hagiograph
Topic Author
Posts: 9
Joined: Tue Jun 21, 2011 6:22 am

Aircraft Exit Signage

Tue Jun 21, 2011 6:33 am

I am new to Airliners.net and it looks like a great resource for all things airliners! I had a question that has been on my mind as I've been spending more time flying these days.

I noted that depending on the plane sometimes they have electrically lit EXIT signs, sometimes they appear to have small red "block" type exit signs which look like they might be more like a "tritium" exit sign.

Is there any standard for aircraft exit signage? Is there any safety issue from having a radioactive exit sign (like a tritium sign) or are these units relatively robust.

Recently I was de-planing from a KLM 737 (300?) in Amsterdam and I noted that there was at least one of these what appear to be "tritium" type signs onboard. As I was leaving I felt my backpack scrape up against something, a bulkhead as I went by?

My question, silly as it may sound, is: if I scraped against one of these tritium-type exit signs is it possible I could have damaged it and gotten anything radioactive on me or my backpack?
 
chuchoteur
Posts: 609
Joined: Tue Sep 12, 2006 9:17 pm

RE: Aircraft Exit Signage

Tue Jun 21, 2011 7:28 am

Hi, don't worry it'll be fine  

Those placards are classed as low-emissive radiation materials. even if you'd scraped right through the placard (which is unlikely), the minute traces that you could possibly pick up would not be a threat to human health.

The issue surrounding those materials is more towards people who handle large quantities, or spend prolonged periods of time surrounded by large quantities (for example it you work in a warehouse storing tritium in barrels prior to printing those signs).
 
Elevated
Posts: 125
Joined: Sun Feb 14, 2010 6:52 am

RE: Aircraft Exit Signage

Tue Jun 21, 2011 8:01 am

This is the type of question I would ask a chemist!   
 
AA737-823
Posts: 4887
Joined: Wed Mar 01, 2000 11:10 am

RE: Aircraft Exit Signage

Tue Jun 21, 2011 9:50 am

Quoting hagiograph (Thread starter):
I am new to Airliners.net and it looks like a great resource for all things airliners! I had a question that has been on my mind as I've been spending more time flying these days.

I noted that depending on the plane sometimes they have electrically lit EXIT signs, sometimes they appear to have small red "block" type exit signs which look like they might be more like a "tritium" exit sign.

Is there any standard for aircraft exit signage? Is there any safety issue from having a radioactive exit sign (like a tritium sign) or are these units relatively robust.

Recently I was de-planing from a KLM 737 (300?) in Amsterdam and I noted that there was at least one of these what appear to be "tritium" type signs onboard. As I was leaving I felt my backpack scrape up against something, a bulkhead as I went by?

My question, silly as it may sound, is: if I scraped against one of these tritium-type exit signs is it possible I could have damaged it and gotten anything radioactive on me or my backpack?

In the 1980's and 1990's, we used the "Indiglo" style illuminated exit sign. Since then, we've gone for a much lower-tech solution, which is to place 5 light bulbs (typically GE 387 bulbs) behind a plain plastic lens.

As far as I know, the only requirements for the signs are that they be illuminated, and able to do so without aircraft power for a period of thirty minutes.

I was heretofore unaware that any of them were even remotely radioactive.....
Even in that case, they're probably not nearly as dangerous as the many pounds of depleted uranium used as balance weights in the control surfaces.... which is something else most people don't know about.
 
hagiograph
Topic Author
Posts: 9
Joined: Tue Jun 21, 2011 6:22 am

RE: Aircraft Exit Signage

Tue Jun 21, 2011 6:57 pm

Quoting Elevated (Reply 2):

I know! Strange isn't it? Radiochemistry was never my thing (I'm organic geochemistry). I actually work with inorganic and mineral materials for coatings. (Not all chemists are non-radiophobes!   )

I was just fascinated that when I started flying more I started noticing the different styles of emergency notification on planes. I was reading about the various inorganic materials they use in floorpath lighting ( like Strotium aluminate) then I began to wonder about the small "block signs" like these:



And I began to wonder if they were, indeed, tritium signs.
 
hagiograph
Topic Author
Posts: 9
Joined: Tue Jun 21, 2011 6:22 am

RE: Aircraft Exit Signage

Tue Jun 21, 2011 6:58 pm

Quoting chuchoteur (Reply 1):
Hi, don't worry it'll be fine

Those placards are classed as low-emissive radiation materials. even if you'd scraped right through the placard (which is unlikely), the minute traces that you could possibly pick up would not be a threat to human health.

The issue surrounding those materials is more towards people who handle large quantities, or spend prolonged periods of time surrounded by large quantities (for example it you work in a warehouse storing tritium in barrels prior to printing those signs).

Chuchoteur,
Thanks!
 
hagiograph
Topic Author
Posts: 9
Joined: Tue Jun 21, 2011 6:22 am

RE: Aircraft Exit Signage

Tue Jun 21, 2011 7:01 pm

Quoting AA737-823 (Reply 3):
In the 1980's and 1990's, we used the "Indiglo" style illuminated exit sign. Since then, we've gone for a much lower-tech solution, which is to place 5 light bulbs (typically GE 387 bulbs) behind a plain plastic lens.

I hadn't realized they used to use an "indiglo" type illumination in planes. Very interesting.


Quote:

I was heretofore unaware that any of them were even remotely radioactive.....
Even in that case, they're probably not nearly as dangerous as the many pounds of depleted uranium used as balance weights in the control surfaces.... which is something else most people don't know about.

I'd heard that certainly in the case of 747's where they needed a lot of weight in the tail end they needed a very dense material and DU was the way to go.
 
kingairta
Posts: 454
Joined: Mon Feb 09, 2009 2:24 pm

RE: Aircraft Exit Signage

Tue Jun 21, 2011 8:36 pm

If you sit in a window seat and let the sun shine on you you'll have about 100x more radiation exposure then what you'd get from brushing up against that sign.
 
B747FE
Posts: 217
Joined: Mon Jun 21, 2004 11:09 pm

RE: Aircraft Exit Signage

Wed Jun 22, 2011 4:41 am

Quoting hagiograph (Thread starter):
I noted that depending on the plane sometimes they have electrically lit EXIT signs, sometimes they appear to have small red "block" type exit signs which look like they might be more like a "tritium" exit sign.

They have both types.
Most of them are lighted exit signs (regular bulbs) but some are the self-illuminating type which have capsules filled with tritium gas.


Quoting hagiograph (Thread starter):
Is there any safety issue from having a radioactive exit sign (like a tritium sign) or are these units relatively robust.

There is no hazard as long as the sign is intact or even with minor scratches or nicks. Normal handling will not damage it, they are pretty sturdy.
The gas capsules are embedded in the sign (plastic) and protected with some kind of silicone rubber.
However the gas may escape if the signs gets cracked or broken.

Quoting hagiograph (Thread starter):
if I scraped against one of these tritium-type exit signs is it possible I could have damaged it and gotten anything radioactive on me or my backpack?

No worries.

Quoting chuchoteur (Reply 1):
The issue surrounding those materials is more towards people who handle large quantities, or spend prolonged periods of time surrounded by large quantities (for example it you work in a warehouse storing tritium in barrels prior to printing those signs).

..and for the maintenance people who works with them also.
I remember reading about a procedure on how to handle a broken sign replacement. Even the airplane A/C had to be on in order to dissipate radioactive gas in case it gets broken. Disposal & storage of this items also have a few procedures as well.

Quoting hagiograph (Reply 6):
I'd heard that certainly in the case of 747's where they needed a lot of weight in the tail end they needed a very dense material and DU was the way to go.

That is correct.
Balance weights made of depleted uranium were/are installed on outboard elevators and upper rudders.
They have an electro plated protective coating on them to contain the radioactive material.
Even though is low level radioactive uranium, ingestion of dust coming from them is toxic and as such any kind of rework that would damage the coating was strictly prohibited.
They were replaced with balance weights made of tungsten, but there may be some still flying around on old 747..

Regards,
B747FE.
"Flying is more than a sport and more than a job; flying is pure passion and desire, which fill a lifetime"
 
kingairta
Posts: 454
Joined: Mon Feb 09, 2009 2:24 pm

RE: Aircraft Exit Signage

Wed Jun 22, 2011 2:21 pm

LOL.

Is it just my screen or does everyone have an advertisement for "afterglow safety signs"?

I find it funny that we are talking about signage and there's an advert. for safety signs.
 
Markhkg
Posts: 838
Joined: Mon Dec 05, 2005 4:13 pm

RE: Aircraft Exit Signage

Wed Jun 22, 2011 11:36 pm

Quoting hagiograph (Thread starter):
Is there any standard for aircraft exit signage?

There are indeed some standards, such as minimum illumination, as required by the FAA, which are outlined here:

http://rgl.faa.gov/Regulatory_and_Gu...3055a86256f3c006b23c8!OpenDocument

Alternatives to tritium readily exist (such as the Saf-T-Glo photo-luminescent pathway system), although using these alternatives are more of an issue of cost rather than safety.

I've also come across a few manual inflation handles from evacuation slides that had tritium encased in the handle to illuminate the words "PULL".
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