Handheld Particle Counter in ISO and GMP Cleanrooms

Generally smaller biotechnology firms often ask about the use of handheld particle counters in monitoring regulated cleanrooms.  Their assumption is that particle counters are a commodity.  That is, one particle counter is just as good as the next, and given the lower price of handhelds... well, why not monitor a cleanroom with a handheld particle counter? 

Unfortunately, this assumption couldn't be farther from the truth. 

In ISO and GMP regulated cleanrooms and other environments it is recommended that handheld particle counters never be used in monitoring. Certainly, no self-respecting cleanroom certifier uses a handheld unit when validating an ISO or EU GMP cleanroom.  There is no reason to believe monitoring should be any different.

Proper Application

Handheld particle counters were initially introduced into the market to measure indoor air quality in residential and commercial environments (i.e., homes, offices, hotels, etc.) where health and comfort concerns and fear of litigation often drive Indoor Air Quality (IAQ) investigations.  Quite simply, the standards of accuracy and assurance required for FDA/GMP environments and cleanrooms is seldom if ever introduced in a inexpensive handheld model. 

From an engineering and design perspective handheld particle counters do not take particle morphology (shape) into consideration when determining particle size; their exhaust is generally unfiltered; they incorporate a very high amount of plastics in their laser and collection optics; and they generally have plastic enclosures. Quite literally, there is nothing in a handheld particle counter to even suggest a high level of accuracy, reliability, ruggedness, or quality.

To this end, handheld particle counters have a notorious reputation for poor quality.

As it pertains to handheld particle counters quality, accuracy and assurance is sacrificed to provide the lowest possible price. 

In short, a particle counter is a precision laser instrument. Very tight calibration is required at all times, during normal use, and throughout its life. QA Managers absolutely do not want to use a particle counter when its calibration constantly drifts from the moment you turn the device on.

The only plausible reason one might want to have a handheld particle counter in an FDA or GMP cleanroom is when an anomalous sample is detected.

Sanitation Considerations

Handhelds are generally (if ever) compatible with VHP and aggressive chemical sanitation methods commonly used in cleanrooms.  They are also subject to impact damage when dropped.  This causes micro-fractures and cracking, which make perfect hiding places for bacteria and other contaminants.

Proper Sampling Techniques

The term "handheld" is also somewhat of a misnomer.  In sterile environments and cleanrooms the particle counter needs to be placed on a counter top in order for an effective sample to be taken.  Holding or walking around a room with a particle counter while attempting to sample leads to poor sampling techniques, and questionable results. 

Flow Rate Considerations

Handhelds typically have a 0.1 Cubic Foot per Minute (CFM) flow rate, and thus require 10 times the amount of man hours to take one sample when compared to a 1 CFM portable model (CI-150 Series). 

Backend Costs

One manufacturer of handheld particle counters sells their unit for approximately $2,000. Most buyers rarely ask what their backend costs are.  The calibration charge quoted for the inexpensive handheld is $800 (annually calibrated).  Does it really make financial sense to pay a low upfront price for an inaccurate instrument, that's not built to last, that is  more than likely contributing to the particle burden of your cleanroom?


There is certainly a place for handheld particle counters, and this is generally in IAQ investigations. 

If you have any further questions, please feel free to contact us and speak with one of our knowledgeable Technical Services Engineers.



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Climet Instruments Company
A Division of Venturedyne, Ltd.

Tel.+1 (909) 793-2788 | Email: sales@climet.com

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