This document provides guidelines for hot bolting procedures when removing and replacing flange bolts on pressurized piping or equipment. Key steps include removing only one bolt at a time, ensuring operating pressure is below 75% of the maximum allowable working pressure at operating temperature, and having emergency plans in place. The document outlines criteria, pre-job requirements, and safety guidelines that must be followed when conducting hot bolting.

1. DOC ID
© Chevron 2005
CABGOC HOT BOLTING PROCEDURE
By FE Construction Group
November 2005

2. © Chevron 2005 2
CONTENTS
SUMMARY
INTRODUCTION
DEFINITION AND SCOPE
CRITERIA
PRE-JOB REQUIREMENTS
SAFETY GUIDELINES
PROCEDURE

3. © Chevron 2005 3
SUMMARY
 Sequential removal and replacement of flange bolts
and nuts.
 Only one bolt at a time.
 On piping or process systems containing
pressurized materials.

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INTRODUCTION
 Each activity should be considered on its individual
merits.
 Each activity should follow the guidelines identified.
 Guidelines are subject to limitations applied to
standard flanges.
 For any doubt consult competent person.

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DEFINITION AND SCOPE
 When preparing for equipment maintenance and
repair.
 Only when all others methods are fully considered
and reasonably dismissed.
 Not advisable when bolts have suffered significant
metal loss.
 Safe approach: depressurize equipment and
change bolts off-line.

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CRITERIA
 No hot bolting during simultaneous hot work.
 Bolt cutting by any hot method is not allowed.
 Consideration must be given for certain cold cutting
equipment.
 If these options are not feasible then a low impact
flogging method is acceptable.
 Operating pressure must be less than 75 % of the
MAWP at the operating temperature.
 Flange must have a minimum of 8 bolts.

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CRITERIA (Continued)
 Temperature must be between 40°F and 160°F.
 No excessive vibration are allowed in the system.
 Gasket must not show signs of leakage.
 Piping, flanges and bolts must not be severely
corroded.
 Existing flange bolts must be tight and of the
correct size and grade.

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PRE-JOB REQUIREMENTS
 PSR & RMP and GWP approvals are required.
 General Work Permit
Pre-job safety meeting and JSA checklist.
 Piping or process system inspection.
 Proper materials and tools.
 MAWP and temperature.
 Emergency plan of action / Spill containment
 Location of upstream and downstream isolation
sources.
 Control of potential ignition source.

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SAFETY GUIDELINES
 Barrier off the hot bolting area.
 Wear appropriate PPE, including safety eyewear.
 Monitor gas presence before and during hot bolting
operations.
 Maintain radio communications with Operations.
 For any significant change, cease all hot bolting and
re-evaluate before continuing.
 Never leave flanges with bolts missing during
breaks or at shift end.

10. © Chevron 2005 10
PROCEDURE

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PROCEDURE (Continued)
 For any doubt contact CABGOC FE-Construction
group for further information.
 Exceptions to the above guidelines must be
reviewed / approved by CABGOC FE Construction
management.

12. © Chevron 2005 12
Questions and answers