Element count, round up or down?

[tatyana.swift]

@coachlizschneider Could you please help clarifying whether to round up or down when calculating number of required items. Here are few examples:

1. Water closets, say we need 1 per 10 people and we have 44 occupancy (22m/22f) would we have 6 (3m/3f) water closets in all?

2. Zoning requires one tree every 20 feet, we have 62 feet, do we plant 4 trees or 3?

3. When occupancy is 49.3, should we think of it as 49 or 50?

Are there any “rules of thumb” for these calculations?

[coachlizschneider]

@tatyana.swift Great question. The rule of thumb for these types of code requirements is to round up. You typically want to make sure that you are providing enough plumbing fixtures or egress width for the maximum number of people.

1. If your occupancy is 44 people and you have to provide 1 water closet for every 10 people you would provide 5 water closets. 4 for the first 40 (40/10 = 4) and 1 for the remaining 4 people.
2. You would provide 4 trees to make sure you have one every 20 feet.
3. If you calculate your occupancy at 49.3 you would round up to 50.

This way you are complying with the strictest interpretation of the code.

[tatyana.swift]

Great, thank you!

[tatyana.swift]

One quick follow up question in regards to the toilet count. Would this one additional toilet be male or female?

Thank you!

[coachlizschneider]

@tatyana.swift Good follow up! For the toilet count you would start by dividing 44 by 2, per 2902.1.1 of the code. So you would have 22 women and 22 men. So using the same rule of 10 water closets per person you would have 3 for the women and 3 for the men. To break that down, that would be 2 for the first 20 (20/10=2) and 1 for the remaining 2 in each case.

[aowen]

Would rounding up be the case if this was for the maximum allowable occupancy for a space?

[coachdarionziegler]

Hi @aowen ,

When calculating occupancy you want to round up, as you can’t have a partial occupant and need to err on the side of caution (which means accounting for more people needing to exit the space) when it comes to occupancy.

You can read more about why you round up in this specific situation in the thread below:

Occupant Load round up or down

Hi @xurubi , My understanding is it is always best to round up when dealing with occupants as you can’t have a partial occupant and when it comes to exiting you always need to deal with the ‘worst case scenario’ which means rounding up to the nearest whole occupant. The reason most jurisdiction require you to round up is this section from IBC 2018. [image] The 2018 IBC Code Commentary goes on to state, “The worst case scenario should be used to determine the requirements for means of egress …

Check out some other related ‘round up or down’ threads at the links below:

Round up or down

I have come across with questions that ask to round to the nearest dollar but in given cases there is additional information in the questions that suggest to round down. For example if a question asks to calculate cost per sqft based on a given budget, but that you have to stay within budget. Let’s say you have a construction budget of $725,000 and a 10,000sqft facility. Your construction cost would be $72.50 per sqft so if you round to $73.00 you would be over budget by $5,000. So far I hav…

Round up or down?

hi any clarification on the round up or down if the occupant is an odd number, how does the plumbing count work, say 43 overall, how do you divide man/women there is one question in PA exam 3, how do you round up or down in this case, any logic basically asking about parking spaces. from the material, it said that the required numbered of spaces is 43. Because 50% is the minimum for standard size spaces, 21 can be compact car spaces. for plumbing , if the calc is 20.1 water closet , do we use…

Hope this helps!
-Darion