BMS abd HVAC Pressures

Hello All,
I was wondering if you could clear something up for me please.
As part of our qualification of the facility, we measure particle counts, room recoveries, air supply velocity and volume, noise and light levels and pressure differentials between rooms (its an ISO class 5 environment).

Our building management system continuously monitors the pressure differentials and alarms if it goes out of spec.

My question therefore is, are we wasting time and effort measuring the room pressure differentials manuallly with a micromanometer as part of the bienniel requalification, when the BMS monitors it all year anyway?

Many thanks for your help guys,


Intent for requalification of any system is to ensure & demonstrate that the subjected system is under state of control since last validation. This is equally applicable to the inter dependent or sub system too. This means that when we talk about periodic Requalification of HVAC system it include Requalification of its sub system like BMS/SCS or DAS up to certain extent as appropriate. For example alarm system of BMS must have successfully challenged periodically, all operational & control set parameters are verified, loop calibration of all instruments is concluded as satisfactory. Then I think differential pressure record from BMS can be considered as data for Requalification assuming that the relation of actual DP in room & reading indicated by DAS is established during initial qualification.
One more thing that In-situ Hepa filter integrity test & air flow visualization may also be considered at appropriate frequency.

If your’e BMS and HVAC system is qualified periodically, your’e Magnehelic Gauges are calibrated yearly, you have a OOS register on you BMS with all the active alarms and you have your’e DP limits i do not think that you need to manually measure DP’S. However as a risk assesment measure it would be to your’e advantage to have this data manually available.