Composite Ribbed Steel Pipe, Precoated and Polyethylene Lined for Gravity Flow Sanitary Sewers, Storm Sewers

A978/A978M: Standard Specification for Composite Ribbed Steel Pipe, Precoated and Polyethylene Lined for Gravity Flow Sanitary Sewers, Storm Sewers, and Other Special Applications

When designing and specifying infrastructure for critical water and wastewater management, the selection of durable, long-lasting materials is paramount. ASTM A978/A978M provides an essential framework for ensuring the integrity and longevity of composite ribbed steel pipe systems, offering superior protection against corrosive and abrasive environments. This industry-leading standard is a cornerstone for engineers and project managers involved in municipal infrastructure development.

What is A978/A978M?

ASTM A978/A978M is a comprehensive standard specification that defines the requirements for composite ribbed steel pipe featuring a precoat and polyethylene lining. Developed by ASTM International, this standard ensures that these pipes are manufactured to meet stringent performance criteria for gravity flow sanitary sewers, storm sewers, and other demanding applications. Its primary purpose is to guarantee enhanced corrosion and abrasion resistance through a robust material composite.

Scope & Purpose

This authoritative standard governs the materials, fabrication, and performance characteristics of composite ribbed steel pipe designed for buried applications. It specifically covers pipes with a metallic-coated steel sheet, a polymer precoat on the exterior, and an extruded polyethylene liner on the interior, with polyethylene filling the ribs. The scope includes provisions for the composite structure and its protective coatings, ensuring suitability for environments requiring exceptional durability. However, this specification explicitly excludes requirements for bedding, backfill, or the detailed structural design calculations related to earth cover load and sheet thickness, which are addressed in complementary standards.

Who Must Comply?

• • Primary audience: Materials Engineers, Civil Engineers, Design Engineers, Project Managers, and Construction Inspectors.
• • Industries affected: Civil Engineering, Municipal Infrastructure, Public Works, Water and Wastewater Management, and the broader Construction sector.
• • Compliance nature: Primarily voluntary, driven by project specifications and client requirements, but often becomes de facto mandatory for public works projects.
• • Enforcement: Compliance is typically verified through project-specific quality assurance and quality control programs, material testing, and site inspections by engineers and municipal authorities.

Key Requirements Overview

The standard requires the use of specific metallic-coated steel sheets that are further protected by a polymer precoat on the exterior. Professionals must ensure the interior of the pipe incorporates an extruded polyethylene liner, thermally bonded to the steel and mechanically secured by polyethylene filling the pipe's ribs. Key provisions include detailed specifications for the rib geometry, ensuring proper mechanical locking of the liner. The standard also mandates material testing to confirm the integrity and performance characteristics of both the metallic and polymer coatings, ensuring proven resistance to corrosion and abrasion.

Related Standards & References

ASTM A978/A978M works in conjunction with several other proven ASTM standards. Practice A798/A798M provides essential guidance on the proper installation of factory-made corrugated steel pipe, which is critical for the successful performance of composite ribbed steel pipe systems. For structural design considerations of buried pipe, Practice A796/A796M offers comprehensive methodologies. Additionally, various ASTM standards related to metallic coatings (e.g., A90/A90