Laundromats and Dry Cleaners: Lint, Gas Dryers and Solvents

Why this matters

Safety first. If you smell gas in a laundromat, everyone leaves, nobody touches a dryer control, a light switch or a phone inside, and you call the gas utility and 911 from outside. If you walk into a dry cleaner's plant and notice a sweet, ether-like solvent odor or anyone is dizzy, step back out and ventilate from outside; do not work in that room until the owner has stopped the release and the room clears. A strong smell that fades while you stand in it is your nose tiring, not the room clearing.

A coin laundry is a room full of gas burners, fans and water heaters running at once, often with nobody from the business on site. A dry cleaner adds a regulated solvent. The trade work is familiar. What catches techs out is who owns the decision when the place is unattended, how much the machines earn while you have them off, and the solvent equipment a tech should never open.

What runs in a laundromat, and why it all depends on air

Dryer banks. Commercial dryers come as singles or stacked pairs (pockets), each pocket with its own gas burner and its own exhaust fan. A store with a wall of 30 pockets is running 30 burners and 30 fans on a busy Saturday. Each pocket exhausts several hundred cubic feet per minute; the number is on the dryer's installation manual, and the manual also sets the duct size, maximum length and whether pockets may share a common duct.

The makeup air question. Every cubic foot those fans throw outdoors has to come back in somewhere. If the store's makeup air (a dedicated intake, often a large louver or a powered unit) is undersized, blocked by lint, or closed by a damper that failed, the store runs negative and the easiest path back in is down the flue of the water heater or boiler. A laundromat whose water heater spills at full dryer load and drafts fine with the dryers off is a classic, and it is a CO problem for customers sitting beside the machines. See related: How a House Pulls Flue Gas Back Down a Vent, and The Clothes Dryer as the Fan Nobody Counts, which carry the pressure mechanics.

Lint. Dryer lint is a fine, dry fuel. It collects in lint screens (emptied by staff), in the ducts behind the dryers, on the roof around exhaust caps, on rooftop unit coils and filters, and in the makeup air louver. Exhaust duct installation for commercial dryers is governed by IMC Section 504, as adopted by your jurisdiction, which defers largely to the dryer manufacturer's instructions; NFPA 211 is a chimney and vent standard and is not the dryer exhaust document. For a roofer, an HVAC tech or an electrician, the useful act is to recognize lint as a fire load and a blockage and to report it to the owner in writing with a photo. Cleaning a commercial lint system is a specialty service.

Gas supply. A bank of dryers plus a large water heater adds up to a big connected load on one meter. Before anyone adds or upsizes a gas appliance, the gas piping and the meter have to be checked for capacity at full load, not at the one appliance being changed. That is a gas fitter's calculation, done by a licensed fitter where your state or locality licenses gas work.

Hot water sizes everything

A laundromat's hot water system is sized for its peak hour, which is usually a weekend morning, not for its average. What matters is recovery rate, the gallons per hour the heater can raise through the needed temperature rise, not tank volume. Tank volume buys a few minutes; recovery carries the morning.

The relationship, for water at about 8.33 pounds per gallon:

 recovery (gal/hr) =
     input (Btu/hr) x efficiency
     ---------------------------
       8.33 (lb/gal) x rise (F)

 rise = outlet setpoint - incoming water temp

That formula assumes the efficiency is the heater's rated thermal efficiency at its rated input; a heater with a scaled exchanger or a derated burner recovers less than its sheet says.

Coin and card machines are the revenue

Every washer and dryer pocket is a cash register. A store does not lose "the laundry"; it loses turns, one machine at a time, and the hours you take are usually the hours customers want. Three things follow:

• Do not unplug, move or reset machines to clear your work area without the owner's go-ahead. Many stores take card payments through a networked system, and a power interruption can drop machines offline or reset their pricing until someone with the system login fixes it. The washers in some stores are leased from a route operator, so the machine may not even belong to your customer.
• Change machines and card kiosks hold cash and are often alarmed. Treat them like a safe. Do not open their panels for access to a wall behind them.
• Plan outages for the dead hours. Ask the owner for them; many stores are busiest early weekend mornings and weekday evenings, and quietest mid-morning on weekdays. See related: What a Business Cannot Shut Down and for How Long.

Who to call when nobody is there

Many laundromats are partly or fully unattended: an attendant for a few hours, cameras and a card system the rest of the time, and an owner who runs several stores from somewhere else. The person who lets you in, if anyone does, is usually not the person who can approve a heater replacement, a long outage or a gas leak repair.

So before work starts, get the owner on the phone, by name. Confirm three things: whether customers may be in the store while machines are off, who posts the out-of-order signs, and who can answer an alarm or a camera call if you trip a door contact. See related: Who Can Actually Authorize Work in a Business, and Keys, Alarm Codes and Access Cards at a Business.

Customers in the store are your hazard too. A trench cut, an open ceiling or a ladder in an aisle of strangers with laundry carts needs a barricade and a sign, and the owner needs to say whether to close sections.

Dry cleaners: the solvent equipment is not yours

A dry cleaner's plant has machines that wash garments in solvent instead of water, stills that distill the solvent for reuse, water separators, filters and cartridges, and drums of waste (still bottoms, used filters, separator water). Most solvents in use are one of these families:

• Perchloroethylene (perc). A chlorinated solvent, heavier than air, a central nervous system depressant, and classified as a likely human carcinogen. Federal air rules for perc dry cleaners sit in 40 CFR Part 63 Subpart M. In December 2024 EPA finalized a rule under TSCA that phases perc out of dry cleaning over a period of years; pull the current rule and its compliance dates from EPA before relying on any date, because a phase-out rule moves. Some states moved first: California phased out perc machines on its own schedule.
• Hydrocarbon and other alternative solvents. Petroleum-based solvents are combustible, which changes the hot-work and electrical picture in the plant room.
• Wet cleaning. Water-based machines with no solvent, which a tech can treat like commercial laundry.

What a trade tech does and does not do here. You do not open, drain, move, disconnect or vent a solvent machine, a still or a separator. You do not cut or braze on a line that may carry solvent or solvent vapor. You do not empty or relocate a waste drum to make room. Spent filters, still residue and contact water from perc machines are generally hazardous waste under federal and state rules, so the owner and their waste hauler handle them.

Inhalation is the route that matters. If your work disturbs the plant room (an HVAC change that alters the room's exhaust, ceiling work above a machine, a drain opened near a separator), ask the owner what solvent the plant uses and whether the machine is running. Work with the machine idle and the room ventilated. Where the owner's assessment calls for a respirator, it is worn under a written program per 29 CFR 1910.134, which 29 CFR 1926.103 applies to work that counts as construction; a crew without that program does not do the work that requires one.

The plant's exhaust and the store's HVAC are linked. Good practice, and some federal and state perc rules for certain machine types, keep the plant room at a slight negative pressure to the shop front and any connected space. Changing a return, adding an exhaust fan or rebalancing a rooftop unit in a strip center can push solvent vapor into the counter area or the business next door. Any HVAC change in a dry cleaner gets the owner's sign-off first.

Worked example: a failed water heater on a Friday

An owner with three stores calls about one: the 100-gallon commercial water heater at a 24-washer store has failed, and the store has no hot water on a Friday afternoon. Nobody is on site; the attendant leaves at 2 pm. The tag reads 199,000 Btu/hr input. Incoming water is about 60 F and the store runs a 140 F setpoint, so the rise is 140 minus 60, which is 80 F.

Step one: what the store needs. Ask the owner what Saturday looks like. The owner's figures: on a busy Saturday morning every washer turns about twice an hour, about half the cycles are on a hot or warm setting, and the washers' sheet gives roughly 8 gallons of hot water per hot cycle (this figure is illustrative; read the real one off the washer's sheet or the owner's metering). That is 24 washers x 2 cycles x 0.5 hot share x 8 gallons, which is 192 gallons per hour at peak.

Step two: what the old heater delivered. At an assumed 80 percent thermal efficiency, recovery is 199,000 x 0.80, which is 159,200 Btu/hr, divided by 8.33 x 80, which is 666.4. That gives about 239 gallons per hour. Check it the other way: 239 gallons x 666.4 is about 159,300 Btu/hr, which closes. Against 192 gallons per hour of demand, that is about 1.24 times the peak.

Step three: the tempting swap. A supply house has a 75-gallon tank heater at 76,000 Btu/hr in stock. Its recovery is 76,000 x 0.80, which is 60,800, divided by 666.4: about 91 gallons per hour, or about 0.47 times the store's 192-gallon peak. It holds three quarters of the old tank's volume and is available today, which is why it gets suggested, and it would run the store cold by mid-morning Saturday. The right replacement matches the old input and efficiency, or exceeds them if the gas supply allows, which the gas fitter checks against the whole dryer bank.

Step four: the outage plan. The matching heater arrives Monday. The owner decides to keep the store open on cold washes over the weekend with signs on the machines, not to close it, because dryers still earn. That decision is the owner's, written on the ticket with the time of the call.

Step five: first fire. When the new heater goes in, you light it with the dryer bank running at full load, every pocket on, and check draft at the heater's draft hood or vent connection under that load. The old heater may have been spilling for months, and the failed one is not evidence it drafted properly.

What would change the answer. If the incoming water were colder (a northern store in winter at 40 F), the rise is 100 F and the same 199,000 Btu/hr heater recovers 159,200 divided by 833, which is about 191 gallons per hour, essentially level with the 192-gallon peak, so the store would need more capacity than the old heater gave even though it "always worked" in the summer. The calculation has to be run at the coldest incoming water of the year, not the day of the call.

The failure mode. A tech replaces by tank size, the store runs out of hot water on its first Saturday, and the owner hears about it from customers before anyone hears about it from the shop.

References

• IMC Section 504 (clothes dryer exhaust) and the IFGC, as adopted by your jurisdiction; the dryer and water heater manufacturers' installation instructions.
• 40 CFR Part 63 Subpart M (perchloroethylene dry cleaning); EPA's 2024 TSCA rule on perchloroethylene, current compliance dates; your state's dry cleaner program.
• OSHA 29 CFR 1910.134 (respiratory protection).
• OSHA 29 CFR 1926.103 (applies 1910.134 to construction work).
• See related: How a House Pulls Flue Gas Back Down a Vent; The Clothes Dryer as the Fan Nobody Counts; Product and Revenue Loss as the Real Cost of a Commercial Call.