Fire pump calculator: the pump set NBC 2016 names, the head checks and the diesel fuel rule

Fire pump calculation rules in IS 15301 and NBC 2016

Fire pump capacity as per NBC 2016: every pump set in Table 7

How the fire pump calculator works, in 6 steps

1. 1

   Pick the use and size

   Occupancy, height, floors and floor area choose one Table 7 row, the same row that sizes the fire water tank.

2. 2

   Read the row's pump words

   The row names a terrace pump of 450 or 900 l/min, or a pump-house set, or no pump at all.

3. 3

   Fill counts from the cited note

   Where a row gives only a note number, the calculator takes the counts from that note: Note 11, for example, is two electric and one diesel pump.

4. 4

   Check the jockey

   IS 15301 asks 3 to 10 percent of the installed capacity, at least 180 l/min; the calculator shows that range beside the row's 180 l/min.

5. 5

   Add your heads

   Static head, friction loss and outlet pressure are added as you enter them; 10 m of water is 1 kgf/cm², about 98 kPa.

6. 6

   Apply the clause checks

   Overload at 150 percent flow, the shut-off ceiling, the 700 kPa and 400 kPa limits of IS 3844, and 20 percent more for a sprinkler pump.

Maharashtra Schedule-I fire pump sets

Maharashtra's 2023 Schedule-I keeps most national pump sets but drops some: a hotel below 15 m with floors over 1,000 m² gets one electric and one diesel pump of 2,280 l/min, and a warehouse under 1,000 m² a 1,620 l/min set.

Only the Schedule-I rows proof-read off the 2023 gazette images are shown. Offices, factories, hospitals and halls in Maharashtra are not, so the calculator says "ask us" for them.

Fire pump head and pressure limits in the codes

Six figures fix whether a pump's head is acceptable, from a shut-off of at most 120 percent to the 700 kPa hose cap. None of them is a head to design to: that comes from the building's hydraulic calculation.

• 120 percent

  Most a horizontal pump's shut-off head may be of its rated head (IS 15301 cl. 6.7) 1IS 15301:2003

• 140 percent

  The same ceiling for a vertical turbine pump, of rated bowl head (cl. 6.7) 1IS 15301:2003

• 65 percent

  Least head, of rated head, at 150 percent of rated flow (cl. 6.7) 1IS 15301:2003

• 700 kPa

  Highest static pressure in a hose with the nozzle shut, about 71 m of water (IS 3844 cl. 7.7) 2BIS, IS 3844:1989

• 400 kPa

  Pressure above which outlets get an orifice plate, about 41 m of water (IS 3844 cl. 7.8) 2BIS, IS 3844:1989

• 20 percent

  Margin a sprinkler pump must exceed the calculated flow and pressure by (IS 15105 cl. 12.1(e)) 3BIS, IS 15105:2021

Fire pump head calculation: 4 worked examples

Flamekite’s working from the official rules; no government publishes this figure.

Flamekite's arithmetic on the clauses above, with heads we chose for illustration. Your designer's figures replace them.

1. Case 1

   A 20 m office on a 2,280 l/min set

   Static head 24 m, friction 12 m, 35 m wanted at the top outlet.

   What applies 71 m rated head, 7.1 kgf/cm² or about 696 kPa. The pump must give more than 46.2 m at 3,420 l/min, and its shut-off may reach 85.2 m, about 836 kPa: over the 700 kPa cap, so the lower outlets need pressure control. 1IS 15301:2003

2. Case 2

   The same pump feeding sprinklers

   Heads of 18, 10 and 15 m at 2,280 l/min, sprinkler pump.

   What applies 43 m becomes 51.6 m at 2,736 l/min with the 20 percent margin. Shut-off at most 61.9 m, about 607 kPa: above 400 kPa, so orifice plates on the outlets that see it. 3BIS, IS 15105:2021

3. Case 3

   Jockey for two 2,280 l/min pumps

   Installed capacity 4,560 l/min.

   What applies 3 percent is 137 l/min, under the 180 l/min floor; 10 percent is 456 l/min. Any jockey from 180 to 456 l/min meets IS 15301; Table 7 names 180. 1IS 15301:2003

4. Case 4

   Diesel day tank for a 15 litre an hour engine

   The engine maker's fuel figure at rated load.

   What applies 4 hours of running is 60 litres on hand at all times. That is your arithmetic on the maker's figure; IS 15301 gives the hours, not the litres. 1IS 15301:2003

Terrace pump or pump-house set: which does your building get?

The row decides, but the pattern is plain: a pump house comes with the underground tank.

1. IfFlats and hostels from 15 m to 35 m

   A 25,000 litre terrace tank and, in Maharashtra, a 900 l/min terrace pump on the down-comer; no pump house. 8MH Act 2023 Schedule-I

2. IfFlats above 35 m to 45 m

   Electric and diesel pumps of 2,280 l/min and a 180 l/min jockey at a 75,000 litre underground tank. 10NBC 2016, Part 4

3. IfOffices above 15 m to 24 m

   A 2,280 l/min set under Note 10: one electric, one diesel and the jockey. 11NBC 2016, Table 7

4. IfOffices above 30 m, malls with cinemas, five-star hotels

   Pumps of 2,850 l/min; malls and five-star hotels two electric and one diesel. 6BIS, NBC 2016 Part 4

5. IfA clinic of up to ground plus 1 without beds

   No pump unless a basement over 200 m²; then a 450 l/min terrace pump. 10NBC 2016, Part 4

Where the fire pump calculator stops

It gives a pump set only where a proof-read row holds the building, and head figures only where a clause states them.

Diesel fire pump fuel and engine rules

The diesel standby runs the system when the grid fails, so IS 15301 sets 5 rules for it.

Fire pump calculation myths

Four beliefs that size a pump wrongly.

• You may have read

  There is a formula for fire pump capacity in the NBC.

  Myth

  What the sources say

  Table 7 names fixed sets of 1,620, 2,280 or 2,850 l/min by building; the calculation is for the head, not the flow. 4NBC 2016, Table 7

• You may have read

  The jockey pump must be 180 l/min.

  Myth

  What the sources say

  180 l/min is the floor. IS 15301 allows 3 to 10 percent of installed capacity, so 180 to 456 l/min for two 2,280 l/min pumps. 1IS 15301:2003

• You may have read

  A bigger shut-off head is safer.

  Myth

  What the sources say

  IS 15301 caps it at 120 percent of rated head, and IS 3844 caps a shut hose at 700 kPa. 2BIS, IS 3844:1989

• You may have read

  The diesel tank is a fixed 200 or 500 litres.

  Myth

  What the sources say

  No Indian code read gives litres; IS 15301 asks 4 hours of running, so the size follows the engine. 1IS 15301:2003

Fire pump set price from an official schedule of rates

Flamekite’s working from the official rules; no government publishes this figure.

Maharashtra PWD's Current Schedule of Rates 2018-19 prices pumps supplied, erected, tested and commissioned, GST extra. It has no diesel engine set or pump panel line.