DESIGN-SELECTION FIRE PUMP

SYSTEM

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ENGINEERING J.S.C
 FIREWATER PUMP
NFPA20
Standard for the Installation of
Stationary Pumps for Fire Protection

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Presented by: Nguyen Thanh Tin ENGINEERING J.S.C
 Purpose of a Fire Pump

• To protect lives and properties against fire by

supplying an adequate water supply to
automatic sprinklers or standpipe systems
• To meet building codes and insurance
requirements

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 Listing Authorities

• Underwriters Laboratories (UL)

• Factory Mutual Research Corporation (FM)

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 Codes and Standards

• NFPA Philosophy
– A fire pump system should operate irrespective of
any damage it may cause to itself
– No element of the system under emergency
conditions should:
• Prevent a fire pump from turning on
• Cause a fire pump to turn off
– Changes to the code must be substantiated by data
or experience (actual scenarios)

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 Water Supply

– Where fire pumps are installed on a city main, a fire flow

test should be performed to determine minimum and
maximum supply pressures as well as suitability of
supply for the fire protection system
– Where adequate city supply water is unavailable,
a suction tank or pit should be installed
– Tank sizing must consider 150% of the fire pump rated
flow
– Total water requirements are defined in NFPA13
(Sprinkler Systems), NFPA14 (Standpipe Systems), NFP
A15 (Spray or Mist Systems), Mains)
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 Pump Requirements

“Centrifugal fire pumps shall be listed for fire

protection service.”
“Pumps shall furnish not less than 150% of rated
capacity at not less than 65% of total rated head.
The shutoff head shall not exceed 140% of rated
head for any type pump.”

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 Pump Requirements

%Rated Head Max Shutoff Head

140%
100%
65%

%Rated Flow
100% 150%

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 Pump Sizing

“A stationary pump for fire protection should be selected in

the range of operation from 90 percent to 150 percent of its
rated capacity. The performance of the pump when applied
at capacities over 140 percent of rated capacity can be
adversely affected by the suction conditions. Application of
the pump at capacities less than 90 percent of the rated
capacity is not recommended. The selection and application
of the fire pump should not be confused with pump
operating conditions. With proper suction conditions, the
pump can operate at any point on its characteristic curve
from shutoff to 150 percent of its rated capacity.”
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 Pump Sizing

Pump Design Flow

Head

100%

Pump Rated Flow

Flow
90% 100% 150%

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 Pump Requirements

• FM & UL require that fire pumps have

packing seals
• Packing requires periodic adjustment and
replacement as it hardens over time
• The packing gland should be tightened until
the seal leaks 30 drips per minute
• If the gland is tightened to much, the seal
receives no lubrication and will burn

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 Allowable Pump Types

– Horizontal Split Case

– Vertical In-Line
– End Suction
– Vertical Turbine

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Horizontal Split Case
Fire Pumps

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 HSC Fire Pumps

• BENFITS • DRAWBACKS
– Available in a wide flow – Large floor space
and head range requirement
– Serviceable without – Restricts mechanical
disturbing piping or driver room layout due to
– Available in electric or direction of rotation
diesel drive – More costly
– More difficult to service

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Vertical In-Line Fire Pumps

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 VIL Fire Pumps

• BENEFITS • DRAWBACKS
– Compact – Only available up
– Serviceable to 1500GPM
– Reliable – Electric Drive
– Cost Effective Only
– Requires suction
strainer

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End Suction Fire Pumps

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 End Suction Fire Pumps

• BENFITS • DRAWBACKS
– Moderate floor space – Only available up to
requirement 1500gpm
– Flexibility in – Single suction design
mechanical room limits hydraulic
layout efficiency
– Available in electric or
diesel drive
– Serviceable

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 Vertical Turbine Fire Pumps

• Used where a flooded suction

cannot be maintained
• Underground water sources or
below ground tanks with above
ground pump room

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 Vertical Turbine Fire Pumps

• BENFITS • DRAWBACKS
– Will operate under – More costly
suction lift – More difficult to service
– Available in electric or and install
diesel drive
– Available over wide
flow and head range

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Typical Application
Wet Pit - Electric Motor Driver

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Typical Application
Wet Pit - Diesel Engine Driver

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NFPA Required Pump
Accessories
Suction &
Discharge
Air Release Gauges
Valve

Pressure Relief Valve

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NFPA Required Pump
Accessories
• Suction gauge must be of the
compound type (capable of reading
negative pressure or vacuum)
• Discharge gauge must read two
times the working pressure of the
pump and not less than 200psi

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Air Release Valve

• 1/2” Air Release Valve is required

• Exception: top centre-line discharge
end suction and vertical fire pumps

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Automatic Air Release and
Pressure gauges

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 Circulation relief valve

• A circulation relief valve allows a

small amount of water to discharge
from the pump to keep the fire
pump from overheating when
operating at no flow or very low
flows.

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Relief Valve

• 3/4” up to 2500usgpm
• 1” over 3000usgpm
• Should be set between the
maximum suction pressure and
minimum suction pressure plus
the closed valve pressure of the
pump
• Piped before the fire pump dischar
ge check valve

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 Eccentric tapered reducer at
suction inlet

• When the pump suction pipe is

larger than the pump suction
flange, an eccentric tapered
reducer is required to minimize
the possibility of air pockets
forming at the pump suction.

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Isolation Valves

• Suction OS&Y Gate Valve

• Discharge Butterfly Valve
• Both must be supervised
• Discharge Butterfly Valve
Installed after “Test Tee” and
pressure sensing line

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Isolation Valves

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 Hose Valve Systems

– Provides testing means

– Sized by pump rated
capacity
– There are hundreds of
different thread types
depending on jurisdiction -
type should be specified on
projects

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 Flow Meters
– Does not replace a hose valve system
– Flow meters must be listed for fire protection service
– Gauge reading is a minimum of 175% the pump rated
flow
– Provides a testing means without wasting water
– Flow meter is installed in bypass back to suction
– Must be installed with isolation valves per
manufacturer’s specifications
– RULE OF THUMB:
Annular Type - 10Ø upstream - 5Ø downstream
Venturi Type - 7Ø upstream - 5Ø downstream
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PETROVIETNAM
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Flow measuring device

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PETROVIETNAM
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Main Relief Valves and Waste
Cones

– Sized by pump rated

capacity
– Spring or pilot operated
– Waste cone provides
visibility of flow through
the valve
– When it is used:
1) Diesel driven systems
2) Electric systems ???

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Main Relief Valves and Waste
Cones
– Recommended on all diesel driven
systems
– Not required on diesel if maximum
supply pressure plus 1.21 x closed
valve pressure does not exceed system
pressure rating
– NFPA allows piping back to suction -
NOT recommended
– Relief valve should be set below
maximum pressure rating of the system

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ENGINEERING J.S.C
NFPA Fitting Sizing

Piping, Relief Valves, Metering Devices, and Hose

Valves should be sized according to Table 2-20
on Page 20-13.

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 NFPA Required Pump
Accessories
Fire Pump Rating Suction Discharge Relief Valve Relief Valve Flow Meter Number & Hose Valve
GPM (L/s) Size (in.) Size (in.) Size (in.) Discharge Size (in.) Size of Hose Manifold
(in.) Valves Size (in.)

25 (95) 1 1 ¾ 1 1¼ 1 - 1½ “ 1
50 (189) 1½ 1¼ 1¼ 1½ 2 1 - 1½ “ 1½
100 (379) 2 2 1½ 2 2½ 1 - 2½ “ 2½
150 (568) 2½ 2½ 2 2½ 3 1 - 2½ “ 2½
200 (757) 3 3 2 2½ 3 1 - 2½ “ 2½

250 (946) 3½ 3 2 2½ 3½ 1 - 2½ “ 3
300 (1136) 4 4 2½ 3½ 3½ 2 - 2½ “ 3
400 (1514) 4 4 3 5 4 2 - 2½ “ 4
450 (1703) 5 5 3 5 4 2 - 2½ “ 4
500 (1892) 5 5 3 5 5 2 - 2½ “ 4

750 (2839) 6 6 4 6 5 3 - 2½ “ 6
1000 (3785) 8 6 4 8 6 4 - 2½ “ 6
1250 (4731) 8 8 6 8 6 6 - 2½ “ 8
1500 (5677) 8 8 6 8 8 6 - 2½ “ 8
2000 (7570) 10 10 6 10 8 6 - 2½ “ 8

2500 (9462) 10 10 6 10 8 8 - 2½ “ 10
3000 (11,355) 12 12 8 12 8 12 - 2½ “ 10

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 Pressure Maintenance Pump
(Jockey)
• Every system has a normal leakage rate that
will result in a pressure drop
• Jockey Pump will maintain the pressure in the
system
• This will prevent the main fire pump from
starting for minor leaks

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 Jockey Pumps

Jockey (pressure maintenance) pumps and jockey

controllers need not be listed for fire protection
service.
“The primary or standby fire pump shall not be used
as a pressure maintenance pump.”
A jockey pump should be sized such that it
CANNOT meet the flow demand of a single
sprinkler fixture.

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 Jockey Pump Sizing

• Jockey pumps should be sized for 1% of the

flow of the main fire pump
• Jockey pumps should be sized to provide 10psi
more pressure than the main fire pump
• Jockey pump should be sized so that it cannot
meet the demand of the lowest flow fire
protection fitting in the system

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Jockey Pump Sizing

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 Fire Pump Operation

– Fire pumps are designed to start on a pressure

switch setting
– Some fire pumps can be started automatically
based on a deluge valve opening, or a remote
signal
– The pressure sensing line is the lifeline for the fire
protection system

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 Fire Pump Operation

– Pressure switches should be rated for maximum pressure

conditions
– Jockey pump and fire pump sensing lines must be separate

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Fire Pump Operation

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PETROVIETNAM
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 CONTROLLER STARTING
METHOD
600

FULL VOLTAGE
% of Full 420 PART WINDING
390
Load PRIM.
Current RESISTOR
252 AUTO-
200 TRANSFORMER
WYE DELTA
100 FULL LOAD
CURRENT

Full speed
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 DIESEL CONTROLLERS

• Serve Three Basic Functions:

• Start the Diesel Engine in an emergency
• Monitor the Operation and Condition of the
Diesel Engine
• Keep the batteries charged

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DIESEL CONTROLLERS

• Diesel Can be Started by Three Methods:

• Pressure Switch (In the Automatic Mode)
• Pressure Switch (In the Test Mode)
• Manual Cranking (In the Automatic or Manual
Mode)
• Starting sequence:
• Alternating cranking sequence
• Six cranks every 30 seconds until diesel starts
• If diesel fails to start, an alarm is activated
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DIESEL CONTROLLERS

• Diesel Can be Stopped by Two Methods:

• Manually by Pushing the Stop Button
• Automatically after 30 minutes during weekly
test
• Overspeed shutdown:
• A diesel fire pump will shut down in an
emergency condition if the diesel operates mor
e than 20% faster than the rated speed

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 DIESEL CONTROLLERS

• Diesel Controller Alarms

• Battery and Charger Failures
• Diesel operating condition (High Coolant Temperature,
Low Oil Pressure, Overspeed, Failure to Start)
• Contacts for remote indication of alarm conditions
• Optional Pump Room Alarms (Low suction pressure,
flow meter on, Main Relief Valve open, Low/High
Pump Room temperature, Low fuel level, Others )

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 DIESEL CONTROLLERS

• Battery Charging Systems:

• One charger for each set of batteries
• Chargers are capable of fully charging the
batteries in 24 hours
• Batteries remain in an overcharged condition

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 Pump Maintenance
• Pump acceptance tests are defined in NFPA20 Chapter 11
• Inspection and maintenance are defined in NFPA25
Chapter 5
• Seals and bearings are the highest maintenance item for a
pump
• The packing should be checked and adjusted each time the
pump is tested
• As fire pumps do not run often, bearings should be checked
for cleanliness and to ensure that adequate oil or grease has
been applied (depending on the type of bearing)
• Motor bearings should also be checked
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ENGINEERING J.S.C
Thank you!

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ENGINEERING J.S.C