SANGATH, AHMEDABAD
Assignment 2
DESC9675 – High performance facades
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Project: Sangath is the architecture studio of Ar. B.V. Doshi. This 40 years old iconic building was designed with a focus to use locally available materials, labor, and construction technique. The construction and design of this building is focused on reducing the amount of heat absorbed by the building and transferred to the interior spaces. The architectural expressionism is earthy, and simple with the crude exposed concrete of the walls juxtaposing the clean reflective white cladding of the roof.
Materials:
Walls: Concrete cavity walls Windows: Single clear Glass and Metal framing Vaulted roof: Concrete sandwich panels with hollow clay fuse. External facing of ceramic mosaic tiles.
Aesthetic features: -
Vault is a major part of the visual expression Simple exposed concrete walls with cavity for thermal mass and insulation Use of local materials Big water channels at the periphery of the roof’s base collecting and channelling. rainwater
(Sangath — A Day in the Life of B.V. Doshi's Studio and Garden - More Margie, 2020)
Material and texture: Ceramic mosaic tile (top) Exposed concrete finish (bottom)
Typical construction: concrete walls, concrete sandwich vault with ceramic cladding
Rainwater channels RCC walls
(Sangath - Data, Photos & Plans - WikiArquitectura, 2020)
Source: Author (Sustainability study, semester 1 2019)
(Sangath — A Day in the Life of B.V. Doshi's Studio and Garden - More Margie, 2020)
Ahmedabad Climate: The climate of the city is characterized by it’s hot and mildly humid summers and mildly cold winters.
Fabric’s thermal performance: Window sizing and placement according to solar radiation
Source: Author (Sustainability study, semester 1 2019)
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Openings are self shading by the façade and by other buildings blocks of the office. Thick concrete walls provide thermal mass for delayed conduction of head. Stack effect is created internally due to the height and volume created by the vaulted roof in combination with ventilation near the ceiling level. Daylighting in the main space is diffused and distributed as it is placed closer to the roof, the ceiling reflects and distributes the daylight towards the floor. Low percentage of glazing employed to reduce solar heat gain by the façade in the hot climate of Ahmedabad, India. A low surface – volume ratio for the façade is good to reduce the solar heat gain by the envelope. A vaulted roof has lower surface to volume ratio. The high reflectivity of white tile cladding reduces the SHG further. Smaller openings on the façade with higher solar radiation and bigger openings only on the façade with the lowest solar radiation.
Thermal mass and surface absorption by dome construction
Source: Author (Sustainability study, semester 1 2019)
Exterior surface temperature of white and gray roofs, same day, two roofs.
Source : (Baruch Giovani,1998)
Precast concrete cladding panels
Metal L angle to support the cladding. Attached to backing concrete wall Backing RCC wall – precast panels Box window with precast panels. Single glazing clear glass Precast sandwich panels with hollow clay fuse and external finish of ceramic tiles Rafter system to support panelized geodesic vault
Source: Author (Sustainability study, semester 1 2019)
Façade buildup Source: Author
2. RCC custom precast panels transported to site via 8WD truck and attached to the base.
(Wuraola-Goldberg, 2016)
3. Reinforcement bars placed connecting exposed horizontal reinforcement of adjacent panels
4. This connection method allows for manufacturing tolerances while installation. The gap between panels is closed by pouring quick-set concrete.
5. Steel angles are attached to notches in the precast panel (See detail 1 for installation tolerance)
1. Reinforcement bar for Attachment of backing wall precast RCC panel to the
8. Window system is attached to the concrete box to finish the facade
Construction sequence
(Wuraola-Goldberg, 2016)
7. Small precast concrete panels are attached to the steel angles. Panels have horizontal lap joints and vertical baffle joints.
The roof is a panelized geodesic vault made of concrete sandwich panels with hollow clay fuse. The gutter is a precast ferrocement channel which is an important part of the architectural expression. The external finish of the panels is done with waste ceramic tiles in a cray mosaic pattern
6. The openings are boxed to seal the cavity between the backing wall and cladding panels
Roof’s structure is supported by metal rafter’s and I beams and the joints between two panels is sealed with a metal capping matching the ceramic finish of panels.
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Calculated R value of solid wall is 1.19 which is quite low Single pane glass has U value of 5.8 – low performance High reflectivity of roof cladding reducing solar heat gain by solid construction Movement and installation toletances are demonstrated below
Precedent buildings for: 1.Precast concrete panels as cladding (Wall): Capital Bank of Jordan
By Paradigm DH
This boutique bank building uses small precast concrete panels for the solid parts of the façade, The concrete cladding is used as a panelised curtain wall system. The openings are inset to the inside edge of the backing structure of the curtain wall. (Capital Bank of Jordan / Paradigm DH, 2020)
Façade assembly and joints Source: Author
Assembly tolerance in joints Source: Author
2.Concrete panels with ceramic tile finish (Roof): Auditorium
And Congress Center Expo By Nieto Sobejano Arquitectos
The building uses a ceramic tile cladding on the roof panels made of GRC to reduce solar heat gain on the roof and to create a dramatic aesthetic value. The expo had to built relatively fast, which was made possible by using concrete precast panels
(Auditorium And Congress Center Expo 2008 / Nieto Sobejano Arquitectos, 2020)
Sydney climate – Proposed design overview Climate zone 5: Warm temperate Climatic consideration: • Region affected by all four seasons, so humidity and heat control is important. • Summers are warm to hot, with average temperatures from 18.6 25.8°C, with humidity of upto 65% • Winter has average temperatures from 8.8 - 17°C, sometimes reaching sub zero ranges at the peak. Problems identified in the performance of the original building: • The thermal performance of the original building is not sufficient for this weather. As Ahmedabad has mild winters, focus was on reducing heat gain in the façade – hence the use of reflective material. But the R-value of the buildup is quite low. • The construction is heavily concrete based. While concrete provides thermal mass, it has high embodied energy, making it less sustainable choice. • Daylighting is not enough as the wall glazing ratio is kept to reduce solar heat gain in hot weather. Windows have single pane low performance glazing. Proposed changes in façade buildup: • More insulation is added to improve performance of the façade. • The aesthetic value of the façade is maintained by creating a skin of Glass Reinforced Concrete (GRC) • The daylighting in the space is increased by addition of recycled optical fibers in the structure which bring in daylight with less solar heat gain (industry waste created by the shift from cable internet to 5G technology) • Concrete used is reduced by replacing it with hempcrete and GRC in walls and roof,
Elevational view (1:10) Source: Author
Roof level
Detail A
Outside
Inside Source: Author
Vertical Section (1:10) Showing joint locations
Source: Author
Horizontal corner Section (1:10) Source: Author
Inside
Detail B
Outside
Inside
Possible structural layout for geodesic vault ESDEP LECTURE NOTE [WG14] (2020)
Outside
Detail B Vertical Sectional detail (1:2)
Detail A: Vertical Sectional detail (1:2)
Source: Author Source: Author
Essential design criteria:
Thermal performance: the original design uses air cavities, thick walls, and thermal mass. While it works in theory, calculations show lack of insulation to maintain the indoor thermal comfort. While redesigning for Sydney climate, the first element added is insulation. A panelised GRC cladding is used to maintain the visual appearance with hempcrete as insulation. The R value of solid wall is increased from 1.1 to 2.5. In the original design, solar heat gain is reduced by self shading, using materials of high reflectivity (ceramic tile) and placing bigger openings on the north façade (least solar radiation). To adapt this principle in Sydney climate, the same external finishes are maintained (concrete on walls and ceramic finish on insulated roof panels) and the smaller openings are moved to south façade where the solar radiation is the least for this hemisphere.
Daylighting: Original design has very less window to wall ratio which is good for reduced solar heat gain but does not provide good daylighting. For the proposed design, optical fibers are embedded in the façade to bring more natural light in, reducing the load on electric lighting.
Materials used:
Glass reinforced concrete (GRC) -
Lighter than concrete results in lighter support system. Easier to mould in different shapes Less production time than concrete as it needs to be cured for only 24 hours Lesser crack failures than concrete It has good chemical resistance Movement and expansion: Allowance for thermal expansion is provided in the lap joints between two panels Allowance for movement via flexi anchors used for connection to the frame attached directly to the superstructure Fire safety: Fire stop and smoke seal is provided at slab level after every floor. Material does not burn Waterproofing Sealant at joints on the external surface between panels Finish A matt concrete like finish is maintained with a mineral silicate coating.
(Sangath — A Day in the Life of B.V. Doshi's Studio and Garden - More Margie, 2020)
Hempcrete: -
Higher thermal resistance than concrete Lighter than concrete It’s a carbon neutral product as the plant absorbs carbon when it is cultivated. Hempcrete is fireproof and highly durable Has good acoustic insulation hence no extra insulation is required. It does not crack as it absorbs moisture and regulated it internally. Waterproofing: A vapour barrier is placed at the external surface of hempcrete for draining of any water penetration Finishing Lime plaster interior finish resembling concrete.
Kingspan roof panel: -
Is a highly insulated roof panel with Polyisocyanurate(PIR) insulation which makes it fireproof and The panels are custom made with a ceramic tiling resembling the original design’s finish, for this project. A butyl sealant layer is applied on site for waterproofing the eaves and ridges,
Source: Author
GRC production
Optical fibers inclusion
Hempcrete production
Spraying of GRC in mold
Anchoring to frame Source: HPF Lecture slides, 2020
Anchoring to frame
Source: Bartos, Peter J. M.. (2017)
Handling and transportation Source: Author assignment 1
Source: Bartos, Peter J. M.. (2017)
Peak load calculation
Indoor temperature =
24
Radiation Summer =
Delta t summer = 8
Summer (32 degree C outside)
North façade South Facade East façade West façade
U value of fabric area of fabric (W/m2K) (m2) 0.48 0.89 0.6 0.4
Delta t winter =
-24
Conducted gain
Temperature Difference inside / outside (K) 22 22 33 33
670
U value of fabric area of fabric (W/m2K) (m2) 0.48 0.89 0.6 0.4
Heat loss/gain (W) 84.48 156.64 158.4 105.6
8 8 8 8
Radiation Winter = 20 Winter (0 degree C outside)
Heat loss/gain (W) -253.44 -469.92 -475.2 -316.8
Temperature Difference inside / outside (K) 22 -24 22 -24 33 -24 33 -24
Radiation gain
North façade South Facade East façade West façade
Horizontal Solar Heat gain Radiation Coefficient (W/m2) 0.276 0.276 0.276 0.276
Area (m2) 670 670 670 670
Solar Heat Horizontal gain Radiation Coefficient (W/m2) 0.276 0.276 0.276 0.276
Heat loss/gain (W) 4068.24 4068.24 6102.36 6102.36
22 22 33 33
Heat loss/gain (W) 121.44 121.44 182.16 182.16
Area (m2) 20 20 20 20
22 22 33 33
Infiltration gains Specific heat capacity of air(J/KgK)
Density of air(Kg/m3)
Volume flow rate of air (Volume of room * air change rate per hr / 3600) (m3/s)
Temperature Heat Difference inside loss/gain / outside (K) (kW)
Heat loss/gain (W)
Density of air(Kg/m3)
Specific heat capacity of air(J/KgK)
Volume flow rate of air (Volume of room * air Temperature Heat change rate per hr / 3600) Difference inside / loss/gain (m3/s) outside (K) (kW)
Heat loss/gain (W)
Poor performace
1.2
0.00278
8
0.027
26.667
1.2
0.00278
-24
-0.08
-80
Good performance
1.2
0.00042
8
0.004
4
1.2
0.00042
-24
-0.012
-12
Poor performance infiltration
Total peak load gains Summer Total peak load gains Winter
North façade
South Façade
East façade
West façade
4179.387
4251.547
6285.667
6234.627
-212.000
-428.48
-373.04
-214.64
Peak load calculation
Window glazing calculation
Faรงade East West South North
Opening area Solid wall area glazing % Faรงade U valuer value 6 0 2 10
27 33 12.5 20.7
22.2% 0.0% 16.0% 48.3%
1.788 0.897 1.573 2.494
0.559 1.115 0.636 0.401
Layer COMPONENT no: 1 EXTERIOR ENVIRONMENTAL CONDI Exterior air film 2 precast concrete cladding 3 Air cavity 4 RCC wall panel 5 Interior air film 6 INTERIOR ENVIRONMENTAL CONDI TOTAL
Thickness Thermal conductivity - Thermal resistance (m) K (W/mK) R (m.sq K/W) n/a
-
0.04
0.1
0.51
0.20
0.005
0.029
0.17
0.3
0.51
0.59
n/a
-
0.12
0.405
R value = 1.114 U value = 0.897
References
1. 2019. Facade Calculator 2019 Volume One. Australian Building Codes Board. 2. ArchDaily. 2020. Auditorium And Congress Center Expo 2008 / Nieto Sobejano Arquitectos. [online] Available at: https://www.archdaily.com/506770/auditorium-and-congress-center-expo-2008-nieto-sobejandoarquitectos?ad_source=search&ad_medium=search_result_projects Accessed 2 June 2020]. 3. ArchDaily. 2020. Capital Bank Of Jordan / Paradigm DH. [online] Available at: https://www.archdaily.com/902421/capital-bank-of-jordan-paradigmdh?ad_source=search&ad_medium=search_result_projects Accessed 2 June 2020]. 4. Bartos, Peter J. M.. (2017). Glassfibre Reinforced Concrete - Principles, Production, Properties and Applications - Whittles Publishing. Retrieved from https://app.knovel.com/hotlink/pdf/id:kt011D3HC4/glassfibre-reinforced/handling-transport-storage 5. Engineeringtoolbox.com. 2020. Thermal Conductivity Of Selected Materials And Gases. [online] Available at: <https://www.engineeringtoolbox.com/thermalconductivity-d_429.html> [Accessed 2 June 2020]. 6. Fgg-web.fgg.uni-lj.si. 2020. ESDEP LECTURE NOTE [WG14]. [online] Available at: http://fgg-web.fgg.uni-lj.si/~/pmoze/ESDEP/master/wg14/l0500.htm [Accessed 2 June 2020]. 7. Fireplacedoorsonline.com. 2020. Why GFRC Is Better Than Precast Concrete. [online] Available at: https://www.fireplacedoorsonline.com/why-gfrc-isbetter-than-precast-concrete.html [Accessed 2 June 2020]. 8. Haico schepers, 2020, High performance Facades Lecture slide, The university of sydney 9. Hebel-usa.com. 2018. HEBEL FLOOR & ROOF SLABS. [online] Available at: https://www.hebel-usa.com/en/content/hebel_floor_roof_slabs_2388.php [Accessed 2 June 2020]. 10. Kingspan | East Asia, South East Asia &amp; Micronesia. 2020. Trapezoidal Roof Panels (KS1000 RW). [online] Available at: https://www.kingspan.com/esea/en-ph/products/insulated-panel-systems/roof-panel-systems/trapezoidal-roof-panels-ks1000-rw [Accessed 2 June 2020]. 11. LZPC precast concrete housing, 2018. LZPC Precast Concrete Housing Technology, And Precast Concrete Wall Element Production Line. [video] Available at: https://www.youtube.com/watch?v=KZxskJojRLY [Accessed 2 June 2020]. 12. Reardon, C., 2013. Precast Concrete | Yourhome. [online] Yourhome.gov.au. Available at: https://www.yourhome.gov.au/materials/precast-concrete [Accessed 2 June 2020]. 13. More Margie. 2020. Sangath — A Day In The Life Of B.V. Doshi's Studio And Garden - More Margie. [online] Available at: http://moremargie.com/article/sagath-a-day-in-the-life-of-doshis-garden-studio [Accessed 2 June 2020]. 14. virtualmaths.org. n.d. TYPICAL THERMAL CONDUCTIVITY OF BUILDING MATERIALS: STRUCTURAL AND FINISHING MATERIALS. [online] Available at: http://www.virtualmaths.org/activities/activities/data-handling/heatloss [Accessed 2 June 2020]. 15. Watts, A 2013, Modern construction handbook., Ambra, Berlin. 16. Watts, A 2019, Modern Construction Envelopes : Systems for architectural design and prototyping , 3rd ed., Birkhäuser,, Basel, doi: 10.1515/9783035617818. 17. WikiArquitectura. 2020. ✅ Sangath - Data, Photos & Plans - Wikiarquitectura. [online] Available at: https://en.wikiarquitectura.com/building/sangath/# [Accessed 2 June 2020]. 18. Windows and Daylighting. (2020). Windows.lbl.gov. U.S. Department of Energy. Retrieved 2 June 2020, from https://windows.lbl.gov/tools/window/software-download 19. Wuraola-Goldberg, D., 2016. Precast Concrete Building Construction. [video] Available at: https://www.youtube.com/watch?v=7Y3ddGdraUQ [Accessed 2 June 2020].