Title 24 Requirements for Laundromats
A laundromat is decided by its hot water. Once the gas water-heating plant reaches 1 MMBtu/h of combined input, Section 140.5(c) requires 90 per cent thermal efficiency across it, and the ventilation table gives coin-operated laundries an outdoor air rate of their own.
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The 1 MMBtu/h line
Section 140.5(c) applies to gas service water heating with a total installed input of 1 MMBtu/h or more. Above it the equipment must reach 90 per cent thermal efficiency — or, with several units, a capacity-weighted average of at least 90 per cent across them, so a high-efficiency unit can carry a less efficient one.
How the total is counted matters as much as the line. Individual gas water heaters of 100,000 Btu/h input or less are left out of both the total and the average, and the requirement falls away where site solar or recovered energy supplies 25 per cent of the annual water-heating load.
Distribution is regulated too
Pipe insulation applies to recirculating piping, including the supply and return at the water heater, and to the first eight feet of hot and cold outlet piping on a storage system that does not recirculate. Insulation outdoors needs a weatherproof cover. In a laundromat the distribution out to the machines is part of the documented scope, not an installation detail.
An outdoor air rate of its own
Table 120.1-A lists coin-operated laundries at 0.3 cfm of outdoor air per square foot, twice the rate for most occupancies, with a default density of 17 people per 1,000 square feet. The per-person term at that density is about 0.26 cfm per square foot, so the area rate governs and outdoor air follows floor area rather than headcount. The air is Class 2, so it may not be recirculated into Class 1 spaces such as an attendant's office.
Lighting, and the 24-hour store
Laundry areas are a function area of their own in Table 140.6-C, with no additional allowance attached. Lighting still needs automatic shut-off — unless it serves an area in continuous use 24 hours a day, 365 days a year, which Section 130.1(c)1 excepts. A genuinely round-the-clock laundromat can use that exception; one that closes overnight cannot.
Where to go deeper
The form family and the pipe insulation detail are covered under commercial water heating. The calculation behind the outdoor air rate is explained under commercial ventilation.