Laboratory exhaust verification

Fume Hood Traverse Calculator

Summarize equal-area face-velocity readings without inventing a universal acceptance limit.

Created · Updated

Summarize a traverse

Paste readings from one hood, sash position, instrument, and operating condition.

Enter values and calculate.

Valid point countreadings
Average face velocityft/min
Minimum / maximumft/min / ft/min
Point rangeft/min
Maximum deviation from average%

How to use this calculator

  1. Divide the open face into the equal-area grid required by the test plan.
  2. Measure at each specified point with the correct, calibrated instrument.
  3. Paste the readings and compare the summary with the owner’s documented acceptance criteria.

Calculation method

Average = sum of point velocities ÷ number of points
Range = maximum − minimum
Maximum deviation (%) = max(|point − average|) ÷ average × 100

Worked example

Nine readings of 96, 101, 99, 100, 104, 97, 102, 98, and 103 ft/min average 100 ft/min. The minimum is 96, maximum is 104, range is 8 ft/min, and maximum absolute deviation is 4%.

Result interpretation

The statistics help document distribution across the opening. They do not determine acceptable average, variation, sash height, test grid, or containment. Record the instrument, calibration status, date, hood identity, sash position, room condition, and project test procedure with the results.

Frequently asked questions

Why is no pass/fail result shown?

Acceptance criteria belong to the owner’s program, applicable requirements, and the selected test procedure; they are not universal defaults.

Can I mix readings from different sash positions?

No. Each set should describe one documented configuration and operating condition.

Does a uniform traverse prove containment?

No. Flow visualization and tracer-gas testing examine performance that an arithmetic velocity summary cannot.

Related resources

Sources