Cleanroom Differential Pressure Monitoring, frequent manual observation

[jlmyers1624]

Hi,
I had a quick question regarding how my job has set up their cleanroom monitoring plan. At the moment, the differential pressure is quantitatively defined once a year during our cleanroom re-certification. In the ISO 14644-2, it says "the pressure differential may be monitored by periodic observation or by automated instrumentation." We don't quantify the pressure ever, but we are supposed to daily check if there is air flow out of the cleanroom grill with our hands. Is that a common practice/ in compliance? Does this require an alert and action limit, and if so, how do we feasibly do that if we don't have much data. I don't necessarily know what they mean by 'periodic observation' and I want to make sure we aren't behind when it comes to how everyone else does it.

Thank you!

 

[indubioush]

Here is how we do it. We have a designated person who checks the calibrated pressure gauges every day to see that the pressure cascade is present. We have a log where we down this check to indicate that the pressure is above the minimum specification. We have our pressure gauges calibrated annually. Also, pressure is checked during clean room monitoring. We trend the pressure values through our monitoring data.

Do you have pressure gauges set up so you can see the actual values?

 

[jlmyers1624]

No, we don't have any type of gauge installed. But thank you for letting me know what you do! I am trying to see what seems to be common practice, thus I may try to initiate the change so we match it. Have you heard of a cleanroom without a gauge or equipment to measure pressure?

 

[indubioush]

Have you heard of a cleanroom without a gauge or equipment to measure pressure?

No, I have not see that. I think having a pressure gauge is pretty typical.

 

[Ajit Basrur]

Differential pressure needs to be monitored for the cleanroom to understand the airflow to avoid any sort of contamination by particulates, and also to understand the pressure cascade between adjacent rooms. Most common are the magnehelic gages but if your clean rooms are not installed with magnehelic gages, you could either install one or can measure the differential pressures using mobile meters.

 

[BradM]

Agree with Ajit. If you don’t have anything yet,

I would purchase some pressure transmitters with alarm contacts that could print to a chart recorder. Set the alarm up to operate a red alarm light or something. You could purchase a spare to switch out for calibration.

I know a chart recorder is ancient. But wouldn’t require validation like a computer storage program.

 

[Jen Kirley]

To add to Ajit and Brad's advice, the chart recorder (yes I know they are ancient technology) leaves you with records supporting the cleanroom's air system is functioning within parameters.