CODES AND STANDARDS

Insulation is often regulated by code requirements. The individual sections of any code must be carefully read in order to determine how flame-spreading or smoke-developing characteristics restrict the use of particular materials in specific areas of a building.

Typically, codes define the class of any building erected into one of four types: I, II, III, or IV. Type I is fireproof, Type II is noncombustible and either protected or nonprotected, and Types III and IV are combustible. The allowable flame-spread rating for any construction material is based on each class of construction.

The specific areas within a building also have restrictions pertaining to the allowable smoke-developed rating. These areas are:

1. Concealed spaces such as chases and shafts, not serving the HVAC system as air supplies or returns.

2. The same spaces as above, but used for air supplies or returns.

3. Rooms and spaces that may have a higher allowable smoke-developed or flame-spread rating, such as mechanical equipment rooms. Here the interior finish and the insulation fire code requirements are relaxed because of the nature of the space.

The building class as a whole usually determines the flame spread, and the specific area within the building usually determines the smoke developed. It is important to determine the most cost-effective insulation based on the code interpretations.

FUNDAMENTALS OF HEAT TRANSFER