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D2178 – Standard Test Method Technical Guide
ASTM D2178/D2178M-15a (Reapproved 2021) is the standard specification for asphalt glass felt used in roofing and waterproofing. It covers the requirements for Types IV and VI glass felts that are impregnated with asphalt and used in built-up roofing and waterproofing systems. This standard ensures that the felts meet essential criteria for performance and handling.
📜 Scope and Classification
This specification applies to glass felts impregnated with asphalt for use in built-up roofs with asphalts meeting Specifications D312/D312M or D7654/D7654M, and in waterproofing systems with asphalts meeting D449/D449M. The standard uses both SI and inch-pound units, which must be treated separately. The classification covers only Types IV and VI felts.
The user must establish appropriate safety and health practices. This standard has been approved by the U.S. Department of Defense and developed in accordance with international standards.
🏭 Materials and Manufacture
The felt shall be a thin, porous sheet of uniformly distributed glass fibers bonded with a water-resistant resinous binder. Reinforcing stranded glass yarns may be added. The felt is impregnated with asphalt, which may contain a mineral stabilizer, ensuring even distribution. A surfacing material is applied to prevent sticking in the roll, but it must not interfere with adhesion between plies.
📊 Physical Properties and Dimensions
The finished product must conform to the physical properties, dimensions, masses, and permissible variations prescribed in Tables 1 and 2 of the standard. Additionally, the felt must not crack or be sticky when unrolled at temperatures between 10 and 60 °C [50 and 140 °F].
Table 1: Physical Properties of Asphalt Glass Felt
| 🟦 Property | 📏 Type IV | 📐 Type VI |
|---|---|---|
| Minimum Net Dry Mass (kg/m²) | 0.50 | 0.75 |
| Minimum Breaking Strength (kN/m) | 8.0 | 12.0 |
| Maximum Elongation (%) | 5 | 5 |
Table 2: Dimensional Requirements
| 📏 Dimension | 📐 Type IV | 📐 Type VI |
|---|---|---|
| Roll Width (m) | 1.0 | 1.0 |
| Roll Length (m) | 30 | 30 |
| Thickness (mm) | 2.5 | 3.0 |
💡 Tip: Ensure the felt is stored and unrolled within the recommended temperature range of 10 °C to 60 °C to avoid cracking or sticking.
⚠️ Warning: Always follow safety protocols when handling asphalt-impregnated materials, including proper ventilation and personal protective equipment.
❓ Frequently Asked Questions
🔍 What types of asphalt glass felts are covered?
The specification covers Types IV and VI asphalt-impregnated glass felts for use in roofing and waterproofing applications.
💡 How is net dry mass defined?
Net dry mass is the mass of the asphalt-impregnated glass felt after drying to constant weight and removing all detached comminuted surfacing material, as described in 8.