Hi,

i have a question regarding the calculation of the daily average and peak total occupants, because we received a review commnt on this topic. I have no idea how to calculate it and i didn't find anything helpful so far. So, i'm sorry if this question already came up.

The project is a hotel and the rating system is LEED v4 BD+C: HP. We calculate the default occupancy according to Appendix 2 of the Reference Guide because the hotel operator didn't know how many employess there will be. According to the table there are 44 FTEs and 93 visitors, hotel guests were calculated according to the Getting started section (Hotel rooms *1.5 *0,6) and is 161. So, the review team askes for a description of the daily average and peak total occupants. My question is now, what are the mubers of the table of A>ppendix 2? Average or peak? And how can i calculate the avergae and the peak? I don't understand why there is no clear guidance about that. It is important for planning.

I'm thankful for any help and advice

## David Posada

Integrated Design & LEED SpecialistSERA Architects

1957 thumbs up

October 4, 2019 - 10:13 pm

This has confused many people.

From the BD&C v4 Reference Guide introduction, Maintaining Consistency in the Application:

“Daily averages take into account all the occupants of a given type for a typical 24-hour day of operation.”

“Peak totals are measured at the moment in a typical 24-hour period when the highest number of a given occupant type is present.”

Note that “transients” and “visitors” means the same thing.

In most cases, I think the numbers in Appendix 2 Default Occupancy Counts would be daily averages.

If you calculate 100 transients, that’s the daily average of total number of visitors. The “peak visitors” is your best guess at the number of visitors in the building during busiest time. This is hard to estimate, as it depends on the type of building and use: For a small restaurant open all day, out of 100 daily average visitors, the peak might be 25, for example.

I wouldn’t worry about being very precise for the number of visitors – the number of peak visitors will affect the number of short-term bike racks, but not much else. And since the minimum number of short-term racks is 4, you’d need more than 160 visitors to require more than 4 bike racks. The daily average visitors is used in the water calculations but changing the number of visitors has only a small impact on the results in the water calculator.

For overnight guest occupancy, as you found, we have the guideline for 1.5 occupants per guest room multiplied by 60%:

“Hotel guests are typically considered regular building occupants, with some credit-specific exceptions. Calculate the number of overnight hotel guests based on the number and size of units in the project. Assume 1.5 occupants per guest room and multiply the resulting total by 60% (average hotel occupancy). Alternatively, the number of hotel guest occupants may be derived from actual or historical occupancy.”

The Appendix 2 default occupancy for a hotel doesn’t distinguish between hotels with only guest rooms, and hotels with large secondary functions such a restaurant, retail, meeting rooms, or conference center, which can result in very different numbers of visitors.

Here’s what I’d suggest:

For an example, let's assume a hotel, 6100 square meters in total area, excluding parking, with 180 guest rooms, and no large secondary function:

From Appendix 2, Hotel default occupancy is 139 sq meters per employee (FTE)

6100 / 139 = 44 employees;

180 rooms * 1.5 * 60% = 162 overnight guests.

162 * 15% = 24 transient visitors (daily average). We might assume a peak of 8 visitors.

Total daily average occupancy = 44 + 162 + 24 = 230

Since a hotel operates 24/7, but presumably has a very small night shift, the peak number of employees at any one time might be a few less than the 44 we calculated for daily average. So we might assume:

Total Peak occupancy = 40 + 162 + 8 = 210

As a general note, if we use consistent numbers across all the related credits, follow the guidelines for calculating, use the definitions of “daily average” and “peak” properly, make reasonable and credible estimations when we don’t have exact numbers, and explain how we arrived at our estimates in a short narrative, that’s more important than being 100% accurate.

Hope that helps!