Guideline Protection Measures on Reinforced Concrete Cooling Towers and Chimneys against Operational and Environmental Impacts VGB-R 612 e Third Edition 2010
Published by: VGB PowerTech e.V. Obtainable from: VGB PowerTech Service GmbH Publisher of techno-scientific papers P.O. Box 10 39 32, 45039 Essen, Germany Phone +49 201 8128-200 Fax +49 201 8128-329 E-mail:
[email protected]
ISBN 978-3-86875-129-1
www.vgb.org Reproduction in whole or in part only with prior permission of the Publishers.
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Preface As a result of particular impacts and stresses affecting reinforced concrete cooling towers and chimneys and strengthend by their special structures and conditions of operation, adequate instructions are required for contractors initially applying or renewing surface protection systems. This Guideline therefore takes the form of additional technical stipulations to supplement the existing standards and codes. In this spirit, the Guideline is intended to assist the customer as an aid to decision-making and a basis for inviting tenders, placing orders and performing work of this kind. The customer in this context may be the owner and/or operator or a company employed by these. Other applicable VGB publications on newly constructed cooling towers and chimneys include the Guidelines “Structural Design of Cooling Towers” (VGB-R 610) [19] and “Planning of Cooling Towers” (VGB-R 135) [18] as well as the Instruction Sheets “Industrial Chimneys – Evaluation of Designs, Notes on Construction and Commissioning” (VGB-M 642) [21] and “Chimneys for Operation without Flue Gas Reheating after FGD” (VGB-M 643) [22]. This Guideline is of particular importance in conjunction with the VGB Guideline “Code of Practice for Lifecycle Management of Reinforced Cooling Towers in Power Plants” (VGB-R 613 e) [20], the practical transposition of which is intended to ensure the usability of cooling towers throughout their service lives, preserving the function of surface protection systems. Recommendations for chimneys can be found in the VGB brochure “Zustandsüberwachung von Schornsteinen” (Condition Monitoring on Chimneys) (VGB-B 602) [23]. This Guideline does not cover measures to protect components in other materials, in particular mounting parts installed on and in cooling towers and chimneys. VGB does not guarantee that the state of the art is completely reflected in every case. No liability is accepted for the factual accuracy of the information presented. Patents and industrial property rights are to be observed by the users on their own responsibility. The Guideline was edited by a Project Group in the VGB Working Panel on “Stacks, Cooling Towers and other Special Buildings” on behalf of the VGB Technical Committee on “Civil Engineering”. The members of the Project Group were as follows: P. Blömeke, Gelsenkirchen S. Bruder, Kriftel D. Busch, Essen A. Dorge, Werne H. Eisenkrein, Dortmund R. Engelfried, Herdecke K. Kothes, Moosburg a. d. Isar Ch. Kotz, Bochum A. Langhorst, Duisburg J. Lenz, Essen
Th. Mark, Stuttgart D. Mey, Moritzburg M. Rolfes, Stuttgart E. Rossmann, Essen H. Scharf, Grevenbroich H. Schwarze, Bottrop M. Sonntag, Peitz R. Stadie, Berlin B. Titze, Cottbus (Chairman) M. Will, Bottrop
They were assisted by the following as consultants: F.-J. Nunier, Essen J. Schmidberger, Cologne The publishers are grateful for their cooperation. Essen, November 2010 VGB PowerTech e. V.
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Exclusion of Liability The VGB-Guidelines and VGB-Instruction Sheets are recommendations which may be applicated by everyone. The person using this guideline must however ensure the right application for each case. They consider the state of technological development at the time of the respective version. No one can be exempted of responsibility for his own actions by using the VGB-Guidelines or VGB-Instruction Sheets. This means that everyone acts at their own risk. A liability for the VGB PowerTech and for the ones involved in the VGB-Guidelines or VGB-Instruction Sheets is excluded.
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CONTENTS 1
General...................................................................................................... 9
2
Additional standards and guidelines ................................................... 10
3
Terms and definitions ............................................................................ 12
4
Constructions and construction areas ................................................ 13
4.1
Natural draught cooling towers ...........................................................................13
4.2
Mechanical draught cooling towers.....................................................................13
4.3
Chimneys ...........................................................................................................16
5
Impacts ................................................................................................... 16
5.1
Environmental impacts .......................................................................................16
5.2
Impacts from the operation of cooling towers .....................................................16
5.3
Impacts from the operation of chimneys .............................................................17
6
Inspection of the existing condition for repairs, upgrading and retrofitting ............................................................................................... 18
6.1
General ..............................................................................................................18
6.2
Requirements for the professional planner .........................................................18
6.3
Duties of the professional planner ......................................................................19
7
Planning of stress-related surface protection systems...................... 19
7.1
Requirements for the surface protection systems ...............................................19
7.2
Application of surface protection systems on cooling towers ..............................21
7.2.1
General ..............................................................................................................21
7.2.2
Cooling towers in normal operation ....................................................................22
7.2.3
Cooling towers in seawater operation .................................................................22
7.2.4
Cooling towers with flue gas discharge ...............................................................22
7.3
Application of surface protection systems on chimneys ......................................23
8
Film thicknesses .................................................................................... 23
8.1
Definition ............................................................................................................23
8.2
Bases of calculation ...........................................................................................24
8.3
Proof of film thickness ........................................................................................25
6
9
Materials ..........................................................................................................26
9.1
Material systems ................................................................................................26
9.2
Requirements and properties .............................................................................27
9.2.1
Usability..............................................................................................................27
9.2.2
Properties ...........................................................................................................27
9.3
Suitability tests related to cooling towers ............................................................27
9.3.1
Corrosion protection ...........................................................................................27
9.3.2
(Surface) Levelling .............................................................................................27
9.3.3
Coating ...............................................................................................................27
9.3.3.1
Cooling towers – normal operation .....................................................................28
9.3.3.2
Cooling towers – seawater operation..................................................................28
9.3.3.3
Cooling towers – flue gas discharge ...................................................................28
9.3.3.4
Chimneys – outlet area.......................................................................................29
9.3.4
Special requirements for crack bridging capability ..............................................29
9.4
Suitability tests on the material systems .............................................................31
9.4.1
Usability tests (basic test) ...................................................................................31
9.4.2
Conformity tests .................................................................................................31
9.4.2.1
In-house production inspection ...........................................................................31
9.4.2.2
Third party inspection .........................................................................................31
9.5
Reference surfaces ............................................................................................31
10
Planning and quality assurance of the work ........................................ 31
10.1
Requirements for the company performing the work...........................................31
10.2
Execution planning .............................................................................................32
10.3
Safety at work on access devices .......................................................................32
11
Application of surface protection systems .......................................... 33
11.1
Preparation of the subsurface.............................................................................33
11.2
Pre-treatment of the subsurface .........................................................................33
11.2.1
Replacement of concrete....................................................................................33
11.2.2
Levelling .............................................................................................................34
11.3
Surface protection systems ................................................................................34
11.4
Surveillance ........................................................................................................35
11.4.1
Performance of internal quality assurance ..........................................................35
11.4.1.1
Film thickness checks.........................................................................................35
11.4.2
In-process inspection by third parties .................................................................35
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12
Inspection ............................................................................................... 35
13
Monitoring .............................................................................................. 36
14
Documentation ....................................................................................... 36
