# Gas mask questions.



## lexsurivor (Jul 5, 2010)

I have been looking to buy a gas mask but I have several questions.
Firstly how long do the canisters last unopened.
Secondly how long do they last while you use them.
And lastly how do you know when to change them.
If anybody has any useful information or the answers to my questions it would be appreciated. Thanks


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## BillM (Dec 29, 2010)

*Gas Masks*



lexsurivor said:


> I have been looking to buy a gas mask but I have several questions.
> Firstly how long do the canisters last unopened.
> Secondly how long do they last while you use them.
> And lastly how do you know when to change them.
> If anybody has any useful information or the answers to my questions it would be appreciated. Thanks


If you google a NIOSH site you can find all the info you need about gas masks.

Resperators are dependant on the seal around the face to be effective.

That means no facial hair. That means the beards have to go.

Resperators are also threat dependant. You have to have the correct carterage for the threat you are protecting yourself from.

The paper filter type with a rubberband are pretty much useless.

SCBA or self contained breathing apperatus is the level of protection you would need to prevent radioactive contamination from entering your lungs.

Most of the masks I have seen on the prepper sites and shows would just be waisted money.

I was a licensed supervisor of asbestos abatment and ran a resperator program proffesionally. I wrote policys and proceedures for thier use.


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## fedorthedog (Apr 14, 2011)

Most of what we would be able to use a mask for is particle filtering. Figuring out what pathogen or chemical to get filter for who be near impossible. The life of a filter for particle is when it plugs. Most start to degrade as soon as they are removed from the package. If still in a vacuum sealed package they should be good. 

In many ways a dusk mask would cover this but they have no eye protection. I plan to have an assortment of filters but only enough to let me leave an area. You cant have enough to live somewhere that requires a mask.

I am SCBA certified and used level B respirators when I was disassembling meth labs as part of my employment.


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## Jezcruzen (Oct 21, 2008)

I cringe when I read the ads for surplus gas masks that appear to be selling well within the "prepper" community. They are old and out of date, or else they wouldn't be on the market. They have a suspect history and their ability to provide any protection at all are suspect as well.

If you feel you need this level of respiratory protection then go with MSA or SCOTT and buy new, dependable equipment. Leave that 30-yr old E. German crap in the dust bin!

"Well, its better than nothing" some will say. Only if you have access to it. I doubt many tote them around with them daily.

Wearing any respiratory protection results in both mental and physical stressors that most are not even aware of. Even being the least bit claustrophobic may preclude someone from wearing a mask more than a few minutes. Thats why OSHA and NIOSH mandate annual fit testings and a pulmonary function test for those workers that may be required to use this protection in the course of their jobs.

Don't put a false hope in junk. Buy new if you just gotta have it. I know from which I speak. I used respiratory protection in various forms as a firefighter and as a Hazardous Materials Specialist for over three decades.


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## lexsurivor (Jul 5, 2010)

Thanks for the help!


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## FrankW (Mar 10, 2012)

Bill made some great points.

I wish ot add a couple of things though:
(I was professionally involved in testing +, selecting protective gear for high end non standard HAZMAT responses that can't be left to standard HAZMAT teams and also worked as a senior scientific analyst for such responses writing the incident site analysis annex for the incident reports etc)

Threat dependent is correct term that really drives everything, however based on some of the comments elsewhere here I think we cannot reply on folks making a coorect choice mos tof the time based on theat analysis.
So As a rule we will see over protecting a lot.
----
if you nto sure what to use. for an effective allrounder a mask in the style of a US M40 is hard to beat ( or similar). 
This would be considered part of a OHSA level C ensemble..
(The business with OSHA , unlike the military, not approving "C" for IDLH atmosphere has more to do with confusion by regulators than performance, but thats for a seperate thread and might not be worth my time writing it or your time reading it.)

for an M40 the standard filter elements contain BOTH activated charcoal and HEPA layers.

HEPA filters are MUCH more effective than most folks give them credit for. 
I will start a separate thread in the next week or so and do a little principles of HEPA filtration class.

There is a lot of confusion by people who should know better in gov't PPE circles and the guidance they give:

SCBA is entirely unnecessary in a radioactive environment. 
HEPA filters will filter out all the radioactive dust you need to be filtered.
Size exclusion is not the only mechanism by which HEPA filters work and this is where i think a lot of the confusion comes from folks feeling they need ot "step up" from level C in certain situations when they really dont.

---

(Disclaimer, the following are my estimates of real world effectivess of surplus gear for prepping purposes and people who don't have $20,000 to spend on SCBA and JSLIST, and the below is not guidance on how to run a business pre-TSHTF )

Filter element effectiveness:

Is effective many many years past the stated expiration year on the wrapping.

reason for this is , is that the filter elements are designed for a very high challenge concentration load in the air that is , frankly unrealistic, even for most first responders to ever see short of being _in the middle_ of a Bhopal sized accident.

So even if they lose say 20% of effectiness after say 5-7 years which would be a fail on inspection, that is still way more effectiveness than you are ever going to need in a realistic survival situation.

For the application of folks on _here_ for a M40 mask these filters are useful for a very long time.

SCBA: *expensive* ,unwieldy , needs a powered air charger and has no application at all for amateur/prepper disaster protection.

There is a saying i like: "PPE Kills" (PPE= Personal protective Equipment)

Why? because people get exhausted, have less situational awareness and mor likely to go bump against dangerous things if wearing PPE.

I used to always say at meetings when people were talking about overloading folks with SCBA " for this incident you need a P95, flip flops and boxershorts as PPE". 

Opened filter elements:

are also much better than their rep.

Gently shake them.. if you dont hear any major wiggling of broken loose elements they will still provide significant protection factor, even if years past their expiration point..

Now its a good idea to keep them dry because this will help the cardboard portion of the charcoal filter assembly ( and the seperate HEPA) stay firm.
The charcoal itself is much less effected by moisture as most people, (even relative experts) think.

While it is true that water vapor will attach to and "cover" the active sites in the charcoal that are supposed to capture threat agent,... it is also true that when presented with say a dangerous gas the charcoal filter "works" for , then the agent molecules will simply displace the water vapor from the active sites and be then held by the charcoal.

this is because Hydrocarbons and their derivatives (such as the ever popular organophosphates) are more strongly attracted to the active sites than the water is.

this is why you see a lot of condensation (depending on weather), around the efflux of big institutional charcoal filter systems like on top of treaty labs.

What do I have at home for PPE?

an old M17 with an older filter element and for dust threats a box of N95's, this will cover the vast majority of threats you should ever encounter in a prepper/survivalist situation .


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## BillM (Dec 29, 2010)

*Very good*



BlueZ said:


> Bill made some great points.
> 
> I wish ot add a couple of things though:
> (I was professionally involved in testing +, selecting protective gear for high end non standard HAZMAT responses that can't be left to standard HAZMAT teams and also worked as a senior scientific analyst for such responses writing the incident site analysis annex for the incident reports etc)
> ...


I would only add one thing to BlueZ remarks.

Negative pressure respirators, (the type most people are familiar with), require forced inhalation and exhalation.

This often results in re-breathing some of the exhaled exhaust from your lungs.

As a result, you may only get an eighteen or nineteen percent oxygen supply when wearing a negative pressure respirator.

This can be very dangerous for people with any kind of pulmonary function problem.


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## FrankW (Mar 10, 2012)

forced inhalation is the reason why OSHA requires a softer inhalation valve ( and therefore less good seal) than the military.
In the military you have a much fitter population than the general public and lung function strenght for inhalation is not an issue.
This is why a military mask is technically not OSHA compliant yet is a superior mask ( as OHSA needs to make sure 70 yr old lady's can still breath in them which is not a cocern in military apps).
Some procurement officials do not understand this issue as many gov't civilians have been promoted beyond their abilities and specify "only OHSA compliant" masks for their specialized response teams not realizing that they are not actually raising the bar but just introducing a weakness into response team acqusition.

I had never heard of the oxygen you issue you mention Bill but that does not mean it isnt a valid concern.


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## RodUSMC (May 25, 2012)

*My FM50*

Gents, some great info here. I agree with the comments on the poor quality of surplus or used masks, and I'd personally stay away from them myself. I was a NBC officer in the Corps, and would highly recommend the FM50, FM53 or C50 family of Avon Protection masks. I have personal experience with these from my time in the Corps. The wide visor of the FM50, C50 or FM53 offers superior field of vision over traditional respirators, greatly enhancing the compatibility with weapons and sights. The FM50 twin filter conformal system sits close against the face, providing the operational user with high protection and very low breathing resistance. It has the added benefit of distributing the weight better, making the mask much more comfortable to wear as compared to masks with one filter. Self-seal valves allow the user to change filters without the need to hold your breath, greatly reducing the risk of contamination. They are expensive, but then you do get what you pay for. Most filters have a five year advertised shelf life, but if you keep them in a cool dry place, unopened, they'll last far longer. If you ever really need one, you are going to wish you bought the best money can buy...its foolish buying some cheap surplus mask that may have been disposed of because it doesn't work properly (bad valve, cracked rubber, leak, age, etc.) Bottom image is their top of line FM53 which works with self-contained breathing gear, powered air, etc. but it uses 40 mm threads, not the new military filters.


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## Marcus (May 13, 2012)

As BlueZ mentioned, SCBA is not needed to protect against radioactive particles. A P95 or P100 dust mask will suffice *as long as you're not in a heavy dust environment.* Goggles to protect your eyes from the dust are a good idea. Home Depot or similar stores carry these masks.
Next up the list is a half-face single or dual cartidge respirator which protect you from vapors and particulates that don't affect the eyes or skin.
If you need eye protection, there is the full face single or dual cartidge respirator. Heat stress will be an issue and you're typically talking minutes of exposure before you need to seek a cold zone.
At the top of the list is the SCBA which is an air tank combined with a full face respirator (think firefighters gear.) It's very expensive and the air supply is 20-30 minutes depending on the task you're performing and your physical state.
If you're seeking protection from chemical exposure, you'll need to determine whether the chemical is a blistering agent or can be absorbed through the skin. If so, you'll need a chemical suit which are expensive.
If you're seeking protection from a nerve agent, you'll be needing a military grade chemical warfare suit or something similar that protects your whole body from exposure.
A usually better solution is to invest in an air filtration/supply system which will overpressure a building to keep the nasty stuff outside.


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