Key code change proposals regarding prescriptive requirements for glazing were addressed over the last few days during the International Code Council (ICC) 2016 Committee Action Hearings.
Among the approved changes in the International Energy Conservation Code (IECC) was CE94. Proposed by the Glazing Industry Code Committee (GICC), this made moderate changes to the solar heat gain coefficient (SHGC) from 0.40 to 0.36 in climate zone 4 and 0.38 in zone 5 to match what will be in ASHRAE 90.1-2016.
That change, approved 12-0, followed the unanimous disapproval of CE42, which would have lowered the SHGC to 0.25 all the way up to zone 6, including places like Minneapolis. “This proposal has been defeated several times before,” says industry consultant Tom Culp, representing GICC and the Aluminum Extruders Council.
Also approved by a 12-0 margin was CE286, which corrects language that would discourage window replacement or other upgrades in existing buildings that already have fenestration and skylight area over the prescriptive limit.
Meanwhile, CE95, proposed by the Department of Energy, would have lowered the SHGC from 0.25 to 0.22 in zones 1-2. It was disapproved, as “there were concerns about the product availability and cost payback,” says Culp.
Another industry related proposal that was disapproved was CE91, which would have required all commercial buildings three stories and below to meet the residential window U-factors.
“This was a 20- to 40-percent increase in stringency, and the debate focused on how commercial applications are very different than residential, including not just small commercial buildings built like residential buildings, but also buildings like schools, clinics, airports and offices,” says Culp. “The proponents also claimed that this huge increase in stringency would only increase costs by 24 cents per square foot, which is completely unrealistic.”
CE93 and CE100, which were disapproved unanimously, would have reversed a change made last cycle that directly lists the required SHGC based on different levels of exterior shading, or completely removed the shading credit.
Language clarification also continues to be a focus. One approved two-part change to the IECC, CE157, was heard by both the residential and commercial committees. It addressed the definitions of commercial buildings and residential buildings, which rely on the occupancy categories found in the International Building Code.
“While used in the Commercial provisions, the terms ‘Group R’ and ‘residential’ are not defined,” proponent David Collins of the Sustainability, Energy and High Performance Code Action Committee wrote as his reason for the proposal. “Group R occupancies can occur in a building defined as a Commercial Building. Non-residential occupancies cannot, by definition, occur in a Residential Building.
“People with an IBC background – when using the IECC-C and encountering the word ‘residential’–are likely to consider one of the Group R occupancies. People with an ASHRAE background, on the other hand, will also include such things as nursing home rooms and hospital patient rooms as ‘residential.’ The result is inconsistent application.”
He says this proposal ends the issue by “defining ‘Group R’ as those having one of the IBC Group R occupancies that can occur in a Commercial building and then it either removes or replaces the word ‘residential’ in various provisions. Group R is already used in various places in the code, most notably the building envelope (insulation) assembly tables.”