Section 675IAC15-2-20. Heat loss; mobile system

   (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. (Fire Prevention and Building Safety Commission; 675 IAC 15-2-20; filed Mar 25, 1986, 1:44 pm: 9 IR 1985, eff Jun 15, 1986; filed Sep 19, 1986, 9:15 am: 10 IR 236; readopted filed Nov 29, 2001, 12:21 p.m.: 25 IR 1306; readopted filed Sep 21, 2007, 9:20 a.m.: 20071010-IR-675070388RFA; readopted filed Oct 10, 2007, 9:16 a.m: 20071031-IR-675070388RFA; readopted filed Aug 4, 2011, 8:35 a.m.: 20110831-IR-675110254RFA)