# Insulator thermal resistance

I have a machine that has power output of 2750 watt, which is blasted to a insulator foam with thermal resistance of 2.1 m2 kelvin/watt where the insulator is 5 cm thick and it drives the heat into ventilation and out of the roof.

I want to make sure that the insulator can withstand the heat blast from the machine. So if I know that 2750 watt can output 9383 btu/hr where 1 watt outputs 3.412 btu/hr, how can I be sure that the insulator can withstand the heat without it getting spread out? regards

Edited additional info: exhaust temp is 40 degree Celsius, room temp is 25 degree Celsius, and outside temp is 32 degree Celsius.

Flammability limit: lower limit for hydrocarbon gas (part of the foam) 1.8% by volume upper limit for hydrocarbon gas: 8.5 % by volume flash point of hydrocarbon gas: -84 degree Celsius

Volume of the exhaust = 50x 60 x 200 cm cube = 600,000cm cube

• there is not sufficient info here to know the exhaust temperature Dec 26, 2017 at 14:23
• @agentp just add exhaust temp info Jan 2, 2018 at 12:19
• Use fiberglass insulation or batting made by Aspen Aerogels, but put a metal heat shield in front of the fiberglass with an air gap between the insulation and heat shield, you should be OK. Jun 3, 2018 at 18:42