Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D4601 – Standard Test Method Technical Guide
📐 Specification Overview and Classification
ASTM D4601/D4601M-04 (Reapproved 2020) specifies the requirements for asphalt-coated glass fiber base sheet used as the first ply in built-up roofing systems. This standard covers two types: Type I and Type II, with or without perforations. When not perforated, the sheet is suitable for use as a vapor retarder under roof insulation with a solid mopping of asphaltic material. The standard has been approved for use by agencies of the U.S. Department of Defense and is developed in accordance with internationally recognized principles on standardization.
⚙️ Manufacturing and Physical Requirements
The base sheet is manufactured from a uniform glass fiber mat bonded with a water-resistant resinous binder. It is impregnated with hot asphalt and coated on one or both sides with hot asphaltic material, which may be compounded with a mineral stabilizer. The material may be surfaced with mineral surfacing and faced with kraft paper on the bottom side. The finished product must not crack or be so sticky as to cause tearing upon being unrolled at temperatures between 4 and 60°C [40 and 140°F]. Small pin holes are permitted throughout the sheet.
| 🟦 Property | 📏 Requirement |
|---|---|
| Asphalt Impregnation | Uniform coating on one or both sides |
| Temperature Range for Unrolling | 4 to 60°C [40 to 140°F] |
| Defects | No cracks, tears, or protrusions; small pin holes permitted |
| Perforations (if applicable) | For venting during application |
💡 Tip: Always verify that the base sheet is unrolled within the specified temperature range to prevent damage or sticking during installation.
📊 Sampling and Test Methods
Sampling and testing of the material shall be performed in accordance with Test Methods D228/D228M. The product must conform to the physical requirements, dimensions, and masses outlined in Tables 1 and 2 of the standard. Perforated materials must also meet the requirements of Table 3. Definitions of terms used in this specification are provided in Terminology D1079.
⚠️ Note: Values stated in SI units and inch-pound units are not exact equivalents. Each system shall be used independently to avoid nonconformance with the standard.
❓ Frequently Asked Questions
🔍 What is the scope of ASTM D4601?
This specification covers asphalt-coated glass fiber base sheet for use as the first ply in built-up roofing and as a vapor retarder when not perforated.
💡 How is the material classified?
It is classified into Type I and Type II based on physical requirements, dimensions, and masses as per Section 4 of the standard.
⚡ What are the critical temperature conditions?
The material must not crack or stick when unrolled at temperatures between 4 and 60°C [40 and 140°F].
📌 Which standards are referenced for testing?
Test Methods D228/D228M are used for sampling and determining properties, and Terminology D1079 provides definitions.