19th Street Baptist Church Lighting Analysis

19th Street Baptist Church

LIGHTING ANALYSIS ARCH 632-001 | Daylighting December 20, 2013 Xiufang Zhao + Jill Sornson Kurtz

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PROJECT OBJECTIVE

Starting with pre-research and site visiting on churches to get a basic pattern of the daylighting environment in church, the 19th Street Baptist Church in Philadelphia is selected for further research.

This church, which is not under a good condition for now, is the project in the Historic Preservation Department of PennDesign, which provides an opportunity for us to cooperate with the Historic Preservation professors and students: what is the daylight condition in this church and what could we do to meet the lighting requirements in a church after restoration?

The goals of our project are as follows: • Provide a LIGHT + DAYLIGHT ANALYSIS FOR the 19th Street Baptist Church.

• COLLABORATE with historic preservation students to understanding existing fixtures and future lighting goals • Identify LIGHTING PROBLEMS by utilizing simulation for illuminance and daylight autonomy studies.

• Define lighting DESIGN OPPORTUNITIES by determining lighting goals, fixture types, and lighting control plan.

REPORT CONTENTS 1. Case Study Analysis 2. Project Context 3. Daylight Simulation 4. Lighting Design 5. Conclusion ARCH 753

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CASE STUDY ANALYSIS As the first step for this project, visiting open churches in Philadelphia could help us better understand what the daylight and lighting conditions in churches in use are. Due to the time and schedule limitation, three of the listed churches are visited and analyzed, shown as the green spots on map: Cathedral Basilica of Saint Peter and Paul (1723 Race Street, Philadelphia, PA), St. Clement’s Church (2013 Appletree St, Philadelphia, PA), St. Marks Church (1625 Locust St, Philadelphia, PA).

The case study includes illuminance measurements and HDR photo analysis, considering on illuminance for pews, aisle, and statues, as well as luminance contrast.

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CASE STUDY ANALYSIS CATHEDRAL BASILICA, SAINT PETER & PAUL Cathedral Basilica of Saint Peter and Paul is well lit by artificial light. The design illuminance for pews is about 150lx, for walkway (dark gap between pews and statues) is about 50lx, for statues is about 120 lux (horizontal illuminance). Recessed downlight luminaries on the ceiling provide main illuminance for the prayer hall. Designed chandelier provides uplight for ceiling and downlight for pews.

SAINT MARKS

Saint Marks Church is less lit than Cathedral Basilica of Saint Peter and Paul, only with 40lx for pews, 20lx for walkway and 120lx directly under the luminaries. With HDR analysis, a luminance pattern could be recognized in these churches: windows and luminaries > target lighting (statues) > pews > walkways (dark gap). Luminaries change the daylight distribution pattern both by high luminance of themselves and artificial light distribution to nearby surfaces. 

9.9

+36lux

+120lux

7.2 5.2 3.8 2.8 +120lux

+140lux

2.1

+250lux

+70lux

+40lux

+20lux

1.5 0 cd/m2

SAINT CLEMENTS CHURCH

Saint Clements Church is measured as 0lx for pews without artificial light. Though the church is not open when we visited, the target lights for choir are still on, emphasizing the choir with low color temperature.

2.6 2.3 2.0 1.7 1.5 1.3

42.5

25.1

15.0

9.0

5.3

3.4

2.0

0 cd/m2

6.6

5.0

3.9

3.0

2.3

1.8

1.4

0 cd/m2

+0lux

1.2 0 cd/m2

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PROJECT CONTEXT As a church first built in 1874, 19th Street Baptist Church is technically the work of Furness’ partner, George W. Hewitt. But the building’s wayward massing, playful asymmetries, and delightful (perhaps winking) palette show the two men spoke a common language. The spatial features of this church create a particular daylight environment, and the old artificial light system in this church provides a current situation with glare and uneven illuminance.

On-site visiting, illuminance measurement and HDR photo analysis could help us get a current daylight and artificial light condition in 19th Street Baptist Church. Transmittance of stained glass is measured with samples from historical preservation lab. Analysis of the current situation in the church is the foundation for further design advice.

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PROJECT CONTEXT

19th STREET BAPTIST CHURCH Designed by Frank Furness and George Hewitt in the High Victorian Gothic style, its use of polychromatic materials on the exterior and interior created a rich and varied visual experience. Inside, the sense of mystical spirituality was facilitated by the natural light that filtered through multiple stained glass windows and was enhanced by the warm glow of the original gas light fixtures. As the Memorial Church of the Holy Comforter, the goals of the church leaders were to provide spiritual guidance and moral uplift to the working class members of the surrounding neighborhood. With these goals in mind, the church was designed with an open nave to facilitate views of the leader of the services and a beautiful, colorful space in which to contemplate the words of God.

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PROJECT CONTEXT SITE PLAN

AREA UNDER INVESTIGATION

The 19th Street Baptist Church is located in the south Philadelphia neighborhood of Point Breeze at the corner of South 19th Street and Titan Street.

ROBE ROOM

BELL TOWER

ALTAR

SANCTUARY

ENTRANCE

CHOIR

BAPTISMAL

OFFICE

OFFICE

PANTRY

FLOOR PLAN

CHANGING ROOM

BATHROOM

BATHROOM

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The 19th Street Baptist Church includes two parts connected by a corridor. The main part on the north is what this project focused on. Its width is 44 feet and length is 102 feet. It has 10 side windows in pairs on north facade, 12 side windows in pair on south facade, and 3 clerestories on both sides on the pitched roof. All glasses are stained glass. The historical students we cooperated with are working on artificial lighting systems in this church. 

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PROJECT CONTEXT MATERIAL MEASUREMENT + ASSUMPTION Following are the materials used now in church. The side window now is two-layer window, with one layer of stained glass and another one with opaque plastic, which blocks a large amount of daylight. The opaque plastic works as a protection for the stained glass. During stained glass measurement, the transmittance varies from 3% to 26%, the transmittance of clear glass is about 80%.

We take 20% as a transmittance for the simulation program as an average value.

Transmittance measurement of stained glass is taken by light meter. By measuring the ratio of the amount of light behind and in front of the stained glass, an estimated transmittance of stained glass could be measured. The interior material now in the church would be repainted or recovered by historic preservation professionals. The reflectivity of different interior materials (ceiling, wall plaster, column painting, floor tile, etc.) is assumed same as normal materials based on historical preservation design: ceiling 80%, wall 50%, column 50%, floor 20%.

56%

26%

20%

11%

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PROJECT CONTEXT ORIGINAL FIXTURES

GAS FIXTURES Based on the research files from historical preservation students, the original lighting fixtures in the 19th Street Baptist Church were gas wall brackets and chandelier.

EXISTING FIXTURES

Three artificial lighting systems exist in the church: halogen luminaries for roof washing, halogen luminaries for stage, and florescent luminaries for aisle. But all the luminaries are not in good conditions: halogen luminaries vary in light distribution, and florescent luminaries are lack of shield or reflection panel. The color temperature is around 3000K for halogen luminaries and 4000K for florescent luminaries. The color rendering index is quite low, which makes the whole church gloomy.

HALOGEN STAGE

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HALOGEN UPLIGHTS

FLORESCENT

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DAYLIGHT SIMULATION With the drawings from historical preservation students, a model with accurate dimensions is built for daylight simulation. It includes basic architectural elements like roof, wall, window, column, floor and was simplified by deleting detailed decorations. The image below is the work from historical preservation students based on our cooperation: discussing the interior material in a 3 dimensional model.

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DAYLIGHT SIMULATION

JUNE 21

SEPTEMBER 21

SUNNY DAY, 9A

300

250

200

150

100

50

33

DECEMBER 21

JUNE 21

CLOUDY DAY, 9A

CLOUDY DAY, 9A

CLOUDY DAY, 9A

42

SUNNY DAY, 9A

0 lux

SEPTEMBER 21 50

DECEMBER 21

SUNNY DAY, 9A

25

17

8

0 lux

SIMULATED DAYLIGHT The illuminance at the height of 800mm is simulated for March 21st, Jun 21st, Sep 21st, and Dec 21st under condition of clear sky with sun and overcast sky.

9 am is chosen as the simulation time based on the daily use schedule of a neighborhood church.

From the simulation results, in both sunny and cloudy days, the daylight design purpose could be recognized: lighting up the front part of the church (choir) with

daylighting coming through the rose window, and keeping the rest of church dark to make a high contrast. South facade of the church is blocked by another part of this building, so the north part in the church is relatively getting more daylight. The worst case is in December with overcast sky, which keeps less than 50 lux all over the church except for the choir. Different scales are taken for clear sky with sun and overcast sky to better demonstrate daylight distribution in two different conditions.

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DAYLIGHT SIMULATION 0

1

26

21

21

21

0

MEASURED ILLUMINANCE

0

0

0

1

2

2

2

The on-site measurement of indoor horizontal illuminance was taken at 9am on November 7th, 2013, under the condition of overcast sky. Measurement point height is 2 feet 7 inch. The church was occupied by a lot of pews in the middle of prayer hall, so measurement points were quite limited: along the columns and in the middle of prayer hall, 22 points in total.

With daylight, the illuminance around middle of the church is almost 0, nearby the side window is about 20-40lx. The whole church was relatively dark, especially in the middle of prayer hall, which led a high contrast between rose window and backdrop.

0 1

11

21

31

21

41

31

0

DAYLIGHT ONLY

OVERCAST, NOVEMBER 7, 9A

50

42

33

25

17

8

0 lux

With daylight and artificial light, there was still not much improvement, horizontal illuminance was only around 20-50 lux. The existing luminaries are not effective on providing enough horizontal illuminance. Due to the uneven distribution of artificial light, it is difficult to recognize the former daylight pattern. Because the artificial luminaries have two different color temperatures, which are different with daylight color temperature as well, mix of these three color temperature doesn’t help the church turn brighter.

21

22

22

25

28

32

29

26

50

18

36

41

20

17

16

23

21

19

26

15

0 12

8

DAYLIGHT + ARTIFICIAL OVERCAST, NOVEMBER 7, 9A

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DAYLIGHT SIMULATION

DAYLIGHT FACTOR SIMULATION

Daylight Factor could give us a more general understanding of the daylight condition in the church.  Two different scales are chosen for daylight factor simulations: 0-1% and 0-5%. The average daylight factor is around 0.2%, which is relatively low compared with building standards on daylight factor.

2% - 5% is usually the optimum range of daylighting for overall energy use. Rooms have a predominantly daylit appearance but supplementary electric lighting is needed away from windows and during dull weather. Rooms types like offices benefit from this range of Daylighting Factor.

1.0%

5.0%

0.8%

4.2%

0.7%

3.3%

0.5%

2.5%

0.3%

1.7%

0.2%

0.8%

0%

However, Daylight Factor could only express daylight condition with overcast sky. Considering climate in Philadelphia, overcast sky condition is not typical. In other words, though Daylighting Factor gives us a general understanding of daylight condition in this church, it is not a representative indicator of daylight environment in the 19th Street Baptist Church .

0% ARCH 753

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DAYLIGHT SIMULATION

DAYLIGHT AUTONOMY

Daylight Autonomy could demonstrate more information about daylight conditions in the church. Both elevation and horizon surfaces are simulated in this project.   With horizontal surface simulation, dark area could be defined. For horizontal surface simulation, 3 scales are chosen: 50lx, 150lx and 300lx. 50lx is the baseline illuminance for walkway, and for most time in the church people could walk without difficulty except for near the doors close to the choir.

150lx is the design illuminance for basic reading task, which need 100lx more from artificial light to fulfill the requirement illuminance in most time. 300lx is the design illuminance for task lighting, could hardly be achieved by daylight only.

50 lux 100%

150 lux

83%

67%

50%

33%

17%

0%

300 lux ARCH 753

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DAYLIGHT SIMULATION

DAYLIGHT AUTONOMY FACTOR With vertical surface simulation, daylight from the rose window in front of the church and clerestories contribute to the vertical illuminance in the church.  Both the lower level near to people and higher level close to roof have lower daylight autonomy, which indicates that the middle part next to the clerestories gets more daylight. Though the side windows on south facade should have get more daylight, the building next to the windows on south blocks large amount of daylight.

ELEVATION FACING SOUTH 100%

83%

67%

50%

33%

17%

0%

On vertical aspect, the daylight condition in this church demonstrates that space around windows with stained glass gets more daylight, in other words, windows are the main character in the church without artificial lighting. In the following design process, keeping the pattern of window recognition could be very important.

ELEVATION FACING NORTH ARCH 753

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LIGHTING DESIGN Lighting design is a cooperation work, considering about possible luminaries locations and wires from historical preservation perspective, trying to avoiding disturb the original pattern of daylighting, and providing enough illuminance for activities in the church.

First, we propose replacing the yellowed protective plexiglass covering the stained glass with clear plexiglass or glazing to improve the daylight transmittance into the church.

Secondly, three artificial lighting systems are designed for this church: front light, sanctuary light, and aisle light. Each of them is based on possible installation location provided by historical preservation students. Basic luminaries are selected to provide appropriate light distribution, with high color rendering index.

Lastly and according to different activities in this church, lighting control groups have been designed for three different situations. With more detailed events schedule in the future, the luminaries could also be dimmed to fulfill further requirements.

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DAYLIGHT SIMULATION 50 lux for Aisle

LIGHTING DESIGN INSIGHTS 100 lux for Congregation

300 lux for Focal Area

250

200

150

100

50

Horizontal illuminance is planned based on IES Lighting Handbook, which assorts worship space into three different kinds: contemporary, traditional and transitional. Defining this church as traditional worship space, which has lowest illuminance reference, we could generate a light level plan.

However, in IES Lighting Handbook, light for congregation only differs between different activities: collective meditation, participatory action, personal meditation, pre/post worship, and sermon. Without recommended illuminance for reading in worship space as reference, participatory action with the highest illuminance of 100lx is taken for the illuminance for pews.

For aisle light, it is referred to narthex illuminance during worship as 50lx.

For front light, high-reflectance focal areas in secondary focal areas for participatory action is 300lx (horizontal and vertical).

RECOMMEND ILLUMINANCE LEVELS 300

Daylight condition varies in the church because of climate, a static lighting plan could interrupt the original daylighting pattern. In sunny days, artificial lighting should be limited; in cloudy days, more artificial light should be provided to supplement daylight.

0 lux

Pew lights could also provide more light for reading for someone especially needs more light due to eye condition.

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LIGHTING DESIGN FRONT LIGHT DESIGN Front light provides both horizontal and vertical illuminance for the choir and altar. Spot light could be adjusted for different activities. It also emphasizes the space in front of the window, which is emphasized by daylight as well. Instead of washing the front roof to decrease the contrast between the window and backdrop and break the original pattern with daylight, the spot light is a more gentle way for front lighting.

ARTIFICIAL DAYLIGHT RENDERING CEILING WASHERS SPOT LIGHTS WALL SCONCES READING LIGHTS

EXPECTED RESULTS

DAYLIGHT

NAME????

CASE STUDY

DAYLIGHT + ARTIFICIAL LIGHT

EXISTING

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LIGHTING DESIGN SANCTUARY LIGHT DESIGN The white ceiling has a relatively high reflectance. Washing roof could provide direct light for both structure and reflecting light for pews. The linear luminary is installed between clerestories, instead of the original luminaries just below the clerestory, which decrease the contrast of the stained glass in clerestory and backdrop. Wide angle uplight could cover more ceiling area.

It could also light up the structure of this roof, which is an important element in this space.

ARTIFICIAL DAYLIGHT RENDERING CEILING WASHERS SPOT LIGHTS WALL SCONCES READING LIGHTS DAYLIGHT

DAYLIGHT + ARTIFICIAL LIGHT

EXISTING EXPECTED RESULTS

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LIGHTING DESIGN AISLE LIGHT DESIGN Aisle light is provided by wall sconces, which provide uplight for aisle ceiling and downlight for floor. Based on the research on former artificial light system in this church, the wall sconces would located in where they used to be. The aisle space, which is used only as transport space, only requires horizontal illuminance of 50 lux. However, considering people might meet each other in the aisle, vertical illuminance is also needed for communication. The wall sconces also provide vertical illuminance for the aisle space.

ARTIFICIAL DAYLIGHT RENDERING CEILING WASHERS SPOT LIGHTS WALL SCONCES READING LIGHTS DAYLIGHT

DAYLIGHT + ARTIFICIAL LIGHT

EXISTING

EXPECTED RESULTS

PROPOSED FIXTURE ARCH 753

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LIGHTING DESIGN PEW TASK LIGHTS We also propose reading lighting at the pews. We believe this is an innovative solution to help the aging population access additional light if needed for reading hymnals or scripture. These lights could be a strip of LED provided under the under top edge of the pew as shown below.

CEILING WASHERS SPOT LIGHTS WALL SCONCES READING LIGHTS

POTENTIAL FIXTURE ARCH 753

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LIGHTING DESIGN LIGHTING CONTROLS

For prayer during daytime, aisle lights near to the front are on to supplement light up to 50 lux for the walking space. The illuminance in rest of space could reach 50lx most of the time, which is sufficient for walking during worship based on IES Lighting Handbook (horizontal illuminance for narthex during worship in daytime). Pew lights can be turned on as needed.

For morning service, aisle lights are all on to provide more horizontal illuminance for aisle space.

Front lights could provide face light for pastor and choir. Pew lights can be turned on as needed.

For evening service or special events, all lights could be turned on, reflecting lights from the ceiling could provide 100 lux for participatory action in the middle of the sanctuary, which is based on the IES Lighting Handbook (traditional forms of worship, in congregation, participatory action). Pew lights can be turned on as needed.

PRAYER CEILING WASHERS

MORNING SERVICE

SPOT LIGHTS

WALL SCONCES

READING LIGHTS

Group control of artificial lighting could fit different activities. It could generate more scenes if it could be dimmed.

EVENING SERVICE ARCH 753

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LIGHTING DESIGN

LIGHTING ANALYSIS

COLLABORATION

LIGHTING PROBLEMS

LIGHTING DESIGN

Our lighting analysis provided the following insights:

Our collaborative process with the historic preservation students provided the following insights:

Our investigation of the 19th Street Baptist Church identified the following issues with lighting conditions in the church:

We used the analysis, collaboration, and identification of lighting problems to respond with the following design proposals:

• The stained glass and yellow plexiglass protection significantly inhibit daylight transmittance.

• We propose replacing yellowed protective panel with clear panel to still protect the stainglass but increase the daylight transmittance (see page 16).

• By visiting existing churches, we saw the importance of high contrast lux levels to emphasize focal points and provide dramatic environments.

• We identified lighting patterns in churches instead evenly distributed light. This also adds to the dynamism of the spaces.

• Spotlighting was used in all churches for emphasizing focus points and usually used for people at the front of the spaces.

• We learned the location of lighting fixtures throughout the history of the building and used that to evaluate where future lighting is both needed and could be placed to still maintain the historic integrity of the restoration.

• Historic Preservation Students were able to provide us with sample materials and properties future paints so that we could determine the reflectance of the material for simulation.

• We helped the historic preservation students by providing insight from daylight simulation conditions to help inform their fixture selection and location.

• The church’s additional building on south side blocks daylight through the lower south side windows while daylight is still able to penetrate through the clerestory windows.

• There are many dark gaps and low light locations that are far below the recommended levels.

• The existing artificial light color temperature is very yellow and varies throughout the space.

• In this report, we defined the varied lighting zones and goal for lighting levels within those spaces (see page 17).

• We have proposed 3 lighting solutions we think are necessary for the church to achieve these goals (see pages 18 - 21). These light fixtures should also reduce the yellowing in the and better control color temperature and color rendering index.

• We developed a lighting control plan to respond to the different activities held within the space (see page 22).

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