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TLCFRS — Firestop Radiation Shield/Joist Shield

How to Specify

Using tables from the National Fuel Gas Code or our Sizing & Application Guide, determine the diameter of venting required. The Sizing & Application Guide also offers tips on good design including multi-appliance system sizing and design. The System Design and Installation Guide is an additional resource.

TLCFRS — Firestop Radiation Shield/Joist Shield


  • Required where an enclosed chimney passes from a lower living space into an upper living space.
  • Maintains the mandatory 2-inch clearance to combustibles.
  • Joist Shield is used in floor/ceiling penetrations, other than those that include a ceiling support.
  • Joist Shield not required when passing through roof.

AV_TLCFRS_Firestop Radiation Shield

Firestop Radiation Shield dimensions (inches)


Firestop/Joist Shield dimensions (inches)

ModelSize(A)(B)( C )(D)
10TLCFRS10"12 1/8141816
12TLCFRS12"14 1/8162018
14TLCFRS14"16 1/8182220