9.25.5.2.Position of Low Permeance Materials (See Note A-9.25.5.2.)

(1) Sheet and panel-type materials described in Article 9.25.5.1. shall be installed (a) on the warm face of the assembly, (See also Article 9.25.4.2.) (b) at a location where the ratio between the total thermal resistance of all materials outboard of its innermost impermeable surface and the total thermal resistance of all materials inboard of that surface is not less than that required by Table 9.25.5.2., or (c) outboard of an air space that is vented to the outdoors. Table 9.25.5.2. Ratio of Outboard to Inboard Thermal Resistance Forming Part of Sentence 9.25.5.2.(1) Heating Degree Days of Building Location(1), Minimum Ratio, Total Thermal Resistance Outboard of Material’s Inner Celsius Degree-Days Surface to Total Thermal Resistance Inboard of Material’s Inner Surface Up to 4 999 0.20 5 000 to 5 999 0.30 6 000 to 6 999 0.35 7 000 to 7 999 0.40 8 000 to 8 999 0.50 9 000 to 9 999 0.55 10 000 to 10 999 0.60 11 000 to 11 999 0.65 12 000 or higher 0.75 Notes to Table 9.25.5.2.: (1) See MMAH Supplementary Standard SB-1, “Climatic and Seismic Data.” (2) For walls, the air space described in Clause (1)(c) shall be drained and ventilated and shall be not less than 10 mm deep behind the cladding, over the full height and width of the wall.