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.
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.
OvermodUV-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.
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.
Overmod UV-sterilizable ducts with no back flow
In RA?
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.
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.
charlie hebdoIn RA?
https://soundcloud.com/user-125862828/amtraks-bill-flynn-and-stephen-gardner
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.
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.
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...
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
This is precisely what I was looking for. Thank you!
another dupliication
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 ?
blue streak 1I 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 ?
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.
OvermodThey 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.
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.
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.
That is the definition of true HEPA filtration system. There are many.
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.
It looks like Knorr Brake Co. has developed a Covid-19 air purification system and installed it in a Merto-North car, and is working on doing the same for Long Island RR. It uses electrostatic filtration, a UV light, and some kind of ionizer. Knorr Brake describes it as follows:
"The new system passes air through three stages. The first stage applies an electrostatic discharge to actively target viruses, and then uses physical filtration to remove the charged particles. The air is then safely exposed within a self-contained unit, to ultraviolet radiation that has long been proven to kill bacteria, mold, and viruses. Third, the air is exposed to a wave of ionized particles that attack pollutants, chemically decomposing them.
The ions further travel deeply through the air distribution ducts of the car and into the vehicle interior to enhance the railroads’ existing disinfection of surfaces inside the cars."
Perhaps Amtrak and others will be following with similar systems.
http://www.mta.info/press-release/mta-headquarters/mta-piloting-state-art-air-filtration-and-purification-system
Jim200It looks like Knorr Brake Co. has developed a Covid-19 air purification system
The first two stages are electrostatic precipitation (of any 'sneeze' droplets) and UV sterilization; the third stage is "oxygen" ions (this is negative ions as in conventional air-purifiers with 'ionizers', not ozone above that induced by the UV.
Not yet established is whether there are common return points in the car AC that have positive full-volume air exchange through them.
If Amtrak has ACH of 12 or so, that's really pretty good ventilation in and of itself. Compare to a typical home with ACH of 0.3 to 0.5.
Not much of a COVID risk from aerosols - they just can't build up enough with that kind of ventilation. Wearing a mask and distancing should be enough for low risk Amtrak train travel.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
The air in passenger cars replace every 4-5 minutes? That means its more less with airplane then. The aircraft always takes in outside air and simultaneously circulates the air inside the aircraft through a High Efficiency Particulate Air filter (HEPA). It takes about two to three minutes for air to travel throughout the entire cabin and perform a complete circulation cycle.
And if you had bleed air from a relatively large turbofan stage on every railroad car, and presumably reduced pressure outside, you could arrange aircraft-like cabin-air exchange comparably.
Without specific knowledge of mass flow and pressures, something the little blue arrows don't indicate, we have little idea of how much cabin air goes through those HEPA filters (and, in turn, what their size, throughput, and cost would be).
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