EEMUA PUB NO 159-2015 Above ground flat bottomed storage tanks A guide to inspection maintenance and repair (Edition 4).pdf

1、THE ENGINEERING EQUIPMENT AND MATERIALS USERS ASSOCIATION This publication has been made available for release by IHS NOT FOR RESALE Any organisation that is a substantial user or substantial purchaser of engineering products may apply to become a member of EEMUA. THE ENGINEERING EQUIPMENT AND MATER

2、IALS USERS ASSOCIATION Above ground flat bottomed storage tanks Guide to inspection, maintenance and repair PUBLICATION 159 Edition 4 Copyright 2014 The Engineering Equipment and Materials Users Association. A company limited by guarantee. Registered in England. Company number 477838. ISBN 978 0 859

3、31 205 9 Imprint reference 05-2015 First published 06-2014 Registered and Trading Address 63 Mark Lane London EC3R 7NQ Telephone: +44 (0)20 7488 0801 Fax: +44 (0)20 7488 3499 E-mail: saleseemua.org Website: www.eemua.org EEMUA Pulication 159 - Flat bottomed tanks - inspection, maintenance and repair

4、 EEMUA ii ENGINEERING EQUIPMENT AND MATERIALS USERS ASSOCIATION About EEMUA The Engineering Equipment and Materials Users Association is usually known by its initials, EEMUA. EEMUA is an Association established by the owners and operators of industrial assets. Any organisation that is a substantial

5、user or substantial purchaser of engineering products may apply to become a member of EEMUA. Membership is subject to the approval of Council. EEMUA aims EEMUA aims to improve the safety, environmental and operating performance of industrial facilities in the most cost-effective way, pursuing and pr

6、omoting leadership in industrial asset management by sharing engineering experiences and expertise, and by the active, enlightened promotion of the distinct interests of users of engineering products. These aims are achieved by various means, including: Providing the organisation within which networ

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12、.org or call +44 (0)20 7488 0801. EEMUA Pulication 159 - Flat bottomed tanks - inspection, maintenance and repair EEMUA iii ABOUT THIS PUBLICATION Legal aspects All rights, title and interest in this Publication belong to EEMUA. All rights are reserved. No part of this Publication may be reproduced,

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17、ive information available at the time of writing and on current good engineering practice, but it is essential for the user to take account of pertinent subsequent developments and/or legislation. Any person who encounters an inaccuracy or ambiguity when making use of this Publication is asked to no

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20、(preferred) or post. Comments are considered by the relevant EEMUA Technical Committees and may be incorporated in future editions of this Publication. New editions are publicised on the EEMUA website. EEMUA Pulication 159 - Flat bottomed tanks - inspection, maintenance and repair EEMUA ivEEMUA Puli

21、cation 159 - Flat bottomed tanks - inspection, maintenance and repair EEMUA v Contents Preface xvi 1 Introduction and scope . 1 1.1 Introduction . 1 1.2 Scope 1 1.3 Codes and history 2 1.4 Abbreviations 2 2 Tanks and their components: Terminology and materials of construction . 5 2.1 Tank components

22、 5 2.2 Glossary of terms 7 2.3 Types of storage tanks . 10 2.3.1 Standard atmospheric storage tanks 10 2.4 Materials 17 2.4.1 Ambient conventional storage tanks . 17 3 Degradation mechanisms and failure modes . 19 3.1 General corrosion 19 3.2 Tank settlement and consequential problems 20 3.3 Structu

23、ral failure and/or failure of tank components/appendages . 20 3.4 Combination of degradation mechanisms and other influences . 21 3.5 Microbial Induced Corrosion (MIC) . 21 4 Corrosion of tanks . 23 4.1 General 23 4.2 Corrosion rates . 23 4.3 Bottom plates . 23 4.3.1 Failure modes under consideratio

24、n . 23 4.3.2 Bottom plates (underside/external) 25 4.3.3 Bottom plates (topside/internal) 26 4.4 Shell plates (internal and external) 27 4.5 Roof plates . 28 4.5.1 Fixed roofs including roof support structure . 28 4.5.2 Floating roofs including supporting legs 29 4.6 Corrosion Under Insulation (CUI)

25、 . 30 4.7 Corrosion of stubs and appendages 31 5 General inspection techniques and interpretation of inspection data 33 5.1 References . 33 5.1.1 Inspection and maintenance . 33 5.1.2 Assessing the tank norm or standard . 36 5.2 Inspection 39 5.2.1 General 39 5.2.2 Operator observations 41 5.2.3 Rou

26、tine and detailed visual inspections . 42 5.2.4 In-service inspection 42 5.2.5 Out-of-service inspection 43 5.2.6 Safety considerations during inspection 45 5.3 Ultrasonic thickness measurements 45 5.3.1 General 45 5.3.2 Phased Array Ultrasonic Testing (PA UT) 46 5.3.3 Alternating Current Field Meas

27、urement (ACFM) 48 5.3.4 Tank shell measurement 49 5.3.5 Tank bottom measurement . 51 5.3.6 Tank roof measurement . 52 5.3.7 Measurement of nozzles and manhole neck plates 54 EEMUA Pulication 159 - Flat bottomed tanks - inspection, maintenance and repair EEMUA vi 5.4 Evaluation of localised shell ins

28、pection data . 56 6. Tank foundations . 59 6.1 General 59 6.1.1 Introduction . 59 6.1.2 Failure modes of tank foundations . 59 6.2 Soil settlement 60 6.2.1 Settlement under loads 60 6.2.2 Consolidated settlement . 60 6.3 Effects of soil settlement 60 6.3.1 Even (uniform) settlement 60 6.3.2 Tank she

29、ll settlement into the foundation 61 6.3.3 Difference in soil settlement between centre and periphery of the tank61 6.3.4 Uneven settlement 64 6.3.5 Edge settlement 65 6.3.6 Planar tilt . 66 6.3.7 Differential shell settlement around circumference . 67 6.3.8 Evaluation and measurements for shell out

30、 of roundness 68 6.4 Leakage . 69 6.5 Maximum tolerances and limits for settlement and out-of-verticality of tank shell . 69 6.5.1 Planar tilt/out-of-verticality . 70 6.5.2 Edge Settlement . 76 6.5.3 Differential settlement . 77 6.5.4 Sagging/centre-to-edge bottom settlement . 79 6.5.5 Bottom ripple

31、s 79 6.6 Re-levelling of tank foundations . 80 6.7 Tank lifting operations 81 6.7.1 Preliminaries . 81 6.7.2 Tank lifting . 82 6.7.3 Wind loading 82 6.7.4 Safety measures against wind damage . 83 6.8 Repair/modification methods - some typical examples 83 7 Tank bottoms (with or without annular plate

32、s) . 85 7.1 General 85 7.2 Introduction . 85 7.3 Determination of floor thickness and condition . 86 7.4 Rejection limits . 88 7.4.1 Floor area 88 7.4.2 Annular area . 89 7.4.3 Annular projection . 90 7.5 Bulges and depressions in tank bottom plates . 94 7.6 Cathodic protection 95 7.7 Repair/modific

33、ation methods - some typical examples 95 8 Tank shells 97 8.1 General 97 8.2 Determination of effective shell plate thickness and condition 98 8.3 Rejection limits for shell plates 99 8.3.1 Liquid Load and vapour pressure . 99 8.3.2 Wind and vacuum loads . 102 8.3.3 Roof loads 103 8.3.4 Pit corrosio

34、n assessment 104 8.4 Minimum thickness calculations for riveted tank shells. . 104 8.5 Top wind girder and intermediate wind stiffeners . 105 EEMUA Pulication 159 - Flat bottomed tanks - inspection, maintenance and repair EEMUA vii 8.5.1 Shell top wind girders 105 8.5.2 Intermediate wind stiffeners

35、. 106 8.6 Buckling problems of tank shells and top wind girders 108 8.6.1 Buckling problems of tank shells 108 8.6.2 Shell top wind girders 111 8.7 Manholes, nozzles and connecting piping 112 8.7.1 Shell manholes and nozzles 112 8.7.2 Connecting piping 113 8.7.3 Rejection limits shell nozzles . 114

36、8.8 Clean-out doors and openings . 115 8.8.1 Clean-out doors 115 8.8.2 Clean-out openings 115 8.9 Earthing . 116 8.10 Repair/modification methods - some typical examples 117 9 Tank roofs - general 119 9.1 Introduction . 119 9.2 Determination of roof plate thickness and condition 119 9.3 Degradation

37、limits fixed roofs 119 9.3.1 Supported fixed roof 119 9.3.2 Roof supporting structure . 121 9.3.3 Self-supporting fixed roof . 122 10 Fixed roofs (cone roofs and dome roofs) . 123 10.1 General 123 10.2 Roof manholes and nozzles . 124 10.3 Roof vents (ventilation of tanks) and emergency relief vents

38、124 10.3.1 The functioning of roof vents . 124 10.3.2 Venting requirements for fixed roof tanks 126 10.3.3 Inspection and maintenance of roof vents . 127 10.3.4 Possible ventilation problems. 129 10.3.5 Flame arresters . 131 10.3.6 Pressure test of the fixed roof 132 10.3.7 Temporary closure of open

39、ings in open vents or pressurevacuum valves during operation 132 10.3.8 Protection against static electricity and lightning 133 10.4 Column supported roofs 133 10.4.1 Internal Inspection and repair . 134 10.4.2 Tank jacking or lifting . 134 10.4.3 Column design 134 10.5 Membrane (self-supporting) ro

40、of 134 10.6 Internal Floating Covers (IFCs) 135 10.7 Repair/modification methods . 137 11 Floating roofs 139 11.1 Types 139 11.1.1 General 139 11.1.2 Pontoon type floating roofs . 139 11.1.3 Double-deck floating roofs 141 11.1.4 Special roofs such as buoy type and radially reinforced roofs . 142 11.

41、2 Degradation limits . 142 11.2.1 General corrosion 142 11.2.2 Pit corrosion . 144 11.3 Roof drains . 144 11.3.1 General 144 11.3.2 Steel articulated primary roof drains . 146 11.3.3 Flexible hose primary roof drains . 147 EEMUA Pulication 159 - Flat bottomed tanks - inspection, maintenance and repa

42、ir EEMUA viii 11.3.4 Special primary roof drains . 148 11.3.5 Siphon drains 148 11.3.6 Emergency roof drains . 148 11.4 Roof seals. 149 11.4.1 General 149 11.4.2 Design . 155 11.4.3 Rim seal materials . 155 11.4.4 Seal replacement . 156 11.5 Roof supporting legs 157 11.6 Floating roof venting 157 11

43、.7 Rolling ladders 159 11.8 Earthing of floating roofs 161 11.9 Guidelines for the operation of floating roofs 161 11.9.1 Introduction 161 11.9.2 Before the roof is taken into service . 161 11.9.3 During the first month of operation 161 11.9.4 During operation . 162 11.9.5 Before landing the roof .

44、162 11.9.6 Roof standing on its supports 162 11.9.7 Recommended filling rates for floating roof tanks . 163 11.9.8 Ballooning of single-deck floating roof 163 11.10 Possible problems 165 11.10.1 Leaking pontoon compartments . 165 11.10.2 Cracking in centre deck due to wind loading 165 11.10.3 Out-of

45、-roundness tolerances . 166 11.11 Repair/modification methods . 167 11.11.1 Overplating . 167 11.12 Snow loading 167 11.12.1 Inspection history 167 11.12.2 Removal of the snow 168 11.12.3 Operation of the tank . 168 11.13 Aluminium dome roofs 168 12 Tank appendages 171 12.1 Shell and roof nozzles 17

46、1 12.2 Floating suction lines 172 12.2.1 Design . 173 12.2.2 Operational experiences . 173 12.2.3 Inspection 173 12.3 Ladders, stairways, platforms/railings and lighting . 173 12.4 Side entry mixers 174 12.5 Tank instrumentation . 174 12.5.1 General/records 174 12.5.2 Instrument and component failur

47、e due to external corrosion 176 12.5.3 Electronic instruments 176 12.5.4 Tank cooling and fire protection system 176 13 Tank coatings 179 13.1 Introduction 179 13.2 External coating systems 179 13.2.1 General 179 13.2.2 Bottom. 180 13.2.3 Shell and roof . 180 13.3 Internal coating systems 180 13.3.1

48、 General 180 13.3.2 Bottom. 182 EEMUA Pulication 159 - Flat bottomed tanks - inspection, maintenance and repair EEMUA ix 13.3.3 Shell and Roof . 182 13.4 Repair/modification methods - some typical examples 182 14 Tank insulation 183 15 Hydrotesting . 187 15.1 General 187 15.2 Hydrotesting after repa

49、ir and modification . 187 15.2.1 Full hydrostatic test . 187 15.2.2 Partial hydrostatic test . 188 15.2.3 No hydrostatic test 188 15.2.4 No hydrostatic test (API 653 exemptions) . 188 15.3 Requirements for hydrotesting . 189 15.3.1 Pipe connections 189 15.3.2 Water quality 189 15.3.3 Test temperature . 190 15.3.4 Filling rates . 190 15.3.5 Maximum filling height . 193 15.3.6 Holding time . 193 15.3.7 Emptying after hydrotest 193 15.4 Settlement monitoring 194 16 Re-siting of vertical tanks . 195 16.1 General 195 16.2 Moving using a crane with spreader beam . 195