Last week my little brother asked me questions on the M17 series gas masks. I have seen some gas mask discussion in the past and on U-Tube and on TV I have seen them on people’s shelves. Today I thought it might make a good article for the Wolf Pack, so here goes.
“Ron… I’m in need your expertise… what agents/viruses/chemicals/bacteria is the M17A1 effective against. Or if it’s easier, what it’s not effective against”.
It all depends on the filters. There were 3 different colored filter rings for the M17 Series masks. Black or M13, Gold or M13A, and Green or M13A1. The black was always intended for Training Use Only. All three would and will still protect against particulates including tear gasses, fallout and bacterial. Assuming that the integrity of the activated charcoal is intact and never exposed to water/high humidity.
The gold and green were capable of protecting against all known Chemical and Biological weapons. HOWEVER, they had a shelf life. The gold ones exceeded their shelf lives in the 70′s. The green ones were starting to go in the late 80′s. It all depended on lot numbers. Since the military was changing over to the MCU-2P as it’s primary NBC full-face respirator in the late 90′s I would strongly doubt any additional fully serviceable green ring filters were purchased and the remaining stock has long ago expired. There use to be a TM/TO (Army Tech Manual and Air Force Tech Order) that listed serviceable filters by lot numbers. I imagine it is long gone as well.
Since vapor absorption was only part of what a filter would do, I would assume that what was in the activated charcoal neutralized some agent would degrad. Yes that was only an opinion but it is based upon the fact that vacuum-sealed packages give up the ghost eventually. That’s why there were lot numbers. Rock Island Arsenal actually recalled and tested lot numbers on a regular schedule and they maintained the TM/TO’s.
Of all of the mask, US and others, the big question will always be the filters. I would not want to trust any of them except against particulates.
“External vs. internal filtered masks, is there an advantage of one over the other”?
By all means externals are easier to change in a NBC environment. Hold breath, unscrew the old, screw on the new, and resume breathing. Internal filters required removal of the mask and you had to process thru decon into a “clean area” to do that. However two filters are better than one and would require replacement less often.
Note that the M17 was designed in the 60′s with a lot of political unrest going on, and you can imagine that in a riot control, or other “hand to hand” situation, the M17 was superior.
Other important parts will be the exhale port valve, the face piece, and the harness. The valve must be flexible enough to open when you exhale and close when you inhale. While wearing the mask for a while moisture will collect on the rubber valve and cause a popping sound. When removed and the moisture dries, this valve will stick to the port. The next time the mask is worn the valve may not open allowing the exhaled air to escape and may cause the lenses to fog up. Simply hold the face piece close to the face and blow hard. The valve will pop free and function properly.
The face piece should be flexible and the harness should not have been over stretched and shaped like bacon.
Everything being equal the limitation with any respirator will always be the serviceability of the filters.