FUNCTION OF JOCKEY PUMPS

A jockey pump is designed to maintain the pressure on the fire protection system between preset limits when the system is not flowing water.

Jockey pump is preferred to be centrifugal pump type.  Jockey pump is not necessary to be listed.

The controller for jockey pump shall be listed.

The jockey pump is not required to have a standby jockey pump.

SIZING A JOCKEY PUMP

The jockey pump shall be sized to replenish the fire protection system pressure due to allowable leakage and normal drops in pressure and shall have discharge pressure sufficient to maintain the desired fire protection system pressure as followings:

1- For situations where the jockey pump serves only above ground piping for fire sprinkler and standpipe system:

The jockey pump should be sized to provide a flow less than a single fire sprinkler. The main fire pump should start and run (providing a pump running signal) for any water flow situation where a sprinkler has opened, which will not happen if the pressure maintenance pump is too large.

2- For situations where jockey pump serves underground main:

NFPA 24 permits the underground mains to have some leakage, one guideline that has been successfully used to size pressure maintenance pumps is to select a pump that will make up the allowable leakage rate in 10 minutes or 1 gpm, whichever is larger

For example:

A fire pump with rated capacity of 1500 USgpm.

The jockey pump selection minimum is 1 % of 1500 USgpm or 15 USgpm.

Discharge Pressure or Head of Jockey Pumps

Discharge pressure of jockey pumps shall be greater than the discharge pressure of main fire pumps by minimum of 10 psi to avoid false starting of main fire pump.