Engineering Branch Assets Delivery Group

Transcription

1 F.1 SCOPE This Technical Specification shall apply to Fibre Reinforced Plastics or Glass Reinforced Plastics (hereinafter referred to as FRP or GRP) structures and the materials used in their manufacture, except where varied by the Specification and/or Drawings. F.2 GENERAL F.2.1 Where not detailed on Drawings, laminates, joints, seams (including those for attachment of fixtures) and repairs shall comply with the design and construction requirements of AS 263 Chemical plant equipment made from Glass Fibre Reinforced plastics (GRP) based on thermosetting resins or BS 99 Specification for design and construction of vessels and tanks in reinforced plastics. Main seam joints not detailed on the drawings shall comply with AS 263 or BS 99. Pipes and flanges shall comply with AS 263 or AS Glass filament reinforced plastics (GRP) pipes-polyester based-water supply sewerage and drainage applications. F.2.2 The amount of glass in any specific direction shall comply with the Specification and/or Drawings. F.2.3 Opaque resin shall be applied only to those surfaces which have been accepted by the Superintendent as complying with the structural requirements of the Specification and will be exposed to solar radiation. All other resin used shall be transparent. F.2. FRP laminates covering embedments shall be 3mm minimum thickness. F.2.5 Construction tolerances not specified in AS 263, BS 99 or shown on the Drawings shall be as specified in BS 265 Specification for manufacture of vertical steel welded non-refrigerated storage tanks with butt welded shells for the petroleum industry. F.2.6 All re-entrant bends and corners not specified in AS 263 or BS 99 or shown on the Drawings shall be internally radiused to a minimum of 15mm. F.2.7 Load bearing surfaces of fasteners shall be in full contact with the laminate. F.2.8 Where cured resin surfaces are to be joined during manufacture or repair work, all surface contaminants, waxes and release agents shall be removed by suitable surface treatment and mechanical abrasion prior to any further laminating. F.2.9 Defects in the FRP shall not exceed the limits specified in Table 1. Some of the common failures in FRP/GRP are shown in Table 2. F.2.10 Defective laminates shall be removed by grinding and reinstated as specified in AS 263 or BS 99. F.2.11 The properties of the FRP shall not be detrimentally affected by environmental conditions during manufacture. 1

2 F.2.12 In the absence of any specific recommendations from the resin manufacturer, the minimum period for adequate resin cure before service shall be: Ambient temperature o C 1 days Ambient temperature o C 10 to 1 days Ambient temperature o C 8 to 10 days Ambient temperature 30 o C 7 days Post curing shall be carried out under cover. Elevated temperature post curing shall be in accordance with the resin manufacturer s recommendations. F.3 MOULD SURFACES Any surface which comes into contact with FRP/GRP during manufacture shall be clean, free from oil, grease, paint, dirt, corrosion products, dyes, pigments or any other foreign contaminant detrimental to the properties of FRP/GRP. Only release agents approved by the resin supplier and the Superintendent shall be used. F. MATERIALS F..1 Materials shall be non-deteriorating in service, accepted by the Health Department for use in contact with potable water and accepted by the Superintendent prior to commencement of fabrication. F..2 Resin F..2.1 The resin shall be as stated in the Specification and/or Drawings. Chemical and physical properties of the resin mix shall be to the manufacturer's recommendations for the work to be carried out. F..2.2 Resins shall be used within the shelf life nominated by the resin manufacturer for the conditions of storage. F..2.3 The catalysing system used shall be as recommended by the resin manufacturer. F..2. Where additives are required by the Specification and/or Drawings, they shall be uniformly distributed through and well wetted by the resin. F..2.5 The styrene content of the resin shall not be varied from the resin manufacturer's specification unless accepted by the Superintendent. The Contractor may add wax-in styrene solution as recommended by the resin manufacturer to prevent moisture and/or air inhibition. 2

3 F..3 Reinforcing Material F..3.1 The reinforcing material shall be of glass fibre cloth, mat or rovings as specified in the Specification and/or shown on Drawings. F..3.2 The reinforcing material shall be free of breaks, streaks, stains, oils, grease, knots and other contaminants and defects likely to affect the strength or performance of the laminate. F..3.3 The reinforcing material shall be treated with a coupling agent compatible with the specified resin. F..3. Fibres used in chopped strand mat shall be a minimum of 50 mm in length. Chopper gun lay up fibre shall be between 20 mm and 60 mm in length. F..3.5 The binder in chopped strand mat shall be readily dissolved by the specified resin. F.5 APPLICATION AND FINISH F.5.1 Prepared surfaces shall not be contaminated by dust, moisture or other contaminants. F.5.2 Wax rich resin surfaces in contact with the mould surface shall be laid up as follows:- F Wax rich resin approximately 0.5 mm thick shall be applied to the mould surface and left to gel. F Further wax rich resin shall then be applied and the surface tissue rolled in. The total thickness of the wax rich resin layer shall be approximately 1.0 mm. F.5.3 Wax rich resin surfaces not in contact with the mould shall be laid up as follows:- F Wax rich resin shall be applied to the prepared laminate surface and the accepted surface tissue rolled in. The thickness of the layer shall be approximately 0.5 mm. F Further wax rich resin shall then be applied to build the total thickness of the wax rich resin layer to approximately 1.0 mm. F.5. Unless specified on the Drawings or otherwise approved by the Superintendent, cut surfaces shall be treated by either of the following methods: F.5..1 Sealed from contact with water with a permanently flexible adherent mastic sealant immediately prior to assembly. F.5..2 Mechanically abraded to minimise the length of exposed fibres and adequately roughened followed by the application of two heavy coats of waxed resin. 3

4 F.6 INSPECTION F.6.1 Plant, equipment, materials and methods used shall be subject to inspection and acceptance by the Superintendent. F.6.2 The Contractor shall give the Superintendent notice of at least one week as to when and where any preparation or manufacturing operation will be conducted and otherwise facilitate the arranging and conducting of inspections. F.6.3 If any component or any part of the structure does not comply with the Specification the Superintendent may order the removal, preparation and delivery of samples. If the results from testing reveal non-compliance with the Specification and/or Drawings, all sampling, preparation, delivery and repair costs shall be borne by the Contractor. F.6. Should the tests reveal compliance with the Specification and/or Drawings, costs will be borne by the Principal. The bases of repair costs shall be materials at current commercial bulk rates and labour in accordance with the current Plastics Manufacturing Award. F.7 CONTRACTOR S RESPONSIBILITY F7.1 All requirements of the Specification shall be met and checked for compliance by the Contractor prior to his request for inspection by the Superintendent. The preceding inspection clauses shall not relieve the Contractor of his responsibility to furnish materials and perform work in accordance with the Specification.

5 TABLE 1 - TOLERABLE DEFECT LEVELS IN FRP/GRP STRUCTURES DEFECT DEFINITION MAXIMUM TOLERANCE LEVEL * Crack Any separation of the laminate None Lack of Bend Insufficient adhesion between surfaces in contact Delamination Any separation between continuous laminate layers None None Cavity Space within finished laminate None, except where given prior approval by Superintendent Crazing Fine cracks at or under the surface None Chip A small piece broken off Length in any direction - 5mm Scratch Shallow mark, groove or channel Depth 0.3mm Lump or Pimple Elevation on the surface of the laminate Diameter 5mm Height 2mm Air Bubble Entrapped air or other gas Diameter 3mm 3% by volume of laminate Pit (pinhole) or crater Small crater in the surface of a part Length in any direction 1mm. Depth less than 50% of resin cover to reinforcement. Dry Spot Non Wetted reinforcement None Foreign Inclusions Resin pocket Particles included in the laminate which are foreign to its composition Accumulation of excess resin in a small localised area Wrinkles, folds or creases of the reinforcement in the cured laminate None Cross sectional area 2.5 mm 2 None * NOTE: Any defect which penetrates through the resin as far as any reinforcing material shall be unacceptable.

6 TABLE 2 SUMMARY OF THE MOST COMMON TYPES OF FAILURES IN FRP/GRP STRUCTURES Defects Brief Description Example Photographs End Damage (Minor) Damage resulting from poor transportation practice. End Damage (Major) Damage to the laminate and fiber from burning out during cutting process. Colour Change Yellowing due to prolonged exposure to UV Exposure. External Blister Entrapped air or other gas resulting in Bubbling. Light whitened areas with entrapped air. Sounds hollow when tapped.

7 Damaged Skin Local damage to structural layers due to mishandling. Fisheye Small globular mass that has not blended into surrounding material. This type of defect resulting from the dirty surface and also from foreign matter falling on resin resulting in cracking of the laminate Surface Scrapes White scrape marks on the internal/external surface (see inside of the red dotted line). Pit or Pinhole Small regular or irregular crater on surface, usually with nearly equal width and depth. Air bubbles that rise to surface, which cures before smoothing out.

8 Mylar Release Film Mylar Release film left in pipe from production process (See inside the red dotted line). This can ne removed by hand. Gouge Mark Created during the removal of Mylar film. Air Pockets/Voids Small air pockets or voids through or just beneath the surface of the pipe. Air pockets can be broken with a ballpoint pen. Encapsulated Foreign Objects Objects such as glass clumps, insects etc, which are foreign to the laminate composition.

9 Edge Delamination Crack on edge of pipe resulting in separation of layers Delamination Disbondment of the laminate layers. Wrinkles, Indentations or Band Impressions Wrinkles arise on the laminate surface. Exposed Fibers Exposed fibers resulting from cutting or drilling.

10 Cracking/Crazing Fine cracks at or under the laminate. Pealing of the laminate Poor sealing of the laminate. End of Document