1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULDecember 5, 20061SUBJECT 693OUTLINE OF INVESTIGATIONFOREXCESS PRESSURE PUMPS FOR WET PIPE SPRINKLER SYSTEMSIssue Number: 3DECEMBER 5, 2006Summary of TopicsThis new issue of SU 693 is being issued
2、 through ULs electronicpublishing system to ensure format uniformity between the PDF andHTML versions of the document. No substantive changes have beenincorporated in the document.The UL Foreword is no longer located within the UL Standard. For informationconcerning the use and application of the re
3、quirements contained in thisStandard, the current version of the UL Foreword is located onULStandardsInfoNet at: http:/ 2006 UNDERWRITERS LABORATORIES INC.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULDECEMBER 5, 2006SUBJECT 6932No Text on T
4、his PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSGENERAL1 General 4PERFORMANCE2 General 43 Installation Test .54 Operational Test 55 Endurance Test .56 Hydrostatic Pressure Strength Test .6MARKING7 General 6DECEMBER 5, 2006 SUBJ
5、ECT 693 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULGENERAL1 General1.1 Excess pressure pumps are intended for installation on wet pipe sprinkler systems as a means ofestablishing excess pressure for suppression of false alarms due to wat
6、er surges (water hammer).1.2 The purpose of the investigation of the excess pressure pump is to determine that it is designed forinstallation on alarm check valve equipped, wet pipe sprinkler systems to provide an automaticallycontrolled means of maintaining excess pressure in the systems, substanti
7、ally in excess of the maximumpressure 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 alarmvalve clapper during surges of the water supply line pressure thus eliminating false alarms due to flowthrough the val
8、ve occasioned by surges. The pump assembly and the required control pressure switchesare to be securely installed on a heavy gauge metal panel which in turn is intended for installation on asprinkler riser immediately above the alarm valve.1.4 The panel is generally fastened to a wall or the sprinkl
9、er riser close to the alarm check valve. Thepanel incorporates a control circuit, armor cable, electric motor, mounting plate, differential pressureswitch, low pressure supervisory switch, pump, and low pressure alarm switch. The electrical componentsare to be covered by the UL Recognized Component
10、Program and each part is clearly identified as such.1.5 All the electrical components are to be reviewed and tested by ULs Burglary Protection and SignalingDepartment and the following tests conducted:a) Input Test,b) Temperature Test,c) Dielectric Strength Test.PERFORMANCE2 General2.1 In addition,
11、the following operational tests of the complete excess pressure pump assembly are to beconducted with the panel installed in a wet pipe sprinkler system.DECEMBER 5, 2006SUBJECT 6934UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL3 Installation
12、 Test3.1 The excess pressure pump panel is to be installed directly on a test sprinkler riser at a pointimmediately above an alarm valve. Connections are to be made between the pump assembly and thealarm valve. A pressure switch is to be connected by piping to the alarm port on the alarm valve and t
13、oa suitable power source and lamp bank to indicate valve clapper movement during the various tests.4 Operational Test4.1 The operational test is to be conducted to develop the characteristics of the excess pressure pumpunder water supply pressure conditions within the limits of its pressure rating a
14、nd under varied entrappedair conditions in the test sprinkler piping. To simulate the entrapped air conditions present in wet pipesprinkler systems, the air volume in the test system is to be varied and the effects on the operation of theexcess pressure pump is to be recorded. In order to evaluate t
15、he entrapped air condition with respect towet pipe sprinkler systems in service, the flexibility of the test system is to be measured. Flexibility is aterm used for the entrapped air conditions of wet pipe sprinkler systems. The flexibility of a wet pipesystem at any stated pressure is the number of
16、 gallons of water which must be withdrawn from the riserwhen the main gate is closed in order to reduce the riser pressure 10 psi. The gallon value reflects theentrapped air volume in the piping system. The time required to initiate alarms in the cases of wet pipesprinkler systems equipped with alar
17、m valves depends upon a number of factors among which are:a) The system flexibility conditions,b) The differential of pressure existing between the supply pressure and the system pressure,andc) Rate of flow from the system.5 Endurance Test5.1 The excess pressure pump will be operated intermittently
18、on and off for a period of 24 hours. Toaccomplish this a small flow will continuously discharge from the test piping. Since the outflow will notexceed the capacity of the pump, it shall permit the pump to undergo a constant on and off cyclingoperation for 24 hours. This test will be conducted to asc
19、ertain whether any failure would occur in themotor, pump, or pressure switches due to abnormal operating conditions and also to observe thefunctioning of the complete unit under the on and off cycling operation.DECEMBER 5, 2006 SUBJECT 693 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUC
20、TION ORDISTRIBUTION WITHOUT PERMISSION FROM UL6 Hydrostatic Pressure Strength Test6.1 The pressure switches in the assembly are to be individually subjected to a hydrostatic pressure of875 psi for 1 minute. The samples are to be subjected to five times the normal working pressure (175 psi)to ascertain whether the water would enter the switch enclosure by leaking past the plunger assembly.MARKING7 General7.1 Each excess pressure pump shall be marked with the manufacturers name, model number, electricalrating, and maximum pressure rating on standard metal nameplate.DECEMBER 5, 2006SUBJECT 6936
