1.1 Excess pressure pumps are intended for installation on wet pipe sprinkler systems as a means of establishing excess pressure for suppression of false alarms due to water surges (water hammer).
1.2 The purpose of the investigation of the excess pressure pump is to determine that it is designed for installation on alarm check valve equipped, wet pipe sprinkler systems to provide an automatically controlled means of maintaining excess pressure in the systems, substantially in excess of the maximum pressure likely to be present in the supply lines.
1.3 Maintenance of excess pressure in systems at all times is intended to prevent movement of the alarm valve clapper during surges of the water supply line pressure thus eliminating false alarms due to flow through the valve occasioned by surges. The pump assembly and the required control pressure switches are to be securely installed on a heavy gauge metal panel which in turn is intended for installation on a sprinkler riser immediately above the alarm valve.
1.4 The panel is generally fastened to a wall or the sprinkler riser close to the alarm check valve. The panel incorporates a control circuit, armor cable, electric motor, mounting plate, differential pressure switch, low pressure supervisory switch, pump, and low pressure alarm switch. The electrical components are to be covered by the UL Recognized Component Program and each part is clearly identified as such.
1.5 All the electrical components are to be reviewed and tested by UL's Burglary Protection and Signaling Department and the following tests conducted:
a) Input Test,
b) Temperature Test,
c) Dielectric Strength Test.