Air-exhausting systems, what has to be paid attention to

Question

Dear expert team,
I move with my daughter (CF, 18 months old) to an appartment, where the bathroom has no window: there is an air-exhausting system (which one exactly, I do unfortunately not know). I have already looked for adequate former questions on the ecorn-cf site, however I could not make really sense of it. Is it true, that the air-exhausting system needs a fungus respectively a bacterial filter? I have read that there should not be a container for condensating water where it quasi recirculates - reportedly the exhausted air is blown to the outside...please give me some feedback, what I have to pay attention to!
Many thanks, best regards, M.L.

Answer

Dear questioner,
in general in case of ventilating systems it deals in connection to CF with the risk of a coloniztaion of the device with Pseudomonas aeruginosa and spores of mould fungi, as well as their potential distribution in the living rooms via the device, which would then present a risk for the CF patient. Therefore, there are the following central questions concerning a device:
Is there a formation of humidity/condensating water, that deposits in the system and is a breeding ground for the above mentioned germs? Besides the discharge of the exhausted air, is there also an air supply into the rooms, via that probably those germs could be spread?
You talk here about a device for the exhausted air. During a research, quite something could be found about such systems, the for you interesting websites are listed below [translator's remark: those Websites are in German, as this was a German question]. There are guidelines on the airing of window-less rooms (see below and also in the Internet); in case of bathrooms it is like this, that the supply with fresh air of the window-less bath room can take place via the other rooms of the appartment, as far as there are openings for the air-exchange between the bathroom and the apparmtent; that means you do not need an extra supply-air ventilation sytem in the bathroom, but rather the by you mentioned system to dispose the exhausted air.
On the below mentioned sites you find information, how much capacity such a system should have, in order to also eliminate sufficiently the humidity from the bathroom and to avoid the formation fo mould fungi via humid air. That means, no air is provided via the device however air is only discharged and blown outside, therefore there is little risk of spreading germs.

With this, the question arises, if a filter in the discharge system of the exhausted air is necessary, as the air is only blown outside so that one would think, this is not necessary.
However I did find on some websites pure filters for exhausted air, so that I would recommend, to talk about this with the company who will install the device for your respectively sells it, in order to find out, why such a filter for the exhausted air could probably be important.
I also listed a website of a company that produces air filters - there was a contact telephone number, via this one could for sure ask if the exhausted air device of a window-less bathroom needs a filter and which particles it withholds (only larger ones like pollen, or also bacteria and fungus spores).
Please try to get more detailed information about this.
As the humid air is blown direclty outside, it seems that there is no formation of condensating water in the system. This would also be of advantage, should however also again be discussed with the technical experts.
Altogether I would say, that a air-exhausting sytsem in a window-less bathroom is not a problem, it should have enough capacity, though, in order to get sufficiently rid of the humidity that occurs in the bathroom. In case a filter should against expectation be necessary, a good maintenance is of course important.
Yours sincerely,
Dr. Daniela d'Alquen

14.05.2014