1、 Guide for hot tapping on piping and other equipment PUBLICATION 185 Edition 2 Released by IHS. NOT FOR RESALE THE ENGINEERING EQUIPMENT AND MATERIALS USERS ASSOCIATION Guide for hot tapping on piping and other equipment PUBLICATION 185 Edition 2 Copyright 2011 The Engineering Equipment and Material
2、s Users Association. A company limited by guarantee. Registered in England. Company number 477838. ISBN 0 85931 186 1 Imprint reference 08-2011 Registered and Trading Address 10-12 Lovat Lane London EC3R 8DN Telephone: +44 (0)20 7621 0011 Fax: +44 (0)20 7621 0022 E-mail: saleseemua.org Website: www.
3、eemua.org EEMUA Publication 185 - Guide for hot tapping on piping and other equipment 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 governed by a Council of member
4、s. This Council is responsible for the policies, financing, membership, and strategy of the Association. Any organisation that is a substantial user or purchaser of engineering products is eligible to apply to become a member of EEMUA. Membership is subject to the approval of Council. EEMUA Aims EEM
5、UA aims to improve the safety, environmental and operating performance of industrial facilities in the most cost-effective way, pursuing and promoting leadership in industrial asset management by sharing engineering experiences and expertise, and by the active, enlightened promotion of the distinct
6、interests of users of engineering products. These aims are achieved by various means, including: Providing the organisation within which networking, information sharing and collaboration among users on non-competitive technical matters can take place Influencing the way written regulations are inter
7、preted and applied in practice Promoting and presenting members views, and encouraging the application of good sound engineering practices Developing user guides, specifications, training and competency schemes Facilitating members participation in national and international standards making Influen
8、cing relevant national and European legislation and regulation. Incorporation, Membership and Other Information The income and resources of EEMUA are applied solely towards the promotion of the aims of the Association. No profit is transferred by way of dividend, bonus or otherwise to members. The w
9、ork of the Association is mainly carried out by members representatives on EEMUA Technical Committees, Working Groups, and Forums, supported by EEMUA staff. For the purposes of conducting its business, EEMUA is incorporated in England and Wales as a company, limited by guarantee, not having share ca
10、pital. All usual aspects of company management and business administration are dealt with by the EEMUA Executive Director, including policy implementation and leadership of the Executive team (the staff). To enquire about corporate Membership, write to enquirieseemua.org or call +44 (0)20 7621 0011.
11、 A list of EEMUA publications for sale is given at the end of this Publication. The full list is also on the Associations website, including details of on-line shopping facilities. EEMUA Publication 185 - Guide for hot tapping on piping and other equipment EEMUA iii ABOUT THIS PUBLICATION Legal Aspe
12、cts All rights, title and interest in this Publication belong to EEMUA. All rights are reserved. 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 other, without the express prio
13、r written agreement of the EEMUA Executive Director. Infringement of copyright is illegal and also reduces the Associations income thereby jeopardising its ability to fund the production of future publications. It has been assumed in the preparation of this Publication that: the user ensures selecti
14、on of those parts of its contents appropriate to the intended application; and that such selection and application is correctly carried out by appropriately qualified and competent persons for whose guidance this Publication has been prepared. EEMUA and the individual members of the Work Group that
15、prepared this EEMUA publication do not, and indeed cannot, make any representation or give any warranty or guarantee in connection with material contained herein. EEMUA and the individual members of the Work Group that prepared this EEMUA publication expressly disclaim any liability or responsibilit
16、y for damage or loss resulting from the use or reliance on this Publication. Any recommendations contained herein are based on the most authoritative 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 s
17、ubsequent developments and/or legislation. Any person who encounters an inaccuracy or ambiguity when making use of this Publication is asked to notify EEMUA without delay so that the matter may be investigated and appropriate action taken. Consultation and Feedback EEMUA encourages constructive comm
18、ents on this Publication from both Members of the Association and others. Comments should be sent on the standard feedback form, a copy of which is provided towards the end of this Publication. An electronic version of the feedback form is available from EEMUA - e-mail your request for a copy to enq
19、uirieseemua.org, telephone your request to +44 (0)20 7621 0011, or download the form from the EEMUA website at www.eemua.org. Submit comments by e-mail (preferred) or post. Comments are considered by the relevant EEMUA Technical Committees and may be incorporated in future editions of this Publicati
20、on. New editions are publicised on the EEMUA website. EEMUA Publication 185 - Guide for hot tapping on piping and other equipment EEMUA iv EEMUA Publication 185 - Guide for hot tapping on piping and other equipment EEMUA v Contents Foreword . vii 1. Introduction 1 1.1 Scope 1 1.2 Definition of Terms
21、 1 1.2.1 Hot Tap . 1 1.2.2 Coupon 1 1.2.3 Trepanning . 1 2. Safety Considerations . 3 2.1 General 3 2.2 Hazard Assessment and Control . 3 2.3 Safe System of Work . 3 3. Technical Considerations . 5 3.1 Chemical Reaction Between Process Fluid and Piping Material 5 3.2 Process Fluid Limitations. 5 3.3
22、 Materials of Construction 6 3.4 Physical Restraints and Limitations . 7 3.4.1 Nozzle Size . 7 3.4.2 Lined Equipment . 7 3.4.3 Underground Piping . 7 3.5 Location . 8 3.6 Wall Thickness, Material Temperature and System Pressure . 9 3.7 Flow 9 3.8 Debris from Tapping Operation 9 4. Design . 11 5. Wel
23、ding . 13 5.1 Welding Procedure . 13 5.2 Buttering 13 5.3 Welding Preparation . 14 5.3.1 Coating Removal . 14 5.3.2 Surface Cleaning . 14 5.3.3 Inspection 14 5.3.4 Roundness Test 14 5.3.5 Internal Condition . 14 5.3.6 Welding Return Cable 14 5.3.7 Welding Engineer/Inspector 14 5.4 NDE of Pipe and We
24、ld 14 5.5 Check on Welding Current 15 6. Leak Testing 17 6.1 General 17 6.2 Procedure and Test Pressures 17 7. Procedure 19 7.1 Planning the Operation . 19 7.2 Documentation and Checklists . 19 7.2.1 Documentation . 19 7.2.2 Checklist for Proposed Hot Tap Operation . 20 7.2.3 Checklist before Commen
25、cing the Operation 20 7.2.4 Checklist before Commencement of Welding . 20 7.2.5 Checklist on Completion of Welding 21 7.2.6 Checklist before Commencement of Cutting 21 7.2.7 Checklist before Removing the Hot Tap Machine 21 8. Special Applications 23 8.1 General 23 EEMUA Publication 185 - Guide for h
26、ot tapping on piping and other equipment EEMUA vi 8.2 Flare Lines 23 8.3 Pressure Vessels . 23 8.4 Tanks 23 8.5 Miscellaneous Equipment 23 Appendix A: Typical Weights/Dimensions of Hot Tapping Equipment . 25 Appendix B: Typical Approval Document . 27 References 29 Bibliography 31 Figures Figure 1 Ex
27、ploded Schematic of Hot Tapping Machine Assembly . 8 Figure 2 Typical Connections . 11 EEMUA Publication 185 - Guide for hot tapping on piping and other equipment EEMUA vii Foreword This Publication has been developed by EEMUA and in particular its Piping Systems Committee, to give guidance on the v
28、arious factors, procedures and activities which need to be considered, implemented and executed before a hot tapping operation can be safely and successfully carried out. As the great majority of hot tapping operations are performed on piping, EEMUA 185 is written with specific reference to that act
29、ivity. Nevertheless, the principles outlined are generally applicable to hot tapping on other types of equipment, taking due account of obvious differences (for example the absence of fluid flow when hot tapping a storage tank). Being a guide, this Publication does not impose mandatory requirements
30、(i.e. avoidance of the use of the word shall). However there are situations in which for reasons of safety it would be inappropriate to carry out a hot tap. In such instances wording such as safety considerations would preclude . is used to draw attention to the potential hazard. Attention is drawn
31、to the need to observe local statutory or other regulatory requirements. These may impose legal obligations on the designer and/or on other persons involved in the operation. Units This Publication employs SI units, but additionally includes Imperial units where appropriate to common usage. Note: ba
32、r signifies bar gauge. EEMUA Publication 185 - Guide for hot tapping on piping and other equipment EEMUA viii EEMUA Publication 185 - Guide for hot tapping on piping and other equipment EEMUA 1 1. Introduction 1.1 Scope This Publication applies to hot tapping into metallic piping systems containing
33、process fluids or their residues. Additionally, information is provided for special hot tapping applications such as on storage tanks. It covers the welding and cutting (drilling/trepanning) operations and other technical considerations, and gives guidance on how to carry out a safe operation. 1.2 D
34、efinition of Terms 1.2.1 Hot Tap A method of making connections to piping (or other equipment) by attaching a fitting to the system, usually by welding, followed by cutting through the pipe wall at the point of attachment utilising an appropriate (hot tapping) machine. This operation is generally ca
35、rried out on a live (hot) system without decommissioning or interrupting flow. 1.2.2 Coupon A disc cut out of the wall of the pipe (or other equipment) during the hot tapping operation. 1.2.3 Trepanning The process of cutting into the wall of the pipe (or other equipment) using shell cutters operate
36、d by a hot tapping machine. It is usually carried out on the live system and involves the removal of a coupon of material. EEMUA Publication 185 - Guide for hot tapping on piping and other equipment EEMUA 2 EEMUA Publication 185 - Guide for hot tapping on piping and other equipment EEMUA 3 2. Safety
37、 Considerations 2.1 General Hot tapping should be undertaken only when no reasonably practicable alternative is available. For systems handling flammable and/or toxic fluids, normal procedures require that welding work be carried out only when the system is free of process fluid (gas free) and open
38、to atmosphere. In some circumstances this requirement may necessitate shutting down a large plant or section thereof, which in itself may introduce hazards for example through the need to remove and store process fluid. In such circumstances there may be justification for giving consideration to hot
39、 tapping. This operation, however, introduces its own hazards which demand careful consideration. 2.2 Hazard Assessment and Control Before undertaking hot tapping, all potential hazards should be identified and assessed, and detailed procedures for their control established. The principal potential
40、hazards associated with hot tapping are: Explosion and fire resulting from the effects of heat on the process fluid contained within the system. Burn-through associated with the temporary loss of strength of the pipe wall during welding. Loss of integrity of the pressure envelope at the point of hot
41、 tap, for example by corrosion or embrittlement of the pipe wall due to reaction with the contents of the process system. The release of the systems contents which may be flammable, toxic or asphyxiating. Carrying out welding operations in a Hazardous Area. For systems that contain or have contained
42、 only non-flammable substances reference should also be made to British Standard BS 6990(1). 2.3 Safe System of Work A written safe system of work or safety plan should be produced. This needs to be fully understood by all those involved with the operation. The document should be based upon expert a
43、dvice, the guidance given in BS 6990, and any legislative requirements. It should anticipate all reasonably foreseeable events and specify the appropriate emergency services required to be in place. It should also define individual responsibilities. The safe system of work should be prepared for eac
44、h hot tapping operation by the person responsible for the hot tap or their nominated representative, and this should be agreed by all relevant parties. The plan should be brief, otherwise it becomes self defeating. Suggested topics are: temporary supports and lifting equipment; EEMUA Publication 185
45、 - Guide for hot tapping on piping and other equipment EEMUA 4 access to site for personnel and equipment; communications on site; foreseeable hazards and contingency actions; roles of dedicated personnel and their responsibilities on site; monitoring of process conditions; monitoring of welding par
46、ameters; warning system and emergency shutdown plan; means of escape; safety equipment and personnel; fire-fighting equipment and personnel; first-aid facilities; and weather protection. EEMUA Publication 185 - Guide for hot tapping on piping and other equipment EEMUA 5 3. Technical Considerations T
47、he considerations which follow are not exhaustive, and due thought should be given to each and every hot tapping operation to identify and take account of any other pertinent factors. 3.1 Chemical Reaction Between Process Fluid and Piping Material Piping containing fluids which under the influence o
48、f heat would react with the metal wall or have a deleterious effect on the physical and mechanical properties of the pipe or weld should not be subjected to hot tapping. Such fluids include monoethanolamine (MEA), diethanolamine (DEA), caustic soda, caustic potash, ammonia, hydrofluoric acid, sour g
49、as (H2S) and any other fluid known or believed to cause stress corrosion cracking. 3.2 Process Fluid Limitations Safety considerations would preclude welding on piping containing the fluids listed below. Flammable gas and air mixtures. Compressed air where oil or oil vapour used for lubrication of equipment may be present, or where the absence of hydrocarbons cannot be assured. Chlorine or chlorine compounds. Oxygen or oxygen-enriched air. Acids, ammonium nitrate, acetylene or
