Part 2-IN: India

SP-1 Room sizes (gate). By NBC 2016 Part 3 §12, or the city's rule (Annex B). There are no grades: fit (SP-2 to SP-4) grades quality. "Width" is the least width of the room's usable rectangle.

Notes.

• NBC words its rules for one and two rooms. "The largest 9.5 m², the rest 7.5 m²" applies them to more rooms, as the city rules write it out.

• Maharashtra's UDCPR 2020 sets no room minimums: where it applies, only the bath and WC rows are gates.

• Kind: model code or city rule.

SP-1 on the method page

SP-2 Bedroom fit. Each bedroom. The levels are discrete. All bed lengths are 75″.

Kind: the bed sizes are a convention. The 750 mm clearance is a recommendation (UK Approved Document M4(2) §2.25); the 600 mm clearance is engine practice.

SP-2 on the method page

SP-3 Living and dining fit. The living room (the hall) and the dining area. P is the design household.

Kind: recommendation (NKBA's 32/36/44″ seating clearances; SMPTE/THX) and convention.

SP-3 on the method page

SP-4 Kitchen capacity. The kitchen. The aisle is in LY-5.

Kind: convention. The platform is 600 mm deep at 850–900 mm high.

SP-4 on the method page

SP-5 Storage. The home: the wardrobe run and the home's storage.

Kind: convention. The UK space standard's built-in storage (1.0–4.0 m²) is the reference.

SP-5 on the method page

SP-6 A balcony to sit out. The home's best sit-out. A flat with none drawn is below the minimum, unless its owner says it has one: then it is taken at the minimum until it is drawn.

Basis.

• MBBL allows group-housing balconies 1.2 m wide, at most 3.5 m² per bedroom and three a flat; city rules allow up to 1.5–2.0 m.

• Kind: our measure. The London Plan's size is the reference [U].

SP-6 on the method page

SP-7 Floor that is only for passing ↓. The home: corridors, passages, foyers, landings and stairs that can't be furnished, as a share of the carpet area. A space the drawing leaves unnamed counts where it is as narrow as a passage (1.5 m or less) and opens into two rooms or more.

Kind: our measure. Its anchors stay provisional: the reference set can't fix them (Annex A).

SP-7 on the method page

SP-8 Ceiling height. Gate and grade. Scored only where printed, or given by the owner.

• Gate fails:

  • a habitable room or kitchen under 2.75 m to the slab soffit;

  • under 2.4 m beneath a beam, or to the false ceiling of an air-conditioned room;

  • a bath or WC under 2.1 m;

  • low-income units under 2.6 m;

  • or the city's rule.

• The grade: 2.75 m scores 50, and 2.95 m or more scores 100. At that height a ceiling fan hangs at its best height and still clears 2.4 m (NBC Part 8). No Indian standard rewards more.

• Kind: model code or city rule, and standard.

SP-8 on the method page

SP-9 Carry-in. Big pieces reach their rooms through every door and turn. The levels are discrete.

Kind: our measure, with Indian sizes.

SP-9 on the method page

SP-10 Utility. The home.

Kind: convention. MBBL allows a 1.2 m drying balcony off the toilet.

SP-10 on the method page

DL-1 Openings (gate). Each habitable room and the kitchen.

• The gate fails when the openable area of windows and ventilators is under the zone's share of the floor:

  Zone	Share
  Hot-dry	1/10
  Warm-humid	1/6
  Temperate and composite	1/8
  Cold	1/12. Where a state follows MBBL, its §4.30.1.2 sets a floor of 1/10

• Kitchens need 25% more.

• What counts: openings to external air or an open verandah: a balcony or a terrace, and the utility, a flat's service balcony, unless it is named a room. They are its windows, its ventilators and its glazed doors, which MBBL §4.30 names among a room's apertures for light and air. A plain door and the frames don't count, the solid parts of a jali are deducted, and only what opens counts: of a partly fixed window, its openable part; of a sliding glass door, the half that opens.

• City rules replace the ratio (Annex B): for example 1/6, with at least 1 m² for every room, in Mumbai; 1/10 in Maharashtra and Delhi; 1/8 in Haryana.

• Kind: model code (NBC 2016 Part 3 §20.1.1–20.1.2, §12.3.3(d); MBBL §4.30) or city rule.

• One gate, two parts. NBC counts only openable area, so this one gate serves both Daylight and Air, and AR-1 is graded only.

DL-1 on the method page

DL-2 How bright by day. Each habitable room and the kitchen.

• The quantity, E50: the illuminance reached over half the work plane (0.75 m) for half the daylight hours. It is the room's median daylight factor × the site's median diffuse horizontal illuminance (the EN 17037 method).

Kinds and sources.

• Minimum: the UK National Annex to EN 17037 for dwellings (standard).

• Medium and high: EN 17037's minimum and medium levels (standard).

• Bedrooms reach 300 at high because Indian bedrooms double as study and work rooms.

Shown with it, not scored:

• IS 2440's daylight test: a median daylight factor under NBC's clear design sky, on the 0.75 m plane, of 50 lux (living), 150 (study) and 200 (kitchen) at the zone's design sky. It needs the engine to model that sky; until then it is shown "estimated".

• IGBC Green Homes v3's test: a glazing factor of at least 1 (2 in kitchens), or 110 lux at noon on 21 September under a clear sky.

Edition 1.1 adds a useful-light guard. A room is capped at medium when more than 25% of its work plane exceeds 2,000 lux for more than 10% of daylight hours (the ECBC and GRIHA useful-daylight upper limit). It needs the annual run. Until then, the clear-sky lux at noon on the equinox is shown.

DL-2 on the method page

DL-3 Depth and evenness. Each habitable room.

• Gate fails when any part of a habitable room is more than 7.5 m from an opening that lights it (NBC 2016 Part 3 §20.1.2 Note 2). UDCPR allows deeper rooms where openings grow in proportion.

• The quantity, E95: the illuminance reached over 95% of the work plane for half the daylight hours.

Kind and source. Standard: EN 17037's minimum and medium second criterion. The minimum is our measure.

Fact shown beside it: depth over window-head height. NBC Part 8 and IS 2440 say a room lit from one side works to 2–2.5 × the head height, and a room 7 m or more across needs openings on opposite sides. With the default 2.1 m head, that is 4.2–5.25 m.

DL-3 on the method page

SN-1 Welcome sun. The living room carries 0.6 and the bedroom with the most sun 0.4.

• The quantity: the hours the room is in sun (Part 1 §5.3) on the cool reference day of 5.6, 21 January. Edition 1.1 averages the typical year's days with cool sunny hours: following the sun through every such day is some ten times a report's work in 1.0.

Kind and source. Standard: EN 17037's levels. India has no rule for sun hours; NBC Part 8 §3.4 asks that homes let winter sun in and keep summer sun out, which the mix applies.

SN-1 on the method page

SN-2 Unwelcome sun ↓. Each habitable room.

• The quantity: solar heat through the glass on hot sunny hours, per m² of floor, in kWh a day. It is computed as clear-sky beam on the glass × SHGC (single clear 0.80 by default), averaged over the hot reference days of 5.6 (edition 1.1: over the typical year's sunny hours at 27 °C or above). Balcony slabs are modelled, and a chajja where the plan has one (the owner's, or an improvement tried), its shadow on the glass and the floor exact; fins are not yet.

What the levels look like (engine runs in Delhi: a 10.8 m² room with 1.44 m² of glass):

Chennai's north glass takes summer sun from the north: 0.22, short of the minimum.

Kind and source. Our measure, fixed on the reference set (Annex A, 7 October 2026): its shape, about a factor of two between levels, from Eco-Niwas Samhita's orientation factors and GRIHA's shading test; its minimum where a quarter of the set's rooms fall short, as a quarter fall short of the standards' own.

Shown with it, not scored: the Eco-Niwas check.

• The plan's part of the RETV: its solar term, c · Σ(A_glass · SHGC · ESF · ω) ÷ A_envelope. A_envelope is the flat's exposed external wall × floor height. Walls onto corridors, shafts and stair or lift cores are left out.

• The full RETV is shown as a range across three walls (200 mm AAC, 230 mm brick, 150 mm RCC), against Eco-Niwas Samhita's limit of 15 W/m² and its planned 12. The report asks the builder for the wall and the glass.

• Rough guide: a solar term of 9.0 W/m² or less keeps the RETV near 15 with AAC walls; 6.5 keeps it near 12.

SN-2 on the method page

AR-1 Openable area. Graded only: the gate is DL-1. Each habitable room and the kitchen.

• The quantity: openable area (what opens of its windows, ventilators and glazed doors, as DL-1 counts it) as a share of the room's floor.

Kinds and sources.

• Minimum: IGBC Green Homes' mandatory level for each room: living 10% and kitchen 8%, falling to 8% and 6% above five floors. In cold zones, Eco-Niwas Samhita's 8.33% applies.

• Medium: Eco-Niwas Samhita's openable ratio for the zone, applied to each room (it is set for the whole dwelling; code, where notified). In hot-dry zones it is IGBC's credit level, 12%.

• High:

  • warm-humid and composite: NBC Part 8 §5.4.3.1, where inlets and outlets totalling 20–30% of the floor bring about 30% of the outdoor wind indoors;

  • hot-dry and cold: our measure (provisional), since large openings there let in heat or cold.

• Shown with it: the dwelling's openable ratio against Eco-Niwas Samhita.

AR-1 on the method page

AR-2 Fresh air. Each habitable room. Its points are the mean of the usual-wind test and the still-air test.

Kinds and sources.

• Usual wind: the purge rate of UK Approved Document F (4 an hour); IGBC's ventilation-simulation route (6 to qualify, 8–10 for a credit). These are recommendations.

• Still air: NBC Part 8 §5.2.2.1's bands (bedroom 2–4, living 3–6), as code guidance.

AR-2 on the method page

AR-3 Cross-ventilation. The home.

• The quantity: the share of regularly occupied floor (living, dining, bedrooms, kitchen, study) in rooms that cross-ventilate.

• A room cross-ventilates when it has openable outdoor openings on two different façade orientations (opposite or adjacent, never the same wall), or a doorless opening to a room that does. Bedrooms are judged with their doors shut. The engine must also find at least 2 air changes an hour flowing through the room in the usual wind, so a token second opening doesn't count.

Kind and source. Standard: Eco-Niwas Samhita 2024's graded levels. IGBC's rule for doorless openings is used.

AR-3 on the method page

AR-4 Wet rooms. Each bath, WC and the kitchen.

• Gate fails when:

  • a bath or WC has no window or ventilator of at least 0.3 m², with no side under 0.3 m, to open air or to a shaft. The shaft's required size grows with the building's height (MBBL Table 4.5: 1.2 m² up to 10 m, up to 9.0 m² above 30 m); above 30 m it needs mechanical ventilation as well;

  • the kitchen has no opening to external air or an open verandah (DL-1's kitchen ratio);

  • a kitchen or bath has no exhaust opening (Eco-Niwas Samhita 2024).

  City rules replace the size (Annex B). Kind: model code, city rule, code.

Basis. IS 3362; NBC Part 8's 6–10. An opening on an external façade rather than a shaft is shown as a fact.

AR-4 on the method page

AR-5 Smells ↓.

• The conditions: the usual wind, windows open by their share, doors open by day, the kitchen exhaust off (4.2).

• The points: half from the first test, a quarter from each of the others.

• Where the home cooks: its kitchen, or the kitchen of an open plan ("LIVING + DINING + KITCHEN"), where the smell is released; the living room an open kitchen is in is one the smell reaches.

Kind and source. Our measure, fixed on the reference set (Annex A, 7 October 2026). The set confirmed the first and third tests' provisional anchors. The second's were an hour, from the Bengaluru study's critical window after cooking; with the windows open in the usual wind, half the set's living spaces clear within 4 minutes, and the minimum is where the shares match: about a fifth take longer than 8. A ducted chimney is offered as an improvement, with its effect.

AR-5 on the method page

AR-6 A breeze you feel. The living space and each bedroom.

• The quantity: the air speed where people are (Part 1 §5.3: over the bed in a bedroom, over the seats in the living space) in the usual wind, windows open, with no fans.

• Shown beside it: the cooling effect in K.

• Chajjas push the breeze upward (NBC Part 8 §5.4.3(12)); they are not yet modelled in the airflow (edition 1.1), so a chajja tried as an improvement leaves the breeze as it was.

Kinds and sources. NBC Part 8 Table 9's desirable air speeds (0.24–0.53 m/s at 30 °C and 70–80% RH) and ASHRAE 55 (1.8 K at 0.9 m/s) are the standards. Field studies in Hyderabad and Chennai flats support the levels.

AR-6 on the method page

AR-7 A WC opening into the kitchen (gate).

• Fails when any room with a WC in it has a door, window or other opening directly into a kitchen or cooking space (NBC 2016 Part 3 §12.4.4; MBBL §4.5; Haryana 7.4(4)).

• A check, not a failure, when it opens into an open-plan living and dining space that contains the cooking counter.

• A WC window onto a shaft that the kitchen's window also faces belongs to AR-5.

AR-7 on the method page

LY-1 Privacy at the entrance. Seen from just inside the main door, and from the sofa. The levels are discrete.

Kind: our measure, after Indian conventions (the foyer, the shoe rack).

LY-1 on the method page

LY-2 Daily routes. The routes are door → kitchen, each bedroom → its nearest bath, kitchen → dining, and door → living. The levels are discrete, with lengths on a mirrored log curve between them.

Kind: the walk ratings (Part 1 §5.3) and our measure.

On a drawing. Each route is walked from where a person stands in its room, on the floor joined to the way in (a room's middle is often under its bed or its table, and a corner its furniture closes off is no way in or out); kitchen → dining ends at the dining table, where one is drawn or placed, and a route to a WC compartment at the bathroom it opens into. A route the drawing's floor doesn't join up (something drawn across a doorway, an opening narrower than a person passes sideways) isn't scored, and the report asks about it.

LY-2 on the method page

LY-3 Zoning. A bedroom reached only through another bedroom is a cap (§8). The levels are discrete.

Kind: convention (the Indian common toilet and service room).

LY-3 on the method page

LY-4 Doors. Every door. The levels are discrete.

Kind: our measure.

LY-4 on the method page

LY-5 How the kitchen works. The kitchen. In an Indian galley kitchen the aisle matters more than the triangle. The levels are discrete.

Kind: recommendation (NKBA; UK Approved Document M4(2)'s 1,200 mm) and convention.

LY-5 on the method page

LY-6 Noise by layout (facts, not scored). From NBC 2016 Part 8 Sec 4 §5.2's layout guidance, never called "quiet" or "noisy":

• a bedroom sharing a wall with a lift, a stair core, a refuse chute or the next flat's living room;

• a WC cistern or soil duct on a bedroom wall;

• a kitchen or WC above a bedroom, where floors stack;

• a bedroom door opening onto the living room.

LY-6 on the method page

SF-1 Widths and doors.

Kind: city rule (UBBL, UDCPR, Haryana) and standard (NBC Annex B; the Harmonised Guidelines).

On a drawing. A width within the drawing's precision of a value (13 mm, across a door's jambs or a passage's walls) is taken as meeting it, as SF-3's stairs are.

SF-1 on the method page

SF-2 Step-free. Most Indian plans don't print floor levels, and sunken toilets (25–50 mm) and raised balcony sills are the norm. Where levels are unknown, the check isn't scored, and the report asks "Is the bathroom floor stepped down?".

Kind: standard (NBC Annex B; the Harmonised Guidelines).

The owner's answer. A bathroom stepped down scores the minimum; a level one, the medium. The rest of the flat is taken as level, as a flat's floors are but for its baths and balconies; the high level asks for the balconies' sills, which a drawing doesn't show.

SF-2 on the method page

SF-3 Stairs. Applies to stairs inside a house or duplex. A block's common stairs are building facts.

• Gate fails when (NBC 2016 Part 3 §12.18; MBBL §4.17; or the city's rule):

  • the width is under 1.0 m (0.75 m in a two-storey row house);

  • the tread is under 250 mm;

  • the riser is over 190 mm;

  • a flight has more than 12 risers (UDCPR and UBBL allow 15);

  • headroom is under 2.2 m.

Kind: model code or city rule (gate); standard (NBC Annex B) for the higher levels.

On a drawing.

• A stair is its flights and landings together: stair outlines within 300 mm of one another. A few steps (fewer than 8 risers drawn: a porch's, a sunk floor's) aren't a stair, nor is anything narrower than 600 mm (a ladder, or a sliver of a stair's reading).

• The width and the going are measured. One within the drawing's precision of the code's value (13 mm across the stair, 6.5 mm in its treads' spacing, measured over all of them) is taken as meeting it.

• The riser is the floor-to-floor height (printed, or the usual ceiling and 300 mm of floor) over the risers drawn. A plan cuts a stair on its way up and draws the rest on the floor above, so a riser steeper than the code allows is asked about (is the whole stair drawn, and what is the floor-to-floor height?), never failed. The flight's count of risers is the drawing's.

• Headroom, handrails, landings' depth and nosings aren't on a drawing: the high level isn't given on the drawing alone.

SF-3 on the method page

SF-5 Falls. It needs the floor; a ground floor isn't scored. With the 900 mm sill assumed, windows from the 11th floor up become "check: a 1.1 m guard is expected", never a failure on the assumption alone.

• Gate fails when balcony, terrace and verandah guards are under 1.0 m (NBC Part 3 §12.11; MBBL §4.12), or the city's height (Mumbai 1.5 m; Gujarat 1.15 m with gaps of 0.15 m at most). It is assumed met unless a lower height is printed.

Kind: standard (NBC 2016 Part 6 Sec 8 Table 35; IS 4912 with Amendment 1).

On a drawing. A printed sill under the height its floor asks fails the minimum; an assumed one is asked about, and the check isn't scored until it is answered. The guards' heights aren't read from a drawing in edition 1.0: the gate is taken as met, and a home with a balcony is held at the minimum until its guards are known. The high level is a home with no sill under 900 mm and no balcony.

SF-5 on the method page

SF-6 Gas and the kitchen (gate and facts).

• Gate fails when:

  • the kitchen has no opening to external air or an open verandah (also a cap, §8);

  • the kitchen is in a basement;

  • the hob stands under, or at the foot of, a stair (NBC 2016 Part 3 §12.3.3(d); Part 4 §4.7.9, §6.1.2(b)).

• Facts:

  • whether the kitchen's exhaust can reach an outside wall directly;

  • where an LPG cylinder can stand in a ventilated spot at floor level (Part 9 Sec 4; IS 6044-1);

  • for piped gas, the meter's vent.