Air circulation in an Amtrak Passenger Car

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Air circulation in an Amtrak Passenger Car
Posted by CMStPnP on Saturday, August 15, 2020 8:48 PM

From Amtraks CEO Mr. Flynn.

"Amtrak passenger cars replace their interior air with air from the outside once every 4-5 min."     I know this was a mention in another thread.    He mentioned that in a very recent Podcast that runs an hour long.

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Posted by Overmod on Sunday, August 16, 2020 2:48 PM

SUPPOSEDLY the HVAC system pulls air from outside and tempers and filters it for IAQ; nominally I'd expect that to the greatest possible extent Amtrak has disabled any return recirculating for 'energy saving' by this late point in the game.

What he may carefully be avoiding is that, to my knowledge, there is no sealed ducted return from all those parts of the car for assured air exchange at that rate.  He, and I, and you, would need to see a diagram of the car ducting and vanes and exchangers (and so forth) to determine that all the exhaust ... which is really the things of concern' in COVID-19 ... is in fact being preferentially sucked into sealed, UV-sterilizable ducts with no back flow or eddying possibility, and is then ejected, preferably treated or effectively filtered, far from any fresh-air or circulation intake.

i don't think he can establish that in a couple of sentences, and yes, I'd need to see the detail design as proof before I accepted it.

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Posted by CMStPnP on Monday, August 17, 2020 12:02 PM

Overmod
UV-sterilizable ducts with no back flow

Lol, OK I think we both know Amtrak is not using UV sterilized ducts for starters I don't think a UV light would last very long with the vibrations in rail equipment and they would be better off with extra filtration.

He mentioned in the same podcast they are looking to adverstize how the ventilation works in addition to making it better in an attempt to calm or convince passengers to come back on board.   I wish I could link to the podcast but ....well you can probably guess what competing publication it's in.   Great interview and good questions were asked.....including those by JPS1 on accounting....heh-heh.

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Posted by charlie hebdo on Monday, August 17, 2020 12:45 PM

CMStPnP

 

 
Overmod
UV-sterilizable ducts with no back flow

 

Lol, OK I think we both know Amtrak is not using UV sterilized ducts for starters I don't think a UV light would last very long with the vibrations in rail equipment and they would be better off with extra filtration.

He mentioned in the same podcast they are looking to adverstize how the ventilation works in addition to making it better in an attempt to calm or convince passengers to come back on board.   I wish I could link to the podcast but ....well you can probably guess what competing publication it's in.   Great interview and good questions were asked.....including those by JPS1 on accounting....heh-heh.

 

In RA? 

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Posted by Overmod on Monday, August 17, 2020 4:31 PM

CMStPnP
... for starters I don't think a UV light would last very long with the vibrations in rail equipment and they would be better off with extra filtration.

I've seen properly-suspended UV tube equipment for 'harsh service' and modern high-frequency drive electronics are very robust.  And filtration of the exhaust has little point -- you want to sanitize it, then get rid of it.  Any 'filtration' would be on fresh air intakes, and you'd need competent return-air boosters for the level of filtration needed on recirculation venting...

The real point is that I don't think those cars HAVE full air exchange, at least not the equipment I had to use to get that kind of air-exchange numbers in roughly comparably-sized RECD house designs in the '90s.  And I was using an exchange wheel in the exhaust, a non-starter 'as designed' for infectious particles in the exhaust flow...

Someone describe for me EXACTLY where the exhaust airflow from various spaces in a Superliner goes, and how it reaches the outside air.

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Posted by Overmod on Monday, August 17, 2020 4:37 PM

charlie hebdo
In RA? 

Rail Group, I think, which is 'more' than just That Other Publication and therefore fair game to post here.  I think this is the podcast of the material in question:

https://soundcloud.com/user-125862828/amtraks-bill-flynn-and-stephen-gardner

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Posted by CMStPnP on Monday, August 17, 2020 7:55 PM

charlie hebdo
In RA? 

   Yes

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Posted by CMStPnP on Wednesday, September 2, 2020 11:18 AM

As Info to everyone....lol

Amtrak is advertising on Facebook now that 4-5 min recirculation on their cars with fresh air.    Saw that one comming.

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Posted by Jim200 on Saturday, September 12, 2020 4:19 PM

Overmod

 

 
CMStPnP
... for starters I don't think a UV light would last very long with the vibrations in rail equipment and they would be better off with extra filtration.

 

I've seen properly-suspended UV tube equipment for 'harsh service' and modern high-frequency drive electronics are very robust.  And filtration of the exhaust has little point -- you want to sanitize it, then get rid of it.  Any 'filtration' would be on fresh air intakes, and you'd need competent return-air boosters for the level of filtration needed on recirculation venting...

 

The real point is that I don't think those cars HAVE full air exchange, at least not the equipment I had to use to get that kind of air-exchange numbers in roughly comparably-sized RECD house designs in the '90s.  And I was using an exchange wheel in the exhaust, a non-starter 'as designed' for infectious particles in the exhaust flow...

Someone describe for me EXACTLY where the exhaust airflow from various spaces in a Superliner goes, and how it reaches the outside air.

 

In the Superliner Maintenance Training Manual below are drawings, figures 1-3, 1-6, and especially 5-4, and general information in 2.2.6 and beyond, and more specific information in section 5.

From what I can determine, the upper passenger level has return air grates at the left hand side wall on the "A" end at the lockers, and on the right hand side wall on the "B" end at the lockers. The ductwork goes down into the equipment bay where it connects with the outside fresh air, is filtered, and heated or cooled and dehumidified, and is blown at 3000 CFM up to the air nozzles above each seat. About 72% recirculated air and 28% fresh air is supplied.

A separate exhaust fan with a smaller duct appears to be hooked into the return duct to lower the pressure and allow the fresh air to enter. It may also take vapors or hot air out of the equipment bay and exhaust them under the floor at a rate of 1200 CFM for both fans. On the "A" end the duct also exhausts odors from the bathrooms on the lower level.

On the lower level "B" end, the return air appears to be located at the ceiling at the back of the passenger area. On the lower level "A" end, it is not certain where it is located but appears to be outside the bathrooms possibly in the vestibule left side. The ductwork then goes somewhat vertically to meet up with that from the upper level.

It is difficult to see how the air in the Superliner can mechanically be made safe from individuals who show no signs of Covid-19. A UV Covid killer sounds like a good way to make it safer. You would need a UV light near each of the two filters and also near each of the two exhaust fans. Maybe Amtrak is already working on this. Even so, you would still need a mask and distancing to help protect you from direct contact with a Covid-19 individual.

http://www.rr-fallenflags.org/manual/sl-om.pdf

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Posted by Overmod on Sunday, September 13, 2020 9:33 AM

This is precisely what I was looking for.  Thank you!

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Posted by blue streak 1 on Monday, September 14, 2020 12:41 AM

another dupliication

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Posted by blue streak 1 on Monday, September 14, 2020 12:42 AM

I would suspect that UV light made by LED lights can be made that would not be compromised by rail  car vibration ?   Anyone know if such are already on the market ?

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Posted by Overmod on Monday, September 14, 2020 4:33 AM

blue streak 1
I would suspect that UV light made by LED lights can be made that would not be compromised by rail  car vibration ?   Anyone know if such are already on the market ?

They are, but they are not very powerful and not very efficient, so you need a lot of them to accomplish what a properly suspended quartz tube does easily, and even in industrial quantity they are still expensive.  Here is a recent IEEE "COVID-19" related story with some of the associated tech discussed:

https://spectrum.ieee.org/tech-talk/semiconductors/optoelectronics/ultravioletled-maker-demonstrates-30second-coronavirus-kill

You will note between the lines just how many of the VioLED modules would need to be deployed in the duct architecture.

Keep in mind that UV-C, the nucleic-acid denaturing wavelength range, also generates ozone which is effective in sanitizing 'downrange' for some distance.  Unfortunately this has a detectable odor and poses a human-health danger and would need to be removed before any return air reached inhabited spaces... this is doable but would have to be perfectly and consistently maintained at all times, even net of tampering, something Amtrak staff and maintenance might not safely assure; I am not sure how cost-effective providing active ozone detectors in ventilated spaces on all the cars, on top of the cost for generating the UV, would be.

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Posted by CMStPnP on Wednesday, September 16, 2020 2:20 AM

Overmod
They are, but they are not very powerful and not very efficient, so you need a lot of them to accomplish what a properly suspended quartz tube does easily, and even in industrial quantity they are still expensive.  Here is a recent IEEE "COVID-19" related story with some of the associated tech discussed: https://spectrum.ieee.org/tech-talk/semiconductors/optoelectronics/ultravioletled-maker-demonstrates-30second-coronavirus-kill You will note between the lines just how many of the VioLED modules would need to be deployed in the duct architecture. Keep in mind that UV-C, the nucleic-acid denaturing wavelength range, also generates ozone which is effective in sanitizing 'downrange' for some distance.  Unfortunately this has a detectable odor and poses a human-health danger and would need to be removed before any return air reached inhabited spaces... this is doable but would have to be perfectly and consistently maintained at all times, even net of tampering, something Amtrak staff and maintenance might not safely assure; I am not sure how cost-effective providing active ozone detectors in ventilated spaces on all the cars, on top of the cost for generating the UV, would be.

I use a IQAir Home purifier and it just uses filtration a series of filters and is able to handle COVID-19 and filters down to .003 microns.    No UV lights at all.   And purifies the air to Hospital standards.    I think the whole UV light thing is someone's neighbor is selling them out of a garage or something.

With the IQAir unit the filters are monitored via a system that keeps track of cfm airflow and time unit is running pushing air through the filters.    Each filter has an indicator light that turns yellow when the filter is getting near the end of it's life and then red when the filter is at end of life.    The filter that is used up first is good for a year to 18 months operation, other filters....they have a carbon filter in there are good for 24 months or longer.    Seems to me you could hook that up to a Superliner ventilation system relatively easily and just check the filters at regular maintenence checks of at least once a year.   And keep the system running.   You might have to buy more powerful fans though.

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Posted by charlie hebdo on Wednesday, September 16, 2020 7:28 AM

CMStPnP

 

 
Overmod
They are, but they are not very powerful and not very efficient, so you need a lot of them to accomplish what a properly suspended quartz tube does easily, and even in industrial quantity they are still expensive.  Here is a recent IEEE "COVID-19" related story with some of the associated tech discussed: https://spectrum.ieee.org/tech-talk/semiconductors/optoelectronics/ultravioletled-maker-demonstrates-30second-coronavirus-kill You will note between the lines just how many of the VioLED modules would need to be deployed in the duct architecture. Keep in mind that UV-C, the nucleic-acid denaturing wavelength range, also generates ozone which is effective in sanitizing 'downrange' for some distance.  Unfortunately this has a detectable odor and poses a human-health danger and would need to be removed before any return air reached inhabited spaces... this is doable but would have to be perfectly and consistently maintained at all times, even net of tampering, something Amtrak staff and maintenance might not safely assure; I am not sure how cost-effective providing active ozone detectors in ventilated spaces on all the cars, on top of the cost for generating the UV, would be.

 

I use a IQAir Home purifier and it just uses filtration a series of filters and is able to handle COVID-19 and filters down to .003 microns.    No UV lights at all.   And purifies the air to Hospital standards.    I think the whole UV light thing is someone's neighbor is selling them out of a garage or something.

With the IQAir unit the filters are monitored via a system that keeps track of cfm airflow and time unit is running pushing air through the filters.    Each filter has an indicator light that turns yellow when the filter is getting near the end of it's life and then red when the filter is at end of life.    The filter that is used up first is good for a year to 18 months operation, other filters....they have a carbon filter in there are good for 24 months or longer.    Seems to me you could hook that up to a Superliner ventilation system relatively easily and just check the filters at regular maintenence checks of at least once a year.   And keep the system running.   You might have to buy more powerful fans though.

 

That is the definition of true HEPA filtration system.  There are many. 

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Posted by Erik_Mag on Wednesday, September 16, 2020 9:58 PM

If the A/C is running and the air is humid enough, the condensation on the (refrigerant) evaporator coils will do a fair job of trapping particulates.

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