REQUIREMENTS GENERAL - The fiberglass reinforced plastic duct (FRP Duct) system shall be specifically designed and constructed to comply with the SMACNA FRP Duct Construction Manual, U.S. Bureau of Commerce Standard PS-15-69, and the following minimum conditions: Corrosion resistance to hydrogen sulfide, chlorine, mercaptans and other gases commonly encountered in industrial chemical and waste water treatment plants. Duct shall be mechanically designed for +/- 6” water column or as otherwise shown on the standards above. Duct and fittings shall be constructed using Class 1 fire retardant materials as called out below with a flame spread of 25 or less as measured by standard ASTM E-84 test methods.GENERAL - The fiberglass reinforced plastic duct (FRP Duct) system shall be specifically designed and constructed to comply with the SMACNA FRP Duct Construction Manual, U.S. Bureau of Commerce Standard PS-15-69, and the following minimum conditions: Corrosion resistance to hydrogen sulfide, chlorine, mercaptans and other gases commonly encountered in industrial chemical and waste water treatment plants. Duct shall be mechanically designed for +/- 6” water column or as otherwise shown on the standards above. Duct and fittings shall be constructed using Class 1 fire retardant materials as called out below with a flame spread of 25 or less as measured by standard ASTM E-84 test methods. MATERIALS RESIN The resin used shall be a corrosion resistant, Class 1 fire retardant polyester or vinyl ester such as Dow Derakane 510-C, Reichhold Chemicals Dion 7704T or Dion 9300, Ashland Chemicals Hetron 99 or 992, or equal. FILLERS AND PIGMENTS The resins used shall not contain fillers except as required for viscosity control or fire retardance. Up to 5 percent by weight of thixotropic agent which will not interfere with visual inspection may be added to the resin for viscosity control. Resins may contain pigments and dyes by agreement between Composites USA, Inc. and purchaser, recognizing that such additions may interfere with visual inspection of laminate equality. Antimony compounds or other fire retardant agents may be added for improved fire resistance, as required, to meet flammability specifications. Standard product contains 3% antimony to provide a class 1 flame performance of <25 as measured by ASTM E-84. REINFORCING MATERIAL The reinforcing material shall be a commercial grade of glass fiber having a coupling agent which will provide a suitable bond between the glass reinforcement and the resin. SURFACING MATERIALS Unless otherwise agreed upon between Composites USA, Inc. and purchaser, material used as reinforcing on the surface exposed to chemical attack shall be a commercial grade chemical-resistant glass having a coupling agent. Alternate surfacing materials suitable for use include Nexus polyester for improved resistance to corrosives which attack glass, Halar or MFA fluoropolymer for premium corrosion resistance, or carbon/ graphite for imparting an electrically conductive surface. LAMINATE The laminate shall consist of an inner surface, an interior layer, and an exterior layer or laminate body. The compositions specified for the inner surface and interior layer are intended to achieve optimum chemical resistance. INNER SURFACE - The inner surface shall be free of cracks and crazing with a smooth finish. Any pitting will average not more than 2 pits per square foot, providing the pits are less than 1/8 inch in diameter and not over 1/32 inch deep and are covered with sufficient resin to avoid exposure of inner surface fabric. Some waviness is permissible as long as the surface is smooth and free of pits. Between 0.010 and 0.020 inches of reinforced resin-rich surface shall be provided. This surface will be reinforced with C-veil glass surfacing mat, unless otherwise specified and agreed between Composites USA and customer. INTERIOR LAYER - A layer next to the inner surface shall be reinforced with not less than 20 percent nor more than 30 percent by weight of non-continuous glass strands (having fiber lengths from 0.5 to 2.0 inches). EXTERIOR LAYER - The exterior layer or body of the laminate shall be of chemically resistant construction suitable for the service and providing the additional strength necessary to meet the tensile and flexural requirements. Where separate layers such as mat, cloth, or woven roving are used, all layers shall be lapped a minimum of 1 inch. Laps shall be staggered as much as possible. If woven roving or cloth is used, a layer of chopped-strand glass shall be placed as alternate layers. Filament wound reinforcement using 250 yield rovings may be used in this layer to achieve the structural requirements. The exterior surface shall be relatively smooth with no exposed fibers or sharp projections. Hand work finish is acceptable, but enough resin shall be present to prevent fiber show. The finished product is to have a Class 1 flame (<25) spread throughout, unless otherwise specified. The exterior of the duct shall be protected from the effect of U.V. degradation through either the addition of U.V. inhibitor in the resin top coat or the application of a pigmented epoxy or acrylic top coat. CUT EDGES - All cut edges shall be coated with resin so that no glass fibers are exposed and all voids filled. Structural elements having edges exposed to the chemical environment shall be made with chopped-strand glass reinforcement only. JOINTS - Finished joints shall be built up in successive layers and be as strong as the pieces being joined and as crevice free as is commercially practicable. The width of the first layer shall be 2 inches minimum. Successive layers are to increase uniformly and provide the specified minimum total width of overlay, which shall be centered on the joint. Crevices between jointed pieces shall be filled with resin or thixotropic resin paste, leaving a smooth inner surface (See INNER SURFACE). The interior of joints may also be sealed by covering with a reinforced resin-rich surface as described in INNER SURFACE and INTERIOR LAYER, if accessible and agreed upon by Composites USA and customer. WALL THICKNESS - The minimum wall thickness shall be as specified in table 3. Isolated small spots may be as thin as 80 percent of the minimum wall thickness, but in no case more that 1/8 inch below the specified wall thickness. SURFACE HARDNESS - The laminate shall have a Barcol hardness of at least 90 percent of the resin manufacturer's minimum specified hardness for the cured resin. This applies to both interior and exterior surfaces. APPEARANCE - The finished laminate shall be as free as commercially practicable from visual defects such as foreign inclusions, dry spots, air bubbles, pinholes, pimples, and delamination. DUCT SIZES AND TOLERANCES SIZE - The standard duct size shall be the inside diameter in inches. Standard sizes are 3/4, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 42, 48, 54, 60, 72 inches. Sizes larger than 72" diameter are available in any increment on our adjustable mandrels, using mitered elbows. The tolerance including out-of-roundness shall be +1/16 inch for duct up to and including 6-inch inside diameter, and +1/8 inch or +1 percent, whichever is greater, for duct exceeding 6 inches inside diameter. This measurement shall be made at the point of manufacture with the duct in an unstrained vertical position. LENGTH - The length of each fabricated piece of duct shall not vary more than +1/8 inch from the ordered length unless arrangements are made to allow for trim in the field. Standard lengths are nominal 20 ft on sizes above 1.5". WALL THICKNESS - The minimum wall thickness shall be in accordance with Table 3. RECTANGULAR DUCT - The size of rectangular duct shall be determined by the inside dimensions. There are no standard sizes for rectangular duct. Unless otherwise specified, the tolerances on rectangular duct shall be +/- 3/16" on sizes up to 18", and +/- 1% on sizes over 18". For rectangular duct, the minimum thickness shall be as specified in Table 3, substituting the longer side of the rectangular duct for the diameter. SQUARENESS OF ENDS - All non-flanged duct shall be cut square with the axis of the duct within 1/8 inch up to and including 24 inch diameter and to within 3/16 inch for all larger diameter duct. FITTINGS - All fittings such as elbows, laterals, T's, and reducers shall be equal or superior in strength to the adjacent pipe section and shall have the same diameter as the adjacent pipe. The dimensions of fittings shall be as shown in Tables 1 and 3. Tolerance on angles of fittings shall be +/-1o through 42 inches in diameter and +/- 1/2 o for 48-inch diameter and above. Where necessary, minimum overlay widths may be less than those specified in Table 4, but the joint strength shall be at least equal to the strength of the adjacent pipe. ELBOW - Standard elbows shall have a centerline radius of one and one half times the diameter. Standard elbows up to and including 48 inches shall be continuous sweep molded of one piece construction. Elbows of 54 inch diameter and larger may be of molded or mitered construction using pipe for the mitered sections. The width of the overlay on the mitered joint may have to be less than the minimum specified in Table 4 to avoid interference on the inner radius, but the joint strength must be at least equal to the strength of the adjacent pipe. Mitered elbows 45o or less will be single-miter, two gore. Elbows above 45o and through 90o shall have a minimum of three gore construction. Incorporation of straight pipe extensions on elbows is permissible. REDUCERS - Reducers of either concentric or eccentric style will have a length as determined by the ratio of the diameters of the reducer as indicated in Table 1 (5X the difference is standard). Alternate reducer lengths are acceptable depending on customer layout requirements. TABLE 2. Requirements for properties of reinforced polyester / vinyl ester laminates Contact Molded Properties at 73.4oF (23oC) Thickness (inches) 1/8-3/16 1/4 5/16 3/8 & up   psi psi psi psi Ultimate tensile strength - minimum 9,000 12,000 13,500 15,000 Flexural strength - minimum 16,000 19,000 20,000 22,000 Flexural modulus of elasticity, tangent - minimum 700,000 800,000 900,000 1,000,000 Filament Wound Modulus (Hoop & Axial, Resultant) 1,100,000 1,600,000 1,700,000 1,700,000 Note: Filament wound resultant modulus based upon ASME RTP-1 calculation methodology  BUTT JOINTS This type of joint shall be considered the standard means of joining pipe sections and pipe to fittings. The procedure used in making the butt joint is as follows: The finished joints shall be built up in successive layers and be as strong as the pieces being joined and as crevice free as is commercially practicable. The width of the first layer shall be 2 inches minimum. Successive layers shall increase uniformly to provide the specified minimum total width of the overlay, which shall be centered on the joint. Crevices between jointed pieces shall be filled with resin or thixotropic resin paste leaving a smooth inner surface. When accessible and when required by operating or design conditions, duct joints may be overlaid both inside and outside. The minimum width of the overlay shall relate to wall thickness and shall be of the dimensions indicated in table 3 for hand lay up construction. Inside overlays may be made to seal the joint if necessary, but shall not be considered in meeting the strength requirement specified. FLANGES The use of flanges shall normally be kept to a minimum with the butt joint being used as the standard means of joining duct sections. All flanges shall be of the minimum thickness given in Table 3 for PS-15-69 flange thicknesses as quoted. Standard flanges are field drilled per PS-15-69 standards. The construction of flanges is the same as that for laminates, using all mat construction, ie., no woven roving, for the flange faces. FLANGE ATTACHMENT The minimum flange shear surface shall be four times the flange thickness indicated in Table 4. The thickness of the flange hub reinforcement measured at the top of the fillet radius shall be at least one-half the flange thickness and shall be tapered uniformly the length of the hub reinforcement. The fillet radius, where the back of the flange meets the hub, shall be 3/8 inch minimum. FLANGE FACE The flange face shall be perpendicular to the axis of the pipe within 1/2o and shall be flat to +1/32 inch up to and including 18-inch diameter and +1/16 inch for larger diameters. The face of the flange shall have a chemical resistant surface as described in SURFACING MATERIALS and INNER SURFACE. TABLE 3. Reinforced polyester or vinyl ester duct dimensions, dimensions in inches and inches water column, except support spacing which is in feet.   Duct I.D. Wall Thick. Allow. Vacuum Allow. Pressure Flange O.D. Flange Thick Bolt Circle Bolt Hole Diameter # of Bolt Holes Support Spacing 2 0.125 405 3115 6-3/8 1/4 5 0.44 4 7 3 0.125 406 2075 7-3/8 1/4 6 0.44 4 8 4 0.125 210 1560 8-3/8 1/4 7 0.44 4 9 6 0.125 64 1040 10-3/8 1/4 9 0.44 8 9 8 0.125 30 780 12-3/8 1/4 11 0.44 8 9 10 0.125 16 623 14-3/8 3/8 13 0.44 12 9 12 0.125 9 518 16-3/8 3/8 15 0.44 12 8 14 0.125 7 445 18-3/8 3/8 17 0.44 12 8 16 0.125 6 389 20-3/8 1/2 19 0.44 16 8 18 0.125 5 346 22-3/8 1/2 21 0.44 16 8 20 0.125 5 311 24-3/8 1/2 23 0.44 20 8 24 0.187 9 389 28-3/8 1/2 27 0.44 20 10 30 0.187 7 309 34-3/8 1/2 33 0.44 28 9 36 0.187 5 255 40-3/8 1/2 39 0.44 32 9 42 0.250 10 368 46-3/8 5/8 45 0.44 36 11 48 0.250 9 233 54-3/8 5/8 52 0.44 44 10 54 0.250 7 206 60-3/8 5/8 58 0.44 44 10 60 0.250 6 185 66-3/8 5/8 64 0.44 52 10 72 0.313 12 240 78-3/8 3/4 76 0.44 60 11 The specified wall thicknesses are based upon a 10 to 1 safety factor for the contact molded tensile strength listed in table 2. Filament wound duct will generally result in higher allowable pressures and vacuum ratings with the same factors of safety. These ratings are suitable for use up to 180o F (82.2o C); for ratings at higher temperatures, consult the manufacturer. Vacuum ratings are based upon duct stiffening ribs on 10'-0" centers. Allowable pressures are governed by the lower of the (CUSA ½” minimum) flange or duct allowable pressure Standard flanges are supplied undrilled in accordance with PS-15-69. Support spacing is typical based upon deflection, stress and cylinder buckling analysis. Consult the factory for specific guidance. TABLE 4. Minimum total widths of overlays for reinforced-vinyl ester butt joints Duct wall thickness, inches..... 3/16 3 1/4 4 5/16 5 3/8 6 7/16 7 1/2 8 9/16 9 5/8 10 11/16 11 3/4 12 Minimum total width of overlay, inches.....