NEPAL NATIONAL BUILDING CODE
NBC 208 : 2003

SANITARY AND PLUMBING DESIGNREQUIREMENTS

Government of Nepal

Ministry of Physical Planning and Works
Department of Urban Development and Building Construction
Babar Mahal, Kathmandu, NEPAL

Reprinted : 2064

NBC108V2.RV9

7 December 1993

NEPAL NATIONAL BUILDING CODE
NBC 208 : 2003

SANITARY AND PLUMBING DESIGNREQUIREMENTS
This publication represents a standard of good practice and therefore
takes the form of recommendations. Compliance with it does not confer
immunity from relevant legal requirements, including bylaws
tTsflng >L % sf] ;/sf/ -dlGqkl/ifb\_ sf] ldlt @)^).$.!@ sf] lg0f{ofg';f/ :jLs[tGovernment of Nepal

Ministry of Physical Planning and Works
Department of Urban Development and Building Construction
Babar Mahal, Kathmandu, NEPAL

Reprinted : 2064

NBC108V2.RV9

7 December 1993

i

PrefaceThis code has been prepared having considered the provisions of Water Resources Act
2049. It contains general guidelines for water supply installations, sewage/ waste waterdisposal installations and rainwater disposal installations in buildings. The objectives areto make adequate water supply available (without any interruption ) for the purpose ofdrinking, bathing, flushing toilets and any domestic use including fire fighting; toprovide a system of self cleansing conditions for conveyance of foul waste water and forthe removal of such waste water/sewage to a sewer or outer outlet without risk of
nuisance and hazard to health and to dispose rainwater in buildings. Due to the limited
technical manpower in the country's construction industry, the code has been simplified
for the ease of use and implementation. It is hoped that with the development of the
manpower and modernization of construction processess, it will be possible to release
more sophisticated set of sanitary installation guidelines in future.

Principal input to this code came from :Mr. Purna P. Kadariya , DG, DUDBC
Mr. Kishore Thapa, DDG, DUDBC
Mr. Mani Ratna Tuladhar, Sr. Div. Engineer, DUDBC
Mr. Gyanesh Bajracharya, Sr. Sanitary Engineer, Water Supply
and Sewerage Co-operation, Tripureswor
Mr. R. R. Pandey, Dept. of Water Supply and Sewerage, Panipokhari
Mr. Sunil Karmacharya, Sanitary Overseer, DUDBC
Mr. Amrit Man Tuladhar, Engineer, DUDBC

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TABLE OF CONTENT
S.NO.

Particulars

Page No.

1A) Water Supply

12

1. Water Supply Requirements for Building

13

2. Water Storage

24

2.1. General Water Storage Tanks25

2.2. Underground Storage

36

2.3. Over Head Storage

37

3. Distribution System and Pipe Work48Fire Fighting Provision

69B) Waste Water Disposal

14

10

1. Collection System

1411

2. Disposal of Sewage/Waste Water and Pipe Work

2712C) Rain Water Disposal

32

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1This code is divided into three main sectionsA) Water SupplyB) Waste Water DisposalC) Rain Water Disposal

A)

Water Supply:
Scope: This section gives guidelines for water supply provisions in different types ofbuildings. The main objectives of such guidelines are to make adequate water supply
available (without any interruption) for the purpose of drinking, bathing, washing,flushing toilets and any other domestic use including fire fighting).

1. Water Supply Requirements for Buildings :The water supply requirement for buildings (excluding fire fighting need ) should bebased on following:
Table- A 1
S.N

Type of Buildings

1
2
3

Apartment Buildings
Auditorium (per seat)
Hospitals (including laundry) per beda) Number of beds <100b) Number of beds >100
Cold Storage
Buildings Higher than 4-Storey
Commercial & Industrial)

45

Minimum requirement per head per day
100 lit
15 lit
340 lit
450 lit
45 lit45 litRecommended
6
7
8
9
10
11

12
13

14
15
16

NBC108V2.RV9Residences
OfficeHostels (including quarters for nurses etc.)
Hotels (per bed)
Restaurants (per seat)
Schools and collegesa)Day schoolsb)
Boarding Schools

100 lit
45 lit
100 lit
100 lit
50 litCinemas, Theatre Halls, Concert hall (per seat)
Factories

15 lita)b)

45 lit30 litWith bathing facilities
Without bathing facilities

Terminal Stations (Bus and Railways)
Airports (Internations )Airports (Domestic )15 lit
100 lit

15 lit70 lit20 lit7 December 1993

2

2

Water Storage :In case water is available in the city mains at sufficient pressure and quantity
throughout the day to rise upto the highest floor, no storage will be necessary at all andall fixtures could be supplied directly But it is usually not so. Storage of water within apremises is thus necessary,a) to tide over period of intermittent supplyb) to provide for interruption of the supply from the main itself, caused by various
reasons like repairs in the system, failure of power etc.
c) to meet the peak flow requirements within a building if the city mains do not meetit.
d) to maintain a storage for fire fighting requirement of the building.
The storage capacity required for a building depends on hours of public supply,
pressure in the mains, demand pattern in the building and the fire fighting need. Water
storage is usually done in underground tank or tanks at the ground level or overheadtanks.
2.1 General Water Storage Tanks :2.1.1 Water tanks should be strong enough to take the vertical load and the naturalpressure of water when full, and also the negative pressure within the tanks
when the water in drawn out.
2.1.2 Water tank should be water tight and constructed with non-corrosive, nontoxic materials and should have smooth surface inside.
2.1.3 Water tanks must have at least one number of manhole of size
450mmx450mm for access and repairs, together with a locking arrangement
and corrosion resistant steps, catch-rings or ladders to reach the bottom forcleaning purpose and maintenance.
2.1.4 Water tanks should have a vent pipe for ventilation as well as for prevention ofnegative pressure when water is drawn out from the tanks.
2.1.5 Water tanks should have an over flow pipe which also acts as a 'warning pipe'
to indicate over flow of water from the already full tank.
2.1.6 Water tanks should have a scour pipe/washout pipe with a plug at the lowest
point so that they can be emptied easily at the time of need.
2.1.7 Under no circumstances should any overflow or scour pipe/wash-out pipe
from a water tank be connected directly to any drain, gully trap or sewer toavoid possible contaminations. These connections should be discharged overproperly designed drains with a minimum air gap of 75-100 mm.
2.1.8 The overflow pipes or vent shafts if provided shall have a wire gauge cover of
1.5 mm mesh properly screwed tight to the opening to prevent the entry ofmosquitoes, vermin, insects etc.
2.1.9 The top of the tank shall be so leveled as to prevent any stagnation of water on
top.

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2.2 Underground Storage.
Underground storage tanks or tanks at ground level are necessary to collect water fromthe city water mains during hours of supply if it does not reach the point of supply or
the overhead tanks. It is then pumped to overhead tank for use within the building.
2.2.1 The capacity of an underground storage tank or tank on the surface should be
the net difference between the peak demand and the flow during the hours of
supply. Provision should be made for supply interruption due to various
reasons like main repair work or power failure etc.
2.2.2 For normal buildings with a reliable public supply, underground storage
capacity is taken at 12-24 hours of the average daily water demand.
2.2.3 Underground tanks should be built watertight and should not leak when empty
or full. There should be no possibility of any ingress of subsoil water.
2.2.4 Underground tanks should not be located in low-lying areas which may
permit entry of surface water from the top. The manhole cover shall be raised
30 cm above the highest flood level in the locality or ground level whicheveris higher.
2.2.5 The underground tanks should not be located near sewers, septic tanks, soak
pits, oil tanks or under car-parking areas to avoid all kind of contamination
due to seepage or leakage.The minimum clearance distance as 5.0 meter.
2.2.6 The overflow water level in the underground tanks should be above thesurrounding ground level to prevent the surface water from entering the tanks
through overflows.
2.2.7 The top slab, the walls and the base should all be designed to take the possible
load of traffic, natural pressure of soil from sides and bulging pressure fromthe base when empty, and the water pressure when full.

2.3 Overhead Storage.
2.3.1 In areas of chronic shortage or intermittent supply, overhead storage is also
required for domestic use and flushing purposes and to ensure constant
supply. The minimum overhead storage shall be in accordance to ;Table-A 2
Type of Building
1. Apartments (Domestic use)
2. Auditoriums
3. Hospitals
4. Cold Storage
5. Buildings more than 4 Stories (Commercial &Industrial)
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Unit
Residence
WC
UrinalWC
UrinalWC/Urinal
Residental

Unit storage
360 lit
500lit
150 lit
300 lit
75 lit300
360 lit7 December 1993

4
Recommendedi) Dwelling Unitsii) Hostelsiii) Hotelsiv) Commercial Building without canteenv) Commercial Building with canteensvi) Restaurantsvii) Day Schoolsviii) Boarding Schoolsix) Nurse’s Hostels and Medical quarter
Flushing Purposei) For tenants having common convenienceii) For residential premises other than (i)iii) For factories and workshopsiv) For cinema halls, public
Assembly halls etc.

Resident
,,
,,
Head
Head
Meal
Head
Resident
Resident

360 lit360 lit
135 lit
50 lit70lit
12lit
12 lit90 lit135 lit

WC
WC
Additional WC in thesame flat
WC
Urinal seatWCurinal seat

500 lit
270 lit180 lit
500 lit180 lit
500 lit
350lit2.3.2 If placed on terraces the tank bottom should be clear off the terrace level toavoid overloading the structural slab, leakages and to make easy for future
maintenance work. In tall buildings, security rail or wall on the top slab must
be provided for safety of maintenance staff.
2.3.3 Lightning arresters must be provided as per the recommended practice on topof tanks in high rise buildings.
2.3.4 Tanks fabricated from galvanized or mild steel sheets should be protectedagainst corrosion from water by painting both on the inside and outside withsuitable paints.

3

Distribution System and Pipe Work:
The piping systems to distribute the water within the building through the different
fixtures must be designed to provide uniform flows and pressure in all areas and floors
within certain practical limitations.

3.1 The sizes of pipes depend ona) the maximum rate of discharge required;b) the length of pipes;c) the head loss due to friction in that length andd) the roughness of the interior surface of the pipe.
Several empirical formulae are used to determine the size of pipe. The Hazen Williams
formula and charts based on the same may be used without any risk of inaccuracy inview of the fact that the pipes normally to be used for water supply are of smaller sizes.

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As per Hazen William's formulaV= 0.849 CR 0.63 S 0.54
Where V= velocity of water in m/sec
C= Coefficient of roughness of the pipe
R= hydraulic means depth / radius= D/4 of circular pipes flowing D= diameter
S= Slope of hydraulic gradient (pressure loss /length of pipe)
And Q = Discharge in cu.m./second = VxA
A = cross-sectional area of pipe in square m. = π d2/4
3.2

In dead systems, Cobbrok-white equation is more justified
Plumbing shall be designed and adjusted to use minimum quantity of water inconsistent with performance and cleaning. There should be at least a residual
head of 0.018 N/mm2 (1.81kg./cm2) at the consumer's tap.

3.3

All premises intended for human habitation/occupancy or use shall be
provided with supply of pure and wholesome water without any hazard of
backflow or back-siphoning.

3.4

All pipe work shall be designed, laid or fixed and maintained as to remaincompletely water tight, thereby avoiding wastage, damage to property and therisk of any contamination.

3.5

Change in diameter and in direction shall preferably be gradual rather thanabrupt to avoid undue loss of head. No bend or curve in piping shall be madewhich is likely to materially diminish or alter the cross-section.

3.6

The cover for the water main shall be at least 1.20 M. under National
Highways,other roads 1.0m and 0.90M in the case of footpaths. This covershall be measured from the top of the pipe to the surface of the ground.

3.7

The service pipe shall pass into or beneath the buildings at a depth of not lessthat 75 cm below the outside ground level.

3.8

The underground water service pipes and building sewer or drain shall be
kept at a sufficient distances apart so as to prevent contamination of water.
Water service pipes shall not be run or laid in the same trench as the drainage
pipe. Where this is unavoidable, the following conditions shall be fulfilled;a)the bottom of water service pipe at all points, shall be at least 30cm
above the top of the sewer line at the highest point.
b)
the number of joints in the water pipe shall be kept to a minimum.

3.9

Distribution pipes shall be made of any of the following materials likegalvanized iron (GI Pipe) of medium class only.

3.10

Testing of the distribution system & fittings:
After the pipe work is completed and the fittings are all installed, it shall becarefully charged with water so that all air is expelled from the system. The
entire system shall there be hydraulically tested to a pressure of 0.5 N /mm2
(5kgf /cm2) or twice the working pressure whichever in greater for a period ofat least half an hour after steady state is reached. The entire installation shallbe inspected visually for leakages, and sweating. All defects found shall berectified by removing and remarking the particular section. Caulking of
threads, hammering and welding of leak joint shall not be allowed.

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3.11

Disinfection of the distribution system and storage tanks :The storage tanks and pipes shall first be filled with water and thoroughly
flushed out. The storage tank shall be filled with water again and a disinfecting
chemical containing chlorine added gradually while the tanks are being filled
to ensure thorough mixing.

4. Fire Fighting Provision.
Water is the most common fire extinguishing agent because it has the ideal properties
for extinguishing the most common fires, it is available in plenty and is very cheap.
4.1

Shortage of water and intermittent public water supply has led to the need tohave captive water storage tanks exclusively for fire fighting operation.

4.2

For water supply for wet riser system a storage tank should be available witharrangement for replenishment of water supply through public supply mains orby an alternate source of supply at the rate of about 1000 ltr/minute. Where
this is not possible the capacity of the static tank will have to be increased. The
storage should last for 90-120 minutes at a nominal pumping rate of 2400
ltr/minute. Storage available from swimming pools, ornamental pools are
considered as supplementary and are not acceptable as replacement for fire
storage tank.

4.3

Some categories of public buildings like Hotels, Boarding Houses,
Restaurants, Schools and buildings used for educational and training purposes,
Hospitals and Nursing Homes, Buildings for devotional congregations such as
Temples, Mosques, Churches etc., Public Halls, Museums, Public libraries,
Record rooms. Commercial offices, Banks, Government offices, Club houses,
Retail shops, Emporia & Stores, Theatres, Cinemas and places ofentertainment etc., which have generally low fire loads but higher personnel
hazards, require to be provided with portables appliances where the total areaof the floors exceeds 1000 sq. meters so that the whole of the floor isprotected. It should be insured that no part of the floor is more than 6 metresfrom the hose nozzle when the hose reel in fully extended. There should beconstant supply of water not less than 23 litres per minute through a nozzle of
not less than 6.5 mm size for half an hour when upto 3 hose reels are operated.
The hose shall be of reinforced rubber lining having a bore of 12/20-mm
diameter. This water supply should be independent of domestic supply
connections. A pressure of at least 3 kg/cm2 should be available at the highest
hydrant outlet.

4.4

Hydrant System :4.4.1

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Dry Risers, so called because they contain no water in the pipes, areinstalled within a building with a landing valve in the staircase lobby.
They terminate at the street level in the form of a fire brigade
connection. The connection enables the five brigades to connect thefire brigade connection either to street fire hydrant directly or to a firebrigade pumper and charge the dry riser with water.

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4.4.2

Wet risers are fixed pipe installations within a building andpermanently charged with water under pressure from available water
source.

4.4.3

Hydrant station is provided to serve an area of 926- 1000 sq.m. It isadvisable of place it in fire-protected areas near each fire escapestaircase or lobby so that it can be located easily.
Each hydrant station comprises,a)a first aid, hose reel with 20mm diameter rubber hoseabout 30-36 m long with a 63 mm diameter landing valve.

b)

two 15m x 63 mm. Reinforced rubber lined hoses withcouplings and a branch pipe with a 12 mm nozzle for use
by fire service personnel.

4.4.4

Fire pumps : To enable the water to reach the topmost floor, it isnecessary to provide pumping sets connected to the fire tank or city
public supply mains when permitted. The pump delivery is connectedto the piping system of the hydrant or sprinkler system. Pumps areelectrically driven and each system provided with a stand by pump.
Pumps for fire hydrant systems and sprinkler system are separated andindependent of each other, though common pumps having appropriate
discharging capacity are used in many parts of the world.

4.4.5

Standby pumps : Where power supply in not dependable, standby
pumps with diesel engine are provided to conduct fire fighting
operations.

4.4.6

The typical fire-fighting installation requirement should be as given in
the table below.

Table- A 3
SnRequirement
Type of building occupancy

1

Residential buildinga)lodging or room
houses dormitories& hotels.
(Noprovision is neededfordormitories
housing less than 25
person .
*upto 15 mtr. In height.
* above 15 m. height but
not exceeding 24 m.

NBC108V2.RV9

Type
installation

Water supplyof Undergro
und statictank

Terracetank

Pump capacity
At the terrace
Near
level
underground
tank

Nil

50000 ltr.

Nil

Nil

Nil

One wet riser
cum down comer
per 1000 m.sq.
floor area. The
riser shall be fully
automaticinoperation.

100000ltr.

Nil

2400 lit/min atpressure not lessthan
0.3
N/mm.sq.
(3kg./cm.sq) atthe
topmosthydrant

Nil

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2

3

4

One or two family private
dwelling & apartment houses(flat)
i)
Upto 15 m. heightii)
Above 15 m.
height but notexceeding 24 m.

Nil
One wet riser
cum down comerwith a provisionof fire service
inlet
at
only
ground level per1000 m.sq. floor
area.

Nil
50000Ltr.

Nil
Nil

Nil
One wet riser
cum down comer
per 1000-m. sq.
floor area.

50000 ltr
50000 ltr

Nil
Nil

Nil
2400 lit/min atpressure not lessthan
0.3
N/mm.sq.
(3kg./cm.sq) atthe
topmosthydrant

Nil
Nil

Upto 15 m. height

One wet riser
com down comer
per 1000 m. sq.
floor area. The
riser shall be fully
automaticinoperation.

100000 ltr

Nil.

1800 ltr/minuteat pressure notless than 0.3
N/mm.sq.
(3kg./cm.sq.) atthetopmosthydrant.

Nil.

ii) Above 15 m. in height but
not exceeding 24 m.

One wet riser
com down comer
per 100 m. sq.
floor area. The
riser shall be fully
automaticinoperation.

100000 ltr

NIL

2400 ltr/minuteat pressure notless than 0.3
N/mm.sq.
(3kg./cm.sq.) atthetoppesthydrant.

Nil

Educational & Institutionalbuildingi)
Up to 15 m. heightii)
Above 15 m. inheight but notexceeding 24 m.

Storage
Buildings.
i)&2400 lit/min atpressure not lessthan
0.3
N/mm.sq.
(3kg./cm.sq) atthe
topmosthydrant

Nil
Nil

Hazardous.

Note : a) A minimum of two hydrants shall be provided in the courtyard.
b) A wet riser cum down comer is an arrangement for fire fighting with in a buildingby means of vertical riser mains not less than 100 mm. Dai ( Internal dia) withhydrant outlet on each floor and landing connected to overhead tank with proper non
return valve.
c) The terrace tank & pump need not be provided if automatic pump at ground levelcan be maintained satisfactorily.
d) The size of riser shall be as under

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9i) Apartment buildings upto 45 m. height---100 mm. with single two hydrant
outlets and hose reel on each floor.
ii) Non apartment buildings up to 24 m. height---100 mm. with single hydrant
outlet and hose reel on each floor.

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Direct O.H. Tank Supply
Illustration A1

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Supply Through Underground Tank
Illustration A2

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Dry Riser/Fire Fighting Installation
Illustration A3

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Wet Riser/Fire Fighting Installation
Illustration A4

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B)

Waste Water Disposal :Scope: This section covers general guidelines for different sanitation provisions in buildings.
The aim shall be to provide a system of self cleansing conditions for conveyance of foul
waste and surface water and for the removal of such wastes to a sewer or a outer outlet
without risk of nuisance and hazard to health .

1Collection Systems : The system to be adopted will depend on the type and planningof the building in which it is to be installed and will be one of the following :1.1

Two Pipe System – A discharge pipe system comprising two independent
discharge pipes one of which conveys soil excreta directly to the drain, the otherconveying waste water to the drain through a trapped gully. The system may also
require ventilating pipes.

1.2

One Pipe System – The plumbing system in which the waste connection fromsinks, baths and wash basins and soil pipe branches are all collected into one main
pipe connected directly to the drainage system. Gully traps and waste pipe arecompletely dispensed with but all the traps of water closets, basins etc. arecompletely ventilated to preserve the water seal.

1.2.1

1.3

Single Stack System – Single stack system eliminates the anti-siphonage
pipe in the one pipe system. To be effective single stack system must be
used in buildings having normal domestic flow. It is not suitable inbuilding where short term high flows are generated in buildings. eg:
schools, workshops, sports building. Where used, the toilets fixtures
must be grouped together around a shaft to provide short and easy
connections. As far as possible the fixture layout should be repetetive
vertically. A long radius bend should be provided at the foot of eachstack and the ground floor connection made directly to the manhole.

All fixtures should be provided with a water seal trap to prevent foul gases, insects
and vermin of the main sewer from entering the building. The depth of water seal
traps for different fixtures shall be as follows :Water closet -50mm.
Floor trap - 50mm

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1.4

All pipes are to be adequately sized and sloped for effective disposal of waste.
Branches and stacks which receive discharge from WC pan should not be less than
100mm except where the outlet from siphonic WC is 80mm in which case a branchpipe of 80mm may be used; for outlet of the floor trap 75mm dia may be used.

1.5

All piping system is to be fully ventilated to allow for the removal of foul gases.
Access to the atmosphere also maintains an equilibrium in the system, thereby
avoiding negative pressure and retardation of flow in the pipes.

1.6

No connections and cross connections are to be made between the water supplies
and the drainage system in order to avoid all possibilities of back flow andcontamination.

1.7

Vertical stacks must continue to roof level as vent pipes without diminishing in
diameter.

1.8

Bends and junctions should be smooth and rounded with access doors or clean out
plugs wherever necessary.

1.9

Pipes used must be strong enough to withstand the internal pressure of the liquid
carried and the external pressures to which it may be subjected particularly ifburied.

1.10 Toilet layouts must be planned so that they are grouped together in an orderly
manner, then allowing easy and direct connection from fixture to vertical stacks or
manholes.
1.11 There should be at least one water tap and arrangement for drainage in the vicinityof each water closet or group of water closets in all buildings.
1.12 Each family dwelling unit on premises or any other structure for human occupancy
abutting on a sewer or with a private sewage disposal system shall have at least one
water closet and one kitchen type sink. It is desirable that a bath or shower should
be installed to meet the basic requirement of sanitation and personal hygiene.
1.13 Where only one water closet is provided in a dwelling, the bath and water closet
shall be separately accommodated.
1.14 Dwellings without individual conviniences shall have the following fitments.
a)
b)
c)

NBC108V2.RV9

One water tap with drainage arrangement in each tenement;
One water closet and one bath for every two tenements;
Water taps in common bathrooms and common water closets.

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1.15 The requirements for fitments for drainage and sanitation in the case of buildings
other than residences shall be in accordance with Table 1 to 13
1.16 A soil pipe conveying to a drain any solid or liquid, shall be circular and shall havea minimum diameter of 100mm.

TABLE B1 - OFFICE BUILDINGS( Including Buildings higher than 4 Storey)
S.No

FITMENTS

FOR MALE PERSONNELFOR FEMALEPERSONNEL

1
I)

2
Water-closets

3
1 for every 25 persons of part thereof

4
1 for every 15 persons ofpart thereofii)

Ablution taps

1 in each water-closet,

1 in each water-closet

1 water tap with draining arrangement shall be provided for every 50 person or part thereofin the vicinity of water-closet and urinals
iii)

Urinals

Nil, up to 6 persons
1 for 7-20 persons
2 for 21-45 persons
3 for 46-70 persons
4 for 71-100 persons
From 101 to 200 persons add at theRate of 3 percent
From over 200 persons add at the rate of 2.5 percent.

iv)

Wash basins

1 for every 25 persons of part thereofv)

Drinking water

1 for every 100 persons with a minimum of one on each floor

fountainsvi)

Cleaner's sinks

1 per floor, Min, preferably in or adjacent to sanitary rooms

This may include adequate number of water-closets of European style, where desired.

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Table B2 - Factories
S.No

FITMENTS

FOR MALE PERSONNELFOR FEMALEPERSONNEL

1

2

i)

Water-closets

3

4

1 for 1-15 persons

1 for 1-12 persons

2 for 21-45 persons

2 for 13-25 persons

3 for 36-65 persons

3 for 26-40 persons

4 for 66-100 persons

4 for 41-57 persons
5 for 58-77 persons
6 for 78-100 persons

ii)

Ablution

From 101 to 200 persons, add at the rate of 3

From 101 to 200 persons,

percent

add at the rate of 5 percent

For over 200 persons, add at the rate of 2.5

For over 200 persons, add

percent

at the rate of 4 percent

1 in each water-closet

1 in each water-closet

1 water tap with draining arrangements shall be
provided for every 50 persons or part thereof in
the vicinity of water-closets and urinals
iii)

Urinals

Nil, up to 6 persons
1 for 7-20 persons
2 for 21-45 persons
3 for 46-70 persons
4 for 71-100 persons
From 101 to 200 persons add at theRate of 3 percent
For over 200 persons add at the rate of 2.5
percent.

iv)

Washing taps draining

1 for every 25 persons or part thereofarrangements withv)

Drinking water fountains

1 for every 100 persons with a minimum of one on each floorvi)

Bath (preferably showers)

As required for particular trades of occupations

Note 1 for many trades of a dirty or dangerous character, more extensive provisions are required by law.
Note 2 Crèches, where provided, shall be fitted with water-closets (one for 10 persons or part thereof) and wash basins (onefor 15 persons or part thereof) and drinking water tap with draining arrangements (one for every 50 persons or part thereof).

•

Some of the water-closets may be of European style, if desired.

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TABLE B 3 – AUDITORIUMS, CINEMAS, CONCERT HALLS AND THEATRES
S.No FITMENTS FOR MALE PUBLIC FOR FEMALE
PUBLIC
1
2
3
4

FOR MALE
STAFF
5

I)

Water-losetsii)

Ablution taps 1 in each water-closet
1 in each water-closet 2 in each water-closet 3 in each water-closet
1 water tap with draining arrangements shall be provlded for every 50 persons or part thereof in
the vicinity of water-closets and urinals.

iii)

Urinalsiv)

Wash basinsv)

Drinking water
fountain

1 per 100 persons up to 3 per 100 persons up to 1 for 1-15 persons
400 personsfor over 400 200 persons for over 2 for 16.-35 persons
persons ad at the rate of 1 200 persons add at therate of 2 per 100
per 250 persons or part
thereofpersons or part thereof

FOR FEMALE
STAFF
6

1 for 25 persons or part
thereof

1 for 1-12 persons
2 for 13-25 persons

Nil, up to 6 persons

1 for 7-20 persons
2 for 21-45 persons
1 for every 200 persons or 1 for every 200
1 for 1-15 persons
part thereof
persons or part thereof 2 for 16-35 persons

1 for 1-12 persons, 2 for
13-25 persons

1 per 100 persons or part thereof

Note 1 Some of the water-closets may be of European styles, if desired.
Note 2 It may be assumed that two-third of the number are males and one-third females.

NBC108V2.RV9

7 December 1993

19

TABLE B 4 - ART GALLERIES, LIBARIES AND MUSEUMS
S.No
i)

ii)

iii)

FITMENTS

FOR MALE PUBLICFOR FEMALE
PUBLICFOR MALE STAFF

I) Water-closets 1 per 200 persons up to 1 per 100 persons up 1 for 1-15 persons
400 persons
to 200 persons
2 for 16.35 persons

Ablution taps

Urinalsiv) Wash basinsv)

Cleaner's sinks
Drinking watervi) fountain

FOR FEMALE
STAFF
1 for 1-12 persons 2
for 13-25 persons

For over 400 persons
add at the rate of 1 per
250 persons or part
thereofFor over 200 persons,add at the rate of 1 per
159 persons or part
thereof1 in each water-closet

1 in each water-closet 1 in each water-closet 1 in each water-closet

1 water tap withdraining arrangements shall be provided for every 50 persons or part thereofin the vicinity of water-losets and urinals
Nil, up to 6 persons
1 per 50 persons
1 for 7-20 persons
2 for 21-45 persons
1 for 1-15 persons
1 for 1-12 persons
1 for every 200 persons 2 for every 200
or part thereof. For over persons or part thereof.2 for 16-35 persons 2 for 13-25 persons
200 persons, add at the For over 200 persons,rate of 1 per 250 persons add at the rate of 1 peror part thereof.
150 persons or part
thereof.
1 per floor, Min
1 per 100 persons or part thereof

Note : 1 some of the water-closets may be of European style, if desired.
Note : 2 It may be assumed that two-third of the number are males and one-third females.

TABLE B 5 - HOSPITAL INDOOR PATIENT WARDS
S.No.
Fitments
12i) i) Water-closetsii) Ablution taps

For Males and Females
3
1 for every 8 beds or part thereof
1 in each water-closet plus one water tap with draining arrangements in the vicinity ofwater-closets and urinals for every 50 beds or part thereof.

iii) Wash basins
2 up to 30 beds; add 1 for every additional 30 beds or part thereofiv) Baths
1 bath with shower for every 8 beds or part thereofv) Bedpan washing sinks 1 for each wardvi) Cleaner's sinks
1 for each wardvii) Kitchen sinks and dish 1 for each ward
washers (where kitchen
is provided)
Note : 1 Some of the water-closets may be of European style, if desired.
Note : Additional and special fitments for specific needs of hospitals may be provided.

NBC108V2.RV9

7 December 1993

20

TABLE B 6 - HOSPITALS, OUTDOOR PATIENTS WARDS
S.No

FITMENTS

12i) Water-closetsii) Ablution taps

FOR MALE

FOR FEMALE

3
4
1 for every 100 persons or part 2 for every 100 persons or part thereof
thereof1 in each water-closet
2 in each water-closet
1 water tap with draining arrangements shall be provided for every 50 persons orpart thereof in the vicinity of water-closets and urinalsiii) Urinals

1 for every 50 persons or part
thereofiv) Wash basins
1 for every 100 persons or part
thereofv) Drinking water fountain 1 per 500 persons or part thereof

2 for every 100 persons or part thereof

Note : 1 Some of the water-closets may be of European style, if desired.
Note : Additional and special fitments for specifick needs of hospitals may be provided.

TABLE B7 - HOSPITALS (ADMINISTRATIVE BUILDINGS, MEDICAL STAFF AND
QUARTERS AND NURSES' HOMESSt No

Fitments

For Administrative Buildings
For malepersonnel

I)

1

2
Water-closets

3
1 for every 25
persons or part
thereofii)

Ablution taps

1 in eachwaterclosets

iii)

Urinals

Nil, up to 6
persons

For Female
Personnel

For Medical Staff Quarters(hostel type)
For Male Staff

For Nurses' Homes(hostel type)

For Female
Staff

4

5
6
7
1
for
4
persons1
for4
persons1
for4
personsor
1 for every 15
part
thereofpersons or part
thereof1 in eachwater- 1 in eachwater- 1 in eachwater- 5 in eachwaterclosets
closets
closets
closets

1 for 7-20 persons
2 for 21-45
persons
3 for 46-70
persons
4 for 41-100
persons

NBC108V2.RV9

7 December 1993

21

From 101 to 200
persons,add at therate of 2-5 percent

iv)

Wash basinsv)_

Bath (with shower)

From 200
persons,add at therate of 2-5 percent
1 for every 25
1for every 25 1 for every
persons or part
persons or part 8persons orthereof
thereofpart thereofvi)

Drinking water
fountains-

1for every
4persons orpart thereof

1 for every
1for every
8persons or part 8persons or part
thereof
thereof1for every
1 for every 4-6
4persons or part persons or part
thereof
thereof1 por 100 persons or part thereof with a minimum of 1 on each floorviii)
Cleaner's sinks

1 per floor, Min

Note : 1 Some of the water-closets may be of European style, if desired.
Note : 2 It may be assumed that two-thirds of the number are males and one-third females.

NBC108V2.RV9

7 December 1993

22

TABLE B8 – HOTELS(Including Buildings more than 4-storey)

St No

For Residental
Public and Staff

Fitments

For Public Rooms

For Non-Residential Staff

For male
For Females
1

2

I)

Water-closetsii)

Ablution taps

iii)

Urinals3
4
5
1 per 8 persons 1 per 100
2 per 100
1 for 1-15
omitting
persons up to persons up to persons
occupants of the 400 persons 200 persons 2 for 16-35
room withFor over 400, For over 200, persons
attached water- add at the rate add at the rate 3 for 36-65
closets; minimum of 1 per 250 of 1 per 100 personsof 2 if both sexes persons or
persons or
4 for 66-100
are lodged
part thereofpart thereof persons

1 in each water- 1in eachclosetwater-closet
1 per 50
persons orpart thereof-

1in eachwater-closet-

iv)

Wash basin

1 per 10 persons 1 per water- 1 per watercloset
omitting the wash closet andbasins installed urinal provided provided
in the room suite

v)

Baths

1 per 10 persons
omitting occupantsof the room withbath in suitevi)

Slop sinks

For Male Staff

1 per 30 bedrooms;

For Female
Staff
6
7
1 for 1-12
persons
2 for 13-25
persons
3 for 26-40
persons
4 for 41-57
persons
5 for 58-77
persons
6 for 78-100
persons

1 in each water- 1 in eachclosetwater-closet
Nil, up to 6
persons 1 for 720 persons 2
for 2-45 persons
3 for 46-70
persons 4 for
71-100 persons
1 for 1-12
1 for 1-15
persons
2 for persons
16-35 persons 2 for 13-25
persons
3 for 36-65
persons 4 for 3 for 26-40
66-100 persons persons
4 for 41-57
persons
5 for 58-77
persons
6 for 78-100
persons

-

-

-

-

-

-

-

-

1 per floor, Min

NBC108V2.RV9

7 December 1993

23

Kitchen sinks and 1 in each kitchendish washersvii)

Note : Some of the water-closets may be of European style, if desired.
Note 2 It maybe assumed that two-thirds of the number are males and one-third females.

TABLE B9 – RESTAURANTS(Including Buildings more than 4 storey)
St No

Fitments

1
I)

2
Water-closetii)

Ablution taps

For Female
For MalePublicStaff
3
4
5
1 for 50 seats up to 200 1 for 50 seats 1 for 1-15
seats For over 200 seats, up to 200 seats persons
add at the rate of 1 per For over 200 2 for 16-35
100 seats or part thereof seats, add at persons
the rate of 1 3 for 36-65
per 100 seats persons
or part thereof 4 for 66-100
persons
For Male Public

1 in each water-closet

For Female Staff
6
1 for 1-12 persons
2 for 13-25 persons
3 for 26-40 persons
4 for 41-57 persons
5 for 58-77 persons
6 for 78-100 persons

1in each water- 1in each
1 in each water-closet
closetwater-closet

1 water tap with draining arrangements shall be provided for every 50
persons or part thereof in the vicinity of water-closets and urinals
iii)

Urinalsiv)

Wash basin

1 per 50 persons or part
thereofNil, up to 6
persons
1 for 7-20
persons
2 for 21-45
persons
3 for 46-70
persons
4 for 71-100
persons
1 for every water-closet
providedv)

1 in each kitchenvi

Kitchen sinks anddish washers
Slop and service
sinks
1 in each Restaurant

Note : Some of the water-closets may be of European style, if desired.
Note 2 It maybe assumed that two-thirds of the number are males and one-third females.

NBC108V2.RV9

7 December 1993

24

TABLE B10 - SCHOOLS AND EDUCATIONAL INSTITUTIONSSt No

Fitments

1

Educational
Institutions (NonResidential)

Nursery Schools

I)

Water-closets

2
1 per 15 pupils or part
thereofii)

Ablution taps

1 in each water-closet

Educational Institutions(Residential)

For Boys
For Girls
For Boys
For Girls
34567
1 per 25
1 for every 8 1 for every 6
1 per 40
pupils or part pupils or part pupils or part pupils or part
thereof
thereof
thereof
thereof1in each
1in each
1 in each
1 in eachwater-closet water-closet water-closet water-closet

1 water tap with draining arrangements shall be provided for every 50 persons or part
thereof in the vicinityof water-closets and urinals
1 per 20
pupils or part
thereofiii) Urinals

1 for every
25 pupils orpart thereof-

iv)

Wash basins

1 for every 15 pupils or part 1 per 60 Min 1 per 40 Min 1 for every 8 1 for every 6
thereof22
pupils or part pupils or part
thereof
thereofv)

Baths

1 bath-sink per 40 pupils orpart thereofvi)

Drinking water
fountains

1 for every 50 pupils or part 1 for every 1for every 50 1 for every 1 for every 50
thereof50 pupils or pupils or part 50 pupils or pupils or part
part thereof thereofpart thereof thereofvii)

Cleaner's sink

1 for every 8 1 for every 6
pupils or part pupils or part
thereof
thereof1 per floor, Min

For teaching staff, the schedule of fitments to be provided shall be the same as in the case of office buildings
Note : Some of the water-closets may be of European style, if desired.

NBC108V2.RV9

7 December 1993

25

TABLE B 11- HOSTELS
S.No

1
I)

ii)

Fitments

2
Water-closets

Ablution taps

For Residents and Residential
Staff

For Non-Residential Staff

Rooms Wherein Outsiders
Are Received

For Males
For Females
For Males
For Females
3
4
5
6
1for 1-15
1 for every 8 1for every 6
person or partperson or part persons
1 for 1-12
thereof
thereof2 for 16-35 persons
persons
2 for 13-25
3 for 36-45 persons
persons
3 for 26-40
4 for 66-100 persons
persons
4 for 41-57

For Males
For Females
7
8
1 per 100
2 per 100
persons up to persons up to
400 persons 200 persons For
For over 400 over200
persons, and persons, and at
at the rate of the rate of 1 for
1 for 250
100 persons or
persons or part thereofpart thereof

1 in each
1in eachwater-closet water-closet

persons
5 for 58-77
persons
6 for 78-100
persons
1in each
1 in each water- 1 in eachwater-closet closet
water-closet

1 water tap with draining arrangements shall be provided for every 50 persons or part
thereof in the vicinity of water-closets and urinals
iii)

Urinalsiv)

Wash basins

v)

Baths

vi)

Cleaner's sink

1 per 25
persons orpart thereof

Nil, up to 6
persons

1 for 7-20
persons
2 for 21-45
persons
3 for 46-70
persons
4 for 71-100
persons
1 per 8
1 per 6 persons 1for 1-15
1 for 1-12
persons or or part thereof persons
persons
2 for 16-35 2 for 13-25
part thereof
persons
persons
3 for 36-65 3 for 26-40
persons
persons
4 for 66-100 4 for 41-57
persons
persons
5 for 58-77
persons
6 for 78-100
persons

1 per 50
persons orpart thereof

1 per each 1 in each waterwater-closet closet provided
and urinal
provided

1 per 6
1 per 8persons or persons or part
part thereof thereof
1 per floor, Min

Note : Some of the water-closets may be of European style, if desired.

NBC108V2.RV9

7 December 1993

26

TABLE B12 – WAREHOUSES, FRUIT AND VEGETABLE MARKETS

S. No
1
I)
ii)
iii)
iv)

FiTMENTS
2
Urinals
Water-closets
Ablution taps
Bathing places

Reqiore,emts
3
Not less than 2 for every 50 persons
2, Min, and an additional 1 for every 50 persons
2, Min, and an additional tap for every 50 persons
suitable numbers with bathing platforms

Note : 1 For layout for regulated market yards for fruit and vegetables, reference may be made for females.
Note : 2 Separate and adequate provision of water-closets shall be made for females.
Note : 3 Adequate washing places for fruit and vegetables shall be provided.
Some of the water-closets may be of European style, if desired.
In this section where reference is made to accepted standards, in relation tomaterial specification, testing or other information, the appropriate document
listed at the end of this section may be used as a guide to the interpretation of
the term.

TABLE B13 - SANITARY REQUIREMENTS FOR LARGE STATIONS ANDAIRPORTS
St. No

Place

1
I)

2
Junction stations,intermediate stations andbus stationsii)

Terminal stations and bus
terminals

iii)

Domestic airports Min

iv)

for 200 persons
for 400 personsfor 600 persons
for 800 persons
for 1000 persons
International airports
for 200 personsfor 600 persons
for 1000 persons

WC For Males

WC For Females

Urinals For Males
only
3
4
5
3 for first 1 000 persons 4 for first 1000 persons and 4 for first 1000
1 for every additional 1000 persons and 1 forand 1 for every
subsequent 1000 persons persons
every additional
1000 persons
4 for first 1000 persons 5 for first 1000 persons and 6 for first 1000
1 for every subsequent 2000 persons and 1 forand 1 for every
subsequent 1000 or part or part thereof.
every additional
thereof.
1000 persons orthereof.
2*
4*
2*
5
9
12
16
18

8
15
20
26
29

6
12
16
20
22

6
12
18

10
10
29

8
16
12

Note : Separate provision shall be made for staff and workers at these traffic terminal stations,*At lease one Indian style water-closet shall be provided in each toilet, Assume 60 males to 40 females inany area.

NBC108V2.RV9

7 December 1993

27

2

Disposal of Sewage/Waste Water and Pipe Work :2.1

Where public sanitary sewers are available, the sewage / waste water from abuilding /premises can be disposed into public sewer with the approval of theconcerned authority. The connection to the public sewerage system should bemade by connecting the building /premises manhole to the service manhole of the
public sewerage system.In this the case level of the public sewers must be lower
than that of the building drains .

2.2

Where public sanitary sewerage is not available, then the sewage of the building or
premises, shall be done through septic tanks or stabilization ponds or any method
approved by the concerned authority.

2.3

The pipes used for disposal /conveyance of sewage /waste water can be either Salt
Glazed Stoneware Pipe, Cement Concrete Pipe (Plain or reinforced) Cast Iron pipe,
Galvanized Iron Pipe , Asbestos Cement Pipe , Lead Pipe , PVC or HDPE Pipe .
The jointing of those pipes will be either spigot and socket type or collar type .

2.4

Gradients : The discharge of water through a domestic - drain is intermittent andlimited in quantity and therefore, small accumulations of solid matter are liable toform in the drain between the building and the public sewer. Gradients shall be
sufficient to prevent such temporary accumulations building up and blocking thedrains.
2.4.1 The sewer pipes are normally designed to take the peak simultaneous flow
flowing half full.Thus the gradient should be maintainced such that the flow
velocity at the minimum flow situation also remains at a minimum self
cleansing velocity of 0.75m/sec, and the maximum velocity at time of peakflow does not exceed 2.4m/sec. (Whereby there is adverse effects on thepipe material.)

Table - B14
Different Diameter Pipes Giving A Velocity of 0.75m/sec. and corresponding discharge .
S. No
1
2
3
4
5
6

NBC108V2.RV9

Diameter( mm )
100
150
200
230
250
300

Gradient
1 in 57
1 in 1001 in 145
1 in 175
1 in 195
1 in 250

Discharge(cum/min )
0.18
0.42
0.73
0.93
1.10
1.70

7 December 1993

28

Table – B15
Different Diameter Pipes Giving AVelocity of 2.4m/sec and corresponding discharge.
S. No
1
2
3
4
5
6

Diameter( mm )
100
150
200
230
250
300

Gradient
1 in 5.6
1 in 9.7
1 in 14
1 in 17
1 in 19
1 in 24.5

Discharge(cum/min )
0.59
1.32
2.40
2.98
3.60
5.30

(Based on Manning s formula with n = 0.015 )2.5

NBC108V2.RV9All sanitary appliances and fitments shall be carefully examined for defects before
they are installed and also on the completion of the work .

7 December 1993

29

Two Pipe System

Sewage/Waste Water Collection
Illustration B1

NBC108V2.RV9

7 December 1993

30

One Pipe System

Sewage/Waste Water Collection
Illustration B2

NBC108V2.RV9

7 December 1993

31

Single Stack System

Sewage/Waste Water Collection
Illustration B3

NBC108V2.RV9

7 December 1993

32C) Rain Water Disposal.
Scope: This section covers general guidelines for provisions for disposal of rainwaterin different buildings.
1

Rainwater falling on roofs, paved areas and other open area must be collected anddisposed off efficiently and quickly. Provision should be made for a separate andindependent storm water disposal system leading to the public storm-water drain or
natural watercourse for individual buildings.

2

Provision should be made for the drainage of wastes/rain water from balconies andterrace in an efficient manner.

3

Sloping Roof: Apart from architectural considerations, the roof system of a building
should take into account the annual frequency and intensity of rainfall also.
3.1

Roofs of single-storey buildings in isolated areas can be sloped in any direction andthe rainwater allowed to fall on the ground to be drained naturally.

3.2

For large and tall buildings free fall of rainwater from the roofs is not advisable. It
is necessary to catch the rainwater in roof gutters provided with downtake pipes atsuitable locations.

4

For designing rain water/storm water disposal systems, the maximum intensity of rainfall
should be used.

5

Catchment area: The plan area that contributes to the down takes/gutter should be taken
as catchment area.
5.1

Catchment from vertical wall surface enclosing a terrace should also be taken into
account. An area equal to 50% of the wall surface projecting above the terrace
should be added to the roof area contributing to a rain water pipe.

5.2

If rain water of any other terrace at upper level is discharging the rain water to rainwater pipe of the lower terrace, the area must be added to the terrace under design.

5.3

For sloping roofs, allowance is to be made for wind borne rain. It is advisable totake the actual roof area rather than the plan area for such situations.

5.4

Slopes in flat roofs are desirable to direct the flow to the outlet and drain off thewater quickly in less than one or two minutes. Flow speed is generated by thehydraulic gradient between the far end and the free fall outlet.

5.4.1 Slopes to be provided depend on the quality and reliability of the water
proofing, surface finishes and spacing of downtakes. Rough and absorbing
surfaces require more slopes.

NBC108V2.RV9

7 December 1993

33

TABLE C1
Suggested slopes for flat roofs for different surface.
1.

Smooth surfaces(Polished stone, cement/terrazzo floor etc.)
Normal surfaces(Brick, rough stone/concrete blocks, tiles etc)
Rough surfaces(Gravel, cobbled etc)

2.
3.

5.5

0.5-0.75%
0.75-1.0%
1.5-2%

Design of rainwater/storm water disposal very much depend on the co-efficient of
run-off. Co-efficient of run-off is the quantity of rainwater which finds it's way into
the drainage system. Some water is lost in evaporation and absorption in soil or thefloor surface by various means. Typical coefficient of run-off figures are as in
Table below;
TABLE C2
Surface TypeCoefficient of Run-off

a)
b)
c)
d)
e)
f)

0.90-0.95
0.85-0.90
0.70-0.85
0.50-0.70
0.50-0.60
0.20-0.50

Terrace, Hard paved surface:
Paved surface, roads:
Gravel paths, loosely paved walks, rocky surface
Brick paved, compacted ground, turf:
General ground
Natural ground, sloping ground:6

If proper streets drain is not available within 30m. of the boundary of the premises,a rain-water pipe may discharge directly into the kerb drain and shall be taken
through a pipe outlet across the footpath, if any, with out obstructing the path.

7

A rain-water pipe shall not discharge into or connect with any soil pipe or its
ventilating pipe or any waste pipe or its ventilating pipe nor shall it discharge into asewer unless specifically permitted to do so by the Authority, in which case such
discharge into a sewer shall be intercepted by means of a gully trap.

8

Rainwater pipes shall be constructed of cast iron, PVC pipe asbestos cement,
galvanized sheet or other equally suitable material and shall be securely fixed.

9

Rainwater pipes shall be normally sized on the basis of roof areas according toTable C3, a bell mouth inlet at the roof surface is found to give better drainage
effect provided proper slopes are given to the roof surface. The spacing of pipes
depends on the position of the windows and arch openings, but 6 m apart is aconvenient distance. The strainer area shall be 11/2 to 2 times the area of pipe towhich it connects.

NBC108V2.RV9

7 December 1993

34

TABLE C3 - SIZING OF RAINWATER PIPES FOR ROOF DRAINAGE
S.No
1

Dia ofPipe
2(mm)

Average rate of rainfall in mm/h
3
50 mm

i)
ii)
iii)
iv)
v)
vi)

NBC108V2.RV9

50
65
75
100
125
150

13.4
24.1
40.8
85.4
-

4

5

75 mm
100 mmRoof Area m2
8.9
6.6
16.0
12.0
27.0
20.4
57.0
42.7
80.5
-

6

7

8

125 mm

150 mm

200 mm

5.3
9.6
16.3
34.2
64.3
-

4.4
8.0
13.6
28.5
53.5
83.6

3.3
6.0
10.2
21.3
40.0
62.7

7 December 1993

35

Sloping Roof
Illustration C1

NBC108V2.RV9

7 December 1993