Interior Lining and Periodic Inspection of Underground Storage Tanks

API STANDARD 1631 FIFTH EDITION, JUNE 2001

REAFFIRMED, MAY 2020

Interior Lining and Periodic Inspection of Underground Storage Tanks

Downstream Segment

API STANDARD 1631 FIFTH EDITION, JUNE 2001

REAFFIRMED, MAY 2020

SPECIAL NOTES

API publications necessarily address problems of a general nature. With respect to partic- ular circumstances, local, state, and federal laws and regulations should be reviewed.

API is not undertaking to meet the duties of employers, manufacturers, or suppliers to warn and properly train and equip their employees, and others exposed, concerning health and safety risks and precautions, nor undertaking their obligations under local, state, or fed- eral laws.

Information concerning safety and health risks and proper precautions with respect to par- ticular materials and conditions should be obtained from the employer, the manufacturer or supplier of that material, or the material safety data sheet.

Nothing contained in any API publication is to be construed as granting any right, by implication or otherwise, for the manufacture, sale, or use of any method, apparatus, or prod- uct covered by letters patent. Neither should anything contained in the publication be con- strued as insuring anyone against liability for infringement of letters patent.

Generally, API standards are reviewed and revised, reaf?rmed, or withdrawn at least every

?ve years. Sometimes a one-time extension of up to two years will be added to this review cycle. This publication will no longer be in effect ?ve years after its publication date as an operative API standard or, where an extension has been granted, upon republication. Status of the publication can be ascertained from the API Downstream Segment [telephone (202) 682-8000]. A catalog of API publications and materials is published annually and updated quarterly by API, 1220 L Street, N.W., Washington, D.C. 20005.

This document was produced under API standardization procedures that ensure appropri- ate noti?cation and participation in the developmental process and is designated as an API standard. Questions concerning the interpretation of the content of this standard or com- ments and questions concerning the procedures under which this standard was developed should be directed in writing to the standardization manager, American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005. Requests for permission to reproduce or translate all or any part of the material published herein should also be addressed to the gen- eral manager.

API standards are published to facilitate the broad availability of proven, sound engineer- ing and operating practices. These standards are not intended to obviate the need for apply- ing sound engineering judgment regarding when and where these standards should be utilized. The formulation and publication of API standards is not intended in any way to inhibit anyone from using any other practices.

Any manufacturer marking equipment or materials in conformance with the marking requirements of an API standard is solely responsible for complying with all the applicable requirements of that standard. API does not represent, warrant, or guarantee that such prod- ucts do in fact conform to the applicable API standard.

All rights reserved. No part of this work may be reproduced, stored in a retrieval system, or transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher. Contact the Publisher,

API Publishing Services, 1220 L Street, N.W., Washington, D.C. 20005.

Copyright ? 2001 American Petroleum Institute

FOREWORD

API Standard 1631 provides recommendations for lining the interior of existing steel and

?berglass reinforced plastic underground petroleum storage tanks and periodic inspections of lined steel tanks. This standard was prepared under the auspices of the API Manufactur- ing, Distribution and Marketing Department and is based upon the experience of knowledge- able members of the petroleum industry and lining manufacturers. This standard is intended for use by API member companies and others to develop safe practices and procedures for lining and inspecting underground tanks storing petroleum products. A number of additional API standards and recommended practices as well as government and industry regulations and publications, noted in the reference section, provide supplemental information applica- ble to the requirements and components of this standard.

API publications may be used by anyone desiring to do so. Every effort has been made by 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 publication and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any federal, state, or municipal regulation with which this publication may con?ict.

Suggested revisions are invited and should be submitted to the standardization manager, American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005.

iii

CONTENTS

Page

1. GENERAL 1

   1. Scope 1

   2. Applicability 1

   3. EPA Technical Standards 1

2. REFERENCES 1

   1. General 1

   2. Industry and Consensus Codes, Standards and Publications 1

   3. United States Government Regulations and Standards 2

3. DEFINITIONS 3

   1. General 3

   2. De?nitions 3

   3. Use of Other Units (Conversion) 7

4. OBJECTIVES, REQUIREMENTS AND SPECIFICATIONS 7

   1. Objectives 7

   2. Permit and Training Requirements 7

   3. Tank Lining Speci?cations 7

5. PREPARATION FOR OPENING THE TANK 8

   1. Safety Precautions 8

   2. Sources of Ignition 8

   3. Tank Isolation 8

   4. Removal of Liquid Product 9

   5. Removal of Flammable Vapors (Vapor-Freeing) and Ventilation 9

   6. Testing Flammable Vapor Concentrations 10

6. TANK ENTRY 10

   1. Providing a Tank Opening 10

   2. Tank Entry Precautions 11

   3. Potential Toxicity and Health Hazards 13

7. PREPARATION OF THE TANK INTERIOR 14

   1. Sludge Removal 14

   2. Potential Toxic Exposures 14

   3. Tank Inspection 14

   4. Surface Preparation 15

8. APPLICATION OF LINING 16

   1. Entry and Safe Work Requirements 16

   2. Lining Requirements 16

   3. Steel Tanks 16

   4. Fiberglass Tanks 17

   5. Lining Testing 17

      
      

      v

      Page

9. RETURNING TANKS TO SERVICE 17

   1. Steel Tanks 17

   2. Fiberglass Tanks 19

   3. Tank Tightness Testing 19

10. PERIODIC INSPECTIONS OF PREVIOUSLY LINED STEEL TANKS 19

    1. General 19

    2. Tank Preparation 19

    3. Video Inspections of Tank Linings 20

    4. Physical Inspections?Tank Lining Requirements 20

    5. Physical Inspection?Tank Metal Thickness Requirements 20

    6. Tank Closure or Upgrading 21

Figures

1. Eductor-Type Air Mover 10

2. Diffused Air Blower 11

3. Method for Installation of Tank Cover Plate 18

4. Alternate Cover Plate Installation Detail 18

Forms

FORM A?CONTRACTOR?S EMPLOYEE CONFINED SPACE

ENTRY & SAFETY TRAINING CERTIFICATION 22

FORM B?INSPECTION AFFIDAVIT 23

FORM C?TANK RE-INSPECTION AFFIDAVIT 25

Interior Lining and Periodic Inspection of Underground Storage Tanks

1. General

   1. SCOPE

      This standard provides minimum recommendations for the interior lining of existing steel and ?berglass reinforced plas- tic underground tanks and periodic inspection of steel under- ground tanks used for the storage of petroleum-based motor fuels and middle distillates. These recommendations include procedures to be followed and operating conditions to be maintained by contractors, workers and engineers preparing, inspecting, testing and lining the interiors of existing under- ground storage tanks. Requirements for vapor-freeing tanks, removing sediment and cleaning interior surfaces of steel and

      ?berglass tanks as well as guidelines to identify tanks that are suitable for lining, are also included. All work associated with the interior lining and periodic inspection of underground storage tanks shall be accomplished in accordance with appli- cable federal, state, and local regulations, including applica- ble environmental and safety requirements.

      
      

   2. APPLICABILITY

      The methods described in this standard are applicable to steel and ?berglass-reinforced plastic tanks used for the stor- age of petroleum-based motor fuels and middle distillates. The procedures are applicable to tanks installed in typical retail service station outlets but may also be used for tanks installed at other types of facilities.

      
      

   3. EPA TECHNICAL STANDARDS

      The U.S. Environmental Protection Agency (EPA) issued its Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage Tanks (UST) (herein referred to as ?Technical Standards?) in 1988. These regulations can be found in the Code of Federal Regu- lations at 40 CFR Part 280. In addition, legislation and regu- lations on all aspects of underground storage tank management have been developed by state and local jurisdic- tions that may have requirements other than those speci?ed in the EPA Technical Standards. Therefore, employers should consult the appropriate government agencies responsible for implementing an approved underground storage tank pro- gram within a geographic area of interest, and determine the applicable requirements before any action recommended or suggested by this standard is taken.

      The EPA Technical Standards allow this standard to be used as a guide for compliance with EPA?s requirements for interior lining and periodic inspection of underground storage tanks. In some respects, the requirements of this standard may be more stringent than the EPA Technical Standards. In addition, this standard is not intended to cover all of the sub-

      1

      
      

      jects included in the EPA Technical Standards. While sub- stantial effort has been made to ensure that none of this standard?s requirements contradict those of the EPA Techni- cal Standards, the API is not undertaking to interpret the EPA Technical Standards and cannot guarantee that the recom- mendations in this standard are completely in accord with them. Also, the API makes no representation that the require- ments of this standard conform with any requirements imposed by state and local agencies.

      
      

2. References

   1. GENERAL

      The following government regulations and standards and industry and consensus standards, codes, and publications ref- erenced herein* provide information related to safe entry, vapor freeing, ventilation, cleaning, lining and inspection of underground petroleum storage tanks. While this standard is intended to be consistent with applicable codes and standards in effect at the time of publication, the most recent edition of each regulation, code, standard or publication that is applica- ble, should be consulted, as appropriate, to assure compliance.

      
      

   2. INDUSTRY AND CONSENSUS CODES, STANDARDS AND PUBLICATIONS

API

RP 651 Cathodic Protection of Aboveground Stor- age Tanks

RP 652 Lining of Aboveground Petroleum Storage Tank Bottoms

RP 1604 Closure of Underground Petroleum Stor- age Tanks

RP 1615 Installation of Underground Petroleum Storage Systems*

RP 1632 Cathodic Protection of Underground Petroleum Storage Tanks and Piping Systems*

RP 2003 Protection Against Ignitions Arising out of Static, Lightning, and Stray Currents

Std 2015 Safe Entry and Cleaning of Petroleum Storage Tanks

RP 2016 Entering and Cleaning Petroleum Storage Tanks

Publ 2027 Ignition Hazards Involved in Abrasive Blasting of Atmospheric Storage Tanks in Hydrocarbon Service

Publ 2217A Guidelines for Work in Inert Con?ned Spaces in the Petroleum Industry

Publ 2219 Safe Operating Guidelines for Vacuum Trucks in Petroleum Service