From: Curtis Gibson <quest!curt@uunet.uu.net>
Subject: Re: Change of M17A2 mask to M40 mask
Keywords: M17 M40 mask
Organization: Quest Research, Inc.
Date: Wed, 18 Nov 1992 14:40:27 GMT


From Curtis Gibson <quest!curt@uunet.uu.net>

92vanatter@gw.wmich.edu Dion VanAtter: writes

> I would like to discuss why the military is changing from the M17A2
> chemical and biological mask to the new M40 mask?
>
> The new M40 seems like a step back, with the filter attached from the
> side of the mask.  I feel the M17A2 was more ergonomically designed
> with the filters integrated within the mask.  Thus your mask would not
> catch on as many things, more freedom of movement.
>
> Anyone that has info, or would like to respond, please e-mail me or
> post on the net.

I'll take a stab at a short answer.  The biggest two reasons are.
 1.  The M17 family of masks have the filters in the cheeks.  You
change them by unbuttoning the compartments from inside the mask.
The buttons are small, about 3/16 inch across with two heads like a
cufflink.  They button the flaps sealing the filter compartment closed
through three layers of rubber with holes just big enough for the heads
to get through.  You really have to stretch the button holes and nearly
turn the mask inside out.  The two buttons near the bridge of the nose
are near impossible to get to.  When you get the flaps open you have to
remove the filter inlet covers on the outside of the mask.  They are
metal rings with a cloth covered opening that snap over the filters
inlet hole, about 1 1/8 or 1 1/4 inch wide and 1/2 inch long.  They
hold the filter inlet tight against the mask making a tight seal.
Now you wiggle the filters around and out the flaps inside the mask.
Its a tight fit, you have to stretch the opening a little.  Now you
put the new filters in, but take note, there is a right and a left
filter.  Wiggle the filters in through the inside flap, this is a bit
harder than getting the old ones out.  When you have them in position,
snap on the inlet covers, the inlet covers have to be installed right
side up, they have the word "TOP" stamped on them.  Now button up the
flaps inside the mask.  The shortest time I ever took to change the
filters in my M17A was over 5 minutes.  You have to change the filters
in a clear area, with clean hands, ie no chemical agents in the area or
on your hands.  We were issued two masks, one to wear, and one to have
ready to wear.  If the filters get wet, ( I never learned how wet )
they will not protect you from the chemical agents and you have to
change them.  The filters are good for verying amounts of time, under
the right(wrong) conditions as little as a few hours.  If in your haste
to change the filters you tear the button holes, loose one of the
buttons, or loose one of the inlet covers, you aren't going to get the
full protection of your mask.

If the M40 is the one under consideration when I was last up on the
future trends of NBC protection.  You remove the new filter from the
shipping bag.  Spin off the old filter, ( just like a oil filter in a
car ) and spin on the new filter.  Total time, zip.  And you NEVER
have to touch the inside of the mask.

 2.  You can't see worth a darn with the M17 family.  The separator
between the eye lens limits close up work.  I needed to turn my head
to the side to see maps, compasses, radio dials, anything written.

The M40 has a single lens, no separator to get in the way.

    The filter could catch on things, but than so can a lot of the
stuff you drape yourself with.  After a few hours of wearing it you
will adapt and allow for it in your movements.

Curtis S. Gibson   curt%quest.uucp@cs.umn.edu       ex-98C

Newsgroups: sci.military