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JL  
#1 Posted : 07 October 2020 08:37:52(UTC)
Rank: Forum user
JL

Has anyone seen the latest guidance on ventilation, thinking about a normal 9- 5 office environment, is it telling us to measure the rate of air change or just open a window . I’m pretty sure what it does say is if you are 2 metres or more away you have little change of catching it.

 https://www.rehva.eu/fileadmin/user_upload/REHVA_COVID-19_guidance_document_V3_03082020.pdf

thanks 1 user thanked JL for this useful post.
Kate on 07/10/2020(UTC)
chris.packham  
#2 Posted : 07 October 2020 09:51:50(UTC)
Rank: Super forum user
chris.packham

There is also the question as to whether you are in the discharge zone. If standing close but behind the person emitting the virus and there is no significant air flow towards you what is the potential for you to inhale the virus?

However, the emitted droplets and aerosol will descent and contaminate objects with which you may then have contact. I have seen more than one study that has concluded that the indirect route may be at least, if not more, significant than the direct, airborne route.

Kate  
#3 Posted : 13 October 2020 07:11:38(UTC)
Rank: Super forum user
Kate

I read it differently - that even at 2 metres apart in a poorly ventilated building, there is a transmission risk.

stevedm  
#4 Posted : 13 October 2020 08:08:56(UTC)
Rank: Super forum user
stevedm

kate I read it the same way...having done this a few times now good ventilation is key...but the correct ventilation...closed systems that push the same air around a building are just as bad as having no ventilation at all...simple solutions like opening windows even slightly to allow air to flow in and out a room is what I think they are trying to get at...there are few CFD models being floated as planning solutions.... we are currently going through the process of using CONTAM to model potential contamination of a room... but only for areas where we have identified the HCID risk is high...not sure it helped any with the OP but REMA are just trying to give some simple guidance to help you just put it in your bank of resources to assit with your assessment of the risk...

aud  
#5 Posted : 13 October 2020 18:15:25(UTC)
Rank: Super forum user
aud

"...there are few CFD models .... the process of using CONTAM to model potential contamination of a room... but only for areas where we have identified the HCID risk is high...not sure it helped any with the OP but REMA are just trying to give some simple guidance ..."

Stevedm. Wow! I have no idea what any of these are!

However, on a simpler tack, I have read that the use of static CO2 monitors to gauge the quality of ventilation can be useful. As we breathe out CO2, high levels (no idea what these are) will indicate poor air quality and so more O2 is needed - open windows / doors etc. I have not researched further, but sounded straight-forward.

Kate  
#6 Posted : 14 October 2020 06:46:10(UTC)
Rank: Super forum user
Kate

Yes and the use of CO2 monitors for that purpose is mentioned in the guidance document.

stevedm  
#7 Posted : 14 October 2020 07:19:43(UTC)
Rank: Super forum user
stevedm

High levels of Co2 in the blood which can be seen in respiratory diseases such as COPD can cause what is known as hypercapnia acidosis...this can impede the bodys immune system and distrupt neurological and cardiac function....so the theory is the higher the CO2 levels in your blood would intrun make you less able to fight a respiratory disease...what you breath out is around 16% oxygen and 4-5% CO2...poor ventilation will increase CO2 levels over time reducing oxygen levels...increasing heart and repiratory rate..not bad memory on one cup of coffee !

Kate  
#8 Posted : 14 October 2020 08:19:24(UTC)
Rank: Super forum user
Kate

Right but the concern here isn't the direct health effects of high CO2 (hopefully workplace ventilation outside designated confined spaces is nowhere near high enough to be an issue in that way), it's just that high CO2 levels are an indicator of poor ventilation which is a factor in virus transmission.

I have a designer Captcha - dKny.

stevedm  
#9 Posted : 14 October 2020 08:56:01(UTC)
Rank: Super forum user
stevedm

...yep just looking at it with health protection glasses on ...:)

seems to know where I am - captcha - 1aFa

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