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Fire Pump Start and Stop Settings

Question asked by ramon.aparece on Jun 13, 2018
Latest reply on Jun 14, 2018 by nocivus

 

 

Actual settings of the fire pumps at the pump room during the visit are as follows;

 

Maintaining pressure :   0.90 Mpa (130.5 Psi)

 

Pump

Rating

Cut in

Cut out

Jockey Pump A & B

15 Kw each

90 Psi (0.62 Mpa)

145 Psi (1 Mpa_

Electric Motor Driven Pump A & B

150 Kw each

A = 57 Psi (0.39 Mpa)

145 Psi (1 Mpa)

B=  84 Psi (0.58 Mpa)

125 Psi (0.86 Mpa)

Diesel Driven Pump

-

50 Psi (0.34 Mpa)

Manual

 

 

Based on Fire pump start and stop settings from 2010 NFPA 20, A-14-2.5. which states as follows;

 

Fire Pump Settings. The fire pump system, when started by pressure drop, should be arranged as follows:


(1) The jockey pump stop point should equal the pump churn pressure plus the minimum static supply pressure.

(2) The jockey pump start point should be at least 10 psi (0.68-bar) less than the jockey pump stop point.

(3) The fire pump start point should be 5 psi (0.34 bar) less than the jockey pump start point. Use 10-psi (0.68-bar) increments for each additional pump.  (Also note that NFPA 20, paragraph 7-5.2.5 also has a proviso for multiple pumps.  The second pump must start 5-10 seconds behind the primary pump starting to prevent water hammer.) 

(4) Where minimum run times are provided, the pump will continue to operate after attaining these pressures. The final pressures should not exceed the pressure rating of the system.

(5) Where the operating differential of pressure switches does not permit these settings, the settings should be as close as equipment will permit. Pressures observed on test gauges should establish the settings.

Hence, the suggested pressure settings are as follows;

 

Maintaining pressure : 1.15 Mpa (166.8 Psi)

 

Pump

Rating

Cut in

Cut out

Jockey Pump A & B

15 Kw each

145 Psi (1 Mpa)

 

1.15 Mpa (166.8 Psi)

135 Psi  (0.93 Mpa)

1.15 Mpa (166.8 Psi)

Electric Motor Driven Pump A & B

150 Kw each

A = 125 Psi (0.86 Mpa)

Manual

B=  115 Psi (0.79 Mpa)

Manual

Diesel Driven Pump

-

105 Psi ().72 Mpa)

Manual

 

 YOUR COMMENTS AND CORRECTIONS ARE MUCH APPRECIATED.

 

 

#fire Pumps Start and Stop Settings

 

 

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