Article #1388 - ASHRAE 90.1-2004 Lighting Requirements Space Definitions

Does the automatic lighting shutoff requirement apply to a building that has multiple tenants with each tenant occupying less than 5000 sq ft of space?

The requirement is based on a total building square footage of 5000 sq ft. This limit is set based on the general potential for energy savings for facilities at this size or larger. In the multiple tenant case, additional area specific control may be required for whole building controllers or one of the alternative compliance methods (i.e. occupancy sensors) could be used instead.

In applying the additional lighting power allowance wattage for retail, how is square footage that this allowance is meant to apply to calculated?

Is there an additional wattage allowance for religious spaces where performance art or music programs are held and where multi-scene controls may be in use?

There is no specific "religious space" exemption for additional lighting specifically for performance art or music programs. However, there is a standard exemption for lighting designed and used specifically for theatrical purposes, performance, stage, and film and video production that could apply in this case. This specific exempted lighting would need to be designed and installed to be in addition to the general lighting for the space and controlled separately from the general lighting.

The 2004 version space control requirement for occupancy sensors in classrooms, conference meeting rooms, and employee lunch and break rooms includes exemptions for "Shop classrooms, laboratory classrooms, and preschool through 12th grade classrooms." Does this mean that occupancy sensor controls are not required in these spaces? What is the rationale for this exemption?

The requirement as written does exempt these specific classroom types. Shop and lab classrooms are exempted primarily to address safety concerns for these areas. K-12 classrooms are exempted due to the expectation that these spaces are likely to be mostly occupied during the school day and would therefore provide much less potential for savings and may not be cost effective locations for this technology in code requirements.

This means that these spaces do not have to have an occupancy based control (occupancy sensor) but other classrooms are required to have them. These exempted spaces (from this specific requirement) still have to meet all other control requirements including the basic automatic shutoff control, which can also be complied with by installing an occupancy sensor.

The standard does not preclude you from putting occupancy controls in these spaces, the standard simply does not require that this type of control be specifically used here.

For project involving animal holding/testing areas, which are being treated as Lab Spaces for LPD purposes, compliance with the 1.4 watts/sq. ft. requirement is difficult. LPD requirements and the client''s requirements of 70-100 footcandles in the space created conflict.

The models for laboratory spaces (#15) is based on an average weighted footcandle level of 50.5 and is lighted with Linear direct-indirect and wall wash type fixtures. These models do incorporate current design practice, common efficient lighting equipment, and the latest 9th edition IESNA light level recommendations that are the basis for most lighting design throughout the world.

If you are asked or required to design to light levels different from the general IESNA recommendations, then meeting the requirements may be difficult. In these cases you will need to either provide a different design that the building owner can agree to that is based more closely on the IESNA recommendations or provide documentation of the desired light levels to building/code officials in an effort to get a waiver of requirements.

Complying with the 2004 requirements for Laboratory spaces is difficult because my laboratory is a Clean Room that requires less efficient recessed fixtures for cleanliness requirements. Is there a more appropriate space type category with a different LPD that could be used?

This is always a problem with having to identify a specific LPD (model) in the limited table provided in the standard to match the reality of the wide variety of space types in real buildings. Until a specific space type that matches your specific situation is developed, the generic laboratory space type is the closest available. One option is to trade off any unused wattage from other spaces in the building to help provide the wattage for this space type.

Code citations that appear in this article are from: Copyright, 2004, American Society of Heating, Refrigerating and Air-Conditioning Engineers , Atlanta, GA. ASHRAE Standard 90.1-2004 . Reproduced with permission. All rights reserved.