Coal Tar Primer Used in Roofing, Dampproofing, and Waterproofing

ASTM D43/D43M: Standard Specification for Coal Tar Primer Used in Roofing, Dampproofing, and Waterproofing

Ensuring the long-term integrity of building envelopes against moisture ingress is paramount in construction and manufacturing. For professionals involved in roofing, dampproofing, and waterproofing applications, specifying and utilizing the correct materials is not just a best practice – it's a fundamental requirement for durable and reliable structures. ASTM D43/D43M provides an essential, industry-leading standard for coal tar primer, a critical component in these protective systems. Understanding this specification is key to achieving optimal performance and compliance.

What is ASTM D43/D43M?

ASTM D43/D43M establishes the authoritative quality and performance requirements for coal tar primer specifically formulated for use in roofing, dampproofing, and waterproofing applications. Developed by ASTM International, this standard ensures that the primer, derived from coal-gas tar or coke-oven tar, meets stringent physical properties necessary for its intended protective functions. Its primary purpose is to serve as a compatible and effective preparatory layer for coal tar pitch and other waterproofing materials on various substrates.

Scope & Purpose

This comprehensive standard governs the physical and chemical properties of coal tar primers intended for application on concrete, masonry, and existing coal tar surfaces. It outlines specific criteria for water content, consistency, specific gravity, and distillation characteristics, ensuring the primer adheres properly and performs its function as a bonding agent and moisture barrier. While the standard focuses on the primer itself, it does not cover the application methods or the final waterproofing membrane systems.

Who Must Comply?

• • Primary audience: Materials Engineers, Quality Control Inspectors, Construction Managers, Specification Writers, and Product Developers involved in the manufacturing or application of roofing and waterproofing materials.
• • Industries affected: Building Materials Manufacturing, Construction, Chemical Processing, and Infrastructure Development.
• • Compliance nature: Primarily voluntary, but often mandated by project specifications, building codes, and contractual agreements.
• • Enforcement: Compliance is typically verified through material testing by independent laboratories, quality assurance checks by project owners or their representatives, and audits by regulatory bodies when applicable.

Key Requirements Overview

The standard requires that coal tar primer be a distillate of coal-gas or coke-oven tar. Professionals must ensure the primer exhibits a low water content, not exceeding 1%. Key provisions include maintaining complete fluidity and freedom from crystals at 5°C (41°F), indicating its workability in cooler conditions. The specification mandates a minimum specific gravity of 1.06 at 38°C/15.5°C (100°F/60°F) and limits the matter insoluble in benzene to a maximum of 0.5%, ensuring material purity. Furthermore, stringent distillation parameters are defined, limiting volatile components and ensuring a sufficient residue for performance.

Related Standards & References

ASTM D43/D43M works in conjunction with other ASTM standards to ensure a complete waterproofing system. Practice D140 for Sampling Bituminous Materials is essential for obtaining representative samples for testing. While some older referenced test methods for specific properties of creosote have been withdrawn, the principles of distillation and residue testing remain critical and are often covered by current, related ASTM standards. Understanding these complementary documents is vital for comprehensive quality assurance