The method
If they can taste it, the seal has failed.
The wearer puts the respirator on, then a clear hood goes over their head. We mist a measured aerosol — Bitrex (bitter) or Saccharin (sweet) — into the hood and ask them to perform seven exercises. If the agent gets past the seal, they taste it. If they don't, the mask fits.
Half Day Rate
Up to 8 tests/persons
Full Day Rate
Up to 16 tests/persons
7 exercises
HSE INDG479 protocol
~20 min
Per wearer, per mask
Suitable for
- FFP3 disposable respirators
- Half-mask respirators (reusable)
Candidate must
- Be clean shaven in area of the seal
- Not have smoked, vaped, eaten, chewed gum in last 30 mins.
- Not have drunk anything except water in last 30 mins.