Via Construction Specifier
Reflecting on Heat Transfer Reduction
by Maria Medina
Most forms of building insulation—fiberglass, mineral fibers, cellulose, and cellular plastic—play a key role in making buildings energy-efficient and in reducing electrical peak demand. However, the amount of material that can be added to building walls or roof-ceiling assemblies is limited either by physical dimensions of the framing (ceiling frames) or adverse effects of over-insulating (weight, heat and moisture retention, and ventilation restrictions). Radiant barriers and interior radiation control coatings (IRCCs) offer another option.
Both radiant barriers and IRCCs reduce the radiant heat transfer across vented spaces between roof decks and ceilings assemblies of buildings. As the ASTM standards indicate, both radiant barriers and IRCCs are characterized based on their surface emittance rather than on R-values. This creates some confusion in the insulation industry, which relies heavily on the use of R-values to rate, compare, and appraise its products.
