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#1 Posted : 05 May 2020 08:35:24(UTC)
Rank: Super forum user

We have been asked to look at the benefits of installing negative air pressure outside a covid 19 ward. We are in the early stages. we know we have to consider air changes and air locks, however the area wants it installing with fans moving the air, not really scvientific. Anyway the question is has any one else considered installing negative pressure to keep contamination in the HOT area? We are saying if you want to do it carry out a air change survey on the requirements and install it properly, not on the cheap, plus will it work.


#2 Posted : 05 May 2020 09:30:43(UTC)
Rank: Super forum user

Surely you require a positive air pressure outside a covid ward to keep the virus inside?

thanks 2 users thanked Mark-W for this useful post.
Wailes900134 on 05/05/2020(UTC), SBH on 05/05/2020(UTC)
#3 Posted : 05 May 2020 09:57:20(UTC)
Rank: Forum user

The use of air pressure differential to maintain environmental conditions for safety or product quality in specific workrooms etc is quite common but does require some engineering consideration. Understanding overall flow and routes, will there be a need for filtration of any hazardous/contaminated air? The prevention of over pressure in any of the rooms, (I investigated the near collapse of an large internal stud wall some years ago due to a very small psi differential across it). And as Mark said, make sure you’re clear on which rooms you want your +ve:-ve relationships...
A Kurdziel  
#4 Posted : 05 May 2020 13:02:40(UTC)
Rank: Super forum user
A Kurdziel

It is a legal requirement to maintain a negative air pressure, relative to the outside corridor, inside a contaminant level 3 or 4 laboratory. There is loads of guidance about this on the HSE website.  You seem to be trying to do the opposite and create a positive pressure in the outer corridor, relative to the ward interior, which I have never heard of before. I have spent many weeks of fun trying to get the different air flows to balance. Typically you would have the lab itself at negative pressure relative to a lobby (which more excitable people call an airlock) which is then negative relative to the outside corridor. The key is ensuring that this remains negative in all circumstances.

The exhaust will need to be HEPA filtered.

The air extraction system is also very noisy, which is something you might have to think about if this is going to be a ward.

I assumed that this ward will be used for people suspected of being infected with Coronavirus. Before you spend a lot of time and money on this check that you actually require this. Current advice is that the virus is to be treated as Hazard group 3 but only if there is a significant risk of aerosols being produced. If everybody in the ward is on a ventilator and/or sedated that might not be a risk.

thanks 1 user thanked A Kurdziel for this useful post.
stevedm on 07/05/2020(UTC)
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