The document compares rules for fire protection systems in power plants according to NFPA and TAC standards. Key differences include: - NFPA has more detailed standards while TAC relies more on recommendatory codes - NFPA requires hydraulic calculations, automatic systems, standby pumps, and prohibits combined water mains. TAC allows thumb rule sizing and non-automatic systems. - NFPA has stricter requirements for pipe sizes, pressures, spacing, and protection of areas. TAC requirements are less stringent.

1. Comparison between NFPA and TAC rules for Power plants
NFPA. TAC
NFPA 850 is standard for power stations where
cross reference is made to following main
standards
NFPA 13,14,15,24 and 850
TAC does not have similar code although there
is a IS code for power plants which is a
recommendatory code. Following are the only
standards with TAC
F P Manual, Rules for spk installations and
Rules for Spray systems
City mains are accepted as an approved source of
supply
City mains are not accepted
Combined fire service and general water mains are
allowed
Combined fire service and general water mains
are not allowed
Hydraulic calculations are must Thumb rule systems are permitted
Rivers are allowed as approved water source Rivers are not allowed as approved water
source
Monitors are must in coal yards. Hydrants are permitted in coal yards
Fire protection systems should be automatic in
operation
Hydrant system being separate from other
water based systems can also be non
automatic in nature. Other systems must be
automatic
When multiple fire pumps are required, pumps
should not be subject to common failure. They
should be of sufficient capacity to meet the demand
with largest pump out of service
TAC does not require standby pumps, however,
all pumps should not have the same drive.
Both electrical pumps are acceptable provided
supply is given from 2 independent sources like
grid supply and a captive plant or DG set
Minimum pipe dia is 150mm. Velocity restriction is
3m/s.
Pipes smaller than 6 inches are permissible
subject to velocity restriction of 5m/s
Elaborate requirements are given for various types
of thrust blocks to be provided in pipe systems
No such details are given
No, outlets size of main hydrant valve opening and
size of hydrant stand-post should be suitable for
protection. Normally 2, 2 and ½ inch outlets are
provided on a 6 inch standpost
Hydrants should conform to IS :5290
Authority having jurisdiction decides on spacing of
hydrants no of risers required and size of pipes
Spacings are 30, 45 and 60m for High Medium
and Light hazard risks. Pipe sizes and no of
risers are given in the rules.
Provision of automatic fire alarm system is must This is optional
Hydrant spacing in main plant area is 91.4m and in
remote areas like coal yards is 152.4m. Hoses are
15or 22.5m on upper floors and 30m long on
ground.Minimum Terminal pressure is 6.9 bars.
Spacing is 45m throughout. Hoses are 15m
long on ground and 7.5 m on upper levels.
Minimum Terminal pressure is 3.5 Bars
Hydraulic calculations are required to discharge
entire flow at farthest and hydraulically remotest
points considering most direct path out of service
Only half the flow is discharged at hydraulically
remotest point, other half being discharged at
most vulnerable point en-route
All Valves except underground valves are
supervised from a central station to ensure that
they are kept in open position at all times
There is no such provision
Hydrant stand posts are 150mm dia Minimum stand post dia is 80mm
A valve is required on every hydrant No such requirement
Hydrants are located at minimum 12.2m from
buildings
Minimum distance is 2m and max 15m
Steel pipes are externally coated and wrapped and
internally galvanized
Internal galvanizing is not required
Working pressures are 10.3 bars Working pressures are 7,8.8 or 10.5 Bars
PVC pressure pipes and chlorinated PVC threaded
fittings as per schedule 80 are permitted
Plastic pipes are not allowed in ordinary and
high hazard risks
Concrete pipes are allowed Concrete pipes are not
allowed
Flushing of hydrant, sprinkler pipes after erection is
must
There is no specific requirement
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2. Pipes are hydraulically pressure tested at 13.2 bars
or 3.5 bars above working pressure for 2 hrs
Pipes are hydraulically tested at 150% of
working pressure for 2 hours
2 hours supply water reservoir should be refilled in
8 hrs time
There is no refilling requirement
Water supply requirement for power plants is is 2
hours supply for largest Fixed fire suppression
system demand plus hose stream demand of 500
GPM
Water supply requirement is 40/90 minutes
supply for largest water spray system demand
and hose stream demand of 1000 GPM.
Protection of following areas by appropriate fixed
fire suppression systems is required to be provided
Thermal power plants.
• Transformer soak pits
• Indoor fuel pumping and heating facilities
• Outdoor fuel storages
• Coal transfer houses
• Coal conveyors
• Coal handling Structures
• Underground Coal Conveyors
• Stacker reclaimers
• Boiler burner Fronts
• Flue gas bag type dust collectors
• Transformers/rectifier sets
• Scrubber Buildings
• All areas beneath the operating floor in
Turbine building
• Lubricating oil Tanks, Oil handling
equipments and Oil lines above the turbine
floor
• Turbine Generator bearings
• Area inside a directly connected exciter
• Clean and Dirty oil Storage Tanks
• false floors in Control Computer and
communication rooms
• Cable Tunnels
• Offices, storage rooms
• Warehouses containing high value
equipments and combustible materials
• Fire pump rooms
• Cooling Towers
Combined Cycle power plants
• Flame and gas detectors in gas turbine
enclosures
• Total flooding gas or water mist or high
expansion foam system in
• gas turbine enclosures
• Appropriate systems on
• Exposed oil piping
• Turbo chargers on IC engines
• Lube oil reservoirs and handling
equipments
• Localized systems for
• units that are not enclosed
• Generator bearings
This is optional. TAC does not insist on any
type of protection, although they may be
desirable.
In the De-Tariff scenario Premium adjustments
are done by insurers based on level of
protections achieved based on certification by
accredited agencies
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3. • Oil piping
• Starting equipments on combustion
turbines
Pipes are laid 0.8m below ground frost level Pipes are laid 1m below ground
For upper floors Maximum travel distance is 45.7m
for non sprinklered buildings and 61m for
sprinklered ones. A riser is provided in each exit
stairway
Hose lengths on upper floors are 7.5m.
Maximum travel distance is 30m. it can be
increased to 45m with 15m hoses
Minimum size of risers is 4 inches Minimum size of risers is 3 inches
Minimum pressures required are 6.9 bars at
remotest point for class I systems and 4.5 bars for
other systems
Minimum pressures required at remotest point
are 3.5 bars in moderate hazard risks
Whilst considering pressure loss in risers Minimum
flow rate shall be 250 GPM per riser with a
maximum of 1250 GPM for non-sprinklered
buildings and 1000 GPM for sprinklered ones. If
sprinkler demand is more, higher of the two govern
the design
Flow is taken as 125 GPM per hydrant. If
sprinkler demand is more, higher of the two
govern the design
For Class II and Class III systems 1and 1/2 inches
hose reels are permitted in lieu of 2 and 1/2 inch
hoses. 1 inch hose reels are allowed in light hazard
occupancies
Only 2 and ½ inch hydrants and hose pipes are
required near fire escape hydrants
No pressure regulating devises are permitted
except on risers where pressures are limited to 6.9
bars on 1 and ½ inch hoses and 12.2 bars on 2 and
½ inch hoses
Orifice plates can be provided
Hydrants in remote areas can be fed by general
service mains
Fire water and service water mains are always
separate
Hoses conform to NFPA 1961 Hoses conform to IS 636
Hoses are kept in hose houses Hoses can be kept in hose boxes or central fire
stations
For Risks other than power plants Supplementary
hose stream demand for a combined sprinkler and
hydrant system is 250 GPM for 90 minutes.
Higher of the two demands govern the pumping
and reservoir capacity for a combined hydrant
and sprinkler system
For Medium velocity Water spray systems, NFPA is
silent on supplementary hose stream demand.
In TAC demand varies from 1150 LPM to
4500LPM for durations ranging from 40 minutes
to 150 minutes for different applications
For HVWS supplementary hose demand is 1134
LPM
For HVWS supplementary hose demand is 1750
LPM.
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