If you can smell the solvent from across the shop, you are being told something. Heavy fumes mean vapour is leaving the tank in quantity — and that vapour is both the health exposure and the fire risk. Neither is solved by opening a door and getting on with it.
Here is how shops actually control it, in the order that matters.
First, understand what flash point is telling you
Flash point is the temperature at which a liquid gives off enough vapour to ignite in the presence of an ignition source. It is the single most useful number on a solvent’s safety data sheet.
A solvent with a flash point comfortably above your shop’s ambient temperature is not producing an ignitable vapour concentration under normal conditions. One with a flash point at or near room temperature is. That difference changes everything about how the tank should be set up — and it is why the solvent you choose is a safety decision, not just a cleaning one. Build-All stocks a 142°F flash point parts washer solvent for exactly this reason.
Fumes are also a health question independent of fire. Read the exposure limits on the SDS, not just the flash point.
Keep the lid shut
The most effective vapour control on a parts washer is the cover, and it is the one most often left open. An open tank evaporates solvent continuously — into the room, into the operator, and onto your solvent bill.
Every Build-All solvent washer ships with a fusible-link lid as standard. The link is a soldered fitting that melts at a set temperature; if there is a fire in the tank, the lid drops and smothers it without anyone present. That only works if the lid is free to close, so keep the travel clear and replace links that have been triggered or painted over.
If operators leave lids open because they are awkward, fix the ergonomics rather than the habit. Gas-shock assists and foot-treadle lids exist because a cover that takes two hands gets propped open.
Remove the ignition source rather than shielding it
A conventional parts washer has an electric pump motor sitting next to a tank of flammable liquid. Enclosures and explosion-proof ratings manage that risk. Eliminating the electricity removes it.
The unit above is the air-operated RTFB40 — a 40-gallon parts washer driven by an air diaphragm pump, with no electrical connections on the machine at all. It runs on shop air. For low-flash-point solvents, or for a bay where an electrical washer would need a classified-area rating, this is the straightforward answer. We build the same idea in stainless: see the air-operated solvent washer and the stainless rinse tank with diaphragm pump.
Ventilate where the vapour actually is
Solvent vapours are typically heavier than air and collect low — at the tank, at floor level, in pits and drains. General building ventilation moving air near the ceiling does very little about that. Local exhaust at the source is what works.
Position the washer with that in mind: away from floor drains and pits where vapour can accumulate or travel, and away from grinders, welding bays, space heaters and anything else that produces sparks or open flame.
Reduce how much solvent you are handling at all
Every drum of dirty solvent is a container that gets opened, poured and transported. Filtration keeps a charge of solvent usable far longer, which means fewer changes and less handling. On-site solvent recycling through our sister company Solvent Recycling Systems goes further — distilling used solvent back to clean and cutting both the volume you buy and the waste you ship out.
Or take the fumes out of the equation entirely
The most complete answer to solvent vapour is not to use solvent. Aqueous parts washers clean with heated water and detergent: no flash point, no flammable liquid stored on site, and VOC emissions low enough that permitting usually stops being a conversation.
It is not free. Parts come out wet, heated tanks want stainless construction, and clean bare steel will flash-rust unless you protect it — which means budgeting for rust preventatives or Cortec VpCI products as part of the process. For a lot of shops that trade is worth making. Our solvent vs. aqueous comparison works through it honestly.
A short checklist
- Read the flash point and exposure limits on the SDS for the solvent you actually use
- Use the highest flash point solvent that still cleans your parts
- Keep the lid closed between parts, and keep the fusible link functional
- Site the washer away from drains, pits, sparks and open flame
- Exhaust at the source, not at the ceiling
- Consider an air-operated unit where electricity and vapour would otherwise share a bay
- Filter and recycle to cut how much solvent gets handled
- Train operators on why the lid matters, not just that it does
This is general guidance, not a compliance document. Your obligations depend on your solvent, your volumes, your building and your jurisdiction — OSHA, NFPA 30 and your local fire code all have a say. Check with your safety officer, your insurer and your local authority before making changes.
Talk it through
Build-All has manufactured parts washing equipment in Milwaukee, Wisconsin since 1971. If you are cleaning with something that fumes and you are not sure the setup is right, tell us what you are running — solvent, volume, and what the bay looks like — and we will tell you what we would do. See the range in industrial parts washers, or watch the machines run in the video library.