NBR / PVC vs. EPDM Elastomeric Insulation Materials

Traditionally, elastomeric insulation has been manufactured from an NBR (Nitrile Butadiene Rubber) polymeric blend. ZEAL RUBBER standard black elastomeric insulation products (tube and sheet) are produced from a UV resistant NBR polymeric blend. Recently, a competitor has introduced an insulation product suggesting it is based on the polymer EPDM (Ethylene Propylene Diene Methylene). A comparison of insulation products based on an NBR Polymeric Blend vs. EPDM will illustrate some of the similarities and differences:

Flame and smoke properties

NBR polymeric blend insulation products have a flame and smoke rating of 25/50 through 1-1/2” wall. The flame-retardant additives used to manufacture EPDM-based insulation create high levels of smoke making it difficult to meet this specification. EPDM insulation products may not meet this standard.

Strength properties

NBR polymeric blend insulations have excellent tensile strength, tear resistance, abrasion resistance, and compression-set resistance. These strength properties make the insulation easier to install and more durable over time. EPDM-based products generally have poor tear and abrasion resistance.

Temperature limits

Air will not easily permeate the cell walls of NBR polymeric blend foams. EPDM on the other hand is more permeable. At higher temperatures air permeability could result in EPDM shrinkage. Shrinking appears in the form of wrinkled skin surface and shortened lengths. The effect of this shrinking is added stress on the sealed joints and exposed pipe / tubing.