I received the following comment from a LEED reviewer;
"The LEED Form states that the project is mechanically ventilated and that the ventilation system has met the minimum requirements of ASHRAE 62.1-2007. However, to demonstrate compliance, the following must be addressed.
TECHNICAL ADVICE
1. The total peak occupancy of 437.05 people documented for this prerequisite varies substantially from the total building users of 1,797 people reported in PIf3: Occupant and Usage Data. The peak occupancy should be reported consistently among all credits. Confirm the appropriate peak occupancy for the building and update the peak occupancy and/or the diversity so the peak occupancy is consistent among all credits or provide a detailed narrative describing the difference in occupants. The ASHRAE default occupancy should not be used when the expected occupancy is known".
As our building is Core and Shell we actually don't have the final occupancy figures. As per the LEED reference guide "Projects that do not have occupancy counts must use the default occupant densities provided in ASHRAE 62.1–2007 Table 6-1, based on the intended use of the space".
I would be of the opinion that we should use default occupancy values ? Whats peoples thoughts on this.
Michael Brown
Energy Analyst & Energy Systems Design EngineerHKS
LEEDuser Expert
9 thumbs up
May 19, 2017 - 12:34 pm
LEED provides a resource that can be referenced for calculating occupancy for Core and Shell projects. The Core & Shell Appendix A outlines default occupancy rates that can be used when actual occupancy counts are not known. Default numbers are given for employees and transients (if applicable); for example an 50,000 SF office (general) would have 200 employees and 0 transients. However; if you are doing an energy model performance path for Energy & Atmosphere where ASHRAE 62.1-2007 would be used, I recommend using the occupancy values calculated from the analysis and provide a narrative to explain the use of these values in lieu of the Appendix for clarification. This method would align more with their comment "Projects that do not have occupancy counts must use the default occupant densities provided in ASHRAE 62.1–2007 Table 6-1, based on the intended use of the space"; however, the first method is much simpler.
Ciaran McCabe
DirectorPassive Dynamics Sustainability Consultants
12 thumbs up
May 19, 2017 - 1:26 pm
Many thanks Michael. We did use ASHRAE 62.1-2007 default values for this credit which I would assume is the correct approach as we don't know the final occupancy numbers - it would be just guess work. The FTE however was based on 1 person per 10m2.