Since 1978

Our insulation covers your building,
our people cover the rest.

COMMON QUESTIONS ASKED ABOUT
RMAX PRODUCTS AND POLYISOCYANURATE FOAMS ANSWERS FROM RMAX'S
TECHNICAL SERVICES

QUESTION: "HOW HIGH A TEMPERATURE WILL YOUR INSULATION PRODUCT WITHSTAND?"

ALTERNATE: "I WANT TO BUILD AN OVEN (DRYING BOOTH, HEATED PAINT BOOTH, ETC) AND WAS WANTING TO USE THIS INSULATION IN THE WALLS. IS THAT ALLRIGHT?"

Consider a question asked of Technical Services regarding heat and the application of a Rmax product behind a 'built-in oven' in a kitchen remodel project. The homeowner, a "do-it-yourselfer", wanted to eliminate the heat transmission from a built-in oven's walls through the kitchen walls to the rest of the house. The desire was to maximize the amount of insulation in a minimum amount of space. I declined to recommend this type of application.

Why?

Generally, polyisocyanurate foam insulations are suitable for use at temperatures between about -40 degrees F and +250 degrees F. Kitchen ovens are capable of temperatures up to 500 degrees F and are most often used in a range of 300 to 450 degrees F. The metal box of the oven is a double-wall construction with a mineral fiber insulation situated in the space between the walls. I do not know what the outside wall's temperature will be when the oven is in use. Nor does the average homeowner or oven-installer. I considered the risk of high temperature exposure to be too great. I declined to recommend the application.

The range of -40 to +250 degrees F is considered a "normal range" for the majority of applications in building constructions. For instance, a dark colored roofing material can heat to temperatures between 140 degrees F and 180 degrees F. Light or white roofing materials can be about 30 degrees less than their dark counterparts. Dark sidewall coverings can heat in the sun to temperatures of 150 degrees F or thereabouts.

Ovens, kilns, drying booths, hot flues, or other heated elements where the temperatures are in excess of +250 degrees F should never use a foam-type insulation around them at all. Surfaces that are heated above 200 degrees F or hotter should be insulated with a high-thermal insulation such as a fiber glass or rockwool or other refractory type insulation product.

The counter argument then is "well, the temperature in this cabinet will be less than 200 degrees F. What about that?" Foam plastic insulations (foam plastics is another name for the type of polyisocyanurate product manufactured by Rmax) are capable of expansive growth under the application of a dry heat or humid heat. It would be possible then to use these products from Rmax in such situations provided that the insulation is covered on both the outside and inside with a metal facing that is thicker than 0.016-inches. No foam product, regardless of the facing on that product, should be left exposed when used as wall insulation within any type of heating or hot equipment.

Frequently Asked Questions was provided by

Mr. John Wickham, Director of Technical Services,

Rmax, Inc.

You may reach Mr. Wickham for additional information at 1-800-527 0890, ext. 106.

Corporate & Sales Office
Rmax, Inc. 13524 Welch Road, Dallas, Texas 75244-5291 972 - 387- 4500
Fax: (972) 387- 4673
Plant Locations
Dallas, Texas 800-527-0890 (Central) Greer, South Carolina 800-845-4455 (Eastern)
Fernley, Nevada 800-762-9462 (Western)