[Code of Federal Regulations]
[Title 24, Volume 5]
[Revised as of April 1, 2001]
From the U.S. Government Printing Office via GPO Access
[CITE: 24CFR3280.502]

[Page 140-141]
 
                 TITLE 24--HOUSING AND URBAN DEVELOPMENT
 
 CHAPTER XX--OFFICE OF ASSISTANT SECRETARY FOR HOUSING--FEDERAL HOUSING 
        COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT
 
PART 3280--MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS--Table of Contents
 
                      Subpart F--Thermal Protection
 
Sec. 3280.502  Definitions.

    (a) The following definitions are applicable to subpart F only:
    (1) Pressure envelope means that primary air barrier surrounding the 
living space which serves to limit air leakage. In construction using 
ventilated cavities, the pressure envelope is the interior skin.
    (2) Thermal envelope area means the sum of the surface areas of 
outside walls, ceiling and floor, including all openings. The wall area 
is measured by

[[Page 141]]

multiplying outside wall lengths by the inside wall height from floor to 
ceiling. The floor and ceiling areas are considered as horizontal 
surfaces using exterior width and length.