Code of Massachusetts Regulations › 780 CMR - STATE BOARD OF BUILDING REGULATIONS AND STANDARDS › Chapter 26 - Plastic › Section 2603 - FOAM PLASTIC INSULATION › Subsection 2603.5 - Exterior walls of buildings of any height

Current through Register 1525, July 5, 2024
Exterior walls
of buildings of Type I, II,
				  III or IV construction of any height shall comply with Sections 2603.5.1
				  through 2603.5.7.
Exterior walls
of cold storage buildings
				  required to be constructed of noncombustible materials, where the building is
				  more than one
story
in height, shall also comply with the
				  provisions of Sections 2603.5.1 through 2603.5.7.
Exterior
				  walls
of buildings of Type V construction shall comply with Sections
				  2603.2, 2603.3 and 2603.4.
2603.5.1
Fire-resistance-rated walls.
Where the wall is required to have a
				fire-resistance rating, data based on tests conducted in accordance with ASTM E
				119 or UL 263 shall be provided to substantiate that the fire-resistance rating
				is maintained.
2603.5.2
Thermal barrier.
Any foam plastic insulation shall be separated from the
				building interior by a thermal barrier meeting the provisions of Section
				2603.4, unless special approval is obtained on the basis of Section 2603.9.
Exception:
One-story buildings complying with
				  Section 2603.4.1.4.
2603.5.3
Potential heat.
The
				potential heat of foam plastic insulation in any portion of the wall or panel
				shall not exceed the potential heat expressed in Btu per square feet
				(mJ/m2) of the foam plastic insulation contained in
				the wall assembly tested in accordance with Section 2603.5.5. The potential
				heat of the foam plastic insulation shall be determined by tests conducted in
				accordance with NFPA 259 and the results shall be expressed in Btu per square
				feet (mJ/m2).
Exception:
One-story buildings complying with
				  Section 2603.4.1.4.
2603.5.4
Flame spread and
				smoke-developed indexes.
Foam plastic insulation, exterior coatings and
				facings shall be tested separately in the thickness intended for use, but not
				to exceed 4 inches (102 mm), and shall each have a flame spread index of 25 or
				less and a smoke-developed index of 450 or less as determined in accordance
				with ASTM E 84 or UL 723.
Exception:
Prefabricated or factory-manufactured
				  panels having minimum 0.020-inch (0.51 mm) aluminum facings and a total
				  thickness of 1/4 inch (6.4
				  mm) or less are permitted to be tested as an assembly where the foam plastic
				  core is not exposed in the course of construction.
2603.5.5
Vertical and Lateral Fire
				Propagation.
The exterior wall assembly shall be tested in accordance
				with and comply with the acceptance criteria of NFPA 285.
Exception:
Wall assemblies where the foam
				  plastic insulation is covered on each face by not less than one inch (25 mm)
				  thickness of masonry, concrete, terra cotta, stucco or ½ inch thick Type
				  X gypsum board and meeting one of the following:
1. There is no airspace between the
				insulation and the masonry, concrete, terracotta, stucco, or ½ inch
				thick type X gypsum board.
2. The
				insulation has a flame spread index of not more than 25 as determined in
				accordance with ASTM E 84 or UL 723 and the maximum airspace between the
				insulation and the concrete or masonry is not more than one inch (25
				mm).