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Section M1306 Clearances Fromcombustible Construction
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M1306.1 Appliance Clearance
Appliances shall be installed with the clearances from unprotected combustible materials as indicated on the appliance label and in the manufacturer's installation instructions.
Note: "A" equals the required clearance with no protection. "B" equals the reduced clearance permitted in accordance with Table M1306.2. The protection applied to the construction using combustible material shall extend far enough in each direction to make "C" equal to "A."
FIGURE M1306.1
REDUCED CLEARANCE DIAGRAM
M1306.2 Clearance Reduction
Reduction of clearances shall be in accordance with the appliance manufacturer's instructions and Table M1306.2. Forms of protection with ventilated air space shall conform to the following requirements:
- Not less than 1-inch (25 mm) air space shall be provided between the protection and combustible wall surface.
- Air circulation shall be provided by having edges of the wall protection open at least 1 inch (25 mm).
- If the wall protection is mounted on a single flat wall away from corners, air circulation shall be provided by having the bottom and top edges, or the side and top edges open at least 1 inch (25 mm).
- Wall protection covering two walls in a corner shall be open at the bottom and top edges at least 1 inch (25 mm).
REDUCTION OF CLEARANCES WITH SPECIFIED FORMS OF PROTECTIONa, c, d, e, f, g, h, I, j, k, l
| TYPE OF PROTECTION APPLIED TO AND COVERING ALL SURFACES OF COMBUSTIBLE MATERIAL WITHIN THE DISTANCE SPECIFIED AS THE REQUIRED CLEARANCE WITH NO PROTECTION (See Figures M1306.1 and M1306.2) | WHERE THE REQUIRED CLEARANCE WITH NO PROTECTION FROM APPLIANCE, VENT CONNECTOR, OR SINGLE WALL METAL PIPE IS: | |||||||||
| 36 inches | 18 inches | 12 inches | 9 inches | 6 inches | ||||||
| Allowable clearances with specified protection (Inches)b | ||||||||||
| Use column 1 for clearances above an appliance or horizontal connector. Use column 2 for clearances from an appliance, vertical connector and single-wall metal pipe. | ||||||||||
| Above column 1 | Sides and rear column 2 | Above column 1 | Sides and rear column 2 | Above column 1 | Sides and rear column 2 | Above column 1 | Sides and rear column 2 | Above column 1 | Sides and rear column 2 | |
| 31/2-inch-thick masonry wall without ventilated air space | — | 24 | — | 12 | — | 9 | — | 6 | — | 5 |
| 1/2-inch insulation board over 1-inch glass fiber or mineral wool batts | 24 | 18 | 12 | 9 | 9 | 6 | 6 | 5 | 4 | 3 |
| Galvanized sheet steel having a minimum thickness of 0.0236-inch (No. 24 gage) over 1-inch glass fiber or mineral wool batts reinforced with wire or rear face with a ventilated air space | 18 | 12 | 9 | 6 | 6 | 4 | 5 | 3 | 3 | 3 |
| 31/2-inch-thick masonry wall with ventilated air space | — | 12 | — | 6 | — | 6 | — | 6 | — | 6 |
| Galvanized sheet steel having a minimum thickness of 0.0236-inch (No. 24 gage) with a ventilated air space 1-inch off the combustible assembly | 18 | 12 | 9 | 6 | 6 | 4 | 5 | 3 | 3 | 2 |
| 1/2-inch-thick insulation board with ventilated air space | 18 | 12 | 9 | 6 | 6 | 4 | 5 | 3 | 3 | 3 |
| Galvanized sheet steel having a minimum thickness of 0.0236-inch (No. 24 gage) with ventilated air space over 24 gage sheet steel with a ventilated space | 18 | 12 | 9 | 6 | 6 | 4 | 5 | 3 | 3 | 3 |
| 1-inch glass fiber or mineral wool batts sandwiched between two sheets of galvanized sheet steel having a minimum thickness of 0.0236 -inch (No. 24 gage) with a ventilated air space | 18 | 12 | 9 | 6 | 6 | 4 | 5 | 3 | 3 | 3 |
For SI: 1 inch = 25.4 mm, 1 pound per cubic foot = 16.019 kg/m3, °C = [(°F)-32/1.8], 1 Btu/(h × ft2 × °F/in.) = 0.001442299 (W/cm2 × °C/cm).
- Reduction of clearances from combustible materials shall not interfere with combustion air, draft hood clearance and relief, and accessibility of servicing.
- Clearances shall be measured from the surface of the heat producing appliance or equipment to the outer surface of the combustible material or combustible assembly.
- Spacers and ties shall be of noncombustible material. No spacer or tie shall be used directly opposite appliance or connector.
- Where all clearance reduction systems use a ventilated air space, adequate provision for air circulation shall be provided as described. (See Figures M1306.1 and M1306.2.)
- There shall be at least 1 inch between clearance reduction systems and combustible walls and ceilings for reduction systems using ventilated air space.
- If a wall protector is mounted on a single flat wall away from corners, adequate air circulation shall be permitted to be provided by leaving only the bottom and top edges or only the side and top edges open with at least a 1-inch air gap.
- Mineral wool and glass fiber batts (blanket or board) shall have a minimum density of 8 pounds per cubic foot and a minimum melting point of 1,500°F.
- Insulation material used as part of a clearance reduction system shall have a thermal conductivity of 1.0 Btu inch per square foot per hour °F or less. Insulation board shall be formed of noncombustible material.
- There shall be at least 1 inch between the appliance and the protector. In no case shall the clearance between the appliance and the combustible surface be reduced below that allowed in this table.
- All clearances and thicknesses are minimum; larger clearances and thicknesses are acceptable.
- Listed single-wall connectors shall be permitted to be installed in accordance with the terms of their listing and the manufacturer's instructions.
- For limitations on clearance reduction for solid-fuel-burning appliances see Section M1306.2.1.
For SI: 1 inch = 25.4 mm.
FIGURE M1306.2
WALL PROTECTOR CLEARANCE REDUCTION SYSTEM
M1306.2.1 Solid-Fuel Appliances
Table M1306.2 shall not be used to reduce the clearance required for solid-fuel appliances listed for installation with minimum clearances of 12 inches (305 mm) or less. For appliances listed for installation with minimum clearances greater than 12 inches (305 mm), Table M1306.2 shall not be used to reduce the clearance to less than 12 inches (305 mm).
Upcodes Diagrams
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