RC must put HEPA FILTERS on its ships

[jceric2002]

Do people from RC read this forum?  If anybody from RC reads this post, i urge you to immediately put HEPA FILTERS on your ships.   As per CNN article in this link, CRUISE SHIPS do NOT HAVE THE HEPA FILTERS thus allowing viruses to spread via the AIRCON SYSTEM currently in place.  This is a simple and cheap solution which all cruise ships should immediately implement, excerpt as follows "

"Cruise ships in principle look like a building, so their air conditioning systems are similar to those in buildings," says Qingyan Chen. "There's nothing wrong with that in normal circumstances, but with a viral outbreak that's a problem, because the filters they use don't block viruses."

That means that the ventilation systems may have spread the virus from one cabin to the next, by recirculating contaminated air that contained tiny droplets expelled by sneezing or coughing passengers."

https://edition.cnn.com/travel/article/airplane-cruise-hygiene-future/index.html

 

 

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[Billy Baltic]

Think back to your last cruise and try to imagine the number of people you sat close to in bars, restaurants, tenders. How many people you were in queues with. How many people were on your bus for excursions. Hepa filters wouldn’t help in any of those situations. There is no comparison between a flight, even a long one, and several days on a cruise. 
 

[taglovestocruise]

Get a flu shot, next year get a flu/corona shot,  By the time you fly in, mingle with the airport crowd, wait in line for a filthy taxi, stand in line to checkin, sit with a few thousand waiting to board, joining the 4000+ in the windjammer eating while using the tongs, spending a crowded 30 minutes at muster, you already have it.  And we are only at lunch time. Best to just sit home.  PS, those in cabin filters are so dirty and filled with dust that no virus could penetrate them.

 

Edited April 5, 2020 by taglovestocruise

[davekathy]

13 minutes ago, taglovestocruise said:

Get a flu shot, next year get a flu/corona shot,  By the time you fly in, mingle with the airport crowd, wait in line for a filthy taxi, stand in line to checkin, sit with a few thousand waiting to board, joining the 4000+ in the windjammer eating while using the tongs, spending a crowded 30 minutes at muster, you already have it.  And we are only at lunch time. Best to just sit home.  

And jump in the hot tub or pool with a gaggle of your new friends. 

[klfrodo]

You get your engineering and design information from CNN? 🤔

[firefly333]

4 minutes ago, klfrodo said:

You get your engineering and design information from CNN? 🤔

Lol well cnn said "may" have gotten in air ducts.

 

I've wondered myself tbh, but we need data.

[Ourusualbeach]

1 hour ago, jceric2002 said:

Do people from RC read this forum?  If anybody from RC reads this post, i urge you to immediately put HEPA FILTERS on your ships.   As per CNN article in this link, CRUISE SHIPS do NOT HAVE THE HEPA FILTERS thus allowing viruses to spread via the AIRCON SYSTEM currently in place.  This is a simple and cheap solution which all cruise ships should immediately implement, excerpt as follows "

"Cruise ships in principle look like a building, so their air conditioning systems are similar to those in buildings," says Qingyan Chen. "There's nothing wrong with that in normal circumstances, but with a viral outbreak that's a problem, because the filters they use don't block viruses."

That means that the ventilation systems may have spread the virus from one cabin to the next, by recirculating contaminated air that contained tiny droplets expelled by sneezing or coughing passengers."

https://edition.cnn.com/travel/article/airplane-cruise-hygiene-future/index.html

 

 

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Let’s get someone a bit more knowledgeable than CNN to weigh in.  @chengkp75

[taglovestocruise]

15 minutes ago, davekathy said:

And jump in the hot tub or pool with a gaggle of your new friends. 

All of whom are pounding down beers and never leaving for a bathroom break. 

[zekekelso]

Not going to solve the problem, but doesn’t sound like a bad idea. 

[chengkp75]

First off, the distance any recirculated air travels in a cruise ship's ductwork is far greater than on an airplane, and there is currently no evidence, as stated by the CDC, that Covid-19 has been spread by a ventilation duct, or every single building in the world would be shut down.  Second, in the cabins, air is only recirculated in that cabin, and as bad as the filter that taglovestocruise has shown, it is a filter for the air taken from that cabin, and returned only to that cabin.  There is no common recirculation of the air in cabins.  Third, in public spaces, where the air is recirculated, there are already sanitizing pads in the condensate pans to deal with bacteria, viruses, and molds.  HEPA filters could be used here, but again, there is little to no data to show that cruise ship ventilation has caused the spread of Covid-19.  As noted, the best evidence of Covid-19 spread is by concentrated droplets, from coughing, sneezing, or speaking close to one another.  These droplets do not stay together for the 30-40 meters that the air must flow (and I'm being low with my estimate here) to get from one person, to the air handler, and back to a delivery vent.  That means the virus will fall out, and just like on surfaces, it cannot replicate without a host, and over time dries out and becomes non-viable anymore.

 

I have no idea of the person quoted in the article's qualifications, but just saying that air is recirculated between cabins tends to make my doubt whether he has actually studied a ship's ventilation system or not.  And while it says the virus can live for 3 hours in droplets, it does not say how far these droplets can travel.  There is also a vast difference between airplanes and ships as to the volume of air that is recirculated, and therefore how quickly that air is recirculated, and hence the velocity of the air, and the faster the air (airplane) moves, the farther the droplet may remain in the flow.

 

You will notice that the study of the Diamond Princess that is mentioned in the article makes absolutely no mention of a transmission vector via the air conditioning system.

[Ourusualbeach]

1 minute ago, chengkp75 said:

First off, the distance any recirculated air travels in a cruise ship's ductwork is far greater than on an airplane, and there is currently no evidence, as stated by the CDC, that Covid-19 has been spread by a ventilation duct, or every single building in the world would be shut down.  Second, in the cabins, air is only recirculated in that cabin, and as bad as the filter that taglovestocruise has shown, it is a filter for the air taken from that cabin, and returned only to that cabin.  There is no common recirculation of the air in cabins.  Third, in public spaces, where the air is recirculated, there are already sanitizing pads in the condensate pans to deal with bacteria, viruses, and molds.  HEPA filters could be used here, but again, there is little to no data to show that cruise ship ventilation has caused the spread of Covid-19.  As noted, the best evidence of Covid-19 spread is by concentrated droplets, from coughing, sneezing, or speaking close to one another.  These droplets do not stay together for the 30-40 meters that the air must flow (and I'm being low with my estimate here) to get from one person, to the air handler, and back to a delivery vent.  That means the virus will fall out, and just like on surfaces, it cannot replicate without a host, and over time dries out and becomes non-viable anymore.

 

I have no idea of the person quoted in the article's qualifications, but just saying that air is recirculated between cabins tends to make my doubt whether he has actually studied a ship's ventilation system or not.  And while it says the virus can live for 3 hours in droplets, it does not say how far these droplets can travel.  There is also a vast difference between airplanes and ships as to the volume of air that is recirculated, and therefore how quickly that air is recirculated, and hence the velocity of the air, and the faster the air (airplane) moves, the farther the droplet may remain in the flow.

 

You will notice that the study of the Diamond Princess that is mentioned in the article makes absolutely no mention of a transmission vector via the air conditioning system.

Thanks Chief. 

[Jimbo]

Tell that to people in Philadelphia back in 1976 when that think the Legionnairies Disease was believed to be spread through the cooling towers for the hotel through the air conditioner.

[chengkp75]

4 minutes ago, Jimbo said:

Tell that to people in Philadelphia back in 1976 when that think the Legionnairies Disease was believed to be spread through the cooling towers for the hotel through the air conditioner.

And, Legionella is one of the main reasons that cruise ships are required to have sanitizing pads in the air handler drain pans.  Besides, Legionella is a bacteria, while Covid-19 is a virus.  Legionella is also the reason that all shower heads on cruise ships must be taken off and sanitized in chlorine solutions twice a year, when was the last time you did this at home, or a hotel did this?

[ONECRUISER]

3 hours ago, davekathy said:

And jump in the hot tub or pool with a gaggle of your new friends. 

People Soup

[JamesEM]

At one time I had a SC Pool and Spa Operators Permit, since then I have not been in a hot tub or pool.

[grapau27]

6 hours ago, Ourusualbeach said:

Thanks Chief. 

+1.

[grapau27]

2 hours ago, JamesEM said:

At one time I had a SC Pool and Spa Operators Permit, since then I have not been in a hot tub or pool.

Very sensible imo.

[L454S]

19 minutes ago, irzero said:

I always get a bad throat on a cruise until i turned off the Aircon. When aircon is in cooling mode it creates moisture which then allows bugs to get in to your lungs via water droplets. Last 2 cruises in inside cabins we kept the aircon so it didnt cool the room and we didnt get throat infections. 

 

These systems need UV lamps which kill pathogens quickly and safely. I have one in my water filter at home and replace it every 12 months.  

 

I thought an air conditioning system would dry out the air somewhat as opposed to adding water droplets as you claim.

At least in cars and home units, that is the case. That's why there is an A/C drain.

[chengkp75]

13 minutes ago, irzero said:

I always get a bad throat on a cruise until i turned off the Aircon. When aircon is in cooling mode it creates moisture which then allows bugs to get in to your lungs via water droplets. Last 2 cruises in inside cabins we kept the aircon so it didnt cool the room and we didnt get throat infections. 

 

These systems need UV lamps which kill pathogens quickly and safely. I have one in my water filter at home and replace it every 12 months.  

Actually, cooler air has less humidity than warmer air, and most AC systems will cool outside air to below a comfortable temperature in order to drop the humidity, and then reheat the air slightly to become comfortable.  When the humidity is lowered by the AC, the moisture drops into the condensate pan (anyone with central AC or mini-splits are aware of these) for draining, and these drain pans have sanitizing pads in them with agents to kill bacteria, viruses, and molds.

 

What the AC is doing to you is because of the low humidity, it dries out your mucus membranes in your nose and throat, and these mucus membranes are the first an most important line of defense against airborne infections.  Use of a saline nasal spray is recommended if you catch URI's in ship's air conditioning situations.

 

The sanitizing pads work just as well, at far less cost, than the UV lights, which is why the USPH requires them in the ship's AC system.

[marci22]

11 hours ago, chengkp75 said:

  Legionella is also the reason that all shower heads on cruise ships must be taken off and sanitized in chlorine solutions twice a year, when was the last time you did this at home, or a hotel did this?

I do it more than twice a year and I do the kitchen one every time I bleach the sink so usually once a week. 

 

I'm not sure I can cruise again after this.

Edited April 5, 2020 by marci22

[chengkp75]

1 minute ago, irzero said:

 

Condensation forms which is why there is a drain. Whilst it will dry the air out over time the issue is the water in the system, that is why they are huge legionella risk. A badly maintained aircon system can kill and this is possibly how the Princess ship had such a problem. They found corona in the air ducts.

Please lead me to your source that stated Covid-19 virus was found in the air ducts.  CDC has stated that they do not have any evidence of transmission via the AC ductwork.

[orville99]

7 minutes ago, irzero said:

https://www.newshub.co.nz/home/world/2020/03/coronavirus-covid-19-samples-found-in-isolation-room-air-vents.html

 

Its not conclusive obviously but lets face it it doesnt have to travel far between cabins.

And as Cheng says, the air recirculates only within a stateroom, and not between staterooms, then the presence of remnants of the virus in the air ducts inside of an infected passenger's cabin is probably not a remarkable find, and certainly not one that can be extended ship-wide.

[orville99]

9 minutes ago, irzero said:

 

So where does fresh air come from on an inside stateroom?

Don't know, not an engineer, and know well enough not to speculate.

[chengkp75]

1 hour ago, irzero said:

https://www.newshub.co.nz/home/world/2020/03/coronavirus-covid-19-samples-found-in-isolation-room-air-vents.html

 

Its not conclusive obviously but lets face it it doesnt have to travel far between cabins.

 

49 minutes ago, irzero said:

 

So where does fresh air come from on an inside stateroom?

As usual, whenever I have a long post, our internet onboard drops out, so I'll answer these together with what I posted before.

 

The problem with their conclusions, and with your statement about "distance" is that it does not reflect how a ship's AC actually works.

 

There are two systems that provide AC to cruise ship cabins.  The firs consists of two fans and an air handler/cooler/filter.  This system takes in outside air, cools it, and delivers it to a bank of cabins, but note that this is one way air flow, from outdoors to the cabins.  This is balanced by the bathroom exhaust, which takes air from a bank of cabins, and exhausts it outside the ship, again being a one way flow, so there is no intermingling of air either in fresh air delivery or in stale air exhaust.  This is true for all cabin types, so that is how an inside gets "fresh air", it wouldn't be from a recirculating system anyway, that wouldn't be "fresh".  The fresh air supply is controlled from a central thermostat, and delivers a constant air volume and a constant air temperature to banks of cabins.  You have no control over this.  The fresh air supply also supplies slightly more air than the bathroom exhaust takes away, so it maintains a slight positive air pressure in the cabin to keep smoke from migrating from the passageways into cabins that are not on fire.

 

The second system is the one controlled by your cabin thermostat.  This takes air from that cabin, passes it over a cooler in that cabin (and through the nasty filter that taglovestocruise showed), and delivers the cooled air back to the same cabin.  So, there is no intermingling of air between cabins in this system either.  This is just like a window AC at your house, when the "outside vent" is closed, it merely recirculates the air.

 

So, given the description above, it is not surprising that they found evidence of the virus on the vents of an isolation cabin, since the occupants were infected and breathing the virus out, and the cabin recirculation system was perhaps not filtering out all of the virus before returning it to that cabin.  What would be significant would be if they found evidence of the virus on the vents of cabins where the occupants were not infected, as this would be evidence of cross-contamination.

[chengkp75]

12 minutes ago, irzero said:

Makes sense. Given the placement of the aircon i always assumed that it was a central system and not recirculation of cabin air. This makes sense given how much it drys the air out and thus causes the sore throats i always got.

The big difference between shipboard AC and home AC or many older building AC, is the use of chilled water.  The ship does not pump refrigerant all around the ship to cool the various places, this would be prohibitively expensive, and way more prone to leakage and problems.  Instead, the ship's AC compressors only circulate refrigerant in the engine room, cooling a system of fresh water called chilled water, to about 38*F.  This water is then circulated around the ship to all the main air handlers (in those long "white spaces" down the middle of the ship) that cool the fresh air supply to the cabin, as well as both fresh air and recirculation air for public spaces.  This chilled water is also used in each cabin's cooler, making for a smaller cooler, simpler piping, and better control.  The cabin thermostat turns on the fan that recirculates the cabin air, and opens a solenoid valve that allows the chilled water to circulate through the cabin's cooler.  If you ever open the "sanitary locker" outside your cabin (that "hidden" panel where the plumbers work when your toilet clogs) you may see the cabin AC unit in there.  Some ships that have bathroom vanities will tuck the cabin cooler under the vanity.

 

HVAC industry standard is to provide 20% fresh air volume per minute, recirculate 80% air volume per minute, and exhaust 20% air volume per minute.  This reduces the energy needed to cool the ship and maintain it cool.

Edited April 5, 2020 by chengkp75