VISUAL COMFORT CRITERION TEN ⋆ Archi-Monarch

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Visual comfort criterion refers to a set of standards used to evaluate the quality of lighting in interior spaces and the degree to which it affects the visual comfort and well-being of the occupants.

These standards are based on various factors, including luminance levels, glare, and color temperature, and are designed to provide a comfortable and usable environment for tasks such as reading, writing, and other visual activities.

The intent of this criterion is to ensure that visual comfort (daylighting and artificial lighting) is provided to the building occupants through an integration of active and passive design measures.

Maximum Points : 4

1) Appraisal

i) Daylighting

Demonstrate UDI or mean DA compliance as per the alternatives mentioned below.

Alternative 1

Appraisal – 1 (Mandatory for 0 points)

Ensure that the WWR does not exceed 60% and the vertical fenestration complies with minimum VLT of 0.27.

Appraisal – 2 (Mandatory for 0 points)

Ensure that the project meets the SHGC compliance as per Table given below / weighted façade average SHGC for each orientation.

Table – Maximum SHGC for vertical fenestration for different climate typologies (based on ECBC 2017)

Use Tables 9 and 10 of SP 41 to design the shading device for all the windows.

Conduct a solar path analysis for windows of AC as well as non-AC spaces, to ensure that they are completely shaded for the duration between 0900 hours on 15th March and 1500 hours on 15th September.

Use any combination of the previously mentioned strategies to show compliance for 100% of fenestrations.

Appraisal – 3 (Mandatory for 0 points)

Ensure that the SRR does not exceed 5% and SHGC for skylights does not exceed 0.35.

Note – Skylights in temporary roof coverings or awnings over non-conditioned spaces are exempted from Appraisal – 3 above.

Appraisal – 4 (Mandatory for 2 or 4 points)

Ensure that all habitable spaces are within the illuminance levels of 100 lux – 2000 lux for the minimum percentage of floor area prescribed in Table (below) for 90% of the potential day-lit time in a year. UDI compliance can be demonstrated through simulation using validated software.

Note – Habitable spaces are building spaces intended for continual human occupancy. Such spaces generally include areas used for living, sleeping, dining, and cooking, but do not include bathrooms, toilets, hallways, storage areas, closets, or utility rooms.

Table (below) UDI benchmarks for percentage of habitable areas for different building typologies (based on ECBC 2017).

Note – For mixed-use buildings, UDI benchmarks can be obtained using extrapolation.

Alternative 2

Appraisal – 1 (Mandatory for 0 points)

Demonstrate through simulation that the project meets mean DA requirement (<3000 lux) for 100% of the annual analysis hours for 100% of the habitable spaces.

Note – Grid size of 1 m × 1 m has to be used in DA simulation.

Appraisal – 2 (Mandatory for 2 or 4 points)

Demonstrate through simulation that the project meets mean DA requirement (>300 lux) for the percentage of annual analysis hours as listed in Table (below) for 100% of the habitable spaces.

Table (below) DA benchmarks for percentage hours exceeding 300 lux for different building typologies

Note – For mixed-use buildings, DA benchmarks can be obtained using extrapolation.

ii) Artificial Lighting

Appraisal – 5 (Mandatory for 0 points)

Demonstrate through simulation that the artificial lighting lux levels fall within limits (lower and higher range) as per recommended space/task specific lighting levels in NBC 2016, Part 8, Section 1, and meet a minimum uniformity ratio of 0.4.

2) Compliance

i) Daylighting

Compliance – 1

Submit drawings (.dwg format) consisting of floor plans, elevations, and sections and doors − windows schedule, skylight schedule highlighting the various shading devices installed in the building with ‘North’ direction marked.

Compliance – 2

Submit narrative detailing the alternative opted for and state the methodology used to demonstrate compliance.

Compliance – 3

Submit technical specification sheets/brochures for all glazing types highlighting their SHGC and VLT.

Submit valid GRIHA Product Catalogue certificate as applicable for the product.

Compliance – 4

Submit purchase orders reflecting the full quantities of all glazing installed in the project.

Compliance – 5

Upload photographs with narrative of measures implemented.

Alternative 1

Compliance – 6

Submit WWR calculation for the entire building envelope along with drawings (.dwg format) highlighting the opaque, translucent, and transparent areas in the façade to demonstrate compliance with Appraisal – 1 (Mandatory for 0 points).

Compliance – 7

Submit effective SHGC calculation as prescribed in ECBC 2017/weighted façade average SHGC calculation for each orientation to demonstrate compliance with Appraisal – 2 (Mandatory for 0 points).

Compliance – 8

Submit the calculations detailing the SRR and SHGC for skylights to demonstrate compliance with Appraisal – 3 (Mandatory for 0 points).

Compliance – 9

Submit simulation report (input and output files) for all the habitable spaces highlighting the areas meeting the requisite UDI requirements to demonstrate compliance with Appraisal – 4 (Mandatory for 2 or 4 points).

Compliance – 10

Submit narrative and calculations showing compliance with the UDI requirements through extrapolation in the case of mixed-use buildings as per Appraisal Appraisal – 4 (Mandatory for 2 or 4 points).

Alternative 2

Compliance – 6

Submit simulation report (input and output files) for all habitable spaces highlighting the areas meeting the requisite mean DA requirements.

Compliance – 7

Submit narrative and calculations showing compliance with the UDI requirements through extrapolation in the case of mixed-use buildings.

ii) Artificial lighting

Compliance – 11

Submit artificial lighting simulation reports for all habitable spaces using validated software demonstrating that the artificial lighting levels meet the recommended lux levels and uniformity ratio as per Appraisal – 5 (Mandatory for 0 points).

Compliance – 12

Submit interior artificial lighting layout plans (.dwg format), reflected ceiling plans (.dwg format) for the project.

Compliance – 13

Submit technical specification sheets for all internal lighting fixtures highlighting the lumen output and wattage.

Submit valid GRIHA Product Catalogue Certificate as applicable for the product demonstrating compliance with Appraisal – 5 (Mandatory for 0 points).

Compliance – 14

Submit purchase orders reflecting full quantities of all interior lighting fixtures installed in the project.

Meeting visual comfort criteria is important in order to ensure that lighting provides the right balance of brightness and contrast, reduces the risk of eye strain and headaches, and supports visual tasks effectively.