Norma isa-20-1981

STANDARD

ISA–20–1981
Formerly ISA–S20–1981

Specification Forms for Process Measurement and Control Instruments, Primary Elements, and Control Valves

Approved 30 October 1981
TM

ISA–The Instrumentation, Systems, and Automation Society

ISA-20-1981, Specification Forms for Process Measurement and Control Instruments, Primary Elements and Control Valves ISBN 0-87664-347-0 Copyright© 1981 by the Instrument Society of America. All rights reserved. Printed in the United States of America. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior written permission of the publisher. ISA 67 Alexander Drive P.O. Box 12277 ResearchTriangle Park, North Carolina 27709

Preface

This Preface is included for information purposes and is not part of ISA-20-1981. This Standard has been prepared as a part of the service of the ISA toward a goal of uniformity in the field of instrumentation. To be of real value this report should not be static, but should be subjected to periodic review. Toward this end the Society welcomes allcomments and criticisms, and asks that they be addressed to the Standards and Practices Board Secretary, ISA, 67 Alexander Drive, P Box 12277, .O. Research Triangle Park, North Carolina 27709, Telephone (919) 549-8411, Fax (919) 549-8288, e-mail: standards@isa.org. This document was prepared by the Subcommittee on Instrument Specification Forms (RP20.1) and was originally published in 1956 underthe direction of G. G. Gallagher of the Fluor Corporation. In 1961 additional forms were published, prepared by Committee 8D-RP20 under the direction of W. Carmack of the Fluor Corporation. This revision was prepared, with the supervision of the Chairman, R. E. Frey of Rohm and Haas Company, by the committee as listed below. SP20 COMMITTEE NAME R. E. Frey (deceased) W. S. Buzzard J. G. Converse G.F. Erk J. Imber R. D. Irwin E. F. Kremer R. Leese R. D. Prescott A. Rosenthol F. J. Ryan, Jr. W. C. Thomas COMPANY Rohm and Haas Company Fisher and Porter Company Sun Oil Company Sun Oil Company Atlantic Richfield Company Honeywell, Inc. E. I. duPont deNemours & Co., Inc. Catalytic Inc. Moore Products Company Catalytic Incorporated Clifford B. Ives & Co., Inc. Clifford B. Ives & Co., Inc.

Theassistance of those who aided in the preparation of this Standard, by their review of the draft and by offering suggestions toward its improvement, is gratefully acknowledged. The following have reviewed the report and served as Board of Review: NAME C. B. Anderson W. A. Bajek A. S. Bartholomew C. S. Beard J. V. Becker O. K. Booth L. R. Brewer
ISA-S20-1981

COMPANY Armstrong Cork Company UOPProcess Division Reliance Electric Company Bechtel Corporation National Load North American Rockwell Koppers Company, Inc.
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A. M. Calabrese F. I. Callisen C. P. Clark G. T. Clawson R. Coel L. Costea W. G. Cozart E. Csaky J. W. Eby M. W. Fifer W. Forsyth G. G. Gallagher W. J. Greter H. P. Haas L. A. Haines M. G. Haines W. Y. Harkins E. J. Hayter J. E. Holland E. A. Houser P. Kindersley L.Kipnis C. D. Kolbe W. B. Kostiw E. R. Langston P E. Larsen . B. G. Liptak R. Loewe F. Maltby C. A. Master A. F. Marks M. W. Marxen C. McCrain R. T. Miller H. E. Nurmi P. L. Pettersen E. Podolak C. Pray H. D. Preszler C. A. Prior G. R. Rauschenberg J. Rellford W. A. Richards E. J. Rogers D. E. Sanchez

M. W. Kellogg Company C. F. Braun & Company United Technology Center Goddard Space Flight CenterThe Fluor Corporation Hunt-Wesson Foods Dow Chemical Company Dow Chemical Company Honeywell, Inc. Proctor & Gamble Honeywell, Inc. The Fluor Corporation Union Carbide Corporation Philco-Ford Valter, Inc. Allied Chemical Corporation Tennessee Eastman Company Allied Chemical Corporation E. I. duPont deNemours & Company Beckman Instruments Kamyr Inc. Instrumentation Consultant NASA Stone & Webster...