ICC Changes Impact Commercial Glass Industry
November 4, 2009
The International Code Council's Code Development Hearings continue in Baltimore this week. A number of code change proposals for the International Energy Conservation Code (IECC) resulted in changes likely to impact the commercial glass industry.
Similar to the increases in efficiency made to residential applications (CLICK HERE for related story), ICC approved a comprehensive proposal from the New Buildings Institute (NBI), American Institute of Architects (AIA) and Department of Energy (DOE) that will significantly increase overall commercial building stringency regarding the envelope, air leakage, HVAC equipment, lighting and commissioning requirements (EC147). This included an incentive - although not a requirement - to use onsite renewable energy systems such as photovoltaics.
A proposal from NBI and AIA (EC165) also was approved that decreased fenestration U-factors in several areas (see EC165 chart).
All other proposals to reformat the fenestration U-factor table and remove the distinction between metal and nonmetal windows were disapproved (EC162, EC163, EC164, EC168 and EC175).
According to Dr. Thomas Culp of Birch Point Consulting LLC, Much of the debate focused on the difference in structural requirements between windows going into low-rise buildings, light commercial applications and medium or high-rise heavy commercial applications. In the end, the committee decided to retain the current format. All proposals to change solar heat gain coefficients (SHGC) or impose minimum visible transmittance (VT) were defeated. (EC169, EC166 and EC180). The only change ICC agreed upon regarding SHGC was a reformatting of the shading credit for overhangs (EC174). Otherwise, maximum SHGC remains the same, at 0.25 in zones 1-3, 0.40 in zones 4-6 and 0.45 in zones 7-8.
EC165 brought about a big change for the glass industry in that the maximum glazing area allowed in the codes prescriptive path was reduced from 40 percent down to 30 percent. The glass industry, as well as lighting designers, expressed concern that this may not actually save energy, but given the political environment and lacking any specific data, this was approved, Culp commented. He added, Larger glass areas can still be used, but the performance path must be used. On a positive note for the glass industry, ICC approved proposal EC173 and its new requirement for a minimum amount of skylights and daylighting controls in certain spaces, notably big box retail and warehouses. As Culp explained, This helps to promote daylighting and glazing for saving energy. Many big box stores use plastic dome skylights for this purpose, but it will also increase the use of glass skylights in other spaces.
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