HT820 Flame Retardant Silicone Sponge Sheet

HT820 flame retardant silicone sponge sheeting (firm density). Boasting higher tear and tensile strength than lighter grade foams, this product offers superior durability and sealing. 

It has excellent memory and low stress relaxation, making it an ideal gasketing material. Further, its resistance to UV, Ozone, extreme temperature and flame allow it to be used in all environments and its cell structure prevents penetration by fine particles and rain. 

Possible applications include, but are not limited to gaskets, anti-vibration/cushioning, HVAC systems, anti-fogging seals and battery pads/cushions in the automotive industry.

This sheeting is 915mm wide and is sold by the metre.

Availability: Out of stock


BISCO HT-820 Firm Cellular Silicone is a firm grade silicone foam that provides enhanced durability and sealing. HT-820 foam offers a higher tear and tensile strength than our lighter grade foams. This material is designed for use in enclosures requiring a more durable, high closure force gasket. HT-820 foam is ideal for sealing and protecting outdoor communication, lighting and electronic enclosures from small dust particles, wind-driven rain and fire.


  • Compact cell structure offers enhanced sealing performance
  • Available in thicknesses from 0.031 to 0.250 in.
  • Typical density of 24 PCF
  • CFD range of 12-20 PSI
  • Resistant to UV, ozone, extreme temperatures and flame


  • Excellent memory and low stress relaxation
  • Enhanced sealing performance
  • Offers consistent performance in all environments
  • Reduces maintenance costs associated with gasket failures due to compression set and softening

Additional information




0.8mm, 1.6mm, 2.4mm, 3.2mm, 4.8mm, 6.4mm