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CS-v4 EAp2:Minimum energy performance

Garage Fan Power Allowance

I have a two story 115,000 ft2 garage, that in the design has both supply and exhaust fans to maintain a pressure neutral design. I am submitting an exceptional calculation method for garage exhaust fan DCV, but am concerned that I will be required to model 0.3 W/CFM in the baseline, which is essentially only an exhaust fan allowance. Only having exhaust fans is not an option in the proposed, as the garage does not have sufficient outdoor air infiltration or ventilation capabilities without sufficient supply air in addition to exhaust air. Will a fan power allowance exception be made if the ECM narrative explains this?

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Fri, 12/20/2019 - 16:03

You should be able to model the supply fans identically to the Proposed case, and apply the 0.3 W/cfm allowance to the Baseline exhaust fans only. 

Thu, 07/15/2021 - 17:04

The previous guidance appears to be incorrect. LEED Interpretation 10371 (https://www.usgbc.org/leedaddenda/10371) defines the 0.3 W/cfm allowance as the "Baseline system fan power." According to Appendix G, the system fan power accounts for all supply, return, exhaust, and relief fans. Therefore, the supply and exhaust fans would both be included in the 0.3 W/cfm allowance for the Baseline and no additional supply fan power would be permitted beyond this. Apologies for the misinformation. 

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