Ventilation and air con

[Porty]

Is anyone familiar with the technical details, design and maintenance of the ventilation systems on different train types?

After reading up on this re. a recent air journey (20 changes per hour, air travels downwards towards floor etc) I wonder how that compares with trains.
Bearing I'm mind the recent indications that minute covid 19 particles can stay suspended in the air for a long time, rather than larger particles dropping to the floor of a surface within a metre or two, I think there ought to be more information on the ventilation of trains. The same applies to buildings that have aircon.

Also are all trains capable of having all relevant doors opening at station stops, rather than being passenger activated. I know it may get chilly in the winter but that be preferable if ventilation is critical for safety and public confidence in the coming months.

 

[30907]

ISTR a study that draughts (in a space like a carriage) are rather better than aircon at spreading the virus, though.

 

[Darandio]

Also are all trains capable of having all relevant doors opening at station stops, rather than being passenger activated. I know it may get chilly in the winter but that be preferable if ventilation is critical for safety and public confidence in the coming months.

Freeze everyone, create more seasonal viruses and have more people coughing and sneezing their germs around. That sounds like a great plan!

 

[Yew]

There is no such thing as a covid particle. They're droplets, and come in two main categories, ballistic (will move through air and fall to the floor) and aerosol (which does not have it's own ballistic authority, and remain suspended in the air for a while)

I don't believe there has been a case of transmission that can clearly be attributed to aerosol droplet.

 

[Porty]

There is no such thing as a covid particle. They're droplets, and come in two main categories, ballistic (will move through air and fall to the floor) and aerosol (which does not have it's own ballistic authority, and remain suspended in the air for a while)

I don't believe there has been a case of transmission that can clearly be attributed to aerosol droplet.

Thanks for your correction, yes I mean aerosol droplets. I thought that there is very little evidence of how transmission occurs. From what I read aerosol droplets seem to be rising up the agenda as a possible issue, whereas early on in the pandemic the main concern seemed to be ballistic droplets.

== Doublepost prevention - post automatically merged: 5 Sep 2020 ==

Freeze everyone, create more seasonal viruses and have more people coughing and sneezing their germs around. That sounds like a great plan!

I take the point but most bus bus companies are encouraging windows to be open at all times. Not much of in issue in September but not much fun in a couple of months time. Plenty of ventilation being practised on the 253 Borders service between Edinburgh and Berwick-upon-Tweed (50mph+ on the A1) yesterday!

 

[Richard Scott]

There is no such thing as a covid particle. They're droplets, and come in two main categories, ballistic (will move through air and fall to the floor) and aerosol (which does not have it's own ballistic authority, and remain suspended in the air for a while)

I don't believe there has been a case of transmission that can clearly be attributed to aerosol droplet.

If we're going to be totally correct it's SARS-CoV-2 not Covid, I believe? Thought Covid-19 was the disease that develops from the virus? Happy to be corrected on that one, though. Just want to make sure my terminology is correct.

 

[Huntergreed]

If we're going to be totally correct it's SARS-CoV-2 not Covid, I believe? Thought Covid-19 was the disease that develops from the virus? Happy to be corrected on that one, though. Just want to make sure my terminology is correct.

That’s correct, SARS-CoV-2 is a specific coronavirus (which is a type of virus), and the disease caused by SARS-CoV-2 is called Covid-19.

 

[Gerald Fiennes]

Well, reports of a Chinese coach journey back in Feb were published last week that implied aerosol transmission was a major factor in Covid spreading, so similar type of risk is likely to apply to trains. What is less clear is how big that risk is, so hopefully RSSB is looking at this....
People who are knowledgeable HVAC say that the key is the amount of fresh air that it is drawn through Air Conditioning systems, as opposed to recirculated air. The 'Conditioning' element of the name is largely about dehumidifying recirculated air so that it is drier. In a Covid world, the best systems are those (like planes) that draw the maximum of outside air: this parameter can be adjusted in most systems in offices/shops. Someone can doubtless advise on how far AC systems on trains can be adjusted.