ASTM D7655/D7655M-12(2022)

Overview

ASTM D7655/D7655M-12(2022), published by ASTM International, is the standard classification for the size of aggregate used as ballast in membrane roof systems. This standard defines size designations and ranges for aggregates commonly used in single-ply membrane roof applications, providing clarity for contract documents and aiding compliance during roofing system design and installation.

Ballasted membrane roof systems rely on the correct size and weight of aggregate to ensure optimal wind resistance. By standardizing aggregate size classifications, ASTM D7655 helps architects, roofing professionals, and contractors design, select, and install safer and more reliable roof systems.

Key Topics

• Aggregate Size Classification: The standard details the size designations and mechanical particle size ranges for aggregates intended as ballast for roofing membranes.
• Testing & Compliance: Guidance is given on sampling (referencing ASTM D75/D75M), and sieve analysis procedures (referencing ASTM C136/C136M and E11) to ensure proper grading and quality.
• Contract Specification: Aggregate size classifications set forth in this standard can be used directly in contract documents to specify required aggregate types for ballasted membrane roof systems.
• Dual Units: Aggregate sizes are provided in both SI and inch-pound units. Each unit system is to be used independently to avoid compliance issues.
• Wind Resistance: Emphasizes the role of aggregate size and weight in achieving wind design requirements, particularly referencing sizing guidelines in ANSI/SPRI RP-4.

Applications

ASTM D7655/D7655M is widely used in the following scenarios:

• Roofing Design: Roofing designers and consultants use this standard to select the appropriate aggregate size classifications that meet desired wind uplift requirements for ballasted single-ply membrane systems.
• Construction Specifications: Contract documents and project specifications often cite ASTM D7655 aggregate size classes to ensure uniformity and compliance across projects.
• Quality Assurance: Roofing contractors and inspectors use this standard to verify aggregate materials on-site align with the specified size class before installation.
• Wind Design Compliance: The standard provides foundational data for compliance with ANSI/SPRI RP-4, ensuring roofs are designed to withstand local wind loads.

Related Standards

When working with aggregate ballast and membrane roofing, several related standards play a key role:

• ASTM C136/C136M – Test Method for Sieve Analysis of Fine and Coarse Aggregates
• ASTM D75/D75M – Practice for Sampling Aggregates
• ASTM E11 – Specification for Woven Wire Test Sieve Cloth and Test Sieves
• ASTM D1079 – Terminology Relating to Roofing and Waterproofing
• ANSI/SPRI RP-4 – Wind Design Standard for Ballasted Single-Ply Roofing Systems

Together, these standards create a robust framework for ensuring aggregate ballast meets the size, uniformity, and performance requirements critical for durable, wind-resistant membrane roof installations.

Keywords: ASTM D7655, aggregate ballast, membrane roof systems, aggregate size classification, wind resistance, roofing standards, ballasted roofing, roofing aggregate sizes, ASTM roofing, roof ballast testing.