’s climatic classification showing the Hot Climates, as humid and dry conditions with respect to the equator.

Figure 3.1.2 Graphs showing the Temperature, Humidity, Solar Radiation and Precipitation for Hot Dry and Hot Humid Climates.

CLASSIFICATION | CLIMATE STUDY Table 3.1.3 Summery of the detailed components and specifications of both the climates (Source : Koch â&#x20AC;&#x201C; Nielsen, 2002)

Table 3.1.4 Design specifications derived from the climate study for Hot Dry and Hot Humid Climates

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

3.2 CLIMATES OF INDIA: The Koppen Geiger classification presents a detailed climatic classification that identifies the sub climates in India. They are as seen in Fig. 3.2.1. The examples of Jaali are widely found in all the hot climates of India, out of which three are studied before carrying out the fieldwork. The climates are: Hot semi arid (JAIPUR) Humid subtropical (AGRA) and Tropical Monsoon (NAGARCOIL) These 3 climates are a gradual change from the dry to humid condition. When the 3 sub climates were compared with one another, the temperature range is found to be very similar in all the 3 cases (see Fig 3.2.2 ). Owing to its location with respect to the equator, the solar radiation it receives is also very close to each other. Hence other factors like Humidity, Precipitation and Wind bring differences in them. Hence the 3 climates are compared with respect to each of the above mentioned factors on the same chart (see Table 3.2.3). Temperature: From the Figure 3.2.2 and 3.2.3, Jaipur and Agra that are above the Tropic of Cancer reaches higher temperatures in the summer than the humid climate. Nagarcoil has a high temperature throughout the year and does not reach lower temperature. Solar Radiation: As mentioned before the temperature of all the three climates are seen to be very close, but the climates in the hot dry zone between the latitude 15N and 30N are seen to have significant seasonal variations, whereas the humid climate has no seasonal variations. Nagarcoil is subjected to low angle solar radiation due to its proximity to the equator. The Table (3.2.3) shows that all the three climates receive the same amount of solar radiation when measured in terms of horizontal global irradiation (kWh/m2). Relative Humidity: Humidity is the amount of water vapour in the air. The water vapour in the air is due to water bodies around, or even any wet surfaces or vegetation. Thus Agra, that is located close to the hot semi dry climate, has higher humid conditions and higher precipitation due to its location beside a river and forest. The graph of the relative humidity (fig. 3.2.5) shows that Nagarcoil has a high humidity of an average of 80% through the year. Jaipur (semi arid) has the least humidity, which is seen increasing in last 3 months of the summer. It is related to the precipitation during that period.

CLIMATES OF INDIA | CLIMATE STUDY

HOT DRY CLIMATE

30 N

TROPIC OF CANCER (23.5N)

HOT HUMID CLIMATE

15 N Figure 3.2.1 Koppen Geiger climatic classification of India showing the 3 places where the fieldwork was carried out.

Figure 3.2.2 Temperature range of the 3 climates over a year. (source : Meteonorm) Table 3.2.3 The climate speifications over a year for the 3 climates that is studied (source: meteonorm)

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

Wind Velocity: Wind velocity in hot climates promotes heat loss in 2 ways, convection and evaporation. But when the air temperature is higher than the skin temperature, neither of these two functions are possible. When the air velocity also increases with the increase in temperature, then there is convective heat ‘gain’ and evaporative cooling, at the same time (Givoni 1976). From the comparative graphs, Jaipur (the semi arid climate) has the highest wind velocity, especially in summer (see Fig. 3.2.6). In the Semi Arid climate due to less humidity does not require evaporative cooling and hence only convective heat gain takes place. The other 2 climates, having higher humidity, will require as much wind velocity as possible. Precipitation: The semi arid climate receives the least rains and has a little or no vegetation, with light color ground resulting in reflective radiation. (The local architecture has no shading devices, as it could be to receive the rains on the surface and prevent reflected radiation indoors). Agra receives rains in the summer increasing the humidity during that period (see Fig 3.2.7). Nagarcoil (the tropical climate) receives the highest amount of rains and hence the ground is dark in color with thick vegetation. (Hence openings in this region is seen slanting towards the ground to avoid the low angle of the sun and as there is no ground reflection).

3.3 COMFORT “Comfort studies for hot climates state that even when there is a rise in temperature, people consider it as acceptable, as the local average annual temperature of the place is higher” (Givoni, 1994). The comfort band for the hot climates were calculated from the formula given by Szokolay (1997) from EN 15251: Tn = 17.8 + 0.31*Tm Where, Tn= neutral Temperature Tm=[T(min) + T(max)]/2 The comfort range maximum is obtained by using Tn+3.5C and minimum by Tn-3.5C. The range of 3.5C is chosen for 80% acceptability. Szokolay (1997) observes that wind velocity beyond 2.0m/s will become annoyingly draughty. Koch-Nielsen (2007) mentions when the wind velocity is less than 1.0m/s the space becomes stuffy. When allowing the maximum air velocity (V) = 2m/s, dT = 6*Ve - 1.6*Ve2, where Ve=V-0.2 = 1.8 dT = 5.6K Hence by allowing a apeed of 2.0m/s, a the comfort band can be extended another 5.6C.

COMFORT | COMFORT STUDY

HORIZONTAL GLOBAL IRRADIATION

Figure 3.2.4 Horizontal Global Irradiation of the 3 climates over a year (source : Meteonorm) RELATIVE HUMIDITY

Figure 3.2.5 Relative Humidity of the 3 climates over a year (source : Meteonorm) WIND VELOCITY

Figure 3.2.6 Wind Velocity of the 3 climates over a year (source : Meteonorm)

PRECIPITATION

Figure 3.2.7 Precipitation of the 3 climates over a year (source : Meteonorm)

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

CHAPTER 4

THEORITICAL BACKGROUND

TRADITIONAL PERFORATED SCREENS OF INDIA

4.1 COMPONENTS OF JAALI Each Jaali has different charecteristics by varying the small components in the screen. For example, the size of the screen varies from dry to humid climates, the design of the perforation is different from one to another. In order to learn what the form has to tell us about its perforamnce, the Jaali is reduced to smaller components with relation to the climatic factors it influences. So from the examples seen, the main components will be 1) Perforation percentage, 2) Thickness and 3) Adaptive strategies. PERFORATION PERCENTAGE: It is the area of the opening in the screen to the area of solid (in percentage) (see Fig 4.1.1). It’s influence on the Jaali’s performance: 1. Admittance of direct solar radiation inside the space 2. It decides the volume of air entering and going out of the space. 3. Light distribution indoors. THICKNESS: This refers to the overall thickness of the Jaali, which influences: 1. Thicker the screen, lesser heat transfer through conduction 2. Right thickness will prevent direct solar radiation inside 3. Daylight levels inside. ADAPTIVE STRATEGIES: Even though most of the examples have predominantly fixed Jaali from history, there are certain adaptive features to be noted in each case. The adaptive features involve opening up the screen more or less, depending on the requirement of ventilation and shading. The humid conditions have more adaptive features, as they require the screens to be as operable as possible for maximum ventilation (see Fig 4.1.2). The ones found in Dry conditions have very small windows that are just the size of the face in some cases (see Fig 4.1.3). Operable windows are present but very small in size, as excess wind is not welcome inside. The screens found in Philippines can be completely moved aside or completely closed as they experience cyclonic winds often. Givoni (1994) noticed that cross-ventilation will not always bring comfort in hot climates unless the comfort is achieved in the outdoor temperature. This is the condition is applicable when there are regular glazed windows, which either brings in wind or totally shuts it off. In the desert conditions well designed spaces with right amount of Jaali bring in a temperature difference till 4.5°C at a particular time of the day (explained in chapter 5.3). The positive and negative pressure created by the spaces and well designed Jaali ventilates the space sensibly without making it completely exposed to outside.

COMPONENTS OF JAALI | THEORITICAL BACKGROUND

30%

50%

70%

Figure 4.1.1 Screens of the same size (450X800), with different perforation percentage.

Figure 4.1.2 Adaptive features in the Jaali in Dry Climate. (Hawa Mahal, Jaipur)

Figure 4.1.3 Adaptive features in the Jaali in Humid Climate. (Padhmanabhapuram Palace, Kerala)

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

ORIENTATION: There are specific patterns of perforated screens noticed in the cases studied so far. The Kerala Perforated screens are horizontal strips, the ones in Egypt are circular perforations and the Malay Houses have vertical strips. This can be related to the orientation the Jaali was designed for, as there is a very close connection between the design of the perforation with respect to the orientation that it is used on. For Northern hemisphere, when the angle of the Sun is more vertical (South orientation), shading will be most efficient when it is horizontal fashion. Similarly when the angle of the Sun is more horizontal (East and West orientations), shading would be most effective when provided in vertical fashion (see Fig 4.1.4) (Givoni, 1976). When there is both horizontal and vertical angle of sun light that has to be avoided, a combination of vertical and horizontal pattern of shading will be most effective.

4.2 PREVIOUS RESEARCH: VENTILATION: 1) Presence of perforated screens prevents complete outdoor air to flow in. 2) Bittencourt (1993) observes that Bernauli’s principle and Venturi effect works perfectly for the perforated screens, that is, when air passes through smaller opening, it gets compressed and released, which cools it down. Hence when the air passes through the perforated screens it’s temperature decreases. Some examples are seen housing a water body in front of the Jaali, in order to promote evaporative cooling. ENERGY EFFICIENCY: Energy efficiency of a space is calculated by Sherif et al based on the heating load and the lighting load, with respect to the above lighting study. For heating and cooling minimum set point was given as 23°C and 35°C respectively. The study was done for perforation percentages of 30%, 50% and 80% and depth ration os 0.1, 0.5, 1.0, and 1.5 (see Fig 4.2.1a). 1. The research proved that 30% of the total energy consumption of the South and the West Façade was saved by adding the perforated screen. The perforation percentage that helped achieve this rate was 80% with a depth/width ratio of 1:1. 2. The table 4.2.1b shows that there is 30% energy saving on the South and West orientations and 25% energy saving on the East facade and only 7% on the North. Providing perforated screens in the North Façade makes very little difference. 3. This enables South, West and East sides of the buildings to have large openings at no risk of over-heating.

PREVIOUS RESEARCH | THEORITICAL BACKROUND

a) South orientation

b) South West orientation

Figure 4.1.4 a) South orientation should have horizontal screens and EW vertical. When Buildings facing b) SW should have a combination of both.

a) Figure 4.2.1 Energy saving (%) is calculated for the Jaali (right) (to use it as solar screens) with different combination of perforation to thickness (above). (source: Sherif et al)

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

LIGHTING: To access the amount of day light received in the space when adding a Jaali, the space is divided into near, middle/central, and far zone, at table level. This study is carried out in Kharga-owaisis, Egypt which has a hot arid climate. The Jaali here was considered to be placed in front of a glazed window. The minimum lighting levels were fixed at 300lux. Perforation percentage - Day light Radiance is used for a space with Jaali of difference perforation percentage (see Fig 4.2.2a). The same process is follwed to test the Jaali for all the orientations, in all the seasons and morning, afternoon and night (see Table 4.2.2b). In order to achieve energy saving with respect to both solar shading and day lighting, perforation percentage of 80%, with the depth ratio of 0.75:0.75 has to be followed. He also observs that, when Perforated screens for South, West and East were proving to be very useful, on the North it proved to be unnecessary and obstructive. Perforation Shape - Day light: Aljofi (2005) proved that horizontal panels/ louvers provide better day lighting as it helps to bounce light into the space, that results in the highest amount of light in the central zone. Rounded edges of the screen allows lesser light into the space. Perforated Screen - Day light: Varied perforations in a screen would help in providing right amount of light at the near and far end of the space (Fathy H, 1986). Sabry et al (2011) found that average room illuminance is directly proportional to the screen rotation angle. When the whole screen is rotated 30 Dec towards the ground, good day lighting results are achieved. As the ground color indesert conditions is light in color, there is ground reflection. Screen thickness - Day light: Sherif et al (2012) has noticed that depth ratio (horizontal and vertical elements of the Jaali) should be 0.75:0.75, in order to maintain both good day light and solar shading.

4.3 ADVANTAGES OF JAALI: 1) Perforated Screens enable a uniform distribution of internal air flow, reducing the occurrence of draught. 2) Unlike a regular window, perforated screens provide a uniform spread of daylight into the room, and light penetration reaches longer distance and glare is reduced. 3) It is adequate to provide continuous ventilation through-out the day, when it is positioned and oriented to the prevailing wind.

PREVIOUS RESEARCH| THEORITICAL BACKROUND

Figure 4.2.2a Daylight Availability distribution in the base case and using different perforation percentages with its relationship to the three zones (source: Sherif et al) Table 4.2.2b shows the perforation percentage that gives minimum day light factor for the far, mid and near zones facing different orientation, throughout the day is listed (source: Sherif et al)

DISADVANTAGES OF JAALI: 1) Designing Jaali for either ventilation or sun protection or controlled day-lighting is simple. But to utilize its complete potential is very challenging. 2) The process of designing itself, starting with accessing the orientation, prioritizing the functionality, and then to run a combination of depth to width ratio and to choose a balanced model. 3) For shading from the sun, each faรงade requires a unique design (shape and size of the perforations). 4) Not preferred due to ingress of insects and dust. ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

CHAPTER 5 FIELDWORK

TRADITIONAL PERFORATED SCREENS OF INDIA

The literature study has shown that a Jaali can be perceived in many individual ways based on the necessity and its most basic function. But what also has to be learnt from the Jaali, is the way it was conceived to address specific issues and how it performed. As it was mentioned in Chapter 3.1, Jaali is seen in all hot climates since time immemorial, and characterized in the local style in all aspects including its function and form. To learn from these examples would give a better understanding.

CHOICE OF PRECEDENTS Jaali is the colloquial name for perforated screens in the north of India. The same in South of India is called Azhi and known in various different names throughout the world. What is it that has made it local and original to each region? Its inevitability in hot climates is the reason. What are the types of buildings that are seen to have Jaali? The existing popular examples are mostly palaces, public buildings and places of worship. There are very few examples of new houses with Jaali that is available for study now, as people have adapted to air conditioning, the new buildings have lost that architectural identity in recent times. In India, there are 5 hot climates that gradually vary from hot-desert to hot-humid. There are very popular examples od Jaali that are seen throughout these climates. Thus the main intent of this fieldwork is to explore its prime feature, the Jaali and its â&#x20AC;&#x2DC;climatic responseâ&#x20AC;&#x2122;. To do this, Jaali in a range of climates have been studied. The fieldwork is conducted in 3 distinct climates, the hot semi-arid climate (Jaipur, India), Humid Sub-tropical Climate (Agra, India) and Tropical Monsoon Climate (Nagarcoil, India) (see Fig 5.1.1). It was chosen from the five hot climates in India, and three were picked based on their gradual variations of humidity, precipitation and wind velocity. There are many historic buildings in these regions that are architecturally significant, as they are the standing examples of the vernacular architecture that demonstrates the lifestyle, comfort levels, value for different spaces and their engineering and designing skills. There are many historic buildings that are popular due to the presence of the Jaali. Some of these popular examples are palaces that are not used today and are open for tourist; the Jaali is appreciated for its intricate carvings and the shadow patterns created by it. In the Hot Semi-Arid Climate of Jaipur, the Jaali in the palace of Hawa Mahal was chosen (see Fig 5.1.2). Hawa means breeze, and being a semi-desert climate, the palace is known to be designed in a way that it admits right amount of air with interesting strategies for summer cooling and winter heating, and constant cross ventilation. In the Humid Sub-tropical Climate of Agra, a very popular place of worship called Tomb of Salim Chisti was chosen for its exotic Jaali (see Fig 5.1.3). This Jaali, made of Marble is an existing example of the craftsmanship of the ancient Indian architecture. In the tropical monsoon climate of Nagarcoil, a palace which is the Padhmanabhapuram Palace, was completely made of timber was chosen, as it is the most ancient example of the Jaali in this climatic region (see Fig 5.1.4). This palace has a unique design of the Jaali, as it is also protects against excessive rains and extreme glare from the sky. 36

CHOICE OF PRECEDENTS | FIELDWORK

Figure 5.1.2 Hawa Mahal, Jaipur

Figure 5.1.3 Tomb of Salim Chisti, Agra

Figure 5.1.4 Padmanabhapuram Palace, Nagarcoil

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

METHOD OF STUDY The literature has shown the main functions of the Jaali is solar protection and glare prevention. The historic references have appreciated it to have the quality of letting in pleasant breeze and providing privacy. As the level of illuminane inside the Jaali is lesser than the outdoor illuminance, the interior space is not visible from outside, thus providing privacy. In the present context, it used for security purposes and it is seen in the buildings of the cold climates also for the control of daylight. Hence the functions of a Jaali are, • Solar Protection • Ventilation • Daylight • Privacy • Security In a naturally ventilated space, with Jaali as the main source of ventilation (opening), it would be very interesting to study the comfort achieved in the space in terms of the specific details as mentioned above. Therefore, the temperature difference the Jaali provides, the amount of wind the Jaali lets in, and the daylight achieved in the space were measured during fieldwork.

Spot measurement tools

Data Loggeres

In order to measure these aspects, spot measurement tools were used, that measured temperature, humidity, wind velocity, surface temperature and luminance. To analyse at the performance of the Jaali in specific, there always has to be a comparison of measurements from outside to inside that has to be taken possibly at the same time. Hence, the spot measurements were taken every 2-3 hours (with help of a friend) over 2 days in order to arrive at an average data, to be more accurate. See figure (6.2.1) for all the tools used in the field work. Data-loggers that measured temperature and relative humidity were installed outside and inside to compare the performance of the space with respect to the outdoor climate. In addition to these measurements, the comfort of the space can be understood better when heard from a person who has to spend more time there. Hence questionnaires have to be used to understand the overall comfort and also specific details of solar protection, daylight and ventilation. All the precedents picked were historically important buildings that are open to public. Questionnaires were answered by the guards who are the main occupants, spending 8 hours in that space.

Thermal Camera

Figure 5.2.1 Tool used in the Fieldwork.

METHOD OF STUDY | FIELDWORK

FIELDWORK VISIT AND MEASUREMENTS The Jaali being the focus of the study, the fieldwork measurements show that the comfort on the space is depends on the design of the space with respect to the Jaali. That is, how the Jaali is incorporated and utilized by the space. Therefore, the measurements of the temperature difference achieved indoors, daylight levels and the air penetration will depend on three important factors that are as follows: 1) The direction of the wind to the orientation of the Jaali 2) Cross Ventilation achieved in the space 3) Presence or Absence of shading element To access the comfort achieved in each case, the factors are first studied before arriving to conclusions.

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

CASESTUDY 1 : HOT SEMI-ARID CLIMATE

TRADITIONAL PERFORATED SCREENS OF INDIA

HAWA MAHAL, JAIPUR The building chosen to conduct the study is the Hawa Mahal, which is a popular example of the local traditional architecture (see Fig 5.3.1). Hawa Mahal is part of the Jaipur Palace, that was used by the royal family, especially the ladies for relaxation. Jaipur, founded in the 16th century by the Rajput kings and is fondly known as ‘pink city’ due to the extensive use of the local material that is pink sand stone in the city. Jaipur is situated close to the Thar Desert or the Indian desert in the North West of India. Jaipur is the capital of the largest state of India, Rajasthan of coordinates 26.9N, 75.8E (see Fig 5.3.2). It is situated 300 km from Delhi and is between the humid climate and the hot desert climate (see Fig 5.3.3). Jaipur has no clear sign of vegetation, but large fields of dried short shrubs are a common sight in the suburbs. The summer is very dry due to lack of rain and less humidity, making it hard for cultivation. Fieldwork was carried out on 22nd and 23rd of June’14, which is a typical summer day, when the dry bulb temperature was 40C, with a wind speed of average 2m/s.

Figure 5.3.1 East Facade of the Hawa Mahal, Jaipur. (Source : www.flickr.com)

Hot Semi Arid Climate: The graph of the yearly climatic data of Jaipur (see Fig 5.3.4) shows that the climate can be classified as a hot period where the average temperature during the day reaches 40C and a cold period with average temperature during the day reaching 10C. The wind velocity is higher during the hot period (6 months from April to September), with an average velocity being 2.6m/s and is 1.2m/s average during the other months. In the fieldwork wind velocity up to 6m/s was recorded. The comfort calculations are based on En15251 as mentioned in chapter 3.3. The comfort band for the the month of June is considered as 26.6-32.6C.

Figure 5.3.6 Graph showing the annual predominant Wind Direction which is East (source: Climate consultant)

A typical day was chosen from the yearly graph, and it shows a diurnal variation of 9C (see Fig 5.3.5). It falls into comfort band only for a period of 7 hours in the night (during absence of solar radiation). The wind velocity reaches 5m/s. The annual predominant wind direction is east (see Fig 5.3.6), however the wind direction for five of the hot months (May, June, July, August and September) is west as seen in Fig 5.3.7 The requirement of this climate will be to 1) Prevent direct sun light inside, 2) Prevent excess hot air inside and 3) To provide night ventilation due to the diurnal variation.

Figure 5.3.7 Graph showing the Wind Direction of the typical hot month (July) to be West (source: Climate consultant)

CASE STUDY 1 | FIELDWORK

Figure 5.3.2 Map showing the location of Jaipur

Figure 5.3.3 Google map showing the extent of the desert with the location of Jaipur and Delhi.

Figure 5.3.4 Graph showing the yearly climatic data of Jiapur with the seasonal differences highlighted (source: meteonorm)

Figure 5.3.5 Graph showing a typical day in the hot season and the diurnal variation that occurs (source: meteonorm).

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

Hawa Mahal: Literally translating into Palace of breeze, it was built in the 16th century, exclusively for the ladies of the palace. The palace is a rectangular block facing East/West, made of pink sand stone. There are three distinct types of Jaali found in this Palace. Glazed Jaali, floral shaped perforated Jaali and rectangular shaped perforated Jaali (see Fig 5.3.8). The two perforated Jaalis are found on the West facade and both are chosen to be studied.

The wind direction for 5 months in summer is West. Hence during summers there will be an unstoppable inflow of wind through the Jaali. In the Palace, the queen’s chambers was chosen for study. It has glazed Jaali towards one side(east) and perforated Jaali on the other (west). This space is also coupled with two courtyards on each side. There is a row of columns in front of the Jaali on the East and West. Figure 5.3.9 shows the two Jaalis measured. On the East side, there is a narrow corridor created by the columns that continue out of the room, into the courtyard. This makes the space permanently open with continuous air circulation from the courtyard which is indirectly from outside (see Fig 5.3.11). Maybe this is why it was called Hawa Mahal, as it is designed with Jaali, windows and constant air movement within the spaces. Hence in climates like these, the Jaali can be used in between spaces internally to enable a steady air movement within the spaces. Table 5.3.13 shows the summery of the fieldwork. The temperature difference achieved indoors, daylight levels and the air penetration. This is achieved due to the design of the space with respect to 1) The direction of the wind being towards the orientation of the Jaali (Fig 5.3.10), 2) Continuous0cross ventilation achieved in the space from the two courtyards (Fig 5.3.11) 3) Absence of shading element that is balanced with smaller perforations and windows (Fig 5.3.12).

c) Figure 5.3.8 Three types of Jaali found in Hawa Mahal

There is no shading element, as the Jaali itself was providing solar shading due to small perforations. The perforations on the Jaali 1 were floral shaped of 30mm diameter and the screen was only 10mm thick, it does not allow direct sunlight inside a) due to its shape and b) the lower part of the screen that receives afternoon light has lesser perforations due to the presence of a window. The perforations are very small counting up to just 11% per sq.m. Hence it allowed a very small volume of air inside the space, nevertheless entering with 60% the speed of the outside air. As the volume is small, the air on the skin was felt only in the narrow corridor till the columns. As the temperature reaches 40°C during the day, the humidity hardly reaches 40%. In dry conditions like this, the hot air is felt on the skin causes discomfort (Givoni, 1976). The spot measurements and datalogger results (see appendix 1) revealed that on an average, the indoors are 3°C lesser than the outdoor. The data loggers showed that in the night, the indoor temperatures goes much higher than the outdoors, as the space is shut down with minimal ventilation. Hence opening up the space more during the night to provide night ventilation in this climate and space would be very beneficial. 42

Figure 5.3.9 Queen’s chamber in the Hawa Mahal, Jaipur. View showing the inrerior space hiding the roof.

CASE STUDY 1 | FIELDWORK

1. WIND DIRECTION

2. VENTILATION / AIR CIRCULATION

Figure 5.3.10 Wind direction of the hot period being towards the Jaali in the Queens’s Chambers.

3. SOLAR SHADING

Figure 5.3.11 The Queens Chambers coupled with the courtyard to enable continuous air movement.

Figure 5.3.12 Front elevation of the Jaali showing the absence of a shading element.

FIELDWORK MEASUREMENTS Table 5.3.13 Summery of fieldwork measurements

DESIGN OF THE SCREEN SECTION

JAALI 1

ELEVATION

TEMPERATURE DIFFERENCE AVG OUTDOOR: 39.6C

AVG INDOOR: 36.5C OUTDOOR - INDOOR TEMPERATURE DIFFERENCE : 3C

JAALI 2

COURTYARD

PERFORATION 30%

WIND PENETRATION

DAY LIGHT LEVEL

AVG OUTDOOR: 2.2m/s

AVG OUTDOOR: 14,560 LUX

AT ANY GIVEN WIND VELOCITY, THE JAALI WAS LETTING IN AN AVG 60% OF THE OUTDOOR WIND

AVG INDOOR: 82 LUX

AT ANY GIVEN WIND VELOCITY, THE JAALI WAS LETTING IN AN AVG 68% OF THE OUTDOOR WIND

AVG INDOOR: 2045 LUX DAYLIGHT FACTOR ACHIEVED INDOOR 14

QUEEN’S CHAMBER 1M

PERFORATION 11%

SPACE OF THE TESTED SCREEN

AVG INDOOR: 36.0C OUTDOOR - INDOOR TEMPERATURE DIFFERENCE : 3.5C

DAYLIGHT FACTOR ACHIEVED INDOOR 0.5

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

FLIP HERE CASE STUDY 1 | FIELDWORK

TRADITIONAL PERFORATED SCREENS OF INDIA

Due to the absence of shading element, It is observed that the semi arid climate receives very little rain and it would be good to let the rain fall on the building surfaces to provide convective cooling. This space receives direct sunlight only when the windows are kept open (Fig. 5.3.15). The lighting levels inside is very low, owing to the small perforations on one side, colored glass on the other, and very dull and rough interior finish. The daylight factor was 0.5 which is sufficient for domestic functions (Krishan et al, 2001).

Figure 5.3.14 Thermal Camera Image of Jaali 2

When discussing the comfort (using a questionnaire) of the Jaali with the guard of the space, she happened to mention a particular spot that is favored by the people working there. The Jaali was very different from the one in the Queen’s chamber. They were found in the courtyard adjacent to the Queen’s chamber that also had a shaded corridor flanked with columns. These screens were made of yellow sand stone, it was much thicker that the adjacent ones, and was also not letting in direct sunlight. The Jaali 2 (as it will be referred) is 100mm thick with rectangular holes that is inclined downwards. As it was inclined downwards, it did not allow direct sun light indoors. It was favored by the guard because it lets in large volume of air and also felt cooler. The screen has a perforation percentage of 30% per sq.m. The thermal camera image shows that only the front part of the screen is heated and rest of the screen is not affected by the sun, and hence the inner part of the Jaali is of lower surface temperature(see Fig 5.3.14). This could also possibly explain that the hot air due to conduction gets cooler as it enters the space.

The front of the building is facing East and it looks over the market place. The Jaali on this façade has tinted or colored glass. As mentioned before the predominant wind direction is East and that façade has no perforated Jaali. The fixed Jaali is however provided with small windows at the bottom. It is part of the Indian tradition to sit on the floor. Hence most of the windows though very small are placed at a lower height, in level to the face.

JAALI

The temperature difference felt in the corridor space was 3.5°C. But because it is in a courtyard space, the thermal performance is also influenced by a micro climate created in the courtyard and the shaded corridor beside the screen and the actual performance of the screen.

The Jaali 1 and 2 overlooks into one of the courtyards of the Palace that is provided with a small pond with a fountain (see Fig. 5.3.18 &19). The fountain is switched on during the afternoons to provide some relief in the heat. It might have been a recent addition, but it shows the requirement of such an element in that climatic condition. Figure 5.3.17 Section showing the second floor with the tested Jaali towards the complex courtyard with a pond.

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

CASE STUDY 2 | FIELDWORK

Figure 5.3.15 Space when all windows are open (source: www. flickr.com)

Figure 5.3.16 Foutain in the courtyard, towards which the both the Jaalis are oriented. (source:www. flickr.com)

POND

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

CASESTUDY 2 : HUMID SUB-TROPICAL CLIMATE

TRADITIONAL PERFORATED SCREENS OF INDIA

TOMBS IN FATEHPUR SIKRI, AGRA

The tomb of Salim Chisti, is a square building with the sacred tomb in the center and Jaali on all four sides, creating a corridor. Beside this tomb, there is another building made of red sand stone called the tomb of Islam Khan, which has the same function, and similar Jaali (see Fig 5.4.1). Agra is a town along the river ‘Yamuna’, it was founded in the 13th century by a Rajput king. Agra is from the word “Agrevana” which means “forest borders” (wikipedia). Situated beside the river and forest, it has a humid sub tropical climate. Agra is located in the North of India at 27.1N and 78.0E (see Fig 5.4.2). It is located 200 km from Delhi and 200 km from Jaipur (see Fig 5.4.3). Even though it is closely located to the desert due to the presence of different geographical features like a river and forest, it has a humid climate. Fatehpur Sikri (where the palace complex is located) is 30 minutes drive from Agra, which served as the home for the Mughal rulers for a short period. During the Mughal reign, in the 14th century, a large palace complex was constructed which houses a significant piece of Islam architecture, a white marble tomb of Saint Salim Chisti. HUMID SUBTROPICAL CLIMATE: The dry bulb temperature is the same as the semi arid climate temperature (previous fieldwork) but the difference being, a comparatively higher humidity and comfortable wind velocity (not exceeding 1.8 m/s). It receives heavy rains during the end of the summer months also causing the humidity to rise during the latter part of the summer. The yearly climatic data of Agra showing the two distinct seasons, hot and cold that lasts for 6 months each (see Fig 5.4.4). The hottest period being May where average temperature during the day reaches 40C and the coldest period being December and January where average temperature during the day is less than 10C. The comfort calculations are based on En15251 as mentioned in chapter 3.3. The comfort band for the the month of June is considered as 26.4-32.4C. A typical hot day from the yearly data is studied (see Fig 5.4.5), which shows a diurnal variation of 10C. Hence the temperature does not fall under comfort band for more than 12 hours in a day.

Figure 5.4.1 Tomb of Salim Chisti and Tomb of Islam Khan, Fatehpur Sikri, Agra. (Source : www. flickr.com)

CASE STUDY 1 | FIELDWORK

Figure 5.4.2 Map showing the location of Agra

Figure 5.4.3 Google map showing the location of Agra between the desert and the greener regions of India.

Figure 5.4.4 Graph showing the yearly climatic data of Agra with the seasonal differences highlighted (source: meteonorm)

Figure 5.4.5 Graph showing a typical day in the hot season and the diurnal variation that occurs (source: meteonorm).

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

So, the climatic requirements would be to a) Prevent direct sunlight indoors b) Allow maximum air indoors (due to less wind velocity) c) Provide night ventilation (due to diurnal variation)

FATEHPUR SIKRI: As seen in typical Islamic architecture, the main campus is walled on all sides, with a large open space in the center, where there are 2 tombs, Tomb of Salim Chisti and tomb of Islam Khan. The first building is made of white marble while the latter is made of red sand stone. From the figure 5.4.6, the white marble building houses the tomb in the center and has a corridor all around it that is covered from all the orientations by Jaali. During the fieldwork, the building was occupied throughout the day by a large number of tourists. As the tomb is a place of worship, people visit the tomb and sit for a short time in the corridors. Figure 5.4.6 shows the Jaalis that are on both the tombs were studied for a comparative study. The Marble Jaali will be referred as Jaali 4 while the sand stone Jaali will be referred as Jaali 5. Table 5.3.10 shows the summery of the fieldwork where the study was to measure the temperature difference achieved indoors, daylight levels and the air penetration. This is achieved due to the design of the space with respect to 1) The direction of the wind being towards the orientation of the Jaali (Fig 5.3.7), 2) Continuous cross ventilation achieved in the space from all the sides (Fig 5.3.8) 3) Presence of shading element that prevents direct sunlight into the space for most part of the day (Fig 5.3.9). The space experiences constant cross ventilation as it is covered on all sides by Jaali (see Fig 5.4.11). As it is a space meant for public use, there is no adaptive strategy in this Jaali. Even though the wind was only in the North part of the complex, the same temperature difference and comfort is achieved on all the orientations. Givoni (1969) observes that in hot conditions, a well cross ventilated space would always experience a wind velocity of 30% of the prevailing wind. Hence the temperature difference is caused by the above mentioned good cross ventilation, the materiality and presence of the shading element. The buildings in this climate are seen with a shading element, which protects the space from direct sun for most part of the day (see Fig 5.4.12). As this tomb is over shadowed on the South by other buildings, the space receives direct sun light in the early mornings and late afternoons, when the sun angle is low. JAALI 4 (Tomb of Salim Chisti): The spot measurements were carried out in this space over two days (see appendix 2 for detailed meaurements). While measuring temperature and other criteria, the wind flow into the space was measured in the Jaali on all the orientations. Even though the wind direction was clearly North, there was minimal air movement measured behind the Jaali of all the orientations. As the space is open on all the sides, there is constant cross ventilation that facilitates night cooling, and the high thermal mass of Marble provided is the reason behind the 3K difference 48

Figure 5.3.9 Tombs in Agra. View showing the inrerior space hiding the roof.

CASE STUDY 2 | FIELDWORK

1. WIND DIRECTION

2. VENTILATION / AIR CIRCULATION

Figure 5.4.7 Wind direction of the hot period being North.

Figure 5.4.8 Jaali on all four sides providing good cross ventilation

3. SOLAR SHADING

Figure 5.4.9 The shading element that prevents direct solar radiation into the space for a large portion of the day

FIELDWORK MEASUREMENTS Table 5.4.10 Summery of Fieldwork measurements

DESIGN OF THE SCREEN

SPACE OF THE TESTED SCREEN

TEMPERATURE DIFFERENCE AVG OUTDOOR: 38.3C

JAALI 4

PERFORATION 64%

AVG INDOOR: 35.1C

JAALI 5

AVG INDOOR: 37.4C

PERFORATION 70%

OUTDOOR - INDOOR TEMPERATURE DIFFERENCE : 3C

OUTDOOR - INDOOR TEMPERATURE DIFFERENCE : 0.75C

WIND PENETRATION AVG OUTDOOR: 1.7m/s

AT ANY GIVEN WIND VELOCITY, THE JAALI WAS LETTING IN AN AVG 65% OF THE OUTDOOR WIND

AT ANY GIVEN WIND VELOCITY, THE JAALI WAS LETTING IN AN AVG 70% OF THE OUTDOOR WIND

DAY LIGHT LEVEL AVG OUTDOOR: 40,250 LUX

AVG INDOOR: 502 LUX DAYLIGHT FACTOR ACHIEVED INDOOR 1.2

AVG INDOOR: 640 LUX DAYLIGHT FACTOR ACHIEVED INDOOR 1.6

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

FLIP HERE

CASE STUDY 3 | FIELDWORK

TRADITIONAL PERFORATED SCREENS OF INDIA

and the comfort achieved in the space. The fieldwork results showed that on an average, the indoor space was 3C lesser than the outdoor conditions over a day. As the interior surfaces were white, there was sufficient amount of day light indoors throughout the day. JAALI 5 (Tomb of Islam Khan): The tomb of Islam Khan is beside the Tomb of Salim Chisti, both of these buildings share very similar features in terms of the Jaali shape and size and orientation, but the second tomb is made of red sand stone and space behind it being smaller and is less visited by tourists. The Jaali 5 (red sand stone) has a bigger perforation percentage than the Jaali 4, bringing in more ventilation, day light and direct radiation as well. The perforation percentage of the Jaali 5 is 70% per sq.m of Jaali. The shading element is also observed to be smaller than the one seen above Jaali 4 and that also contributes to the ingress of direct sunlight throughout the afternoon. Hence Jaali 5 was not performing the basic function of preventing direct solar radiation into the space. The fieldwork revealed that the Jaali 5 was providing a average temperature difference of 0.75K, much lesser than the Jaali 4 which provided 3K. The traditional architecture has a central open space and a tank in the center (Fig. 5.4.11). This tank is located in front of the Tomb of Salim Chisti. There would be good evaporative cooling inside the tomb, as the wind direction is such that it flows over the tank before entering the building. But the tank was dry when the study was carried out due to water shortage. The monument featured various patterns of Jaali that formed interesting shadow patterns on the floor (see Fig 5.4.12)(see appendix 4 for more shadow patterns). The pattern that was constantly repeated on all the orientations was chosen for study and measured. Even under direct sun light, people were sitting, as the space was cool and also they spent only for a short period (see Fig 5.4.13).

Figure 5.4.11 The open central space housing the two tombs, Agra. ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

CASE STUDY 3 | FIELDWORK

Figure 5.4.12 a)

Figure 5.4.12 b) Figure 5.4.12 a & b This Pattern is chosen for study as it is repeated on all the orientations.

Figure 5.4.13 Space receiving direct sunlight during the late afternoons.

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

CASESTUDY 3 : TROPICAL MONSOON CLIMATE

TRADITIONAL PERFORATED SCREENS OF INDIA

PADMANABHAPURAM PALACE, NAGARCOIL

Figure 5.5.1 The Padhmanabhapuram Palace, Nagarcoil (source : www.flickr.com)

The Padhmanabhapuram Palace is the largest timber palace in India. The Tropical Monsoon climate is also known as tropical wet climate due to the abundant water source and fertility the climate permits. The constant dependable monsoon rains keeps this part of India wet and green all year. The availability of good vegetation enabled the construction of a whole palace with timber (see Fig 5.5.1). It is located at 8째N to the equator (see Fig 5.5.2), hence experiencing a high amount of glare due to clear sky and sun being at a higher angle. It is located in the Southern tip of India, 2800 km from Delhi, and very close to the ocean (see Fig 5.5.3).

Tropical Monsoon Climate: The yearly climatic data (see Fig 5.5.4) shows that variation in the temperature through the year is very minimal, creating no seasonal variations, except rainy and non-rainy seasons. Due to the large amount of rain, average humidity level over a year is 80%. It also to be noted that the outdoor temperature falls into the comfort band throughout the year, but the constant high humidity makes sure that the comfort is not achieved unless there is a minimal wind flow to promote evaporative cooling. The average wind velocity is (1.3m/s) least among all the other hot climates, making it more important to keep the space as open as possible. The comfort calculations are based on En15251 as mentioned in chapter 3.3. The comfort band for the the month of June is considered as 24.7-30.7C Located at 8N from the equator, it is also subjected to low sun angles and clear sky causing glare. Hence, when keeping the opening as big as possible to allow wind for cooling, it is also required to prevent glare.

CASE STUDY 1 | FIELDWORK

Figure 5.5.2 Map showing the location of Nagarcoil

Figure 5.5.3 Google map showing the location of Nagarcoil at the tip of India.

Figure 5.5.4 Graph showing the yearly climatic data of Agra with the seasonal differences highlighted (source: meteonorm)

Figure 5.5.5 Graph showing a typical day in the hot season and the diurnal variation that occurs (source: meteonorm). ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

From the climate study, the requirements posed by it are to a) Prevent direct sunlight (long periods of direct sun, due to low sun angle) b) Prevent glare (caused due to cloudless sky conditions) c) Provide maximum air flow (to facilitate evaporative cooling) PADMANABAPURAM PALACE: The Padmanabhapuram Palace was built partly in the 14th century and partly in the 15th century has typical traditional features that handle the climatic requirements. The Jaali is one of the traditional features that contribute to this. Seen on the right is the Figure 5.5.6 shows the Kingâ&#x20AC;&#x2122;s court in the Palace. The Jaali is towards the West. The Jaali here is made of horizontal strips. The Jaali that is measured is also a typical architectural element of that climate and culture. The Jaali 3 (as it will be referred to) is made of horizontal strips of wood that is fixed in a sloping design (see Fig 5.5.11). It is inclined towards the ground, completely avoiding any sky view factor (see Fig 5.5.12). When an element is inclined towards the ground it is subjected to ground reflection (sun, wind & light). In this case, as the ground is darker in color due to good vegetation and fertile dark soil, there is no ground reflection. But the humidity demands maximum open walls as possible to let in continuous flow of air. Table 5.5.10 shows the summery of the fieldwork which was carried out with an intension to access the performance of the Jaali through the temperature difference achieved indoors, daylight level differentces from outdoor to indoor and the air penetration. The differences that is measured are mainly influenced by the following: 1) The direction of the wind being diagonal to the orientation of the Jaali (Fig 5.5.7), 2) No cross ventilation due to walls on three sides and Jaali on one side (Fig 5.5.8) 3) Presence of shading element that prevents direct sunlight and rain (Fig 5.5.9).

Figure 5.5.6 Kingâ&#x20AC;&#x2122;s Court in Padmanabhapuram Palace. View showing the interior spaces, with the roof hidden.

CASE STUDY 3 | FIELDWORK

1. WIND DIRECTION

Figure 5.5.7 Wind direction of the hot period being North West.

2. VENTILATION / AIR CIRCULATION

3. SOLAR SHADING

Figure 5.5.8 Jaali one one side and no openings on the other walls result in no cross ventilation.

Figure 5.5.9 Shading from sun, rain and glare that the roof and the Jaali provide.

FIELDWORK MEASUREMENTS

Figure 5.5.10 Summery of Fieldwork measurements

DESIGN OF THE SCREEN

SPACE OF THE TESTED SCREEN

TEMPERATURE DIFFERENCE AVG OUTDOOR: 30.5C

WIND PENETRATION AVG OUTDOOR: 1.1m/s

DAY LIGHT LEVEL AVG OUTDOOR: 4640 LUX

JAALI 3

AVG INDOOR: 29.3C OUTDOOR - INDOOR TEMPERATURE DIFFERENCE : 1K

0.9M

1.9M

0.6M

PERFORATION 32%

AT ANY GIVEN WIND VELOCITY, THE JAALI WAS LETTING IN AN AVG 90% OF THE OUTDOOR WIND

AVG INDOOR: 82 LUX DAYLIGHT FACTOR ACHIEVED INDOOR 0.9

Figure 5.3.10 Elevation of the Jaali and the Section of it showing the furniture infront of the lower part of the Jaali.

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

FLIP HERE

CASE STUDY 3| FIELDWORK

TRADITIONAL PERFORATED SCREENS OF INDIA

The king’s court is in the First floor, and has brick walls on 3 sides and Jaali on the West. Below the Jaali (wooden strips) were flat wooden panels with floral shaped Jaali (panels)(see Fig 5.5.15). But from the inside it is covered with sitting furniture, that had small windows towards the front of it in the level of the feet, when opened would provide wind into the space (see Fig 5.5.10 and 5.5.14). It is said that the space under the furniture was filled with herbs (using it like potpourri), as the wind flowing in would bring in the goodness and the fragrance of it. The furniture is a feature that is found only in the King’s court. The other kind of Jaali found in corridors were fixed (see Fig 5.5.16). Just like the adaptive feature in the lower part of the screen, the upper part is also adaptive, as a few screens can be completely opened and are provided with shutters fitted with transparent slate that lets in light. Every third Jaali panel, there is such a window. When the perforation percentage was calculated, the window was not taken into account as most of them were kept closed during the two days of fieldwork. The perforation percentage is 32% per sq.m of the Jaali (see Fig 5.5.13). The interior is very dark due to the dark wood of the Jaali, tile roof and the floor that is a composition of local herbs which makes the floor black in color and is also highly reflective. This keeps the space very cozy at all times, but dark as well. The wind flowing into the space was nearly the same speed of the outside wind with a slight delay. This condition was not found in any other screen. It could be because of the absence of vertical elements, and horizontal slits let in wind unobstructed. When accessing the comfort inside that space, even though the outdoor temperature was not very high, comfort was achieved only when the wind was felt on the skin. Periods when there is no wind flow, clear discomfort is felt, because of the high humidity in the indoors. Spot measurements were taken in this space for a period of 2 days (see appendix 3 for detailed meaurements). Data loggers were also installed in this space for the same period. The results showed the temperature difference from the outdoor to indoor is 1°C. As mentioned before, the wind coming through the Jaali has 90% velocity of the outside wind and that could be a reason for the indoor temperature so closely following the outside. But in the previously studied precedents, cross ventilation was an important factor to provide comfort. This space does not have an effective way of cross ventilation and in addition is being covered in the lower portion. The questionnaire was used to question the guard who uses the space all day and it was again confirmed that when there is less or no wind flow into the space, there is significant discomfort. Most of the buildings in the Palace complex have similar Jaali, and unlike the Jaali 3, the lower part was not covered with seating.

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

56 56

CONCLUSION| FIELDWORK

Figure 5.5.11 a) The Jaali in the Kingâ&#x20AC;&#x2122;s Court.

Figure 5.4.14 Operable parts of the Jaali and the seating space having a small window to let in air and prevent direct solar radiation.

Figure 5.5.12 Jaali angled downwards meeting the sloping roof.

Figure 5.4.15 The lower part of the Jaali is panels of floral patterns, that is covered with furniture.

Figure 5.5.13 Timber used for walls, furniture and structure and the floor made of local material.

Figure 5.4.16 Jaali found in other parts of the Palace.

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

The average internal The average internal temperature is the corre- temperature is the corresponding to the average sponding to the average external temperature. external temperature. 58

TABLE | FIELDWORK

The thickness is measured at the perforation and in the Jaali 1, the thickness varies, as the perforations are funnel shaped.

The average external temperature is the measurements taken during the fieldwork. Measurements were taken every 3 hours from 10am to 5pm (during the day time).

The average internal temperature is the corresponding to the average external temperature.

this is the average value that was measures from 10am to 5pm over 2 days, when the lux fluctuated from 70,000 to 20,000.

The daylight levels inside was also influenced by the color of the Jaali, the indoor space, and the surface reflectance.

TRADITIONAL PERFORATED SCREENS OF INDIA

Though this Jaali allows 60% the velocity of the outdoor air, owing to its small perforation percentage, only a small amount of air enters the space and it provides solar shading. Hence it allows basic ventilation in the space, preventing the feel of the wind on the skin.

This Jaali has comparitively bigger perforations, providing a larger volume of air, hence it is used in the semi open space. The angled perforation prevents direct solar radiaiton and prevents view.

Horizontal slits allows the same velocity of air as the outside. The inclination of the Jaali prevents glare. Even though the space achieves only 1 C lesser than the outdoor temperature, it still falls into the comfort band according to the standards. But comfort in humid conditions depends only on the velocity of air coming in. Hence this design by letting in the maximum air from outside provides comfort.

Large perforation percentage provides good night ventilation. Shading element prevents sunlight for most of the day.

Large perforation percentage and a smaller shading element allows direct sunlight for most of the day.

In Jaali 1, the outdoor wind velocity measured reached upto 6m/s, and the average is 2.6m/s.

Air penetration is the percentage of the outdoor wind velocity entering indoor. This was measured simultaneously outside and inside by 2 people using 2 instruments.

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

60 60

CONCLUSION| FIELDWORK

CONCLUSION: The fieldwork results explain the influence of the Jaali in the comfort achieved inside the space, along with other influencing features for each climate. First case where the Jaali was also a shading element and preventing direct sunlight throughout the day (even though it was facing West), because of the presence of lesser perforations in the middle part of the Jaali. The Jaali 3, that had slits of openings, with not just bringing in the same velocity as the outside, but also effectively avoiding glare. The Jaali 4, though having no adaptive features, providing night ventilation that keeps the space cool throughout the day and enabling constant cross ventilation even where there is no direct wind. This study of the Jaali in the three sub climates have provided the basics of the decisions behind designing a Jaali that is capable of bringing complete comfort in the space. The research is taken forward by using the measurements from the fieldwork to establish the relationship between the design of the Jaali to its performance. Further analysis of this fieldwork reveals the possible strategies that can be followed to design a well performing Jaali for given climatic conditions.

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

CHAPTER 6

QUANTIFYING THE JAALI

6. ANALYSIS:

TRADITIONAL PERFORATED SCREENS OF INDIA

The perforation percentage decides the amount of direct sunlight the space receives, volume of air that enters/exits the space that provides basic ventilation. The vital factors that decide the design of the Jaali is Solar protection and air penetration, but also daylighting. A particular perforation percentage can have perforations of any size and a particular perforation size can be a part of any perforation percentage. When a perforationâ&#x20AC;&#x2122;s size or area provides a particular air velocity into the space, Perforation percentage influences the volume of air entering the space along with the direct sunlight. To design a perforated screen based on a particular climate and a function, the study from the fieldwork is used as the basis to explore the fundamental nature of the Jaali with more research carried out with the help of physical models and solar geometry. The design for the Jaali in this research is proposed only for hot climates. The Jaali is to be designed stage by stage based on the corelations between each dimension of the Jaali to the climatic aspects. The design starts with deciding the perforation percentage (depending on the climate), and then the size of the perforation, and then the thickness is chosen from the corelations that are established. The design criteria focuses on 2 main requirements, 1)Prevent direct solar Radiation and 2)Provide appropriate air velocity. As the fieldwork confirmed the literature study about the provision of daylight in these spaces, the design tries to optimise the daylight in the interior spaces.

PERFORATION % | ANALYSIS

6.1)

PERFORATION PERCENTAGE:

Perforation percentage is the percentage of open to close in a Jaali. The first stage for designing a Jaali is to decide the perforation percentage that is based on the following criterias. 1) Dry/ Humid Climate From the study of the climate and the built precedent, it is realized that the dry climate wants to prevent large volume of air entering the space. Humid conditions require large amount of air required to enable evaporative cooling. 2) Shading from the direct sun The climates with a criteria of rains are generally provided with shading element, where as in the dry climate the Jaali with small perforations itself will also act as a shading element. 3) Daylighting The amount of daylight is directly related to percentage of the perforation(Sherief et al). 4) Prevention of Glare For tropical climates, have predominantly overcast sky condition which causes very high illuminance levels, that causes glare or visual diacomfort (Krishan, Baker). By providing the right amount of shading the glare can be eliminated. The table 6.1.1 is a compilation of the details from the Fieldwork. Here the perforation % and its applicability to each factor listed. As a first step in designing a Jaali for a particular climate, function, and the indoor requirements like shading, air movement, daylighting is decided or prioritized, and the perforation percentage is chosen. Table 6.1.1 The factors that decide the perforation percentage of the Jaali. This table is drawn from the data obtained from the fieldwork.

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

6.2)

TRADITIONAL PERFORATED SCREENS OF INDIA

PERFORATION SIZE:

When specifying the perforation percentage the size of each perforation is not decided. The same perforation percentage can be designed in different ways and hence will perform differently. For example, the perforation percentage in Jaali 1 is 11% due to Hot dry climate, which had perforations of size 0.003 m2 each. But the same Jaali of perforation percentage of 11% can be designed with a larger perforation area (bigger perforations), which might not perform as well as the Jaali with smaller perforations. The Jaali 2 and 3 are of the same perforation percentage (30%). As the Jaali 2 allows 68% of the velocity of the outside air, the Jaali 3 allows 90% of the outside air. Hence the size of the perforation influences the air velocity achieved inside the space. To further support the fieldwork results physical models with mdf board were made of varying perforation sizes. By using a fan infront of the screen, the difference in the air velocity inside the screen was measured with varying the air velocity of the fan (see Fig 6.2.1). The fan had 3 speed settings which is 2.2m/s, 3.0 m/s, and 3.5m/s. All the measurements were taken by placing the screen 300mm from the fan. Four different perforation sizes were tested with a fan at a standard wind velocity (see Table 6.2.2). The smallest perforation size is allowing lesser wind velocity inside the screen and the wind velocity increases as the perforation size increases. From the above mentioned study, the relationship between the perforation size and the percentage wind entering the space (see Fig. 6.2.3) is given as Y=0.011X-0.003

(equation 6.2)

where, Y= Perforation size/area [sq.m] X= Percentage of wind speed entering the Jaali To calculate x, the average wind velocity of that climate [Vo] is considered, and the wind velocity welcome into the space [Vi] is decided from the standards suggested by Szokolay (1997). For example, if the average outdoor velocity of the climate is 2.0m/s and the velocity that is required indoor is 1.0m/s. X, Air Perforation % = (Vi/Vo)x 100 where, Vi = Air velocity requied indoor [m/s] Vo= Outdoor Air velocity [m/s] The smallest perforation tested was a square perforation of dimensions 20mmx20mm (0.0004m2), that let in a constant air velocity of 0.6-0.7 irrespective of increasing or decreasing the wind velocity from the fan. Table 6.2.4 shows the relation between the air penetration results from the field work and the same from the above mentioned equation. The first case shows a difference of 20%. This difference could be due to factors like the thickness of the screen, or the shape of the perforation being floral or wind direction being not as 66

Table 6.2.1 Models of Jaali of different perforations were tested with the help of a fan.

straight as in the experiment. Thus from the comparison proving that the equation gives similar results to the ones measured on site.

PERFORATION SIZE | ANALYSIS Table 6.2.2 The percentage of the wind velocity passing the perforations of the Jaali, varying the perforation size of the model and the wind velocity of the fan.

Figure 6.2.3 Graph showing the corelation between the size of the perforation to the percentage of the wind velocity that enters thrugh it. Table 6.2.4 Air penetration percentage of the Jaali studied in the fieldwork, and a comparison of the air penetration achieved when used the equation 6.2.

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

6.3)

TRADITIONAL PERFORATED SCREENS OF INDIA

PERFORATION SIZE : THICKNESS

The field work has shown that the examples that as the size of perforation increases, a shading element is introduced or vise versa. But the horizontal or the sloping shading element cannot prevent the direct sunlight throughout the day. When the sun is at itâ&#x20AC;&#x2122;s lowest (during the mornings and the late afternoons) there is sure to be direct sunlight into the space like seen in the Jaali 4 and 5. By providing the right thickness for the perforation size, the direct sun can be avoided except when the sun angle is exactly perpendicular to the screen. The thickness will depend on the height of the perforation size irrespective of the shape that is chosen. Hence depending on the shape that is chosen, the height of the perforation is taken into consideration to establish a relation with the thickness Figure 6.3.1 shows that for any given shape, the height can be measuring factor.

Figure 6.3.2 Map of India with the 2 of the fieldwork locations which was used to calculate the solar angle to provide shading.

Figure 6.3.1 Irrespective of the shape of the perforation, the height of the perforation can be used to prevent the direct solar radiation inside.

In order to do that, the sun angles of two climates of coordinates 27.1N and 8.0N (see Fig. 6.3.1) from the fieldwork was measured for the early morning and evenings. This was done using the Ecotect with the climate file from meteonorm 7. South orientation was considered for the Jaali in order to find the design specifications for the worst possible scenario. In India, sun raises 6am and sets at 7pm during the hot period with very little variations. Hence this study is carried out on a Jaali facing South, without considering a shading element or possible over-shadowing. Four heights are considered for this study that are 30mm, 50mm, 100mm and 200mm (see Fig 6.3.2). The required depth is measured for these heights, at times 7am, 8am and 5pm, 6pm. From the results (see Table 6.3.4), an optimal ratio betweem the height to the thickness is chosen. Hence by providing a 1:1 ratio of the height : thickness, in the heigher latitude (28.6N), direct sunlight can be prevented from entering indoors from 7am to 6pm. In the lower latitude, with the same 1:1 height : thickness, direct sunentering indoors can be prevented from 8am to 5pm.

THICKNESS | ANALYSIS Table 6.3.4 Shows that for various perforation heights, when the required thickness to prevent the ingress of direct sunlight into the space for the respective times.

Figure 6.3.3 The least of the sun angle of Delhi and Nagarcoil when added on the required height of the perforation gives the required thickness to prevent the direct sunlight inside,

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

6.4)

DAYLIGHTING : PERFORATION %

The Jaali 1 from the fieldwork proves the Bakerâ&#x20AC;&#x2122;s (2002) observation of the source of daylight being different from the source of ventilation. But in the other examples, the Jaali is the only source of ventilation, daylight and solar protection. Hence the fieldwork results are summerised in the table 6.4.1. In order to compare the indoor light levels of different climates with different climates, the daylight factor is calculated. The daylight factor is calculated from the following formula. Daylight Factor = (Indoor lux/Outdoor lux) X 100 from Baker (2013), Thus relating the perforation percentage of the screen to the daylight factor available inside, a correlation is drawn which is shown in the Fig. 6.4.2. It has a relation of 0.8. Hence from the correlation, Y = 4.160X - 0.095

(equation 6.4)

where, Y = Daylight factor X = Perforation Percentage Hence, for a given perforation percentage, the daylight factor that is achievable is given. The above relation can also be used in a condition when the design is based on the daylight factor, then using which the perforation percentage can be chosen.

6.5) ADAPTIVE/OPERABLE STRATEGIES: The presence of adaptive strategies are important (refer) for adaptive comfort. It will help in the following functions: a) Night ventilation (for the climates with high diurnal variation) b) For the cooler period of the year c) When more daylight is required Hence the adaptive strategies should range from the minimal openings to the maximum openable condition, depending on the function of the space. 6.6) Varying the Perforation percentage within the Jaali Here is looking at options to vary the perforation percentage and thickness within the screen, inorder to achieve a balance of daylight along with air penetration and solar shading. a) Varying the thickness where shading is not required, to optimize daylight. b) Differing Perforation sizes, like having bigger perforations at the upper portion of the screen that will not let in direct sunlight and provide better daylight distribution. c)Providing Jaali with angled vertical slits at the bootom of the wall to promote large airflow and cut down direct sunlight.

DAY LIGHTING | ANALYSIS

Table 6.4.1 Fieldwork spot measurement summery of the perforation percentage the daylight factor received indoors with respect to the outdoor illuminance.

Figure 6.4.2 Graph showing the correlation between the Perforation percentage to the daylight factor indoor based on the fieldwork results.

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

CHAPTER 7

DESIGN APPLICATION The previous chapter has given the parameters with which a Jaali can be designed for a particular climate and function. Before the Jaali is designed for a space, the climate study and the fieldwork show that the comfort in a space in a hot climate will also be determined by the following: a) Effective cross-ventilation b) Presence of Thermal Mass c) Sufficient day light based on the function of the space The Jaali, when designed effectively will facilitate all the factors mentioned above. Further in this research, the previously stated parameters are used to design a screen for the 3 climates from the fieldwork. Assuming that the space that is going to have the Jaali on one or more of its external facades, has all the above mentioned basic factors ike cross ventilation, thermal mass and suitable color, the Jaali it is designed for the climatic requirements.

TRADITIONAL PERFORATED SCREENS OF INDIA

7.1) HOT SEMI ARID CLIMATE (JAIPUR): 1) Perforation %: Perforation percentage for dry climate will be between 10%30%. The Jaali like other openings found in this climate should be small and will start from the sill level and end at the lintel level. 2) Perforation Size: Szokolay (1994) observes that the wind velocity between 0.25-0.5 m/s will be pleasant. From table 6.2.2, the smallest perforation size provides a velocity of 0.6-0.7 at any outdoor wind velocity. The Psychometric chart proves that significant cooling will take place when a wind velocity of uoto 2.0m/s is received indoor (see appendix 5). Hence the perforation size of 0.0004 m2 is chosen for the screen with 10% perforation percentage from Table 6.1.1 (see Fig 7.1.1).

Figure 7.1.1 Jaali of 10% perforation as the screen to provide shading and small perforations to let in the minimal air inside. This Jaali is slidable.

This climate has a cold period for six months in a year when the average temperature is 22C, during when the larger volume of air would bring comfort indoors. Hence, in addition providing a daptive strategy of increasing the perforation % to 20% when increasing the size of the perforations to twice as the existing ones (see Fig 7.1.2). To continue preventing direct solar radiation indoor when the perforation percentage increases, the upper part of the screen is capable of increasing in perforation percentage (see Fig 7.1.3), when the Jaali with smaller perforation is slided. There have to be completely openable windows for pleasant periods, that can have a small part of the Jaali with fixed bigger perforations at the upper regions. The Figures 7.1.4 on the right showing the fixed and the movable parts of the Jaali as red and gray ones respectively. The small windows are openable with hinges, as the other Jaali with smaller perforations that slide sideways for the Jaali to provide larger air penetration, higher daylight, still preventing afternoon direct sun light.

Figure 7.1.2 Fixed part of the Jaali with higher perforations in the upper part of the Jaali.

Figure 7.1.3 The elevation of the Jaali with the fixed and the movable Jaali. 74

HOT SEMI ARID CLIMATE | PROPOSAL

HOT PERIOD

OUTSIDE VIEW

UPPER PART OF THE FIXED JAALI HAVING BIGGER PERFORATIONS TO OPTIMIZE DAY LIGHTING.

HOT PERIOD

INSIDE VIEW

OUTSIDE VIEW

BIGGER PERFORATIONS IN HIGHER PART OF THE JAALI TO PREVENT AFTERNOON DIRECT SUNLIGHT INDOORS

MILD PERIODS INSIDE VIEW (slided windows let in more air)

Figure 7.1.4 View of the Jaali from outside and insidde at its different stages. ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

7.2) HUMID SUBTROPICAL CLIMATE (DELHI) 1) The Table 1 shows that for humid climates, the perforation percentage should be bigger than 30% and smaller than 70%. This climate requires ventilation thorughout the wall, provding air movement from head to foot. Hence the lower part that receives the lower angle solar radiation should have smaller perforations (see Fig 7.2.1). Perforation percentage of 30% with perforation size of 0.0009 m2 (30x30mm) and thickness of 1:1, hence 30mm.

Figure 7.2.1 Elevation of the Jaali and the Section of it showing the furniture infront of the lower part of the Jaali.

The Jaali studied in the fieldwork is not operable and had a perforation percentage of 64% and is a public space. For this design, the Jaali is operable to a extent to provide night ventilation. To also be used in a personal space, the perforation percentage is chosen as 50% from the Table 6.1.1. From the Climate data from meteonorm, the average wind velocity annually is 1.7m/s. Szokolay (1994) observes that wind velocity indoors from 0.5-1.0 will be bring comfort. Hence to receive 1.0m/s into the space and calculate the perforation size required, the equation is used. The Psychometric chart proves that significant cooling will take place when a wind velocity of uoto 2.0m/s is received indoor (see appendix 5).

Figure 7.2.2 Elevation of the Jaali and the Section of it showing the furniture infront of the lower part of the Jaali.

Velocity outside, Vo = 1.7m/s Velocity Inside, Vi = 1.0m/s Using equation 6.2, Air Penetration %, X = (Vi/Vo) * 100 = 60% Size of Perforation sq.m, Y = 0.011X - 0.003 = 0.0036 sq.m The main/middle part of the Jaali is designed to have 50% perforation percentage with Perforation size 0.0036 m2 (60x60mm) and thickness of 1:1 and hence 60mm (see Fig 7.2.2). As the cold period ( 6 months from October to March) have average temperature of 15C, it would be benefitial to allow direct solar radiaition into the space. Hence the middle part of the Jaali can become thinner (from 60mm to 30mm) to let the direct sun inside. Due to the frequent rains, shading element is used. Hence the part of the Jaali just below the shading element can have bigger perforations and be thinner to let the hot air to go out and provide good day light (see Fig). Perforation percentage of 70% with perforation size 0.00081(90x90mm) and thickness of 30mm (see Fig 7.2.3). The Figure 7.2.4 on the right showing the fixed and the movable parts of the Jaali as red and gray ones respectively. The Jaali on the two ends of the walls having completely openable windows, which could also provide cross ventilation by itself. The middle 3 Jaali are slidable to make the Jaali thinner.

Figure 7.2.3 Elevation of the Jaali and the Section of it showing the furniture infront of the lower part of the Jaali.

ARID CLIMATE HUMIDHOT SUB SEMI TROPICAL CLIMATE | | PROPOSAL PROPOSAL

HOT PERIODS OUTSIDE VIEW

OPERABLE CORNER WINDOWS TO PROMOTE CROSS VENTILATION SECTION

INSIDE VIEW

MILD PERIODS SLIDING JAALI TO MAKE IT THINNER TO RECEIVE DIRECT SUN LIGHT INDOORS

INSIDE VIEW Figure 7.1.4 View of the Jaali from outside and insidde at its different stages. ARCHITECTURAL ASSOCIATION ASSOCIATION | | MSc MSc Sustainable Sustainable Environmental Environmental Design Design ARCHITECTURAL

TRADITIONAL PERFORATED SCREENS OF INDIA

7.3) TROPICAL MONSOON CLIMATE (NAGARCOIL) The temperature being not as high as the other 2 climates, the challenge is to prevent glare while let in maximum wind inside. The sloping roof to responds to the frequent rains. It is also proved that using horizontal strips both prevents direct solar radiation inside while providing maximum wind inside. So this design is incorporating the sloping roof and horizontal strips in the Jaali. The built precedent of this climate has handled glare by slanting the Jaali downwards (see Fig 7.3.1). Glare is caused due to high illuminance levels in the clear sky conditions (as mentioned in chapter 2.1). Glare is experiances in other skyconditions when opeing is facing a high reflective surface.

Figure 7.3.1 Jaali that is seen in the fieldwork.

First the Jaali was designed with a straight panel with downward sloped strips. Yannas (1994) has observed that a negative pressure is created at the upper region to allow the air from inside to flow out (see Fig 7.3.2). Likewise this Jaali will create a negative pressure between the roof and the screen (like seen in fig 7.3.2). This will cause air from inside to flow outside in the middle part of the screen. By slanting the panel with the strips downwards, the negative presssure shifts to the inner part forcing wind into the screen (see fig 7.3.3). The bottom part is designed with strips but verticle arrangement, to provide large volume and velocity of air and cutting down the lower angle sun.

Figure 7.3.3 Sloping the strips and keeping the frame straight.

The Figure 7.3.5 on the right show the fixed and the movable parts of the Jaali as red and gray ones respectively. The Jaali in the middle can be moved to be completely open. The lower part can be moved from a particular angle to prevent the sun in the afternoon, to turning straight during the mornings or cloudy days to let in maximum air inside.

Figure 5.3.4 Slanting the frame brings in better air velocity.

Figure 7.3.2 The pressure differences created around a building (source : Yannas, 1994).

TROPICAL HOTMONSOON SEMI ARID CLIMATE | PROPOSAL

OUTSIDE VIEW DURING HIGH GLARE

INSIDE VIEW

OUTSIDE VIEW WHEN NO GLARE

Bottom part is opened to let in maximum wind

INSIDE VIEW

Figure 7.1.5 View of the Jaali from outside and insidde at its different stages. ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

CHAPTER 8 CONCLUSION

TRADITIONAL PERFORATED SCREENS OF INDIA

The study of the origin of the Jaali has shown that the diversity in the Jaali, from its role in the vernacular architecture of the hot countries across the globe. Each example of the Jaali found shows its sensitivity to the differences within the hot climates and the functions it performs. Hot climate is the term that covers a range of climates that vary from dry to humid. The Jaali in some cases are also used in the interior walls, to enable air movement within the house that occurs due to pressure differences between the spaces. Some published research proving that using the Jaali as solar screens will save 30% of the energy that is used for cooling the space, the intent of this research is to take forward the Jaali to exploit its other vital qualities of providing ventilation, and daylight. Field work helped to estimate the measure of perforations that would provide the volume of air inside, along with shading to achieve comfort in a particular hot climate. The difference in the Jaali with respect to the climate and the type of space measured provides a correlation. This gives a clear understanding of the factors that will influence the comfort in a particular climatic condition. As it is established from the climate study that the basic function for the screen would be to prevent solar radiation inside the spaces, the three sub climates show the specific requirement of letting in small amount of air penetration but maintain good air movement within spaces, or allow maximum air penetration at the same time prevent glare due to bright sky conditions. The Jaali is seen have been designed very sensitively depending on the climate and function of the space. Hence quantifying this element through fieldwork brought correlations between the Jaali to the space and its function. The four findings from the research are as follows: 1) The correlation between the size of the Jaali (perforation percentage) to the volume of air, shading, day lighting it is going to provide. 2) The comfort of the space can be specified by the velocity of air that is required in the space or the amount of day light required in the space. Based on this priority, the size of the perforation is chosen. 3) Shading an added requirement when it comes to preventing the low angle afternoon sun light indoors that cannot be prevented even with the presence of an overhung shading element. Hence by increasing the thickness of the element to be the ratio of 1:1 to the height of the perforation, the direct sunlight into the space is prevented for most part of the day. 4) The amount of day light received into the space is directly proportional to the perforation percentage. Higher the perforation percentage the better the day light inside the space will be. The fieldwork examples also taught the importance of having adaptive features in the Jaali to optimize it for night ventilation or other periods of the year. Keeping these guidelines in mind, a Jaali in a wall of 3m height and 5m long is designed, for each of the three climates designed. It is designed in such a way as to cater to optimize all the 3 functions of shading, ventilating and providing day light. The design also suggests simple adaptive measures

CONCLUSION

with respect to each screen. This research has helped in the understanding of the complexities the hot climates provide, and the wide differences between the sub climates, that provide new problems. Nevertheless, these complexities can be dealt with a simple element, Jaali. If the connection between climatic requirements to the components of the Jaali is understood to the detail, this element can be used to contribute to the natural comfort of a space.

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

CHAPTER 9 REFERENCES

TRADITIONAL PERFORATED SCREENS OF INDIA

REFERENCES

(1) Bittencourt, Leonardo Salazar., (AA Thesis 1993). Ventilation as a cooling resource for warm-humid climate : an investigation on perforated block wall geometry to improve ventilation inside low-rise buildings. London AA 1993. (2) Givoni, Baruch (1998). Climatic Considerations in Buildings and Urban Design. New York Van Nostrand Reinhold 1998 3) Fathy (3) Nicol,J.F., M.Humphreys, S.Roaf (2012). Adaptive Thermal Comfort. Routledge. (4) Yannas, S. (Ed. 2000). Designing for Summer Comfort. EC Altener Programme. Environment & Energy Studies Programme, AA Graduate School, London. (5) Givoni, B. (1994). Passive and Low Energy Cooling of Buildings. Van Nostramd Reinhold. (6) Wikipedia Contributors (2013). Retrieved on April 22 2014 http://en.wikipedia.org/wiki/Mashrabiya (7)E.Aljofi, The potentiality of reflected sunlight through Rawshan Screens, in: Proceedings of the international Conference Passive and Low Energy Cooling for the Built Environment, Santorini, Greece, 2005. (8) Unknown Author. Retrieved on April 25 2014 from https://www.saudiaramcoworld.com/issue/197404/the.magic.of.the.mashrabiyas.html (9) Unknown Author (2004). “Traditional for Comfort”. Retrieved Aprin 20, 2014 from http://www.hindu. com/mp/2004/02/19/stories/2004021901510200.htm (10) Koch – Nielsen, H. (2002). Stay Cool. A design guide for built environment in hot climates. James & James Ltd (11) Oliver, Paul (1997). Encyclopedia of vernacular architecture of the world. Volume 2. Cambridge university Press 1997 (12) Koenigsberger, Otto H. et al., (1974). Manual of tropical housing and building. Part 1, Climate Design. Longman, London, 1974. (13) Varanashi, S.P., (2011). “Perforate the wall to let in light and air”. Retrieved April 25, 2014 from http://www.hindu.com/thehindu/thscrip/print.pl?file=2011012250180200.htm&date=2011/01/22/&prd=pp& (14) Krishan, A. et al (Eds 2001). Climate responsive Architecture : a design Handbookfor Energy Efficient Buildings. Tata McGraw Hill, New Delhi. (15)Bowen, A., et al (Eds. 1981). Passive Cooling. American Solar Energy Society. (16) Littlefair, P. (1999). Solar Shading of Buildings. Buildings research Establishment. (17) Givoni, Baruch (1976). Man, Climate and Architecture. Applied Science Publishers, 1976. (18) Sherif, A. (2012). “Eternal perforated solar screens for daylighting in residential desert buildings : identification of minimum perforation percentages”. Vol 86, Issue 6, Solar Energy, Elsevier Science B.V., Amsterdam. (19) Sherif, A. (2012). “Eternal perforated window solar screens : the effect of screen depth and perforation ratio on energy performance in extreme desert environments”. Vol 52, Energy and Buildings, Elsevier Science B.V., Amsterdam. (20) Fathy H. (1986). “Natural Energy and Vernacular Architecture”, pg no 42-51. tLondon : University of Chicago Press for the United Nations University, 1986 (21) Williams, Monier. “Sanskrit-English Dictionary”. Cologne Digital Sanskrit Dictionaries. Cologne University. Retrieved 2009-11-08 (22) Baker, N. and K. Steemers (2002). Daylight Design of Buildings, James and James Science Publishers. (23) Szokolay, S, (2003/2008). Introduction to Architectural Science. The basis of sustainable design. Architectural Press. (24) Brown, G.Z. (1985). Sun, Wind and Light : architectural design strategies. New York WIley 1985. (25) Tillotson, G.H.R.(1987). Rajput Palaces : The development of an architectural style, (1450-1750). London:Yale University Press,1987. (26) Mostafavi (2001). Enriching identities: the architecture of Laurie Baker. A+U=Architecture and Urbanism, no.363. Tokyo : A+U Publishing, 2000. WEBSITE REFERENCES: www.flikr.com www.imarabe.org LECTURES: Bruneli, G. (2014). AA E+E Sustainable Environmental Design. London Velodrome. 18 FEB’14.

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

CHAPTER 10 APPENDICES

TRADITIONAL PERFORATED SCREENS OF INDIA

APPENDIX 1

APPENDICES

APPENDIX 2

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

APPENDIX 3

APPENDICES

APPENDIX 4 Patterns created by the Jaali inside the Tomb of Salim Chisti between 16.00-18.00.

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design

TRADITIONAL PERFORATED SCREENS OF INDIA

APPENDIX 5 Psychometric Chart for Jaipur, India (Hot - Arid Climate)

Psychometric Chart for Nagarcoil, India (Warm - Humid Climate)

APPENDICES

ARCHITECTURAL ASSOCIATION | MSc Sustainable Environmental Design