FAQ - Airborne Particles

Question
Our Zero Count measurement is done weekly, with results at the ninth and tenth measurement being "0" for the 5.0,1.0, and 0.5 um particle sizes. Does the Lasair have a similar procedure?

Answer

The zero counting ability of an instrument is for the first channel accumulative counts only, therefore if the first channel is 0.3 um then this is 0.3 and greater, similarly for 0.5 um. As it is an accumulative count it does include all values at 3 um 5 um etc.

Particle Measuring Systems follows the JIS standard for zero counting as outlined below-

4.6 Zero Count Expected: (JIS B 9921)

• Time: 25 min . . . 50 min . . .75 min . . . 100 min
• Pass: <2 . . . . . <6 . . . . . . . <11 . . . . . . <20
• Fail: . >9 . . . . . . >14 . . . . . . >19 . . . . . . >19