_API_STD_527.PDF

Seat Tightness of PressureRelief ValvesAPI STANDARD 527THIRD EDITION,JULY 1991REAFFIRMED,MAY 1996GAmerican National Standards InstituteANSI/API 527-1992亚AmericanPetroleumInstituteC0540gSeat Tightness of PressureRelief ValvesRefining DepartmentAPI STANDARD 527THIRD EDITION,JULY 1991AmericanPetroleumInstituteFOREWORDThis standard describes tests to determine the seat tightness of metal-and soft-seatedpressure relief valves.Valves of conventional,bellows.and pilot-operated designs are cov-ered.Acceptable leakage rates are defined.Tests with air,steam,and water are described.This standard requires the purchaser to specify certain details and features.Although itis recognized that the purchaser may desire to modify,delete,or amplify sections of thisstandard,it is strongly recommended that such modifications.deletions.and amplificationsbe made by supplementing this standard,rather than by rewriting or incorporating sectionsthereof into another complete standard.API standards are published as an aid to procurement of standardized equipment and ma-terials.These standards are not intended to inhibit purchasers or producers from purchasingor producing products made to specifications other than those of APl.API publications may be used by anyone desiring to do so.Every effort has been madeby the Institute to assure the accuracy and reliability of the data contained in them;however,the Institute makes no representation,warranty,or guarantee in connection with this pub-lication and hereby expressly disclaims any liability or responsibility for loss or damage re-sulting from its use or for the violation of any federal,state,or municipal regulation withwhich this publication may conflict.Suggested revisions are invited and should be submitted to the director of the RefiningDepartment,American Petroleum Instirute,1220 L Street,N.W.,Washington,D.C.20005.IMPORTANT INFORMATION CONCERNING USE OFASBESTOS OR ALTERNATIVE MATERIALSAsbestos is specified or referenced for certain components of the equipment described insome API standards.It has been of extreme usefulness in minimizing fire hazards associ-ated with petroleum processing.It has also been a universal sealing material,compatiblewith most refining fluid services.Certain serious adverse health effects are associated with asbestos,among them the se-rious and often fatal diseases of lung cancer.asbestosis,and mesothelioma(a cancer of thechest and abdominal linings).The degrce of exposure to asbestos varies with the productand the work practices involved.Consult the most recent edition of the Occupational Safety and Heaith Administration(OSHA),U.S.Department of Labor.Occupational Safety and Health Standard for As-bestos,Tremolite,Anthophyllite,and Actinolite.29 Code of Federal Regulations Section1910.1001;the U.S.Environmental Protection Agency,National Emission Standard for As-bestos,40 Code of Federal Regulations Sections 61.140 through 61.156;and the U.S.En-vironmental Protection Agency(EPA)rule on labeling requirements and phased banning ofasbestos products,published at 54 Federal Register 29460(July 12,1989).There are currently in use and under development a number of substitute materials to re-place asbestos in certain applications.Manufacturers and users are encouraged to developand use effective substitute materials that can meet the specifications for,and operatingrequirements of,the equipment to which they would apply.SAFETY AND HEALTH INFORMATION WITH RESPECT TO PARTICULARPRODUCTS OR MATERIALS CAN BE OBTAINED FROM THE EMPLOYER,THEMANUFACTURER OR SUPPLIER OF THAT PRODUCT OR MATERIAL,OR THEMATERIAL SAFETY DATA SHEET