1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULUNDERWRITERS LABORATORIES INC. CERTIFICATION REQUIREMENT DECISIONThis Certification Requirement Decision is prepared by UL LLC. It is normative for the applicable ULProduct Certification Program(
2、s); however, it is currently not part of the UL Standard(s) referencedbelow.Product Category (CCN): YIOZ, YIOZ2Standard Number: UL 429Standard Title: Standard for Electrically Operated ValvesEdition Date: November 6, 2013Edition Number: 7Section / Paragraph Reference: Clause 31.7Subject: Determinati
3、on of Worst Case Media for Endurance TestDECISION:31.7 If a valve is intended to handle more than one fluid, the endurance test is to be conducted with thefluid imposing the most severe service. Most severe service for a family of valves shall be determined byperforming the endurance test with all i
4、ntended fluids, as referenced in 31.5. A separate sample shall beused for each fluid. Visual inspection of the plunger, sealing element, gasket materials and stopper shalldetermine which fluid is worst case. If most severe service cannot be determined by visual inspection, theperformance requirement
5、s from UL 157 may be used. The number of cycles may be increased from thosereferenced in 31.1 and 31.2, if necessary.RATIONALE FOR DECISION:UL 429 allows the Endurance Test on a valve intended for use with multiple fluids to be performed on thefluid which is considered to be the most severe service.
6、 However, there are no criteria or prescriptiverequirements on how to determine what fluid is most severe service. This CRD provides thoserequirements.Copyright 2016 UL LLCUL LLC, in performing its functions in accordance with its objectives, does not guarantee or warrant thecorrectness of Certifica
7、tion Requirement Decisions it may issue or that they will be recognized or adoptedby anyone. Certification Requirement Decisions are the opinion of UL LLC. in practically applying therequirements of the standard. They do not represent formal interpretations of the standard underAmerican National Sta
8、ndards Institute (ANSI) processes. UL LLC shall not be responsible to anyone forthe use of or reliance upon Certification Requirement Decisions by anyone. UL LLC shall not incur anyobligation or liability for damages, including consequential damages, arising out of or in connection withthe use or re
9、liance upon Certification Requirement Decisions. The electronic version of the CertificationRequirement Decision is the current version and previously printed copies may be outdated.This document is published as a service to ULs certification customersUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULSTANDARD NUMBER: UL 429 -2-No Text on This Page
