Hand tools, pliers and a rotary sanding tool lying on a dark workbench in a home workshop

Fire Code and Your Garage Workshop: Fuels, Finishes, Batteries and Extinguishers

ByGarage Business Blueprint

This guide is part of our Garage Business Legal Guide.

Most garage businesses involve something that burns: gas for a mower or generator, stains and finishes, solvents, propane, or a shelf of lithium-ion tool batteries on chargers. Once the garage becomes a workshop, the amounts grow and your town’s fire code and home-occupation rules start to matter.

Here is where those rules come from, the limits a few real jurisdictions publish, and a checklist to work through before you scale up.

Where the fire rules for a garage workshop come from

There is no single national fire code for homes. Instead, rules reach your garage from several directions:

  • The fire code your state or city adopted. Many places adopt a version of the International Fire Code (IFC), sometimes with local changes. Utah’s Unified Fire Authority, for example, points residents to IFC limits on how much flammable liquid a residence may store.
  • The residential building code. The International Residential Code (IRC) sets how an attached garage must be separated from the living space. A workshop that weakens that separation (removing drywall, swapping the door) can create a code problem.
  • Your city’s home-occupation rules. Zoning codes often say a home business can’t create a fire hazard, can’t change the building’s fire or occupancy classification, or can’t store hazardous materials beyond normal household amounts.
  • Your insurer. Even where a practice is legal, a homeowner’s policy may not cover business property or business activities. See our guide to home business insurance.

Which version of each code applies, and how it’s enforced, varies by state and city. The local fire marshal’s office is usually the place to ask.

How home-occupation codes treat fire hazards: three examples

Zoning codes rarely list gallon limits; they set general standards instead. Three examples show the range:

  • Sonoma, California (Municipal Code 19.50.040). A home occupation must not change the fire safety or occupancy classification of the home, and must not create nuisances such as toxic or hazardous materials beyond what’s normal for nearby homes. The same section lists welding and machining among the prohibited home occupations, and it generally confines the business to the dwelling unit, with accessory structures needing a conditional use permit.
  • Keizer, Oregon (Development Code Section 2.407). The business may be run in the dwelling, an attached garage or a detached accessory building, but it must not create an off-site nuisance, which the code says includes a fire hazard. On-site storage of hazardous materials, including combustible and explosive materials, is limited to what a home would normally have, and vehicle repair, body work and painting are prohibited.
  • Utah fire departments’ published storage limits. Lehi’s fire department, citing the IFC as adopted in Utah, lists a 25-gallon residential maximum for gasoline, preferably in a detached garage or shed, with no more than 10 gallons in an attached garage and none in a basement. Utah’s Unified Fire Authority cites a 30-gallon limit for gasoline and 120 gallons for diesel in residential occupancies, and says the amount must be limited to what’s needed for maintenance and running equipment.

Notice that the two Utah numbers aren’t identical. Fire departments read and summarize the code differently, and local amendments matter. Treat any published number as a starting point and confirm it with your own fire marshal.

Fuels and flammable liquids

Gasoline, thinners, mineral spirits, lacquer and similar liquids are the most regulated items in most garages. Common rules in the fire department guidance above include:

  • Use approved containers or the original retail container, never glass jars or milk jugs. Lehi counts empty containers as full.
  • Keep fuel out of the house and out of basements.
  • Keep ignition sources away and don’t smoke in the storage area.
  • Keep amounts to what you actually use. Lehi recommends using fuel within about six months.

If your business genuinely needs more than household quantities (a small-engine repair shop with a lot of fuel on hand, for example), ask the fire marshal before buying in bulk. Some home-occupation codes, like Keizer’s, would not allow that storage at all.

Propane and other gas cylinders

Lehi’s guidance keeps portable propane cylinders outside the home, in a detached garage or shed, with a total of up to 25 gallons of portable cylinder capacity. It allows up to two 1-pound disposable cylinders inside the home or an attached garage, citing NFPA 58, and says propane should be kept at least 10 feet from flammable or combustible liquids. If you use propane for a torch, forge or heater, check your local limits before stocking spares.

Finishes, solvents and oily rags

Woodworkers and furniture refinishers face a specific risk: rags soaked with oil-based stains, varnishes or paints can heat up and catch fire on their own as they dry. Montgomery County Fire and Rescue (Maryland) notes that water-based finishes don’t do this.

Its guidance, in short:

  • Never leave used rags in a pile.
  • Take them outside at the end of the day and spread or hang them to dry, weighted down and away from buildings.
  • Once dry, store them in a metal container with a tight lid, filled with water and detergent, in a cool spot away from heat and sun.
  • Ask your town how to dispose of them.

Spray finishing adds overspray and vapors to the picture. Codes and insurers often treat spray booths and large-scale spraying differently from brush-on work, so if spraying is a regular part of your process, talk to the fire marshal and your insurer first.

Lithium-ion batteries and chargers

Cordless tools, e-bikes and scooters (for a repair or rental business) all bring lithium-ion batteries into the garage. The Seattle Fire Department’s guidance includes:

  • Use only devices, batteries and chargers certified and labeled by a recognized testing lab, and use the charger that came with the device.
  • Unplug chargers when batteries are full, and charge one battery at a time so you don’t overload a circuit.
  • Don’t charge below 32°F or above 105°F, and keep batteries out of direct sun and hot cars.
  • Store batteries and devices away from exit doors and away from anything hot or flammable.
  • Recycle lithium-ion batteries instead of putting them in the trash.

An unheated or very hot garage may not be a good charging spot.

The garage-to-house separation

In an attached garage, the wall, ceiling and door between the garage and the house are part of the home’s fire protection. A building department summary from Gig Harbor, Washington, based on IRC Table R302.6 (2015 edition with state amendments), describes typical requirements:

  • At least 1/2-inch gypsum board on the garage side of walls shared with the house, and 5/8-inch Type X gypsum board on ceilings below habitable rooms.
  • A door to the house that is 1-3/8-inch solid wood, 1-3/8-inch solid or honeycomb-core steel, or 20-minute rated, with a self-closing device.
  • Ducts in the garage of at least No. 26 gauge sheet metal, with no register openings into the garage, and sealed gaps where pipes and wires pass through.

For a workshop, this means: don’t remove drywall to gain storage space, don’t prop the door to the house open with the closer disabled, and don’t cut holes in the separation wall for dust collection or wiring without a permit. Your local edition of the code may differ.

Fire extinguishers

Most home-occupation codes don’t require a specific extinguisher, though fire department guidance may. Lehi’s guidance, for example, calls for at least one 2A10BC extinguisher 10 to 50 feet from the storage area once you store more than 5 gallons of gasoline.

The Tempe, Arizona, fire department explains that multipurpose ABC extinguishers cover the three common fire classes (ordinary combustibles, flammable liquids and electrical) and that home extinguishers aren’t meant for large or spreading fires. It teaches the PASS method (pull, aim at the base, squeeze, sweep) and says to call 911 first and leave if the fire is spreading or could block your escape. Most extinguishers empty in about 8 to 10 seconds.

Fire-safety checklist for a garage workshop

  • Find out which fire code edition your city or county adopted and whether it has local amendments.
  • Read your city’s home-occupation section for fire, hazardous material and prohibited-use rules (welding, painting and vehicle repair are common restrictions).
  • List every flammable liquid, gas cylinder and battery you keep, with quantities, and compare them with your local limits.
  • Store fuels and solvents in approved containers, away from the house door, heaters and water heaters, and out of basements.
  • Set up an oily-rag routine (dry outside, then a lidded metal can with water and detergent).
  • Set up a battery charging spot away from exits and flammables, using certified chargers.
  • Check that the garage-to-house wall, ceiling and door are intact and the door closes on its own.
  • Mount an ABC extinguisher within easy reach and learn how to use it.
  • Pull permits for new 240V circuits, dust collection or wall changes. Our garage workspace setup guide covers layout and ventilation.
  • Tell your insurer what you do in the garage and what you store there.

When to call the fire marshal

Call before you buy, not after. Contact the local fire marshal or fire prevention office if you plan to store more than household amounts of fuel or solvents, spray finishes regularly, use a forge, kiln or torch, charge many batteries at once, or move the business into a detached shed or accessory building.

This article is general information, not legal or safety-engineering advice. Fire and zoning codes differ by state, county and city, and they change. Confirm the rules for your address with your local fire marshal, building department or planning office, or with a qualified professional.

More in the Garage Business Legal Guide

Sources

Share this article:FacebookXLinkedInPinterestRedditEmail

Similar Posts