_API_RP_551_1993.pdf

API RP*55193073229005118b8371Process MeasurementInstrumentationAPI RECOMMENDED PRACTICE 551FIRST EDITION.MAY 1993American Petroleum Institute1220 L Street,NorthwestWashington,D.C.20005亚COPYRIGHT 2002:American Petroleum Institutethe Document Policy Management Group at 1-800-451-1584.API RP*5519307322900511870T2TSPECIAL NOTES1.API PUBLICATIONS NECESSARILY ADDRESS PROBLEMS OF A GENERALNATURE.WITH RESPECT TO PARTICULAR CIRCUMSTANCES,LOCAL,STATE.AND FEDERAL LAWS AND REGULATIONS SHOULD BE REVIEWED.2.API IS NOT UNDERTAKING TO MEET THE DUTIES OF EMPLOYERS,MANU-FACTURERS,OR SUPPLIERS TO WARN AND PROPERLY TRAIN AND EQUIPTHEIR EMPLOYEES,AND OTHERS EXPOSED,CONCERNING HEALTH ANDSAFETY RISKS AND PRECAUTIONS,NOR UNDERTAKING THEIR OBLIGATIONSUNDER LOCAL,STATE,OR FEDERAL LAWS.3.INFORMATION CONCERNING SAFETY AND HEALTH RISKS AND PROPERPRECAUTIONS WITH RESPECT TO PARTICULAR MATERIALS AND CONDI-TIONS SHOULD BE OBTAINED FROM THE EMPLOYER,THE MANUFACTUREROR SUPPLIER OF THAT MATERIAL,OR THE MATERIAL SAFETY DATA SHEET.4.NOTHING CONTAINED IN ANY API PUBLICATION IS TO BE CONSTRUED ASGRANTING ANY RIGHT,BY IMPLICATION OR OTHERWISE,FOR THE MANU-FACTURE,SALE,OR USE OF ANY METHOD,APPARATUS,OR PRODUCT COV-ERED BY LETTERS PATENT.NEITHER SHOULD ANYTHING CONTAINED INTHE PUBLICATION BE CONSTRUED AS INSURING ANYONE AGAINST LIABIL-ITY FOR INFRINGEMENT OF LETTERS PATENT.5.GENERALLY,API STANDARDS ARE REVIEWED AND REVISED,REAF-FIRMED.OR WITHDRAWN AT LEAST EVERY FIVE YEARS.SOMETIMES A ONE-TIME EXTENSION OF UP TO TWO YEARS WILL BE ADDED TO THIS REVIEWCYCLE.THIS PUBLICATION WILL NO LONGER BE IN EFFECT FIVE YEARS AF-TER ITS PUBLICATION DATE AS AN OPERATIVE API STANDARD OR,WHEREAN EXTENSION HAS BEEN GRANTED,UPON REPUBLICATION.STATUS OF THEPUBLICATION CAN BE ASCERTAINED FROM THE API AUTHORING DEPART-MENT TELEPHONE(202)682-8000.A CATALOG OF API PUBLICATIONS ANDMATERIALS IS PUBLISHED ANNUALLY AND UPDATED QUARTERLY BY API,1220 L STREET,N.W.,WASHINGTON,D.C.20005.Copyright 1993 American Petroleum InstituteCOPYRIGHT 2002:American Petroleum Institutethe Document Policy Management Group at 1-800-451-1584.API RP*55193073229005118719bbFOREWORDThe procedures for installation of the instruments covered in this recommended practiceare based on experience with and evaluation of many installations.They represent the in-stallation practices that yield the most consistently accurate results and have proved to bepractical and safe.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 Manufac-turing,Distribution and Marketing Department,American Petroleum Institute,1220 LStreet,N.W.,Washington,D.C.20005.COPYRIGHT 2002:American Petroleum Institutethe DoPolicy Management Group a1-004511584.API RP*5519307322900518728T2IMPORTANT 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 degree of exposure to asbestos varies with the productand the work practices involved.Consult the most recent edition of the Occupational Safety and Health 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.COPYRIGHT 2002:American Petroloum Institutethe Document Policy Management Group at 1-800-451-1584.