As reported by multiple local news outlets across the country and documented by an investigation by local NC television station WRAL, there are concerns regarding how low-e windows’ high reflectance could concentrate sunlight and contribute to the melting of vinyl siding of houses and plastic on cars.
The NC Building Code Council adopted an Emergency Rule regarding requirements for low-e windows at the June 10, 2014, meeting. This emergency rule was signed by an Administrative Law Judge on June 24, 2014.
The effective date for the Rule is July 2, 2014, which means that it is available for use by the permit holder until a temporary rule is adopted by the Council and approved by the Rules Review Commission. The Council also adopted a Temporary Rule at the same time for continuation of the rule process and has indicated it will move quickly to develop a permanent rule to address the issue.”
The Council cited the following as need for an emergency rule:
“A serious and unforeseen threat to the public health, safety or welfare. We now have information that reflective energy from some Low-E windows can cause damage to property and may have the potential to create a fire hazard.”
Effective July 2, 2014, the emergency rule gives builders of one-and two-family dwellings and townhouses the option to substitute non-low emissivity glazed fenestration products for low emissivity glazed fenestration products without energy penalty when judged by the permit holder to be a safety concern due to reflection of concentrated sunlight.
Footnotes to that effect were added to the 2012 NC Residential Building Code in the following Tables:
1. TABLE N1102.1 INSULATION AND FENESTRATION REQUIREMENTS BY COMPONANT (See the addition of footnote l in the FENESTRATION U-FACTOR column and the addition of footnote m in the GLAZED FENESTRATION SHG column)
2. TABLE N1102.1.2 EQUIVILANT U-FACTORS (See the addition of footnote e in the FENESTRATION U-FACTOR column).
Identical notes were added to the corresponding Tables in the 2012 NC Energy Conservation Code, TABLE 402.1.1 INSULATION AND FENESTRATION REQUIREMENTS BY COMPONANT and TABLE 402.1.3 EQUIVILANT U-FACTORS.
There are instructions in the accompanying commentary for the emergency rule that addresses substitute fenestration products and how they are allowed to be modeled in the REScheck program without penalty.