Pressurisation - Fresh Air ?
 

This may be off topic and sound silly, but here goes ...

Once an Aircraft has pressurised, does it still have the facility to re-cycle air from outside ?
If not, is it technologically possible and what (if any) disadvantages are there (weight/space/noise)?
What is the effect on re-using the same air on an ultra-long haul flight (14hours +)?

Thank you in advance.


Invictus

Hope the following answers your question.

The House of Lords Science and Technology Committee held an inquiry into air travel and health in 2000. Their findings on the issue of recirculation of air and the transmission of disease are set out below:

1.61 The typical cabin air flow of 20 cfm of air per occupant equates to a full change of cabin air every 2 to 3 minutes, i.e. 20 to 30 times per hour. As half of the air being changed is re-circulated cabin air, this is equivalent to an entire exchange of cabin air with fresh air 10 to 15 times per hour. (Paragraph 5.5)

The cabin air is not a static thing. It is constantly renewed although some systems will essentialy rerun it through before exhausting it overboard. (Simple answer)
Re your question about using the same air for a 14 hour flight. Suspect you would have a splitting headache at best, or probably have assumed room temperature before arrival.

So then it would not be unreasonabl to have a smoking room on board the ultra long-haul flights? Of course the smoke should not effect the non-smoking passengers and perhaps be the last place the air goes before being exhausted.

Hi Invictus

Do you not remember the days that smoking was allowed on all flights worldwide??

Well yes it’s true that the air at the back of the aircraft won’t affect the other non-smoking passengers. But this causes another problem with tar from the smoke clogging up outflow values and plumbing throughout the system with a resin like yellow substance (Horrible stuff)….

I notice from your profile that you’re from an area much like the Mediterranean countries where smoking is still allowed and accepted in such places as restaurants.

Are you aware of the smoking bans in place in countries such as Australia and US?? Where you cant even smoke within so many meters outside of a public building…..let alone an confined aircraft cabin for 14 hours....

Hey smoking is bad for you anyway!!!! I know I’m a smoker too :}

Smoking onboard....
 

A wise old captain of my acquaintance used to say "You're not allowed to smoke because there's a distinct lack of fire engines up here....." .....and he made pa announcements to that effect!!

Always seemed to make sense to me.

There is some recirc, but your still sucking in all those farts from people getting bloated from the pressure increase. :E

i'm one of those who farts at least 10 times an hour

:E :E :E

OK we're in my territory here.

The air also (fortunately) gets circulated front to back and ceiling to floor, as we Self Loading Farters in the back know :cool:

Architects use a target of 18 air changes per hour for public buildings. The figure of 10 to 15 changes per hour is therefore superior and suggests that airliners are not especially unhealthy places to be, at least compared to other crowded venues. Many places don't achieve anything like the 18 norm - our draughtproofed homes for a start. The recirculated air in the cabin is filtered before being reintroduced into the cabin so in theory it is pretty clean. Airbus claim that their air is cleaner than the stuff you get in an operating theatre, and they are probably right when the aircraft and filters are new, and assuming they are talking about a UK NHS operating theatre. Of course, if the airline scrimps on servicing the air filters the situation will deteriorate. Personally I improve the air quality on board with a brandy and ginger. It doesn't make the air any better but it stops you worrying about it.