Wis. Admin. Code Department of Safety and Professional Services SPS 323.045

Current through November 25, 2024

Section SPS 323.045 - Solid-fuel-burning appliances

(1) GENERAL. Solid-fuel-burning appliances shall be installed as specified in this section unless the manufacturer or listing specifies the use of protection or clearances other than those specified in this section. All solid-fuel-burning appliances shall be tested and listed by an accepted testing agency.

Note: Factory-built fireplaces shall comply with s. SPS 321.32.

(2) LOCATION OF APPLIANCES.

(a)Servicing. Every appliance shall be located to permit access to the appliance. Sufficient clearance shall be maintained around the equipment to permit cleaning of surfaces; the replacement of air filters, blowers, motors, controls and chimney connectors; the lubrication and servicing of moving parts; and the adjustment and servicing of stokers and appliance components.

(b)Garages. Solid-fuel-burning appliances may not be installed in a garage unless listed for that application.

(3) CHIMNEYS.

(a) Solid-fuel-burning appliances shall be connected to one of the following types of chimneys:

1. 'Factory-built chimneys or vents'. A listed residential-type and building heating appliance chimney may be used with solid-fuel-burning appliances if the chimneys have been tested 3 times to a minimum flue gas temperature exposure of 2100° F, under the conditions specified by the listing agency, for at least 10 minutes each time.

Note: Products listed and labeled as complying with UL 103 - "Type HT" meet this requirement. UL 103 uses several temperature ranges for different products but only the "Type HT"-designated products have met the 2100° F testing requirement.

2. 'Masonry chimneys'. Masonry chimneys shall be constructed as specified in s. SPS 321.30.

(b) Wood-burning equipment shall not be connected to a flue serving a fireplace or other equipment.

(c) The chimney shall be designed to create a natural draft to carry away the products of combustion or provision shall be made for mechanically maintaining constant updraft during equipment operation.

(d) A cleanout opening shall be provided.

(e) A listed, multifuel appliance may be vented into a single flue.

(4) CHIMNEY CONNECTORS.

(a) All solid-fuel-burning appliances shall be connected to chimneys with factory-built chimney material, Type L vent material or steel pipe with minimum thicknesses as specified in Table 323.045-A.

TABLE 323.045-A

METAL THICKNESS FOR PIPE CONNECTORS

Diameter of Connector (inches)	Sheet Gage No.	Minimum Thickness (inches)
6 to 10	24	.023
over 10 to 16	22	.029
over 16	16	.056

(b) The required clearance to combustibles for chimney connectors shall be 18 inches. This clearance may be reduced in accordance with Table 323.045-B. The specified protection shall be applied to and cover all combustible material as specified in Figure 323.045-A.

(c) Connectors and chimneys for solid fuel-burning appliances shall be designed, located and installed to permit ready access for internal inspection and cleaning.

(d)

1. Chimney connectors shall have no more than two 90° elbows.

2. The horizontal length shall not exceed 75% of the total vertical height of the entire venting system measured from the appliance outlet.

3. The connector shall maintain a rise of at least 1/4 inch per foot from the appliance outlet to the chimney inlet.

4. Connectors shall be securely supported and joints fastened with a minimum of 3 sheet metal screws or rivets.

5. Appliances used mainly for wood burning shall have the joints assembled so that the crimped end points towards the stove. Appliances burning coal shall have the joints assembled so that the crimped end points away from the appliance.

6. A connector to a masonry chimney shall extend through the wall to the innerface of the liner but not beyond.

7. The effective area of the connector shall not be less than the area of the appliance flue collar

(e) No chimney connectors may pass through any floor, ceiling, window, door or combustible wall nor be concealed in any closet, attic or similar space. A connector may pass through a combustible wall if the connector is guarded at the point of passage by one of the following methods:

1. Metal ventilated thimble not less than 12 inches larger in diameter than the connector

2. All combustible material in the wall is cut away from the connector a sufficient distance to provide the required 18-inch clearance. Any material used to close up such openings shall be noncombustible.

(f) A manual, cast iron damper to control draft shall be provided in the chimney connector The damper shall not obstruct more than 80% of the connector area. Listed solid-fuel appliances whose listing prohibits the use of manual dampers in the connector shall not require a manual damper to be installed.

FIGURE 323.045-A

CONSTRUCTION USING COMBUSTIBLE MATERIAL

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"A" Equals the required clearance with no protection, specified in s. SPS 323.045(4) (b).

"B" Equals the reduced clearance permitted in accordance with Table 323.045-B. The wall protection should extend far enough in each direction to make 'C' equal to 'A'.

TABLE 323.045-B

CONNECTOR CLEARANCES WITH SPECIFIED FORMS OF PROTECTION^1,2,3,4

Type of Protection	Minimum Required Connector Clearances (inches)
0.013 in. (28 gage) sheet metal spaced out a minimum of one inch.	9
31/2 in. thick masonry wall spaced out a minimum of one inch and adequately tied to the wall being protected (see Note 4).	9
0.027 in. (22 gage) sheet metal on one-inch mineral wool batts reinforced with wire or equivalent spaced out a minimum of one inch.	3

¹ Spacers and ties shall be of noncombustible material.

² All methods of protection require adequate ventilation between protective material and adjacent combustible walls and ceilings.

³ Mineral wool batts (blanket or board) shall have a minimum density of 8 pounds per cubic foot and a minimum melting point of 1550° F.

⁴ If a single wall connector passes through the masonry wall there shall be at least 1/2 inch of open ventilated air space between the connector and the masonry.

(5) MOUNTING ON FLOORS. Appliances shall be placed on surfaces as described in Table 323.045-C. Solid-fuel-burning appliances listed specifically for installation on a floor constructed of combustible material may be installed in accordance with the terms of the listing and the manufacturer's instructions.

(5m) MOUNTING ON THE GROUND. Ground-based solid-fuel-burning appliances shall be installed in accordance with the manufacturer's specifications.

(6) CLEARANCES.

(a)General. Solid-fuel-burning appliances shall be installed with clearances not less than specified in Table 323.045-D, except as provided in pars. (b) and (c).

(b)Listed appliances exception. Listed appliances shall be installed in accordance with the terms of their listing if greater clearances other than those specified by Table 323.045-D are required in accordance with the listing.

(c)Clearance with protection exception. Solid-fuel-burning appliances may be installed with reduced clearances provided the combustible material is protected as described in Table 323.045-E. The specified protection shall be applied to and cover all combustible material as specified in Figure 323.045-B.

(7) ACCESSORIES. Accessories for solid fuel-burning appliances such as heat exchangers, stove mats, floor pad and protection shields, shall be listed and shall be installed in accordance with the terms of their listing.

(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:

(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.

(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.

(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.

(d)Thermostat. The thermostat control on the supplemental heating unit shall activate the blower motor at a temperature between 100° and 120° F.

(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.

TABLE 323.045-C

FLOOR MOUNTINGS FOR SOLID

FUEL-BURNING APPLIANCES

Kind of Appliance	Allowed Mounting
(1) All forced air and gravity furnaces, steam and water boilers. or	Floors of fire-resistive construction with noncombustible flooring and surface finish, or fire-resistive arches or slabs. This construction may not have combustible material against the underside. Such construction shall extend at least 18 inches beyond the appliance on all sides.
(2) Residential-type ranges, water heaters, fireplace stoves,room heaters and combination fireplace stove/room heaters, having less than 2 inches of ventilated open space beneath the fire chamber or base of the appliance.	These appliances shall not be placed on combustible floors.
(3) Residential-type ranges, water heaters, fireplace stoves, room heaters and combination fireplace stove/room heaters having legs or pedestals providing 2 to 6 inches of ventilated open space beneath the fire chamber or base of the appliance.	On combustible floors when such floors are protected by 4 inches of hollow masonry, laid to provide air circulation through the masonry layer. Such masonry shall be covered with 24 gage sheet metal. The required floor protection shall extend at least 18 inches on all sides of the appliance. Noncombustible floors shall extend at least 18 inches on all sides of the appliance.
(4) Residential-type ranges, water heaters, fireplace stoves, room heaters and combination fireplace stove/room heaters having legs or pedestals providing over 6 inches of ventilated open space beneath the fire chamber or base of the covered appliance.	On combustible floors when such floors are protected by closely spaced masonry units of brick, concrete or stone, which provide at least 2 inches of thickness. Such masonry shall be covered by or placed over a sheet of 24 gage sheet metal. The required floor protection shall extend at least 18 inches on all sides of the appliance. Noncombustible floors shall extend at least 18 inches on all sides of the appliance.

TABLE 323.045-D

STANDARD CLEARANCES FOR

SOLID-FUEL-BURNING APPLIANCES

Type of Appliance	Above Top of Casing or Appliance. Above Top and Sides of Furnace Plenum or Bonnet (inches) Above Top of Casing or Appliance. Above Top and Sides of Furnace Plenum or Bonnet (inches)	Minimum Standard Clearances (inches)
Type of Appliance		From Front	From Back	From Sides
Residential Appliances Steam Boilers - 15 psi Water Boilers - 250° F max. Water Boilers - 200° F max. All Water Walled or Jacketed	6	48	6	6
Furnaces Gravity and Forced Air	18	48	18	18
Room Heaters, Fireplace Stoves, Combinations	36	36	36	36
			Firing Side	Opp. Side
Ranges
Lined Firechamber	30	36	24	18
Unlined Firechamber	30	36	36	18

TABLE 323.045-EMINIMUM ALLOWABLE

APPLIANCE CLEARANCE WITH

PROTECTION 1,2,3,4,5,6

Unprotected Clearances (inches) From Table 323.045-D
Type of Protection	For Ceilings				For Walls
Type of Protection	6	18	30	36	6	18	24	36	48
3 1/2 in. thick masonry wall without ventilated air space	-	-	-	-	4	12	16	24	32
1/2 in. thick noncombustible insulation board over 1 in. glass fiber or mineral wool batts without ventilated air space	4	12	20	24	3	9	12	18	24
0.024 in. (24 gage) sheet metal over 1 in. glass fiber or mineral wool batts reinforced with wire, or equivalent, or rear face with ventilated air space	3	9	15	18	2	6	8	12	16
3 1/2 in. thick masonry wall with ventilated air space	-	-	-	-	2	6	8	12	16
0.024 in. (24 gage) sheet metal with ventilated air space	3	9	15	18	2	6	8	12	16
1/2 in. thick noncombustible insulation board with ventilated air space	3	9	15	18	2	6	8	12	16
0.024 in. (24 gage) sheet metal with ventilated air space over 0.024 in. (24 gage) sheet metal with ventilated air space	3	9	15	18	2	6	8	12	16
1 in. glass fiber or mineral wool batts sandwiched between two sheets 0.024 in. (24 gage) sheet metal with ventilated air space	3	9	15	18	2	6	8	12	16

¹ Spacers and ties shall be of noncombustible material. No spacers or ties shall be used directly behind appliance or conductor.

² With all clearance reduction systems using a ventilated air space, at least two sides of the protection shall be open to provide adequate air circulation. There shall be at least one inch between the clearance reduction system and combustible walls and ceilings.

³ Mineral wool bats, blanket or board shall have a minimum density of 8 lb. per cubic foot and have a minimum melting point of 1,500° F

⁴ Insulation material used as part of a clearance reduction system shall have a thermal conductivity (k) of One (Btu) (in)/(Sq. ft.) (Hr.) (°F) or less. Insulation board shall be formed of noncombustible material.

⁵ If a single wall connector passes through a masonry wall used as a wall shield, there shall be at least 1/2 inch of open, ventilated space between the connector and the masonry.

⁶ Clearances in front of the loading door or ash removal door of the appliance shall not be reduced.

FIGURE 323.045-B

PROTECTION OF COMBUSTIBLE WALLS

AND FLOORS

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FIGURE 323.045-C

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FIGURE 323.045-D

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(9) SUPPLY DUCTS. Supply ducts connected to solid-fuel-burning appliances shall have the following minimum clearances to combustibles:

(a)Horizontal ducts. The clearance from combustibles for horizontal ducts shall be as specified in Table 323.045-F.

TABLE 323.045-F

Distance of Ducts From Bonnet or Plenum (inches)	Clearance to Combustibles¹ Required (inches)
0 to 36	18
over 36 to 72	6
over 72	1

¹ Clearance can be reduced in accordance with Table 323.045-B

(b)Vertical ducts.

1. Air shall travel 6 feet and change directions equivalent to one 90° turn before entering an enclosure of combustible material.

2. Ducts shall have 3/16 inch clearance between the duct and any combustible material.

(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

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Wis. Admin. Code Department of Safety and Professional Services SPS 323.045

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.

Amended by, 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.1/1/2016