How to measure paint usage for air permit

A. No self respecting regulator would object to dividing the three gallons per day by an estimate of the surface area coated by each of the three guns. Production based usage is perfectly acceptable, because it is so obvious, and simple to calculate.

A. Another way to track, is to record gun spray time and use that to divide your three gallons per day. This assumes that each gun sprays at the same rate, which is probably as safe as measuring surface area and assuming the same amount of overspray for each painter. And a lot easier to calculate.

A. David, The best way I have found to calculate paint use is to weight the amount used per hour. As production rate changes this will change and not cause you more work. I have 4 booths,(2 automatic and 2 hand spray), our permit states we need to record paint consumption (VOC'S) per hour, day, week, month and yearly. I use 5 gallon paint pots and have them setting on a scale, every hour they record the weight, the weight of the pot is a known. As they add paint they start with a total and go from there. You can get your daily usage, weekly, monthly and yearly from that one sheet. The City was very pleased and asked for copies of some blank reports.

Good Luck,

A. [17 years later] there are systems which take all the guess work and calculations from paint usage monitoring.

A. First thing is to determine the fluid-tip flow rate of the gun. This should be available from the manufacturer (grams per second). Now use an available digital monitor that tracks when and for how long the gun trigger is pulled (Seconds).
Simple math (seconds x delivery rate = total litres used).
Most digital monitors will do the calculations for you and track your usage for later download!