Office building renovation: 60 workers over 9 months. How many units?

Two units is the legal minimum, but I'd order three and put the third one as the ADA unit. Quick correction on the OSHA math though: 1926.51 Table D-1 says one toilet seat and one urinal per 40 workers once you're past 20 people. So at 60 you're looking at 2 seats and 2 urinals, not just 2 toilets. A standard unit with a built in urinal counts toward both, which is how most of our jobs cover it.

On the ADA side, the 2010 ADA Standards say that when portable toilets are clustered, at least 5 percent and never less than one has to be accessible. Three in a row behind the building is a cluster, so one ADA unit handles it. It also gives the guys a bigger box to change in, and you won't scramble if someone gets hurt and needs it.

Service is where I'd push back hardest. I ran a 55 person interior job on weekly pumping and by Thursday the units were rough, paper gone, tanks close to the seat. We went to twice a week and the complaints stopped. With 60 people and nine months, ask for twice weekly from day one and lock it into the contract so you're not renegotiating in month three.