Welding Booth Ventilation Calculator
Local exhaust airflow for a welding booth.
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ⓘ Live results
Results
- Extraction arm airflow
- 500 CFM
- Capture distance
- 12 in
- Guidance
- Keep hood inlet within 12-18 in of the arc for effective capture
Quick answer
Welding fume extraction typically needs 150-350 CFM per welder for a flexible capture arm positioned close to the arc, or 100-150 CFM per sq ft of a backdraft bench plenum.
CFM = capture area x capture velocity
How to use the Welding Booth Ventilation Calculator
- 1Choose flexible extraction arm or a fixed downdraft/backdraft bench.
- 2For an arm, enter its distance from the arc — closer is far more effective.
- 3For a bench, enter its working area to size the plenum airflow.
Worked example
Using the values the calculator loads with:
Inputs
- Capture methodFlexible extraction arm
- Arm distance from arc12 in
- Bench width4 ft
- Bench depth3 ft
Results
- Extraction arm airflow500 CFM
- Capture distance12 in
- GuidanceKeep hood inlet within 12-18 in of the arc for effective capture
Frequently asked questions
Why is distance so critical for arms?
Capture airflow needed rises with roughly the square of the distance from the source, so doubling distance can quadruple the CFM needed.
Do I need a fume filter or can I exhaust outside?
Either works; filtered recirculation units need periodic cartridge replacement and monitoring.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.