Question About Calculating the Parking Spaces based on Base ratios of Appendix 4

Hi Stephan,

The reduced parking footprint calculation is based on Gross Floor Area (GFA). ASHRAE Definition below:

Gross Floor Area:

Gross floor area (based on ASHRAE definition) is the sum of the floor areas of the spaces within the building, including basements, mezzanine and intermediate‐floored tiers, and penthouses wi th headroom height of 7.5 ft (2.2 meters) or greater. Measurements m ust be taken from the exterior 39 faces of exterior walls OR from the centerline of walls separating buildings, OR (for LEED CI certifying spaces) from the centerline of walls separating spaces. Excludes non‐en closed (or non‐enclosable) roofed‐over areas such as exterior covered walkways, porches, terraces or steps, roof overhangs, and similar features. Excludes air shafts, pipe trenches, and chimneys. Excludes floor area dedicated to the parking and circulation of motor vehicles. ( Note that while excluded features may not be part of the gross floor area, and therefore technically not a part of the LEED project building, they may still be required to be a part of the overall LEED project and subject to MPRs, prerequisites, and credits.)

Therefore, you should probably exclude the area assigned to underground parking from this. What you need to do is determine the required baseline figure in terms of parking for your project i.e. if your offices are 12,000sqft and the rest as you say is 8,000sqft (WCs, entrances and parking). Let's assume the WCs and entrances make up 2,500sqft and the parking makes up 5,500sqft, the below would be how you calculate your baseline figure:

GFA of Building (Parking Excluded) = 14,500sqft = 14,500sqft / 1,000sqft = 14.5 x 3.8 = 55.1 (rounded up to 52) parking spaces

Therefore in order to show the reduction that you can achieve (20% or 40% depending on whether you need to comply with case 1 or case 2), your proposed parking layout needs to be the following:

20% reduction from baseline = 41.6 (rounded up to 42) parking spaces

40% reduction from baseline = 31.2 (rounded up to 32) parking spaces

Hope this help!