Code tag rejects ACI masonry thermal-bridging standard after extended debate

The State Building Code Council’s commercial energy code tag on Feb. 7 voted to disapprove two proposals from masonry industry proponents that would have incorporated an American Concrete Institute (ACI) thermal-bridging standard as an alternative method for calculating envelope performance.

The tag rejected proposal 204 in an 8-2 vote with four abstentions and then disapproved a closely related proposal, 205, 7-2 with five abstentions. Proponents framed the ACI approach as a practical, industry-developed compliance alternative; opponents said the changes would reduce the stringency of existing thermal-bridging protections in the energy code.

Why it matters: the energy code requires designers to account for conductive thermal bridges such as concrete transfers, cantilevered balconies and other highly conductive elements that bypass insulation. Tag members said the ACI standard would substitute a different set of default assembly values that, critics argued, can allow higher effective heat loss from concrete elements without…