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A vapor barrier on the warm side of the envelope must be combined with a venting path on the cold side of the insulation. This is because no vapor barrier is perfect, and because water may get into the structure, typically from rain. In general, the better the vapor barrier and the drier the conditions, the less venting is required. [7]
Open-cell foam is porous, allowing water vapor and liquid water to penetrate the insulation. Closed-cell foam is non-porous, and not moisture-penetrable, thereby effectively forming a semi-permeable vapor barrier. (N.B., vapor barriers are usually required by the Building Codes, regardless of the type of insulation used.
In order to achieve these objectives, all building enclosure systems must include a solid structure, a drainage plane, an air barrier, a thermal barrier, and may include a vapor barrier. Moisture control (e.g. damp proofing) is essential in all climates, but cold climates and hot-humid climates are especially demanding. [8]
A fire proximity suit (also, silvers, silver bunker suit, or asbestos suit) is a suit designed to protect a firefighter or volcanologist from extremely high temperatures. They were first designed and used in the 1930s.
Fire barriers are continuous through concealed spaces (e.g., above a ceiling) to the floor deck or roof deck above the barrier. Fire partitions are not required to extend through concealed spaces if the construction assembly forming the bottom of the concealed space, such as the ceiling, has a fire resistance rating at least equal to or greater ...
Concrete normally allows moisture to pass through so a vertical vapor barrier is needed. Barriers may be a coating or membrane applied to the exterior of the concrete. The coating may be asphalt, asphalt emulsion, a thinned asphalt called cutback asphalt, or an elastomer. [9] Membranes are rubberized asphalt or EPDM rubber. Rubberized products ...
In March, 2008, the city of Portland, Oregon, granted a waiver of the requirement for a vapor barrier or retarder when using cellulose insulation. [11] This appeal cited industry guidance that the combination of an exterior vapor retarder (as required by code) and an interior one could trap moisture in the wall, leading to damage.
A firestop or fire-stopping is a form of passive fire protection that is used to seal around openings and between joints in a fire-resistance-rated wall or floor assembly. . Firestops are designed to maintain the fire-resistance rating of a wall or floor assembly intended to impede the spread of fire and