new design considerations for fire pump installations

8/8/2019 New Design Considerations for Fire Pump Installations

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New Design Considerationsfor

Fire Pump Installations

Milosh Puchovsky, PE, FSFPE

Professor of PracticeWorcester Polytechnic Institute

Dept. of Fire Protection Engineering


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Agenda

•

Very Tall Buildings

•

Redundancy

•

Fire Pump Access• Water Supply

• Pressure Control

•

Testing & Piping Arrangements


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Should all high rise buildings be

considered the same way?


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Very Tall Buildings

What about buildings beyond the pumping

capability of the fire department?


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Very Tall Buildings

•

Not connected to a specific height.


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Very Tall Buildings

Where primary water

supply is from tanks,

how many tanksshould be provided?


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Very Tall Buildings

•

Total volume of all tanks or compartments

to be sufficient for the full fire protection

demand.•

Each individual tank or compartment to be

sized so that at least 50% of the fire

protection demand is stored with any one

compartment or tank out of service. (20:5.6.1)


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Very Tall Buildings

•

Automatic & manual refill valves sized and

arranged to independently supply the

system fire protection demand for eachwater tank or compartment. (20:5.6.1)


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Very Tall Buildings

•

Should redundant fire pumps be provided?

•

Under what conditions?


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Very Tall Buildings

Fire pumps serving zones that are partially or whollybeyond the pumping capability of the fire department

apparatus to be provided with one of the following:

(1)

A fully independent and automatic backup fire pump

unit(s) arranged so that all zones can be maintained in

full service with any one pump unit out of service.

(2) An auxiliary means that is capable of providing the fullfire protection demand and that is acceptable to the

AHJ, i.e. gravity fed standpipe systems. (20:5.6.2)


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Auxiliary Power for Pumps in

High Rise Buildings•

Where electric motors are used, and the

height of the structure is beyond the

pumping capability of the fire departmentapparatus, an alternate source of power to

be provided. (20:9.3)

•

Alternate source not required where the

following are provided: – Back up engine driven pump

– Back-up motor driven pump on independent

power source


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Terminology

On-Site Standby Generator. A facility

producing electric power on site as the

alternate supply of electric power. It differsfrom an on-site power production facility, in

that it is not constantly producing power.(20:3.35)


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Pump Room Access in High

Rise BuildingsConsiderations to be addressed with the

Fire Department (20:5.3)

–

Access directly from outside –

Locations above and below grade (protected

passageways)

– Discharge of pump equipment (packing

glands, relief valves, etc.)


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Pressure Fluctuations – Water

Supply


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Confirmation of Water Supply

•

Water flow tests to be completed not more

than 12 months prior to the submission of

working plans

•

Acceptance Testing. Unadjusted fire

pump discharge flows and pressures to

meet or exceed the system demand.

•

Comparison with shop curves still

required.


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Low Suction Throttling Devices

•

Friction loss through a low suction-

throttling valve in the fully open position

must be taken into account during design.


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System Overpressures


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System Overpressures


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System Overpressure –

Variable Speed Control


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Acceptance Testing

•

Where variable speed pressure limiting

control is employed, fire pump

performance to be tested at: churn, 25%,

50%, 75%,100%,125% and 150% of rated

pump capacity.


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Pressure Relief Valve Discharge

Back to Suction• Relief valves only

permitted to

address

abnormal

conditions.

• Dischargepermitted to be

piped back to

suction.

Concerns for diesel engine driven pumps that incorporateheat exchanger cooling for the engine.


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Flow

Meters &

Testing

Devices

Where a

installed in alooped

arrangement

for flow

testing, an

alternate

means of

measuring

flow to be

provided.


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Break Tank Sizing


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Series Fire Pump Arrangement

Should all pumps

comprising a series

fire pump installationbe located in the

same fire pump

room?


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Final Remarks

Given the same conditions, will a fire behave

differently based on it geographic location?


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Thank You

new design considerations for fire pump installations

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