675 IAC 15-2-20
675 IAC 15-2-20 Heat loss; mobile system
Cite as Ind. Admin. Code tit. 675, r. 15-2-20
Sec. 20. (a) The total calculated heat loss of the unit at the outdoor design temperature shall not exceed forty (40) Btu/hour/square feet
of the total floor area or 275 Btu/hour/lineal foot of the perimeter of the space to be heated to 70° F, whichever is greater. The minimum total
resistance value (R), excluding framing, windows and doors shall not be less than:
Wall 11.0
Ceiling 19.0
Floor 10.0
(b) "R" values and "U" factors shall be calculated as outlined in the latest edition of the Indiana Energy Conservation Code ( 675
IAC 19).
(c) Framing Heat Loss. In the absence of specific data, for the purpose of heat loss calculations, the following framing areas shall be
assumed:
Wall 20% of net wall area
Ceiling 5% of total ceiling area
Floor 10% of net floor area
(d) Infiltration Heat Loss. Infiltration heat loss shall be determined as outlined in the Indiana Energy Conservation Code ( 675 IAC
19).
Outside Design Temperature
Degrees F Infiltration Allowance Btu/hr
40 3330
30 4440
20 5550
10 6660
0 7770
minus 10 8880
minus 20 9990
minus 30 11100
minus 40 12210
(e) Duct Heat Loss. The supply duct heat loss shall be calculated separately using the actual duct surface area and the actual thickness of
insulation between the duct and outside of the mobile structure. If there is an air space of one-half inch (1/2") or less, the heat duct shall be assumed
in contact with the insulation. If there is an air space of over one-half inch (1/2") between the duct and the insulation, no special heat loss need be
calculated if the cavity in which the duct is located is assumed to be at 70° F. The average temperature inside the supply duct shall be assumed
to be at least 130° F for the purpose of calculation.
(f) The wall, roof and floor assembly R values are typical and are not intended to be all inclusive. Other assemblies may be used provided
documentation is submitted indicating overall equivalent thermal transmittance for the structure. Such documentation shall be consistent with
accepted engineering practice.