ASHRAE 110 is a fume-containment test method; utility fog is a supplementary observation
A visible tracer can help identify cross-drafts, wake effects and capture tendencies near a laboratory hood. Formal performance evaluation requires the applicable standard, calibrated instruments, approved tracer and qualified personnel.
What to examine before and during qualified testing
Cross-drafts
Supply diffusers, doors, aisle traffic and fans can disturb the hood face.
Sash and opening geometry
Changes in opening area can alter visible entry and recirculation patterns.
Operator wake
Body position and arm movement can influence the observed path.
Equipment placement
Large apparatus can block internal flow or create recirculation near the opening.
Exhaust interaction
Nearby exhaust devices can compete for air or affect room pressure.
Door state
Opening a door can temporarily reverse or disrupt the observed direction.
Keep the preliminary observation reproducible
- Use the approved sash position and operating state.
- Remove or document non-routine obstructions.
- Record room pressure and supply/exhaust status.
- Use minimum fog output and avoid direct exposure to personnel.
- Do not use unauthorized fluids around samples or sensitive processes.
- Record wide views and close views with fixed reference points.
- Escalate BSC, isolator and aseptic work to the applicable qualified protocol.
Localized water-based fog is often the starting category—but approval comes first
For localized observation, teams may evaluate the CRF2 or CRF3 ultrasonic category. Larger enclosures or rooms may require CRF6 or an AP-series LN₂ system. The selection depends on purity, output, runtime, hose geometry, remote operation and whether water or cryogen use is allowed.
Questions this page should settle
Can I certify a fume hood with a utility fogger?
No. Use the applicable fume-hood performance test method and qualified personnel. Utility fog can support preliminary visualization and troubleshooting.
Can I use fog in a biological safety cabinet?
Only under the cabinet standard, facility procedure and qualified certification method. Use the dedicated cleanroom/cabinet guidance rather than treating this page as a certification protocol.
Turn the airflow question into an equipment specification.
Send the environment, scale, purity constraint, target visibility, delivery geometry, runtime and operating restrictions. Applied Physics can compare current ultrasonic and LN₂ platforms without treating one model as a universal answer.