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What are mask MWOs?

Dear Editor,

We teach at the Ft Sill Chemical School and encounter many NBC NCOs who aren't aware of the modification work orders that have come out for the M40/M42 and M45 protective masks. We think it; would be an excellent; idea for PS to list the MWOs so NBC NCOs can check to see if their masks need modifying.

Also, the zip ties used with one of the MWOs are starting to wear out; and NBC NCOs are local purchasing new ones. We don't think they should do that.

Todd Hall

James Hardison

Richard Hammonds

Ft Sill, OK

MWO 3-4240-346-20-1

This MWO applied a retaining clamp (zip tie) to the facepiece to prevent the silicone rubber from separating from the outlet valve housing. The NBC NCO can do the MWO with a special tensioning tool that comes with the MWO kit. The kit also contains a set of PMCS cards that should be added to the carrier. All M40, M40A1, and M42A2 masks should have had this modification done by now.

If zip ties wear out, NBC NCOs should not local purchase new ones. For new ties, contact TACOM's Jim Morphew at DSN 793-6415/(309) 782-6415 or email:


MWO 3-4240-346-20-2

This MWO replaced the outlet valve disk with an improved disk that minimizes the chance of the disk collapsing into the outlet valve housing during extreme negative pressure checks. The NBC NCO does the MWO. All M40, M40A1, and M42A2 masks should have the modification done by 31 Dec 06. The new disk is olive green. If your masks' outlet valve disks aren't green, the masks haven't been modified.

MWO 3-4240-346-20-3

This MWO replaces the the quick disconnect coupling half in all M40/M42-series masks. Some of the older masks have adhesive applied to the coupling half. In that case, you must order a new facepiece. The NBC NCO does the modification. You can tell if your masks have the new quick disconnect coupling half by checking for three knurling stripes (or raised ridges) on the coupling. The old coupling had two stripes. This MWO should be done immediately because some of the old coupling halves may leak and let chemical agent in the mask.


MWO 3-4240-348-20-1

This MWO replaces the quick disconnect coupling half on the M45 land warrior and M45 masks. It's done by the NBC NCO. The new coupling half has three knurling stripes. The old coupling half had two. This MWO should be done immediately because some of the old coupling halves may leak and let chemical agent in the mask.

If you need copies of any of these MWOs, contact your local MWO officer or TACOM's Jim Morphew at the numbers and email on Page 24.
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Title Annotation:M40/M42-Series Masks, M45 Mask ...; Letter to the editor
Publication:PS, the Preventive Maintenance Monthly
Article Type:Letter to the editor
Date:Jun 1, 2006
Previous Article:Check for drink system blockage.
Next Article:CBRN on the Internet.

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