See guidelines outlined for each method below.
Complete Building
There are four options to calculate lighting power allowance when using the Prescriptive approach to compliance. The Complete Building Method is described in the Standards in §140.6(c)1 and is the most simple calculation method. It can only be used when at least 90% of the building area or tenant space is of the same occupancy type. When this is the case, the entire project is documented as if 100% of the building or tenant space is of that occupancy type. To use the Complete Building Method for a parking garage, whether it's stand alone or attached to the building, the parking garage must show compliance seperately from the building.
To determine your lighting power allowance using this method, the building (or garage) square footage is multiplied by the lighting power density allowance (w/ft2) from Table 140.6-B. The designed wattage, minus any adjustments made for lighting controls, must be less than this allowance to comply. More information about lighting control adjustments (Power Adjustment Factors) can be found in §140.6(a)2. If at least 90% of your project is of the same occupancy, it may be worth pursuing the Complete Building Method since it is very simple to document. If you'd like to proceed using this method, enter your project information and we'll tell you if you comply.
Area Category
There are four options to calculate lighting power allowance when using the Prescriptive approach to compliance. The Area Category Method is described in the Standards in §140.6(c)2 and is typically used when less than 90% of the building or tenant space is of the same occupancy type because it's more involved than the Complete Building Method. The Area Category Method can be used by itself for all function areas in the building, or it can be used in conjunction with the Tailored Method.
To determine your lighting power allowance using this method, the square footage of each function area is multiplied by the lighting power density (w/ft2) from Table 140.6-C. This table includes additional lighting power allowance for specific types of lighting systems such as ornamental, accent, display, task work, etc. The designed wattage, minus any adjustments made for lighting controls, must be less than this allowance to comply. More information about lighting control adjustments (Power Adjustment Factors) can be found in §140.6(a)2. If you'd like to proceed using this method, enter your project information and we'll tell you if you comply.
Tailored
There are four options to calculate lighting power allowance when using the Prescriptive approach to compliance. The Tailored Method is described in the Standards in §140.6(c)3 and is typically used when there is specialty lighting such as display or ornamental that prohibits the project from complying using the Area Category Method. The Tailored Method may be used by itself, or in combination with the Area Category Method when there are specific spaces that include specialty lighting. The Tailored Method can be used only for spaces which need the additional allowance, and does not need to be used for every space when combined with the Area Category Method.
To determine your lighting power allowance for general lighting using this method, the allowed power density (w/ft2) is calculated based on the function area of the space and the room dimensions. This power density is then multiplied by the room area (ft2). Additionally, the power allowance for specialty lighting involves calculating an allowance and comparing it to actual designed lighting to determine the additional allowance for the specialty lighting. This tool will do all these calculations for you, but the information necessary to do the calculations is more involved, so the Tailored method is typically used when specialty lighting prohibits the project from complying using another method. If you think Tailored is necessary, enter your project information and we'll tell you if you comply.
Rated Power Reduction
There are four options to calculate lighting power allowance when using the Prescriptive approach to compliance, however the Rated Power Reduction Method may only be used for one-for-one luminaire alterations within a building or tenant space of 5,000sf or less. This method documents a power reduction of at least 40% compared to total pre-alteration wattage. The method entails documenting all luminaires (fixtures) being removed and being installed as part of the alteration, including wattage. If the alteration meets the required minimum power reduction, the project complies.
The advantage to this method for alterations is that space square footage is not necessary for the calculations. If you'd like to proceed using this method, enter your project information and we'll tell you if you comply.
