How many accessible units should an event order?
This site does not state a required ratio. The organizer decides how many and confirms requirements with the city, and the Department of Public Health permit application and the special event application both ask about portable restrooms. Ask the provider what mix of standard and accessible units they recommend for your crowd.
For a public event the paperwork starts in the city's Office of Special Events, which is the one-stop shop for parades, festivals, runs and regattas, and its special event application asks for the total number of portable restrooms. The count of accessible units is a part of that planning, not an afterthought.
If your crowd is in the tens of thousands, as with the Philadelphia Marathon's roughly 37,000 participants over the weekend, one accessible cabin is not a plan. The event toilet guide discusses how big crowds have stressed supply in this city.
Where should an accessible unit go?
Put it on firm, level ground near the main route, with a clear approach to the door and room for a wheelchair to turn. Do not hide it behind a stage or beyond a soft verge. Check the surface in rain too, because mud ends the usefulness of an otherwise perfect unit.
Philadelphia surfaces vary within a few blocks. Chestnut Hill has cobblestone streets and historic frontage along Germantown Avenue, where a rolling chair on cobbles is a poor experience. A park lawn can look flat and still turn soft after rain, which is a problem for a wheelchair wheel.
A paved lot, a closed street surface or a temporary mat is often the better choice. If an event will fill a pavement, tell the provider the width and any step at the curb, so the unit and the route can be matched.
Do private jobs and work sites need accessible units?
Sometimes the decision belongs to the site manager, the employer or the organizer rather than to this site. Some crews have a member or a visitor who needs a larger cabin, and a long project may want one for that reason. Ask the provider what they hold in stock.
OSHA's table at 29 CFR 1926.51(c) sets minimum toilet counts by crew size. It is a headcount rule, so ask the site manager whether the job calls for a larger cabin as well. A larger unit can still be the right call for a long job where people spend many hours on site.
A wedding in a park, estate or tent is another case. Guests with mobility aids will need a firm path from the seating to the unit, and the provider needs to know about it before the dress rehearsal, not on the morning.
What does an accessible unit change for the service truck?
It needs a bigger footprint, so the provider needs room to place it and to reach the tank. A narrow street, a closed route or a soft lawn can all complicate that. Tell the provider about gates, slopes, parked cars and ground conditions when you book.
This is where Philadelphia's streets bite. Where a rowhouse block is narrow and a festival closure stops traffic, the delivery and servicing routes are the first thing to settle. The provider can tell you if a spot works for a larger cabin.
Ask also when the servicing visit will happen on the day. A unit serviced mid-event needs the truck to reach it, and a crowd standing around it is not helpful.