Thermal Resistance of Airspaces and Fibrous Insulations Bounded by Reflective Surfaces

摘要

Observed insulating values are presented for 28 test panels, of which 23 were insulated with reflective membranes used alone or in combination with fibrous insulations. The panels were tested at five different orientations corresponding to use as walls, ceilings, or floors. The observed insulating values of panels are compared with calculated values based on a method and data developed in previous work at the National Bureau of Standards, and summarized in an appendix to this report. Observed values for panels agreed within 10 percent, in most cases, with calculated values. Departures of observed from calculated values are attributed to such factors as nonuniformity of airspace thickness, moisture condensation on reflective surfaces, air circulation between tandem airspaces, and effects due to local high conductance at edges of insulations or radiation from framing members.