D1415-18 – Standard Test Method Technical Guide

📐 Specimen Geometry and Test Type Selection

ASTM D1415-18 provides four distinct procedures to accommodate a wide range of rubber hardness levels and specimen geometries. The selection of the correct test type is critical for obtaining valid International Rubber Hardness Degree (IRHD) measurements:

• Types S1 and S2 (Standard tests): The primary methods for specimens having a hardness from 35 IRHD to 85 IRHD, usable within 30 to 95 IRHD.
• Type M (Micro-hardness test): A scaled-down version of the standard test, permitting the testing of thinner and smaller specimens within the 35 to 85 IRHD range (usable 30 to 95 IRHD).
• Type L (Low hardness test

  © 2026 TNLab — This article is a technical interpretation for reference only. The original standard as published by ASTM International takes precedence.