We are in the process of submitting a Laboratory for LEED certification. The building contains a two-story, 6650 square foot Electromagnetic Compatibility (EMC) Laboratory which houses several shielded enclosures. Experiments are performed in and around the shielded enclosures that are very sensitive to electromagnetic interference (EMF). To minimize EMF issues, a two-tiered lighting scheme was developed. Tier 1 consists of thirty-one (31) industrial high bay luminaires, containing 1000 watt incandescent lamps, which are to be operated when experiments are running because they are EMF neutral. Tier 2 consists of thirty (30) industrial high bay luminaires containing 400 watt metal halide lamps (455 watts with ballast) which are to be operated for maintenance and general illumination when experiments are not running for higher efficiency. The space also contains 1200 watts of accent lighting. The lighting power density (LPD) of Tier 1 is 4.7 watts per square foot. The LPD of Tier 2 is 2.1 watts per square foot. Even if we take into account the Exception to 9.2.4 in ASHRAE 90.1-1999: "if two or more independently operated lighting systems in a space are capable of being controlled to prevent simultaneous user operation, the installed interior power shall be based solely on the lighting system with the highest wattage", the 4.7 watts per square foot in this space still far exceeds the 1.8 watts per square foot prescribed in the space-by-space method for laboratories. Because of the highly specialized nature of the EMC Laboratory and the fact that incandescent lamps sources had to be deployed, we feel that the LPD requirements stipulated in ASHRAE 90.1-1999 cannot be achieved. Therefore, we are asking to exclude the EMC Laboratory from our lighting power allowance calculations.
The applicant is seeking a waiver to exclude the EMC Laboratory from their lighting power allowance calculations. Based on the narrative, it would be appropriate to consider the lighting systems that are required only during the experiments as a process load. The lighting that is used for maintenance and general illumination and when experiments are not running needs to be accounted for. However, even this LPD is higher than stipulated. Please note that if the project is targeting EAc1, the applicant must include the larger lighting power density on the appropriate schedule to generate accurate equipment sizing scenarios.