Fire Water demand Calculation

REFERENCE
Regulations and Standards

IS:12469
: Specification for Pumps for Fire Fighting System

IS: 13039
of Practice
: External Hydrant Systems-Provision and Maintenance-Code

IS: 15325
: Medium & High Velocity Spray System

IS:12835
: Design and Installation of Fixed Foam Fire
Extinguishing System-Code of Practice

IS:15105
: Design And Installation Of Fixed
Automatic
Sprinkler
Fire
Extinguishing Systems

OISD116
: Fire Protection Facilities for Petroleum Refineries &
Oil/Gas Processing Plants
1.0

OISD117 : Fire Protection Facilities for Petroleum Depots,
Terminals, Pipeline Installations & Lube Oil
Installations

Petroleum Rule, 2002

National Building Code

Tariff Advisory Committee (TAC) Guidelines

TAC Rules for Water Spray System
FIRE DEMAND CALCULATIONS

For plants where process are carried out in spread open area and multistorey structures the firefighting system will be provided as per OISD
116, IS:9668, IS:12469, IS:13039, IS:15394,IS:15325 and TAC
guidelines.
1

Spray system will be provided as per OISD116 & IS: 15325 guidelines in
Class B Storage
Tank farm (Storage tanks) and Class A Storage Tank farm (Storage
tanks).

FW demand is estimated considering two demands.
o
Based on number of hydrant points as per IS: 12469.
o Based on water requirement of spray system in respective area
as per OISD 116 & IS:15325.2003

Water application rate for tanks in same dyke as per OISD is 3 LPM/m2
for tank on fire and tanks with in R+30 m. For tanks which are located
outside R+30m from center of tank on fire within the same dyke area,
the water application rate is 1 LPM/m2 as per
OISD.

As water requirement for tank farm calculated by OISD is conservative
we have consider same for the design.
A. FIRE WATER DEMAND BASED ON NUMBER OF HYDRANTS Hydrant System
Equivalent No. of Hydrant calculation
Particulars
Single Headed External
Hydrant
Fire Escape Hydrant
(Landing valve)
Water cum Foam Monitor
Phase
Future
Equivalent
12
-
12
3
6
6
-
Total (Nos.)
18
33
Note : One fixed monitor of 63 mm size having nozzle bore of 32 mm shall be counted as
three hydrant as per IS 13039

The fire water mains will be laid all over plant with monitor and hydrants
installed on it.Refer Annexure-1 Preliminary FW network diagram.


All areas are covered through these hydrant points.
As per IS: 12469 & TAC Rules, plant is categorized as “High Hazard (A) ”
considering“Storage Tank Farm of Class A & Class B Material”
2
We are coming in “High Hazard (A)” category and No. of hydrants are not exceeding 100
Nos. Hence as per IS: 13039 Table-1 as above, 1 nos. of 273 m3/hr pumps are required to
cater the hydrant system.

Fire water Demand for Hydrant System = 273 M3/Hrs.

IS 13039 - Clause no. 5.1.7, compression ignition engine driven pump of similar
capacity be installed as a standby.

IS 13039 - Clause no.5.1.9 ,The capacity of the jockey pumps shall neither be
more than 5 percent of the installed pumping capacity nor less than 3 percent
 Pumps requirements
(1) Main electrical pump: 1 no. of 273 m3/hrs capacity.
(2) Standby diesel pump: 1 no. of 273 m3/hrs capacity.
(3) Jockey pump: One no. of 10.8 m3/hrs capacity
B.
FIRE WATER DEMAND FOR SPRAY &FOAM SYSTEM- PETROLEUM CLASS-B
(STORAGE TANKS) STORAGE TANK FARM
FW Demand for Petroleum Class-B Storage tank farm area – Spray
The water requirement for Petroleum Class-B & Class C Tank Farm area spray system is
calculated as below:
3
Sr
.
Description
Equipment
Description
No
.
1
2
3
4
5
6
7
8
9
10

C
Size (m)
Dia (m)
Storage
Tank
Storage
Tank
Storage
Tank
Storage
Tank
SD
SBulk
store
SDS Bulk
store
SDS Bulk
store
SDS Bulk
store
SDS Recv
SDS Recv
Height
(m)
Area
Applicable
Density1
Tank
Capacity
Qty
m2
lpm/m2
`KL
Nos
FW
Demand
required
m3/hr
Ethanol
8.85
8
222.17
3
491
1
39.99
Ethanol
8.85
8
222.17
3
491
1
39.99
Ethanol
8.85
8
222.17
3
491
1
39.99
8.85
8
222.17
3
491
1
39.99
8
8
201.06
3
402
1
36.19
201.06
3
402
1
3
402
1
36.19
Ethanol
Ethanol
8
Ethanol
8
36.19
Ethanol
8
8
Ethanol
8
8
201.06
3
402
1
36.19
Ethanol
5.4
6
101.78
3
137
1
18.32
Ethanol
5.4
6
101.78
3
137
1
18.32
201.06
FW Demand requirement for spray in Petroleum Class-B and Class C is 341.36 m3/hr.
Fire Water requirement for Foam System for Petroleum Class-B tank farm

Foam solution concentration will be 3% -
4

Foam solution application rate : 5 LPM/m2 of liquid surface area of tank as per
OISD 117

Area of largest Storage tank covered by foam: 61 m2

Foam Solution required = (Foam solution application rate) X (Area covered by
foam for biggest tank)
= 5 X Area of toluene Storage tank covered by foam)
= 5 X 61 m2

Water Required
x= 305 LPM = 18.3 m3/hr
= 18.3 m3/hr
Total requirement for Spray & Foam System of Petroleum Class-A

Water Demand for Spray & foam = 341.36 + 18.3 = 359.66 m3/hr

Supplementary Water Supply = 50 m3/hr…… as per IS 15325:2020 (11.1)
Total Water Demand for Petroleum Class-A = 359.66 + 50 = 409.66 m3/hr
FINAL FIRE WATER DEMAND
The maximum Fire Water demand for Network is highest of below systems,
a) Fire Water Demand based on number of hydrants : 273 m3/hr.
b) Fire Water Demand requirement for spray & foam system in Petroleum Class-B and C:
409.66 m3/hr.
*
4.1.
Final Water Demand for facility A+B is 682.66 m3/hr.
FW STORAGE

Based on the Water Demand, the following capacity of water storage
tank shall be providedfor firefighting system.

The storage of fire water shall be based on IS: 13039 Table-4.

For Fire water storage requirement for plant is for 3 hrs.
Water Requirement
Static Water Storage Tanks Capacity
682.66 m3/Hr. x 3 = 2048 m3
5