When calculating the load of a mixed use building, an office occupancy would be square feet x 1.3 (per T220.42(A)), a retail occupancy would be square feet x 1.9 (also per T220.42(A)). If there was a common area restroom or hallway, what would be the square foot multiplier for the common area(s).?
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Load for common areas of mixed use building
- Thread starter dnem
- Start date
If it is of any value, I will include the only material that I have found so far. ATP Electrical Systems based on the 2023 NEC on page 109 begins a section addressing "house load". It says on page 110, "Once the connected loads are totaled, the demand factors in (T220.45, T220.47, T220.84(B), T220.86, T220.88, T220.102(B), T220.103, T220.110.1, T220.110(2), T220.120, whichever apply) are applied, providing a demand load for the feeder or service-entrance conductors. The total load is then calculated by adding the house load at 100% of the demand load." The text then talks about an "All Others" section of T220.45 but does not address how this load is established.
I can only assume there is no multiplier (from T220.42(A) or anywhere else and no square foot multiplier) and the load must be added as manufacturer listed VA for each load installed (in the same way you would include parking lot lighting), but this is only my guess.
For those of you that produce load calcs or do electrical plan review, how are common area loads included.?
I can only assume there is no multiplier (from T220.42(A) or anywhere else and no square foot multiplier) and the load must be added as manufacturer listed VA for each load installed (in the same way you would include parking lot lighting), but this is only my guess.
For those of you that produce load calcs or do electrical plan review, how are common area loads included.?
And the answer might even be more complicated. The building in question has only retail occupancies on the ground floor. So multiplying the outside dimension of the building (per 220.5(C)) would scoop up all tenant and common areas (including the stairs to the second floor). The second floor has a mix of retail and office with a common hallway down the middle (and common area public restrooms). Using outside dimensions (per 220.5(C)) doesn't work because T220.42(A) gives separate multipliers for retail and office. How are the second floor common areas included in the load calc.?
dissonant
Member
- Location
- Honolulu, HI
- Occupation
- Electrical Engineer
Was there no follow up to your questions? I have a similar question with regards to calculating the non-dwelling lighting load for multiple types of occupancy within a building. What about an office building with parking underneath? Can I use the building footprint to assign that area as a "Parking Garage" occupancy? For some storage areas on the ground level, can I break off that space and use the "Warehouse" occupancy for that area? I'm assuming that for the upper floors the hallway and (interior) stairs can just be grouped into the office occupancy, but what about the stairwells on the 1st floor going up to the 2nd floor office building?