Check whether this job is in spec before you treat this list as a purchase order.
4 HEPA leak tests food plants actually use
If you need to know whether air misses the media, scan the seal with a challenge aerosol. Everything else is a clue, not the test.
| Test | Sees a seal gap? | Good for |
|---|---|---|
| Photometer frame scan | Yes | The integrity question |
| Particle counter scan | Yes, if you scan the frame | Rooms that ban challenge oil |
| Pressure drop | No | When to change a loaded pack |
| Face velocity | No | A rough airflow check only |
Photometer scan of the seal and the media
You challenge upstream and walk the downstream frame. A hit at the gel or the knife edge is bypass. A hit in the sheet is a hole. This is the test the Elk Grove page asks you to date.
Discrete particle counter scan
A counter can map the same frame if your SOP allows it. It is slower to interpret in a noisy food plant. Use it when the photometer oil is the thing your quality group will not allow in the room.
Installed pressure drop across the housing
A loaded filter raises resistance. A torn seal can lower it or do nothing you will notice. Useful for change-out timing. Useless as a leak map.
Face-average velocity
Tells you the fan is moving air. Hides a finger-wide gap at the corner. Do not pay for this and call it an integrity test.
How we ranked them
Ranked by whether the method can show a gel-seal bypass. A method that only averages the face cannot. We are not selling instruments, and we did not put a vendor link on the winner.
Questions
Not in the village codes or the food rules we cited. Your customer spec or your own SOP might. Elk Grove Village section 7-3-4 does not. It is a sewer penalty.
That figure describes the media. A scan looks for local leaks, often against a percentage of the upstream challenge. Do not mix the two numbers on the report cover.