Round up or down?

[coachdarionziegler]

Hi @xurubi ,

There was actually recently another post asking the same thing! Check out this response below:

Element count, round up or down?

@coachlizschneider Could you please help clarifying whether to round up or down when calculating number of required items. Here are few examples: 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? Zoning requires one tree every 20 feet, we have 62 feet, do we plant 4 trees or 3? When occupancy is 49.3, should we think of it as 49 or 50? Are there any “rules of thumb” for these calculations?

In general, if you are looking at things like code requirements, it’s best to round up and remember that you can’t split have a partial person when calculating occupancy loads.

1. In the case of fixture counts it is actually ok (unaddressed by the building code) to have a half of a person if you have an odd number of occupants in the space. I think it’s important to also note that whether you round up to an even number of occupants or use .5 occupants for each gender the number of fixtures you need is unlikely to change. However, you need to always remember to round up the number of fixtures you need to have. For example, if you find you need to have 1.2 lavatories serving your space you must design for 2 lavatories.

2. This is a zoning code question. Typically, you might see in zoning code that 50% may be compact. You cannot have more than 50%. Therefore, you must round down to 21 from 21.5.

3. See response to question 1. 22 water closets.

I also found this resource that does a great job explaining fixture counts.

The Code Corner No. 33 - Calculating Plumbing Fixture Counts - docshare.tips

Hope this helps!