AMERICAN NATIONAL STANDARD
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ANS 1/1 SA-9 1.O0.O 1-2 O0 1
Identification of Emergency Shutdown Systems and Controls That Are Critical to Maintaining
Safety in Process Industries
ISBN: 1-55617-756-9
Copyright O 2001 by ISA-The Instrumentation, Systems, and Automation Society. All rights reserved. Not
for resale. 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
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P. O. Box 12277
Research Triangle Park, North Carolina 27709
USA
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ANSI/ISA-91.00.01-2001
-3-
Preface
This preface, as well as all footnotes and annexes, is included for information purposes and is not part of
ANSI/ISA-91.00.01-2001.
This document has been prepared as part of the service of ISA-The Instrumentation, Systems, and
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welcomes all comments and criticisms and asks that they be addressed to the Secretary, Standards and
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Telephone (919) 549-8411; Fax (919) 549-8288; E-mail: standards@isa.org.
The ISA Standards and Practices Department is aware of the growing need for attention to the metric
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APPLICATIONS OR ADDRESS ALL POSSIBLE SAFETY ISSUES ASSOCIATED WITH USE IN
HAZARDOUS CONDITIONS. THE USER OF THIS STANDARD MUST EXERCISE SOUND
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ANS 1/1 SA-9 1.O0.O 1-2 O0 1
-4-
PROFESSIONAL JUDGMENT CONCERNING ITS USE AND APPLICABILITY UNDER THE USERS
PARTICULAR CIRCUMSTANCES. THE USER MUST ALSO CONSIDER THE APPLICABILITY OF ANY
GOVERNMENTAL REGULATORY LIMITATIONS AND ESTABLISHED SAFETY AND HEALTH
PRACTICES BEFORE IMPLEMENTING THIS STANDARD.
NAME
COMPANY
G. Ramachandran, Chairman
V. Maggioli, Managing Director
R. Adamski
A. Barrett
L. Baruwa
N. Battikha
K. Bond
R. Boyd
L. Brown
J. Carew
M. Casada
W. Cohen
A. De Souza
R. Ehrlicher
A. Engels
D. Fritsch
W. Goble
J. Gray
C. Hardin
D. Haysley
T. Hurst
W. Johnson
N. Kohatriya
D. Leonard
E. Lewis
G. McFarland
N. McLeod
W. Mostia
I. Nimmo
R. Raghavan
J. Shaw
C. Sossman
H. Storey
R. Szanyi
T. Walczak
Cytec Industries, Inc.
Feltronics Corp.
Premier Consulting Services
Control Equipment Corp.
Bechtel Power Corp.
Bergo Tech, Inc.
Equilon LLC
RVB Management and Engineering Consultants, Inc.
Advanced Technology Applications Corp.
Consultant
JBF Assoc., Inc.
Kellog Brown & Root
Tandem Technology Group
Sy ngenta
Praxair, Inc.
Fritsch Consulting Service
Exida Com LLC
As pen Tech nology
CDH Consulting, Inc.
Albert Garaody & Associates
Hurst Technologies Corp.
E. I. du Pont
H-R International, Inc.
D. J. Leonard Consultants
Consultant
Westinghouse Process Control, Inc.
Atofina
WLM Engineering Co.
Baw Architecture UCDS
Raytheon Systems, Inc.
Process Control Solutions
WG-W Safety Management Solutions
Equilon Enterprises LLC
Exxon Mobil Research Engineering
GE Fanuc Automation
This standard was approved for publication by the ISA Standards and Practices Board on
21 March 2001.
NAME
COMPANY
M. Zielinski
D. Bishop
M. Cohen
M. Coppler
Fisher-Rosemount Systems, Inc.
Consultant
Senior Flexonics, Inc.
Ametek, Inc.
Copyright The Instrumentation, Systems, and Automation Society
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The following people served as members of ISA SP91:
B. Dumortier
W. Holland
E. Icayan
A. Iverson
R. Jones
V. Maggioli
T. McAvinew
A. McCauley, Jr
G. McFarland
D. Rapley
R. Reimer
J. Rennie
H. Sasajima
I. Verhappen
R. Webb
W. Weidman
J. Weiss
M. Widmeyer
R. Wiegle
C. Williams
G. Wood
Copyright The Instrumentation, Systems, and Automation Society
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Schneider Electric
Southern Company
Advanced Control & Engineering Solutions
Ivy Optiks
Dow Chemical Co.
Feltronics Corp.
Merrick & Co.
Chagrin Valley Controls, Inc.
Westinghouse Process Control Inc.
Rapley Consulting Inc.
Rockwell Automation
Factory Mutual Research Corp.
Yamatake Corp.
Syncrude Canada Ltd.
Altran Corp.
Parsons Energy & Chemicals Group
EPRI
EG&G Defense Materials
CANUS Corp.
Eastman Kodak Co.
Graeme Wood Consulting
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ANSI/ISA-91.00.01-2001
-5-
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Copyright The Instrumentation, Systems, and Automation Society
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-7-
ANSI/ISA-91.00.01-2001
Contents
9
2 Scope ...............................................................................................................................................
3 Definitions
4 Procedure .........................................................................................................................................
5 References .....................................................................................................................................
10
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1 Purpose ............................................................................................................................................
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Copyright The Instrumentation, Systems, and Automation Society
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ANSI/ISA-91.00.01-2001
-9-
Purpose
1.1 Establish a procedure to identify the emergency shutdown systems and safety critical controls that
are keyto maintaining safety in the process industries as defined in the Mechanical Integrity and Maintenance
sections of Process Safety Management (PSM) regulations such as Occupational Safety and Health
Administration (OSHA) Federal Regulation 29 CFR 1910.119 (reference 5.1), and Risk Management
Program (RMP) regulations such as U.S. Environmental Protection Agency Regulation 40 CFR Part 68
(reference 5.2).
1.2 Mechanical integrity and maintenance are major elements in PSM and RMP programs. In this
standard, provisions for mechanical integrity and maintenance apply to the following equipment:
a) Emergency shutdown systems
b) Safety critical controls (including monitoring devices and sensors, alarms, and interlocks)
Scope
2.1 This standard addresses the instruments that are classified as emergency shutdown systems and
safety critical controls and establishes requirements for testing and documenting the test results of these
systems.
This standard does not address codes, regulations, and other requirements that apply only to the nuclear
power industry.
Definitions
3.1 basic process control system:
the control equipment installed to perform the normal regulatory functions for the process (e.g., PID control
and sequential control).
Other common terms used for emergency shutdown systems include safety instrumented systems, safety
shutdown systems, protective instrument systems, and safety interlock systems.
3.3 safety critical control:
a control whose failure to operate properly will directly result in a catastrophic release of toxic, reactive,
flammable, or explosive chemical.
4
4.1
Procedure
Identifcation
4.1.1 Emergency shutdown systems and safety critical controls should be identified during a process
hazard analysis for those events judged likely to occur at an unacceptable frequency.
4.1.2 Emergency shutdown systems and safety critical controls shall be identified and documented in a
manner that clearly distinguishes them from other control systems, such as the basic process control
system.
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3.2 emergency shutdown system:
instrumentation and controls installed for the purpose of taking the process, or specific equipment in the
process, to a safe state. This does not include instrumentation and controls installed for non-emergency
shutdowns or routine operations. Emergency shutdown systems may include electrical, electronic,
pneumatic, mechanical, and hydraulic systems (including those systems that are programmable).
ANS 1/1 SA-9 1.O0.O 1-2 O0 1
4.2
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Maintenance and testing
4.2.1 All emergency shutdown systems and safety critical controls shall be periodically tested and
maintained in accordance with user system test procedures taking into account system manufacturer
recommendations.
Date of inspection
Name of person who performed the test
Serial number or other unique identifier of the equipment
Results of the test as compared to user-defined acceptance criteria
A description of the test(s) performed
References
U.S. Department of Labor, Occupational Safety and Health Administration (OSHA), Federal
Regulation 29 CFR 1910.119, Process-Safety Management of Highly Hazardous Chemicals, Explosives,
and Blasting Agents; Final Rule, February 24, 1992.
5.2 U.S. Environmental Protection Agency (EPA), Federal Regulation 40 CFR Part 68, Risk Management
Programs for Chemical Accidental Release Prevention.
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4.2.2 The periodic tests of the emergency shutdown systems and safety critical controls shall contain
the following minimum documentation:
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Developing and promulgating sound consensus standards, recommended practices, and technical reports
is one of ISA's primary goals. To achieve this goal the Standards and Practices Department relies on the
technical expertise and efforts of volunteer committee members, 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
Society's standards program, please write:
ISA
Attn: Standards Department
67 Alexander Drive
P.O. Box 12277
Research Triangle Park, NC 27709
USA
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ISBN:1-55617-756-9
Copyright The Instrumentation, Systems, and Automation Society
Provided by IHS under license with ISA
No reproduction or networking permitted without license from IHS
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