Resources & Specifications

Industry/Construction Design Standards

There are many industry standards being used and referenced, some have been replaced. The more widely used standards are issued and maintained by ASTM International and American Society of Mechanical Engineers (ASME). Other standards writing organizations for composites include American Water Works Association (AWWA) and American Petroleum Institute (API).

One of the earliest standards was the National Bureau of Standards PS 15-69. This voluntary standard had an effective date of November 15, 1969 and is no longer published but is frequently referenced. This standard covered tanks, piping, and ductwork and other standards have been developed since that cover construction of these components.

All standards address the basic issues of scope of applicability, design, materials, construction, quality control, testing and record keeping. The following lists the current standards and their applicability by type of component and/or construction:

  • ASTM 3299 – Above Ground Vertical tanks of Filament Wound Construction
  • ASTM 4097 – Above Ground Vertical tanks of Contact Molded Construction
  • ASTM 2996 – Filament Wound pipe
  • ASTM 3982 – Contact Molded Duct and Hoods
  • ASTM 4024 – Reinforced Thermosetting Plastic (RTP) Flanges
  • ASTM D2583 – Barcol hardness for composites
  • ASTM D790 – Test Method Flexural Strength and Modulus
  • ASTM D638 – Test Method for Tensile Properties
  • ASTM C582 – Specification for Contact-Molded Reinforced Thermosetting Plastic
  • ASME X – Code Stamped FRP pressure vessels (Boiler and pressure vessel jurisdiction)
  • ASME RTP-1 – ASME Stamped vessels for up to 15 psig and full vacuum
  • API 652 – Lining of Aboveground Petroleum Storage Tanks
  • AWWA M45 – Fiberglass Pipe Design

What Every Composites Technician Needs to Know About ASTM C582

ASTM C582 is a standard specification for contact-molded reinforced thermosetting plastic (RTP) laminates for corrosion-resistant equipment. It covers the composition, thickness, fabrication procedures, and physical property requirements for qualified resin laminates comprising the materials of construction of RTP corrosion-resistant tanks, piping, and equipment by contact molding.

For Composite Technicians working on the shop floor, the most important part of C582 is the fabrication procedures. If C582 is being followed, there a certain rules that must be followed that impact the technique. Knowing these rules can help avoid time consuming rework.

Laminate Fabrication

Initiated resin is being applied to a properly prepared mold or mandrel surface having a release agent or film that is suitable for the lay-up resin. Then the specified surface mat or veil is applied and rolled to draw the resin through the mat for thorough wet-out and air release. In all C582 fabrications, resin is applied and two plies of 1.5 oz/ft2 (459 g/m2) mat or two equivalent passes of chopped roving may be applied by spray-up process equivalent in weight and thickness to 3 oz/ft2 (918 g/m2) of chopped mat. Each pass of the chopped roving or ply of chopped strand mat shall be thoroughly rolled out. Also, these layers shall be allowed to exotherm before proceeding with the structural layers.

The lay-up sequence that is continued following the exotherm is tabulated for the specified laminate type. Each ply shall be rolled for thorough wet-out and air release. Interruption of laminate construction for exotherm shall follow the instruction noted on Table 1 or Table 2 for the particular laminate type.

The final ply before interruption for an exotherm shall be 1.5 oz/ft2 (459 g/m2) mat or chopped roving equivalent. The initial ply of the continuing lamination shall be 1.5 oz/ft2 (459 g/m2) mat or chopped roving equivalent.

The outer surface of the laminate shall be smooth and free of exposed glass. The final ply shall be chopped strand mat or chopped roving unless otherwise specified. The surface resin may require the addition of paraffin of film overlay to ensure proper cure.

Pigment shall only be used in the final laminate ply.

All edges of reinforcement, except surfacing mat, shall be lapped 1 inch (25.4 mm) minimum. Lapped edges of adjacent layers shall be staggered. Surfacing mat shall be butted or have overlaps no more than ½ in. (12.7 mm). Gaps are not permitted.

Section 9. Workmanship and Finish

The finished laminate shall conform to visual acceptance criteria of Table 5.

  • Cracks – None
  • Crazing – None
  • Blisters – None
  • Wrinkles – See Table 5
  • Pits – See Table 5
  • Surface porosity – See Table 5
  • Chips – See Table 5
  • Dry spot – None
  • Entrapped air – See Table 5
  • Exposed glass – None
  • Burned areas – None
  • Exposure of cut edges – None
  • Scratches – None over 0.005 in. deep and 4 in. long
  • Foreign matter – None

The surface exposed to the chemical environment (process side) shall be smooth, resin-rich, and fully cured. The exterior shall also be fully cured. The degree of cure shall be measured by a Barcol hardness test in accordance with Test Method D2583. At least 80% of the random readings shall exceed 90% of the resin manufacture’s recommended hardness for the cured resin.

Sources of Standards:

ASTM Standards: ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA, 19428-2959 USA Phone: (610) 832-9585 Fax: (610) 832-9555

ASME Standards: ASME, P.O. Box 2300, Fairfield, NJ 07007-2300, 800-843-2763
973-882-1167 (outside North America), Fax: 973-882-1717, Email:

API Standards: American Petroleum Institute, 1220 L Street, NW, Washington, DC 20005-4070, USA, 202-682-8000,

AWWA Standards: American Water Works Association,6666 W. Quincy Avenue, Denver, CO. 80235,