SPS 323.045(8)
(8) Supplemental units. Supplemental solid-fuel-burning units connected to a furnace shall be connected to the warm air side of the furnace as illustrated in Figures 323.045-C to E, and shall be installed in accordance with all of the following:
SPS 323.045(8)(a)
(a) Return air duct. The area of the return air duct shall be at least equal to the area of the warm air supply duct. The return air duct shall be of the same material as specified for supply air ducts. Return air grilles shall not be located in bathrooms, kitchens, garages, utility spaces or in a confined space defined under
s. SPS 323.06 in which a draft diverter or draft regulator is located.
SPS 323.045(8)(b)
(b) Blower. The blower on the furnace shall maintain the manufacturer's specifications for cubic feet per minute air flow and static pressure when the supplemental unit is in operation.
SPS 323.045(8)(c)
(c) Outside air intake. The outside air intake shall be connected to the cold air return plenum of the furnace. A volume damper shall be placed in the duct for the fresh air intake.
SPS 323.045(8)(d)
(d) Thermostat. The thermostat control on the supplemental heating unit shall activate the blower motor at a temperature between 100
° and 120
° F.
SPS 323.045(8)(e)
(e) Supplemental units. Supplemental solid-fuel-burning units shall be installed to maintain a 3-foot clearance between the unit and the furnace or shall be installed in accordance with the listings of both the supplemental unit and the furnace if such an installation is specifically covered by the listings.
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See PDF for table 
TABLE 323.045-D
STANDARD CLEARANCES FOR
FIGURE 323.045-B
PROTECTION OF COMBUSTIBLE WALLS
AND FLOORS
FIGURE 323.045-C
FIGURE 323.045-D
SPS 323.045(9)
(9) Supply ducts. Supply ducts connected to solid-fuel-burning appliances shall have the following minimum clearances to combustibles:
SPS 323.045(9)(a)
(a) Horizontal ducts. The clearance from combustibles for horizontal ducts shall be as specified in Table 323.045-F.
SPS 323.045 Note
1 Clearance can be reduced in accordance with Table 323.045-B
SPS 323.045(9)(b)1.1. Air shall travel 6 feet and change directions equivalent to one 90
° turn before entering an enclosure of combustible material.
SPS 323.045(9)(b)2.
2. Ducts shall have 3/16 inch clearance between the duct and any combustible material.
SPS 323.045(10)
(10) Combination appliances. Appliances capable of burning multi-types of fuel shall be listed and installed in accordance with their listing.
FIGURE 323.045-E
SPS 323.045 History
History: Cr.
Register, February, 1985, No. 350, eff. 3-1-85; am. (1), (3) (a) 1., (4) (b), (5), (6) (a), (6) (b) 2., (8) (intro.) and (9) (a), renum. Tables 23.045-B to E to be Tables 23.045-C, D, B and F and am. B and F, Figures 23.045-C to E renum. from Figures 23.01-A to C, cr. (2) (c), (3) (b) to (e) and (8) (e), Table 23.045-E and Figure 23.045-B, r. and recr. (6) (b) 1.,
Register, January, 1989, No. 397, eff. 2-1-89; am. (1), (2) (b) (intro.), (3) (a) 1., (8) (a) and Table A, cr. (2) (b) 4., r. and recr. Table C,
Register, March, 1992, No. 435, eff. 4-1-92
; am. Table C,
Register, November, 1995, No. 479, eff. 12-1-95; r. (2) (b) and renum. and am. (2) (c) to be (2) (b),
Register, March, 2001, No. 543, eff. 4-1-01;
CR 08-043: am. (2) (b)
Register March 2009 No. 639, eff. 4-1-09; correction in (3) (a) 2., (4) (a), (b), (5) (a), (6) (a) (intro.), 1., 2., (8) (intro.), (a), (9) (a), Figure 323.045-A, Table 323.045-E, 323.045-F made under s.
13.92 (4) (b) 7., Stats.,
Register December 2011 No. 672;
CR 15-041: renum. (5) (a) to (5), cr. (5m), cr. (6) (a) (title), renum. (6) (a) (intro.) to (a) and am. (intro.), am. (8) (intro.) Register December 2015 No. 720, eff. 1-1-16. SPS 323.05
SPS 323.05
Safety controls. High limit, maximum outlet air temperature and similar safety controls shall be provided on heating equipment.
SPS 323.05 History
History: Cr.
Register, November, 1979, No. 287, eff. 6-1-80.
SPS 323.06(1)(a)(a) Naturally vented appliances and other appliances that require air for combustion and dilution of flue gases to be taken from within the building shall comply with this section.
SPS 323.06(1)(b)
(b) Appliances that are provided with a direct supply of outside air for combustion in accordance with the manufacturer's installation instructions and listing are not required to comply with this section.
SPS 323.06(1)(c)
(c) Where the appliance listing and manufacturer's instructions are more stringent than the provisions of this section, the listing and manufacturer's instructions apply.
SPS 323.06(1)(d)
(d) Listed fireplace stoves are not required to comply with this section if permitted in the manufacturer's instructions.
SPS 323.06(1)(f)
(f) Listed factory-built fireplaces shall comply with the manufacturer's recommendations and shall conform with the requirements of
s. SPS 321.32.
SPS 323.06(2)
(2) Methods for providing air. Air for combustion and dilution shall be provided in accordance with one of the following:
SPS 323.06(2)(a)
(a) If the vapor retarder is not continuous on walls and ceilings exposed to the outside atmosphere as allowed by
s. SPS 322.38, air may be provided from inside the building in accordance with
sub. (3).
SPS 323.06(2)(b)
(b) Air may be provided from outside the building in accordance with
sub. (4).
SPS 323.06(2)(c)
(c) The appliance may be installed in accordance with its listing and manufacturer's instructions. Where all walls and ceilings exposed to the outside atmosphere are provided with a continuous vapor retarder, any requirements for unusually tight construction shall be met.
SPS 323.06(2)(d)
(d) An engineered system providing an adequate supply of air for combustion ventilation and dilution of flue gases may be installed if approved by the department.
SPS 323.06(3)(a)1.1. The equipment shall be located in a space with a volume not less than 50 cubic feet per 1000 Btu/h of the combined input rating of all fuel-burning appliances drawing combustion and dilution air from that space.
SPS 323.06(3)(a)2.
2. The space may be made up of more than one room if the rooms are connected through doorways without doors or connected through sets of openings described in
par. (b).
SPS 323.06(3)(b)1.1. When needed to connect rooms, two openings shall be provided, one within one foot of the ceiling of the room and one within one foot of the floor.
SPS 323.06(3)(b)3.
3. The net free area of each opening shall be a minimum of one square inch per 1000 Btu/h of combined input rating of the fuel burning appliances drawing combustion and dilution air from the communicating rooms, but shall be not less than 100 square inches.
SPS 323.06(4)(a)(a) When air for combustion and dilution is provided from outside the building, as allowed under
sub. (2) (b), one of the methods specified in
pars. (b) to
(d) shall be used.
SPS 323.06(4)(b)
(b) Openings may be provided to connect rooms containing appliances to the outdoors.
SPS 323.06(4)(b)1.a.a. Two openings shall be provided, one within one foot of the ceiling of the room and one within one foot of the floor.
SPS 323.06(4)(b)1.b.
b. Openings may connect directly to the outdoors or to the outdoors through a horizontal or vertical duct.
SPS 323.06(4)(b)2.
2. The net free area of each direct opening to the outdoors not using a duct shall be a minimum of one square inch per 4000 Btu/h of combined input rating of the fuel-burning appliances drawing combustion and dilution air from the room.
SPS 323.06(4)(b)3.a.a. The net free area of each opening connected to the outdoors through a horizontal duct shall be a minimum of one square inch per 2000 Btu/h of combined input rating of the fuel-burning appliances drawing combustion and dilution air from the room.
SPS 323.06(4)(b)3.b.
b. The cross-sectional area of the duct shall be equal to or greater than the required size of the opening.
SPS 323.06(4)(b)4.a.a. The net free area of each opening connected to the outdoors through a vertical duct shall be a minimum of one square inch per 4000 Btu/h of combined input rating of the fuel-burning appliances drawing combustion and dilution air from the room.
SPS 323.06(4)(b)4.b.
b. The cross-sectional area of the duct shall be equal to or greater than the required size of the opening.
SPS 323.06(4)(c)1.1. Where all appliances drawing air for combustion and dilution from the room are gas appliances, air may be provided via a single opening to connect the room to the outdoors in accordance with this paragraph.
SPS 323.06(4)(c)2.b.
b. The opening may connect directly to the outdoors, may connect to the outdoors through a horizontal duct, or may connect to the outdoors through a vertical duct.
SPS 323.06(4)(c)3.a.a. The net free area of the opening shall be a minimum of one square inch per 3000 Btu/h of combined input rating of the fuel-burning appliances drawing combustion and dilution air from the room, and not less than the combined cross-sectional flow areas of the appliance flue collars or draft hood outlets.
SPS 323.06(4)(c)3.b.
b. The cross-sectional area of the duct shall be equal to or greater than the required size of the opening.
SPS 323.06(4)(c)4.
4. The appliances shall have a minimum clearance to the surfaces of the room of one inch at the sides and back of the appliance and 6 inches at the front of the appliance.
SPS 323.06(4)(d)1.1. A combination of openings to the outside and openings to other rooms may be used in accordance with this paragraph.
SPS 323.06(4)(d)2.a.a. One opening shall connect directly to the outdoors, connect to the outdoors through a horizontal duct, or connect to the outdoors through a vertical duct.
SPS 323.06(4)(d)2.c.
c. The net free area of the opening shall be a minimum of one square inch per 5000 Btu/h of combined input rating of the fuel burning appliances drawing combustion and dilution air from the room.
SPS 323.06(4)(d)2.d.
d. The cross-sectional area of a duct, if used, shall be equal to or greater than the required size of the opening.
SPS 323.06(4)(d)3.a.a. The equipment shall be located in a space with a volume not less than 50 cubic feet per 1000 Btu/h of the combined input rating of all fuel-burning appliances installed in that space.
SPS 323.06(4)(d)3.b.
b. The space may be made up of more than one room if the rooms are connected through openings without doors or connected through sets of openings described in
subd. 4.
SPS 323.06(4)(d)4.a.a. When needed to connect rooms, two openings shall be provided, one within one foot of the ceiling of the room and one within one foot of the floor.
