The International Building Code (IBC) requires that energy efficiency measures are utilized in the design and construction of buildings. The International Energy Conservation Code (IECC) allows the designer to comply either with ASHRAE 90.1 or the requirements as stated in the IECC.
In brief, ASHRAE 90.1 and IECC work in the following way:
Determine the allowable watts/square foot based on occupancy use and allowable W/SF as listed in the code. Confirm actual lighting W/SF is equal to or less than the allowable W/SF. The building as a whole must comply, so you are able to trade watts, as long as the total allowable W/SF is less than the actual total.
A few building spaces are exempt from these code requirements such as dwelling units and remodels. Remodels do not require compliance as long as less than 50% of the fixtures are replaced and the lighting power has not been increased.
Control Requirements:
Provide ability for an occupant to reduce lighting levels by a minimum of 50%.
Buildings over 5,000SF are required to have automatic shut-off. This can be achieved with local occupancy sensors or a programmable relay panel.
Similar to interior lighting, exterior lighting is not to exceed an allowable W/SF based on use.
Compliance forms are required to be submitted with the permit documents, stamped by a professional engineer.
As jurisdictions start adopting the new 2006 IBC we should be aware of changes from the previous version.
The exterior lighting compliance is new to the 2006 IECC.
Revised building use classification in the table for determining the allowable W/SF. These numbers have also been reduced in some areas by about 10%.
Following are a few common allowable W/SF:
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Exercise Center
1.0W/SF
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Gymnasium
1.1W/SF
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Hotel/Motel
1.0W/SF
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Offices
1.0W/SF
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Retail
1.5W/SF
The allowance for decorative fixtures has been removed from the allowable lighting power densities table. In the 2003 IECC an additional allowance was available for decorative lighting fixtures within specific building uses, but this has been removed in the 2006 IECC.
