1、Environmental Conditionsfor Process Measurementand Control Systems:Mechanical InfluencesApproved 12 January 1995ANSI/ISAS71.031995AMERICAN NATIONAL STANDARDCopyright 1995 by the Instrument Society of America. All rights reserved. Printed in the UnitedStates of America. No part of this publication ma
2、y be reproduced, stored in a retrieval system, ortransmitted in any form or by any means (electronic, mechanical, photocopying, recording, orotherwise), without the prior written permission of the publisher.ISA67 Alexander DriveP.O. Box 12277Research Triangle Park, North Carolina 27709ANSI/ISA-S71.0
3、3, Environmental Conditions for Process Measurement and Control Systems: Mechanical InfluencesISBN: 1-55617-576-0ANSI/ISA-S71.03-1995 3PrefaceThis preface, as well as all footnotes and annexes, is included for informational purposes only and is not part of ANSI/ISA-S71.03.This standard has been prep
4、ared as part of the service of ISA, the international society for measurement and control, toward a goal of uniformity in the field of instrumentation. To be of real value, this document should not be static but should be subject to periodic review. Toward this end, the Society welcomes all comments
5、 and criticisms and asks that they be addressed to the Secretary, Standards and Practices Board; ISA; 67 Alexander Drive; P. O. Box 12277; Research Triangle Park, NC 27709; Telephone (919) 990-9227; Fax (919) 549-8288; e-mail: standardsisa.org.The ISA Standards and Practices Department is aware of t
6、he growing need for attention to the metric system of units in general, and the International System of Units (SI) in particular, in the preparation of instrumentation standards, recommended practices, and technical reports. The Department is further aware of the benefits to USA users of ISA standar
7、ds of incorporating suitable references to the SI (and the metric system) in their business and professional dealings with other countries. Toward this end, this Department will endeavor to introduce SI-acceptable metric units in all new and revised standards to the greatest extent possible. The Met
8、ric Practice Guide, which has been published by the Institute of Electrical and Electronics Engineers as ANSI/IEEE Std. 268-1992, and future revisions, will be the reference guide for definitions, symbols, abbreviations, and conversion factors.It is the policy of ISA to encourage and welcome the par
9、ticipation of all concerned individuals and interests in the development of ISA standards. Participation in the ISA standards-making process by an individual in no way constitutes endorsement by the employer of that individual, of ISA, or of any of the standards, recommended practices, and technical
10、 reports that ISA develops.This document is one of several standards that address various environmental conditions affecting process measurement and control systems. In developing this standard, the committee goals included the following:1) To provide a practical standard that can be applied with a
11、minimum of research and technical effort by the user.2) To provide a concise method of stating environmental classifications for convenient communications between all users of the standard.3) To cover real-world ranges of each classified parameter.The following people served as members of ISA Commit
12、tee SP71:NAME COMPANYK. Gulick, Chairman Digital Equipment Corporation*M. Zielinski, Managing Director FisherRosemountD. Boyle Consultant*One vote per company4 ANSI/ISA-S71.03-1995NAME COMPANY*D. Brown FisherRosemountR. Calcavecchio ConsultantR. Cowles Union Camp CorporationE. Demers Foxboro Company
13、L. Falat Westvaco Technical CenterR. Funwela U.S. SteelM. Hopkins KeyTek Instrument CorporationM. Huza Flanders/FCP MicroenvironmentalE. Lee U.S. Nuclear Regulatory AgencyL. Leonard ConsultantT. Mallory Power Safety InternationalC. Muller Purafil, Inc.A. Perkins Rhorback Cosasco SystemsJ. Saine Weye
14、rhaeuser Company*T. Schey Allen-Bradley CompanyT. Shelton Westvaco CorporationK. Stickrod ABB*R. Turk Allen-Bradley CompanyJ. Vajda Modicon, Inc.*C. Yi FisherRosemountThis standard was approved for publication by the ISA Standards and Practices Board on January 2, 1995.NAME COMPANYM. Widmeyer, Vice
15、President Washington Public Power Supply SystemH. Baumann H. D. Baumann, Inc.D. Bishop Chevron USA Production CompanyP. Brett Honeywell, Inc.W. Calder III Calder EnterprisesH. Dammeyer Phoenix Industries, Inc.R. Dieck Pratt shock class C1 would represent a class C location and a level 1 severity.4 D
16、efinitions4.1 operating conditions, normal: The range of operating conditions within which an instrument is designed to operate and for which operating influences are stated.4.2 storage conditions: The conditions to which an instrument may be subjected prior to installation. Also included are the co
17、nditions that may exist during shutdown. No permanent physical damage or impairment of operating characteristics shall take place under these conditions.5 Location classification5.1 Explanation of instrument locations and mechanical influence classesA broad distribution of shock and vibration levels
18、 exists within industries that use process measurement and control equipment. Each of these levels may produce an effect that ranges between insignificant and catastrophic. The effects of shock and vibration depend on the type of equipment, method of application, and frequency of occurrence. They ar
19、e also influenced by external factors such as temperature and corrosion. See ANSI/ISA-S71.01 and ANSI/ISA-S71.04 standards for Environmental Conditions for Process Measurement and Control Systems.ANSI/ISA-S71.03-1995 11Table 1 is set up in such a way as to classify exposures by environment type and
20、frequency-acceleration response, as described in Annex A.5.2 Instrument locations5.2.1 Environment “A“ locations, defined as controlled mechanical influence environments, are those areas usually provided for sensitive process measurement and control systems that require a controlled environment.5.2.
21、2 Environment “B“ locations, defined as uncontrolled mechanical influence environments, are process measurement and control system areas outside the controlled environment but not affected directly by the process.5.2.3 Environment “C“ locations, defined as uncontrolled mechanical influence environme
22、nts, are process measurement and control system areas outside of the controlled area that are directly affected by the process.5.3 Class of mechanical influence5.3.1 Class 1, low severity This designation applies to an environment that is within the 90th percentile of the data recorded, as described
23、 in Annex A.5.3.2 Class 2, moderate severityThis designation applies to an environment that is within the 95th percentile of the data recorded, as described in Annex A.5.3.3 Class 3, harsh severityThis designation applies to an environment that is within the 99th percentile of the data recorded, as
24、described in Annex A.5.3.4 Class X, severeThis designation applies to an environment in which the mechanical influence causes total and unrecoverable loss of the use of an essential function. In this environment, the limit exceeds the 99th percentile of the data recorded and described in Annex A or
25、is subject to negotiation between user and supplier.12 ANSI/ISA-S71.03-1995Table 1 Vibration1Refer to Annex A.2See 5.2 for definition of operating environment.3See 5.3 for definition of mechanical influence.4See 5.3 for percentile occurrence classification.5Constant acceleration measured in meters m
26、/sec2. Divide by 9.81 to get acceleration in gs (based on value of gat sea level: g=9.81 m/sec2.)6Peak displacement measured in millimeters (mm).7Use peak displacement (s) below 8 Hz to 9 Hz. Use constant acceleration (a) above 8 Hz to 9 Hz.8TBS = To Be Specified.Table 2 Shock1TBS = To Be Specified2
27、Not to exceed values listedOperation vibration classes, percentiles, and environment(1, 3, 7)Environment2Class3/Percentile41/90th 2/95th 3/99th X/SpecialConstant acceleration5/Peak displacement6VA 1.0/0.35 2.0/0.75 5.0/1.6 TBS8VB 2.0/0.75 5.0/1.6 10.0/3.5 TBSVC 10.0/3.5 20.0/7.5 50.0/16.0 TBSWeight
28、(kg) Environment ClassFree fall Height(cm)1/2 sine acceleration2(m/sec2)200 SC1x30TBS20TBSANSI/ISA-S71.03-1995 136 Example of intended usage6.1 The manufacturer and/or user should specify the system performance in a stated environ-mental class. The following example shows how a manufacturer or user
29、might specify several sets of environmental classes for operating or maintaining the same system.Example 1Conditions Shock and vibration classNormal operating conditions, vibrations VA2Normal operating conditions, shock SB1Storage and handling VC3 SC1 This example might be used by an instrument manu
30、facturer to indicate the following:a) The system is designed to operate within a control room type of environment with a maximum indicated vibration mechanical influence class 2.b) The system is designed to operate at shock levels normally experienced by equipment located on the shop floor with a ma
31、ximum indicated limit mechanical influence class 1.c) The system can be stored and handled with a vibration maximum indicated limit listed as class 3 and a shock maximum indicated limit listed as class 1.ANSI/ISA-S71.03-1995 15Annex A Vibration test programA.1 IntroductionIn the preparation of this
32、series of standards that deal with environmental conditions for process measurement and control systems, it was determined that insufficient data were available to describe the vibration levels of operating instrumentation. Therefore, in conjunction with the preparation of this standard, a study was
33、 conducted to gather vibration information through the process industry in the United States and Canada. The data gathered were used to establish the vibration tables of this standard.NOTE All raw test data used in the preparation of this standard are the property of ISA.The vibration analyzer that
34、was purchased for this study is normally used on rotating machinery. After each series of tests, the analyzer was recalibrated to assure repeatability. A.2 Testing procedureA.2.1 Test equipmentThe accelerometer of the vibration analyzer was mounted to a magnet and was sensitive in the direction perp
35、endicular to the force of the magnet. Measurements were taken on three planes for each location where equipment would normally be mounted. Peak acceleration was recorded for frequency ranges of 0-100 Hz and 0-2000 Hz.The field data were then processed to generate frequency-acceleration graphs and sh
36、ow the 99th, 95th, and 90th percentiles for all the data collected in this program.A.2.2 Surfaces to be testedA device measurement requires that the vibration levels be recorded in three different directions.The accelerometer was mounted:a) perpendicular to the mounting surface;b) parallel to the mo
37、unting surface; andc) perpendicular to the first two positions.A.2.3 Testing procedureAfter mounting the accelerometer, the test chart was placed in the platen, the battery level was checked, the range switch was set to 2000 Hz, and the test was started. The test was completed in about one minute. I
38、f any information existed in the 0-200 Hz range, the pen color was changed, the range switched to 200 Hz, and the test run again.The test was repeated with the accelerometer placed in each of the positions listed in 2.2 above.16 ANSI/ISA-S71.03-1995A.2.4 Documentation of dataIn addition to specific
39、test technician, date, and other relevant information, the following data were collected for each test.A.2.4.1 Process description: Identify industry and process as petroleum, pulp and paper, steel, mining, etc.A.2.4.2 Type: Identify application and instrument as temperature, pressure, flow, level,
40、computer, etc.A.2.4.3 Type of mounting: State type and description such as pipe, floor, panel, rack, etc.A.2.4.4 Location Environmental: Specify exposed, sheltered, control room.A.2.4.5 Remarks: Describe anything that may have significantly influenced the test or the analysis of its results (e.g., t
41、ruck passing during test).Developing and promulgating technically sound consensus standards, recommended practices, and technical reports is one of ISAs primary goals. To achieve this goal the Standards and Practices Department relies on the technical expertise and efforts of volunteer committee mem
42、bers, chairmen, and reviewers.ISA is an American National Standards Institute (ANSI) accredited organization. ISA administers United States Technical Advisory Groups (USTAGs) and provides secretariat support for International Electrotechnical Commission (IEC) and International Organization for Standardization (ISO) committees that develop process measurement and control standards. To obtain additional information on the Societys standards program, please write:ISAAttn: Standards Department67 Alexander DriveP.O. Box 12277Research Triangle Park, NC 27709ISBN: 1-55617-576-0
