Planesmart
Posts: 1766
Joined: Sun Dec 05, 2004 3:18 am

Cabin Air Refresh Rates

Sat Dec 18, 2004 6:51 pm

If cabin air was replaced as frequently as in the 70's to mid 80's, (partly because smoking was permitted back then), bleedless engines wouldn't be viable, as the power req'd to heat incoming air for cabin use would be too great. As cabin air standards are currently set so low, bleedless is possible.

What is the maximum cabin refresh rate the 7e7 is going to be capable of at 30,000 feet versus 777, 767, 757, 747, A32, A33, A38, MD11?

How will 7e7 operators raise the refresh rate if a higher standard is demanded / req'd by customers and/or the World Health Organisation?
 
JetMechMD80
Posts: 370
Joined: Fri Jul 09, 2004 2:27 pm

RE: Cabin Air Refresh Rates

Sun Dec 19, 2004 12:06 am

There is no difference between the rate the cabin air was "replaced" in the 70s. and 80s. The same aircraft are in service, with the same packs, recirculation fans, and out-flow valves. They are operated the same way they always have been. The goal is to pressurize the cabin, and heat it to a comfortable level. That's it. Nothing has changed. I can not answer your other questions about the 7E7's rate, or WHO standards. Sorry.
"I get along great with nobody"~ Billy Idol
 
SlamClick
Posts: 9576
Joined: Sun Nov 23, 2003 7:09 am

RE: Cabin Air Refresh Rates

Sun Dec 19, 2004 1:49 am

Great! Disease runs rampant all over the globe. In parts of Africa, AIDS is more common than electricity and WHO decides to set standards for airliner cabin air.

What a useless bunch of fops!
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
JetMechMD80
Posts: 370
Joined: Fri Jul 09, 2004 2:27 pm

RE: Cabin Air Refresh Rates

Sun Dec 19, 2004 2:03 am

SlamClick,

If you were not already on my rec list, after that comment I would be adding you. Thanks for the laugh. Big grin
"I get along great with nobody"~ Billy Idol
 
Dalmd88
Posts: 2412
Joined: Fri Jul 28, 2000 3:19 am

RE: Cabin Air Refresh Rates

Sun Dec 19, 2004 6:41 am

The current rate of air refresh is actually very high. Somewhere I read a report from Boeing detailing the 767 system. The air exchange rate actually exceeds the rate for an infectious desease area of a hospital. I'll bet the 7e7 will still have a similar rate.
 
schooner
Posts: 138
Joined: Wed Oct 31, 2001 10:29 pm

RE: Cabin Air Refresh Rates

Sun Dec 19, 2004 7:12 am

The refresh rate is much better than that which you would get in an office.

Cheers.
Untouched and Alive
 
ha763
Posts: 3168
Joined: Mon Jan 06, 2003 5:36 pm

RE: Cabin Air Refresh Rates

Sun Dec 19, 2004 2:37 pm

According to Boeing, the norm on most Boeing aircraft is 50% recirculated and 50% fresh air. I say, "most Boeing aircraft," because the 717 is 100% fresh air. Also current cabin air systems circulate enough air to replenish the whole cabin every 2-3 minutes. This is way better than the air exchange rate in an air-conditioned building. More info can be found here:

http://www.boeing.com/commercial/cabinair/
 
User avatar
HAWK21M
Posts: 29867
Joined: Fri Jan 05, 2001 10:05 pm

RE: Cabin Air Refresh Rates

Sun Dec 19, 2004 2:57 pm

The B732 I remember correctly did not have Recirculating Fans,so the Air was 100% Fresh bleed extracted Air.Later versions did come up with One or Two Recirculating fans & so the percentage of Recirculated Air Increased.
However Present Day Aircraft have a refresh rate thats adequate,With no Smoking on board,things are more better.
regds
MEL
I may not win often, but I damn well never lose!!! ;)

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