Rationale

Currently no criteria are set forth in the standard to define the level of water repellency required for a material to be classified as Grade 2B, hydrophobic insulation. The change to the standard would incorporate criteria and testing in accordance with ASTM C1763, Standard Test Method for Water Absorption by Immersion of Thermal Insulation Materials, to establish a maximum level of water absorption allowed to classify a microporous insulation as Grade 2B hydrophobic insulation.