Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D6510-00 – Standard Test Method Technical Guide
📐 Scope and Significance of ASTM D6510
This standard guide (Designation D6510 −00, Reapproved 2006) provides advice for the selection of asphalt used in the construction of built-up roofing (BUR) systems. It supersedes the slope guidelines of Appendix X1 of Specification D312. The primary function of hot-applied roofing asphalt is to serve as both the waterproofing agent and adhesive for BUR membranes. This guide addresses the use of asphalt with various reinforcements, including ply sheets (Specifications D226, D2178, D5726), base sheets (D2626, D4601, D4897), and cap sheets (D3909), consisting of glass, organic, or synthetic fibers. It also covers the use of asphalt in vapor retarders and rigid roof insulation but does not address waterproofing, cold-applied, or modified bituminous roofing.
⚙️ Selection Criteria: Durability, Slope, and Climate
Specification D312 describes four types of roofing asphalt. The softest (least oxidized) asphalt is generally considered the most durable. The accepted rule for selection is to choose the softest bitumen that is commensurate with the slope of the roof. Following the Equiviscous Temperature (EVT) guidelines from the NRCA, the application rate is expected to be between 1.0 and 2.0 kg/m² (20 to 40 lb/100 ft²). Table 1 outlines the fundamental selection criteria.
| 🟦 Selection Criterion | 📏 Guideline from Standard |
|---|---|
| Durability Principle | The softest (least oxidized) asphalt is generally the most durable. |
| Primary Selection Rule | Select the softest bitumen commensurate with the roof slope. |
| Application Rate (EVT) | Expected range: 1.0 to 2.0 kg/m² (20 to 40 lb/100 ft²). |
Climate plays a decisive role in final selection. In hotter climates, harder (higher viscosity) bitumens must be chosen to minimize the risk of slippage. Table 2 provides a general framework for matching asphalt type to climate.
| 🌡️ Climate / Exposure | 🎯 Recommended Asphalt Type | ⚡ Purpose |
|---|---|---|
| Cold Climates / Steep Slopes | Softer Types (e.g., D312 Type I) | Maximize durability and flexibility. |
| Moderate Climates | Medium Grade (e.g., D312 Type III) | Balance durability with flow resistance. |
| Hot Climates / Low Slopes | Harder Types (e.g., D312 Type IV) | Minimize slippage potential. |
⚠️ Important Note on Climatic Selection: While the softest asphalt is typically the most durable, this characteristic must be balanced against the roof slope and local climate. A soft asphalt applied in a hot climate can lead to membrane slippage and system failure.
📊 Specification Guidelines and Referenced Documents
The selection of asphalt must be made within the context of a complete roofing system. This guide references several critical ASTM standards, including Test Method D92 for flash and fire points, and Practice D3791 for evaluating the effects of heat on asphalts. The physical properties of the reinforcing felts, whether from glass, organic, or synthetic fibers, are governed by their respective specifications (D226, D2178, D2626, etc.). Accurate terminology is defined in Terminology D1079. It is essential to consult these documents alongside the slope and climate guidelines provided in this standard to ensure a durable