COOLING TOWER INSTITUTE

CTI CODE TOWER Standard Specifications

Cooling Tower Filament WoundFiberglass Piping Systems

April 2008 STD-154 (08)

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ForewordThis Cooling Technology Institute (CTI) publication is published as an aid to cooling tower purchasers and designers. It may be used by anyone desiring to do so, and efforts have been made by CTI to assure the accuracy and reliability of the data contained herein. However, CTI makes no warranty of fitness for particular purpose or merchantability nor any other warranty expressed, implied or statutory. In no event shall CTI be liable or responsible for Incidental, Consequential or Commercial losses or damage of any kind resulting from this publication's use; or violation of any federal, state, or municipal regulation with which this publication may conflict or for the infringement of any patent resulting from the use of this publication.

All CTI codes and standards are copyrighted with all rights reserved to CTI. The reproduction of any part of this or any other CTI code or standard is a violation of Federal Law. One must recognize and appreciate commitment by a number of volunteer members who donate their time to develop and update CTI codes and standards. The monies spent for code development, administrative staff support and publication are essential and constitute a substantial drain on CTI. The purchase price of these documents helps to offset these costs. Reproduction and distribution by others, in addition to being unethical, undermines this system and constitutes a further financial drain on CTI. When copies are needed, you are requested to call or write the Cooling Technology Institute, P.O. Box 73383, Houston, Texas 77273, (281) 583-4087. Please request that your associates buy the required codes and standards rather than copy them. Your cooperation in this matter is greatly appreciated.

Nothing contained herein is to be construed as granting any right for the manufacture, sale or use in connection with any method, apparatus, or product covered by letters patent, nor as insuring anyone against liability for infringement of letters patent.

This guideline document summarizes the best current state of knowledge regarding the specific subject. This document represents a consensus of those individual members who have reviewed this document, its scope and provisions. It is intended to aid all users or potential users of cooling towers.

Approved by the CTI Executive Board.

This document has been reviewed and approved as part of CTI’s Five Year Review Cycle. This document is again subject to review in 2013.

Copyright 2008 Approved by the by Cooling Technology Institute CTI Executive Board Printed in U.S.A. STD-154 (08)

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TABLE OF CONTENT

Page

Section 1 Disclaimer ................................................................................................................................................ 3

Section 2 References ................................................................................................................................................ 3

2.1 American National Standards Institute (ANSI) ............................................................................. 3

2.2 National Bureau of Standards (NBS .............................................................................................. 3

2.3 American Society of Testing and Materials (ASTM) .................................................................... 3

Section 3 Material Requirements ............................................................................................................................. 3

3.0 Material Requirements .................................................................................................................. 3

3.1 Resin and Related Materials .......................................................................................................... 3

3.2 Reinforcements .............................................................................................................................. 4

3.3 Gaskets .......................................................................................................................................... 4

Section 4 FRP Piping Requirements ........................................................................................................................ 4

4.0 Fabricated Piping Requirements .................................................................................................... 4

4.1 Filament Wound Piping ................................................................................................................. 4

4.2 Piping Property Requirements ....................................................................................................... 5

4.3 Fittings ........................................................................................................................................... 5

4.4 Shop and Field Joints ..................................................................................................................... 5

Section 5 Testing Requirements ............................................................................................................................... 6

5.0 Testing Requirements .................................................................................................................... 6

5.1 Shop Testing .................................................................................................................................. 6

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Cooling Tower Filament Wound Fiberglass Piping Systems Design, Manufacturing and Testing Specification

Section 1. Disclaimer

1.0 Disclaimer: The information within this standard is for the design,

manufacturing, installation and testing of FRP piping to be used in Cooling Tower applications. However, the system must have an engineering review for the supporting system, pressure and any other outside requirements (i.e. Seismic, etc.). This review must be between the tower manufacturer and the piping manufacturer.

Section 2. References 2.0 Referenced Standards: Reference to the standards of any technical society,

organization, or association or to the laws, ordinances or codes of governmental authorities shall mean the latest code, or specification adopted, published and effective at the date of taking bids unless specifically stated otherwise in the specification. In the case of a conflict with the referenced specification, codes, or standards and these specifications, the latter shall govern to the extent of such difference.

2.1 American National Standards Institute (ANSI) B31.1 Power Piping B16.1 Cast Iron Pipe Hangers and Flanged Fittings B16.5 Steel pipe flanges, Flanged Valves & Fittings

2.2 National Bureau of Standards (NBS) NBS PS-15-69, Custom Contact Molded Reinforced

Polyester Chemical Resistant Process Equipment 2.3 American Society of Testing and Materials (ASTM)

C581 Standard Method of Testing for Chemical Resistance of Thermosetting Resins Used in Glass Fiber Reinforced Structures

D2290 Test Method for Apparent Tensile Strength of Ring or Tubular Plastics and Reinforced Plastics by Split Disk Method

D2292 Standard Practice for Obtaining Hydrostatic or Pressure Design Basis for “Fiberglass” (GFRTR) Pipe and Fittings

D2996 Standard Specification for Filament Wound “Fiberglass” (Glass-Fiber-Reinforced Thermosetting- Resin) Pipe

D3517 Standard Specification for Fiberglass (GFRTR) Pressure pipe

D1599 Short-Time Hydraulic Failure Pressure of Plastic Pipe

D2105 Longitudinal Tensile Properties of RTRP and Tube

D2563 Classifying Visual Defects in Glass- Reinforced Plastic Laminate Parts

D2583 Indention Hardness of Plastics, Barcol Impresser

D2584 Ignition Loss of Cured Reinforced Resins D2992 Standard Practice for Obtaining Hydrostatic or

Pressure Design Basis for “Fiberglass” (GFRTR) Pipe and Fittings

D3262 Standard Specification for “Fiberglass” (GFRTR) Sewer Pipe

D2412 Standard Test Method for Determination of External Loading Characteristics of Plastic Pipe by Parallel Plate Loading

D4161 Standard Specification for “Fiberglass” (GFRTR) Pipe Joints Using Flexible Elastomeric Seals

F477 Specification for Elastomeric Seals (Gaskets) for Joining Plastic Pipe

Section 3. Material Requirements 3.0 Material Requirements: 3.1 Resin and Related Materials

3.1.1 Resins – Piping and fittings shall be manufactured with a resin system suitable for handling the contained and surrounding environment. For non-fire retardant systems, the pipe corrosion barrier shall be a vinyl ester resin such as Ashland Chemical Hetron 922, or Dow Chemical Derakane 411 or an isophthalic polyester resin system such as Ashland Chemical Aropol 7341 or equal. The structural wall of the pipe shall be manufactured with any of the above resins. The exterior of the structural wall shall contain an ultra violet screen. For fire retardant systems, the pipe liner shall be a vinyl ester resin such as Ashland Chemical Hetron 922, or Dow Chemical Derakane 411 or an Isophthalic polyester resin system such as Ashland Chemical Aropol 7341. The structure wall of the pipe shall be manufactured with Ashland Chemical Hetron FR992 or isophthalic polyester resin system such as Ashland Chemical Aropol 99P or equal. The exterior of the structure wall shall contain an ultra violet screen. The manufacturer must have at least 5 years of product history manufacturing filament wound pipe using the resins listed above. 3.1.2 Adhesive – Polyester resin based materials containing short milled glass fibers and other reinforcements may be used to bond components, form a transition material in fiberglass butt joint welds and

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to mate surfaces prior to placement of an overlay. Such materials shall be compatible with the intended service, used sparingly in keeping with specific design requirements, and properly catalyzed. Asbestos may not be used.

3.1.3 Catalysts – The type and amount of resin catalysts, promoter and/or retardant shall be per the resin manufacturer procedures to develop the proper cure of the resin.

3.1.4 Fillers – The pipe shall not contain fillers, except for viscosity control and to aid in pigmentation with a weight percent limitation of 2 % by weight. The pipe shall not contain filler bulking agents such as micro spheres, sand, alumina, etc.

3.2. Reinforcements - 3.2.1 Surfacing Veil – A layer of “C” glass, or equivalent glass substitute, shall be used to reinforce the inner most ply of all pipe and fittings. The veil shall have a finish and binder compatible with the resin system to be used. 3.2.2 Synthetic Surfacing Veil – An organic polyester veil such as Nexus style 100-10 (12 – 16 mils) may be used as a substitute for “C” glass veil at the option of the pipe manufacture. 3.2.3 Chopped glass weighing 1.5 ounces per square foot and having a fiber length of 2 inches shall be used where required. Chopper gun applied material is only permitted where a mechanical mechanism controls the liner progression of the application rate, and the manufacturing procedure manual has a provision to validate by testing that this equivalent amount of chopped glass is applied. The glass shall be a “E” or “ECR” type material with a finish, which is compatible with the resin system to be used. 3.2.4 Filament Winding Glass – “E” type continuous strand roving of 247 yards per pound minimum yield, with a finish compatible with the resin system to be used in the filament winding. 3.2.5 Directional Glass Reinforcement – A woven directional fabric such as “E” glass with a finish compatible with the resin system to be used, shall be used in the contact molded (hand lay up) fabrication as approximate alternate layers with chopped glass. The reinforcement shall be a maximum of 24 ounces per square yard.

3.3 Gaskets – The gaskets shall conform to ASTM specification F477 with a vulcanized splice, a minimum Shore A durometer hardness of 50(plus/minus 5) and shall be made from a EPDM neoprene, or other compound suitable for the contained media, and service conditions.

Gaskets for flanges above 24-inch diameter and 50 psi shall be an “O” Ring type; lesser sizes and pressure may be flat face gasket 1/8-inch minimum thickness.

Gaskets and the design and testing of the joint for pipe Bell and Spigot gasket joints shall conform to the requirements of ASTM D4161. The gasket may be an “O” Ring or profile gasket configuration, which has historical experience and test confirmation for piping system.

Section 4. FRP Piping Requirements 4.0 Fabricated Piping Requirements: Fabricator shall

manufacture the fiberglass piping system having at least 5 years of experience providing filament wound fiberglass piping systems in diameters of 14 inch and larger. The fabricator shall provide a company certified report demonstrating ASTM D 2992 strain verified testing results with the bid or have on file with the cooling tower company. The fabricator shall state compliance per ASTM D2310, Classification RTRP-12EU. Failure to provide this documentation will be grounds for rejection of the bid as technically non-compliant.

4.1 Filament Wound Piping- The fiberglass piping shall be of a filament wound construction. Filament wound piping shall be designed and manufactured to comply with AWWA C950 standard and its Appendix being Type 1, Grade 2, Liner C, 25 PSI pressure class minimum, ASTM D 2310, Classification RTRP-12EU. Failure to provide this documentation will be grounds for rejection of the bid as technically non-compliant. The piping system shall be suitable for hydrostatic field testing to the hydrostatic test pressure, 1.5 times the design pressure. The piping shall be produced in a single length without intermediate joints and with an integral bell. The pipe minimum one piece produced lengths unless otherwise stated, shall be:

2” through 4” , 20 foot lengths, 6” , 30 foot length, 8” to 18” 40 foot lengths, Larger sizes in 60 foot lengths,

Or as otherwise defined by the purchaser who can permit a factory joint instead of one piece lengths.

4.1.1 Corrosion Barrier For Piping- All piping shall have an internal reinforced corrosion barrier. The internal corrosion barrier shall be .050 inches nominal thickness. This inner most surface shall be reinforced with surfacing veil having a maximum of 90 % resin content and the thickness of .010 inches. The balance thickness of the internal corrosion barrier shall be made using chopped glass (1.5 ounces per square foot minimum) and shall have a glass content of 24 to 31 percent by weight when tested per ASTM D2584. The corrosion barrier, when cured, shall have Barcol hardness at least 90 % of the resin manufactures listed hardness when tested per ASTM D2584. 4.1.2 Filament Wound Structure Wall- Just prior to the start of the filament winding, a chopped glass layer

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shall be applied over the cured corrosion barrier. The structural pipe wall shall be filament wound with a helix angle of 60 degrees plus/minus 5 degrees (measured relative to the axis of the pipe). The filament wound structure wall shall have a minimum glass content of 63% by weight. The last five feet, the maximum helix angle is permitted to be 65 degrees. The maximum laminate layer thickness shall be .060 inches. All fiberglass strands shall be completely wet out and must lay flat and parallel without open gaps between strands. Piping shall be designed for the existing spans where possible having a maximum deflection not to exceed .500 inches. Filament wound pipe found to have open resin starved bridging between strands, or at the corrosion barrier interface, exceeding 2 inches in length and .062 inch height and greater than 2 per square foot, will be rejected. 4.1.3 Exterior Surface Coating – The external surface finish shall be resin rich and a thickness of .006 inch minimum. This finish must contain a tac free wax additive and ultraviolet screener

4.2 Piping Property Requirements – Piping shall be designed such that the imposed service loads will not result in a pipe wall strain exceeding the following:

Design Criteria Maximum Strain Internal Pressure 0.0015 inch / inch Internal pressure + 0.0030 inch / inch Hoop bending Internal Pressure + 0.0024 inch / inch Axial Loads

For Burial loading, the combined pressure plus Hoop Bending may be increased to the allowable of AWWA C950 using the long term HDB testing results.

Design Conditions Fluid Water Design Temperature 32degF/150deg F Design Pressure 25 PSI Design Vacuum 0 PSIG Field Hydrostatic Test Pressure N/A AWWA C950 25 PSI Required Pressure Class

(Design, manufacture, test conformance to this standard, its Appendix, and this Specification is required.)

Safety FactorsDesign safety factors using documented and certified test data for physical properties shall not be less than:

6.7: 1 for filament wound pipe 3: 1 for contact molded fittings 3: 1 for contact molded flanges

4.3 Fittings – All fittings shall be constructed such that their strength is at least equal to the adjacent pipe. Fittings shall have the same inside diameter as the adjacent pipe. Fittings shall be manufactured by either the filament winding process or by contact molded per NBS PS 15-69, no compression-molded fittings are permitted between sections of fiberglass piping. 4.3.2 Elbow Fittings – Elbows shall be of the filament wound or contact molded construction and of a 1.5 radius sweep construction through 48-inch diameter unless otherwise specified on the drawings. Mitered fittings are only permitted where shown on the drawings with a maximum deflection angle of 22.5 degrees. Elbows over 48 inch diameter will be of mitered construction. 4.3.3 Tee and Lateral Fittings – Where main run header piping sections connect as a lateral or tee fitting, the junction shall be reinforced to compensate for the removed material area. The connection shall have at least the same strength as the pipe. As a minimum, the shear length of the branch joint shall be at least sixteen (16) times the thickness of the placed overlay. Reinforcement shall also be placed internal for all joints 18-inch diameter and larger.

4.4 Shop and Field Joints – The fabricator shall be responsible for the detailed design of shop and field joints to meet the requirements of the project. Field joints may be flanged, butt and strap welds or gasket as defined on the drawings and per the engineer’s preferred design. 4.4.2 Butt and Strap Fiberglass Overlay Joints – (used for length adjustment at fittings and rigid connections). Joints shall be at least as strong as the piping with a thickness at least equal to or greater than, the adjacent thickest section and with a bond adhesion shear length of at least thirteen (13) times the material thickness. Materials required for these connections shall be provided as a kit, (precut glass in layers as to be applied) and resin in suitable sized containers. The fabricator shall have a qualified fiberglass Laminator instructor or supervisor to instruct witness and approve the fiberglass field joint. 4.4.3 Flanged Connections – Flanges shall not be less than 25 psi rated, 150# drilling, Contact molded flanges are permitted. Compression molded or filament wound flanges are not permitted. Flanges shall be designed for all imposed combined thermal plus pressure plus bending loads. Note: FRP flanges shall seal against flat faced flanges unless drawings define a special type flange face, such as wafer or raised face, where a special FRP flange shall be designed for the additional bending load.

4.4.4 Single Gasketed Joints – The straight lengths of pipe shall be field connected using Single gasketed joints for installation, unless otherwise indicated on the drawings. The gasketed joint shall conform to the

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requirements of ASTM D4161 (Standard Specification for Fiberglass pipe joints using flexible elastomeric seals) and the additional requirements of this specification.

Section 5. Testing Requirements 5.0 Testing Requirements:

5.1 Shop Testing – Optional: Most piping has open ends so manufacturer Hydro testing not included in this requirement. As minimum the fiberglass pipe and fittings shall be subjected to the following test:

Glass Content - One test of corrosion barrier and structural wall, each pipe size.

Barcol Hardness - Corrosion Barrier shall be at least 90% of resin manufacturer’s minimum published value. Testing shall be conducted on each pipe or fitting as manufactured.

HDB ASTM D 2992 - Provide proof of design results from prior testing.

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COOLING TECHNOLOGY INSTITUTEPO Box 73383 - Houston, Texas 77273 - 281.583.4087 - Fax 281.537.1721

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