46193922-TM-3-4240-346-20P-12645908.pdf

*TM 3-4240-346-20&PTM 09204A/09205A-20&P/2

UNIT MAINTENANCE MANUAL(INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST)

FOR

CHEMICAL BIOLOGICAL MASK: FIELD M40A1

(4240-01-370-3821-SMALL)(4240-01-370-3822-MEDIUM)(4240-01-370-3823--LARGE)

CHEMICAL BIOLOGICAL MASK: COMBAT VEHICLE M42A2

(4240-01-413-4100-SMALL)(4240-01-413-4101-MEDIUM)(4240-01-413-4102--LARGE)

* This manual supersedes the M40A1 part of TM 3-4240-300-20&P / TM 09204A/09205A-20&P/2, 31 July96, and the M42A2 part of TM 3-4240-343-20&P/TM 09204A/09205A-20&P/2, 31 July 96.

WARNING - This document contains export-controlled technical data whose export is restricted by the Army ExportControl Act (Title 22, U.S.S.S., Sec 2751 et seq.) or Executive order 12470. Violation of these export laws is subject tosevere criminal penalties.

DISTRIBUTION STATEMENT - Distribution authorized to U. S. Government agencies and their contractors toprotect technical or operational information This determination was made on 24 June 1987. Other requests for thisdocument will be referred to: Technical Director, U.S. Army, Edgewood Research, Development & Engineering Center,ATN: SCBRD-ENL-V, Aberdeen Proving Ground, MD 21010-5423.

DESTRUCTION NOTICE Destroy by any method that will prevent disclosure of contents or reconstruction of thedocument.

HEADQUARTERS, DEPARTMENT OF THE ARMYAND, HEADQUARTERS, MARINE CORPS

1 AUGUST 1998

PCN 182 092041 00

WARNINGS point out dangerous steps in the procedures in this manual Your safety depends on following the instructionsincluded in all WARNINGS. Several general WARNINGS are included below:

The mask will not be fully effective in confined spaces when the oxygen content of the air is too low. The CB maskhas only been tested and verified to protect against all known military agents.

DO NOT touch your skin (or the soldier) with n-Amyl acetate (banana oil). It could irritate the skin. Wear rubbergloves.

DO NOT smoke around n-Amyl acetate (banana oil), it is flammable.

DO NOT test mask assembly with n-Amyl acetate (banana oil) in a closed, poorly ventilated area. Test outdoors or ina well-aired room, n-Amyl acetate may be toxic if inhaled in quantity.

DO NOT wear contact lenses (soft or hard) while wearing CB Protective Masks. Inadequate oxygen supply to thecorneal surface, exposure to dust, dirt, and smoke/gas may cause serious vision loss or eye damage. Soldiersrequiring vision correction are provided optical inserts for their protective masks.

HEALTH/ENVIRONMENTAL HAZARD

There are two Mask Filter Canisters, the C2 and the C2A1. The C2 canister contains Chromium VI and damaged orunusable canisters are considered Hazardous Waste. (Chromium VI is a known carcinogen if inhaled or swallowed.)

The C2A1 canister is chromium-free but must continue to be disposed of in accordance with State and LocalEnvironmental Laws.

DO NOT throw away damaged or unusable canisters as ordinary trash.

DO turn in damaged or unusable canisters to your hazardous waste management office or Defense Reutilization andMarketing Office (DRMO).

FIRST AID

For first aid refers to FM 21-11.

SAFETY DATA SHEETS

http://www.apgea.army.mil/RDA/pmnbc/c2aldisp.html

TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

TECHNICAL MANUAL

DEPARTMENT OF THE ARMYAND HEADQUARTERS, MARINE CORPS

Washington, D.C., 1 AUGUST 1998

UNIT MAINTENANCE MANUAL

(INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST)

FOR

CHEMICAL BIOLOGICAL MASK: FIELD M40A1

(4240-01-370-3821--SMALL)(4240-01-370-3822--MEDIUM)(4240-01-370-3823--LARGE)

CHEMICAL BIOLOGICAL MASK: COMBAT VEHICLE M42A2

(4240-01-413-4100--SMALL)(4240-01-413-4101--MEDIUM)(4240-01-413-4102--LARGE)

REPORTING ERRORS AND RECOMMENDING IMPROVEMENTS

You can help improve this manual. If you find any mistakes or if you know of a way to improve the procedures, please let usknow. Mail you letter, DA Form 2028 (Recommended Changes to Publications and Blank Forms), or DA Form 2028-2located in the back of this manual direct to: Technical Director, U.S. Army, Edgewood Research, Development &Engineering Center, ATTN: SCBRD-ENL-V, Aberdeen Proving Ground, MD 21010-5423.

Marine Corps Users - Submit NAVMC FORM 10772 directly to Commander, Marine Corps Logistics Base (Code 850), 814Radford Blvd, AIbany, GA 31704-5000. In addition, a copy of the NAVMC 10772 or naval message should be sent toMARCORSYSCOM (Code CSLENBC), 2033 Barnett Ave., Suite 315, Quantico, VA 22134-5010.

In either case, a reply will be sent to you.

i

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TABLE OF CONTENTS

HOW TO USE THIS MANUAL .................................................................................................................. iii

CHAPTER 1 INTRODUCTION.................................................................................................................. 1-1

SECTION I. GENERAL INFORMATION .................................................................................................. 1-1

SECTION II. EQUIPMENT DESCRIPTION AND DATA ............................................................................ 1-2

SECTION III. PRINCIPLES OF OPERATION ........................................................................................... 1-12

CHAPTER 2 UNIT MAINTENANCE INSTRUCTION................................................................................. 2-1

SECTION I. REPAIR PARTS, SPECIAL TOOLS, TMDE, AND SUPPORT EQUIPMENT........................... 2-3

SECTION II. SERVICE UPON RECEIPT .................................................................................................. 2-3

SECTION III. EQUIPMENT/USER FITTING INSTRUCTIONS................................................................... 2-19

SECTION IV. TROUBLESHOOTING ........................................................................................................ 2-29

SECTION V. PREVENTIVE MAINTENANCE CHECKS AND SERVICES.................................................. 2-39

SECTION VI. HOSE ASSEMBLY CONVERSION ..................................................................................... 2-45

SECTION VII. MAINTENANCE PROCEDURES ....................................................................................... 2-53

SECTION VIII. CLEANING AND SANITIZING........................................................................................... 2-77

SECTION IX. PREPARATION FOR STORAGE OR SHIPMENT .............................................................. 2-95

APPENDIX A - REFERENCES ................................................................................................................ A-1

APPENDIX B - MAINTENANCE ALLOCATION CHART (MAC) ............................................................... B-1

APPENDIX C - UNIT MAINTENANCE REPAIR PARTS AND SPECIAL TOOLSLIST ......................................................................................................................... C-1

APPENDIX D - EXPENDABLE AND DURABLE ITEMS LIST .................................................................. D-1

CROSS-REFERENCE INDEXES ............................................................................................................. I-1

INDEX....................................................................................................................................................... INDEX 1

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HOW TO USE THIS MANUAL

The safest, easiest, and best way to do maintenance on the Chemical-Biological Mask, M40A1/M42A2 is to use this manual.Learning to use this TM is as easy as reading through the next few pages. Knowing what's in this manual and how to use itwill save you time and work, and will help you avoid exposing yourself to unnecessary hazards while you do your job.

ORGANIZATION

Page ii has a table of contents to provide easy access to the manual. Pages are numbered consecutively within eachchapter; each page number is prefixed with a chapter number or appendix letter. For example, page 5 of Chapter 2 isnumbered 2-5 and page 3 of appendix B is numbered B-3.

This manual is divided into two chapters, four appendixes, and an alphabetical index. Chapter 2 has an index at thebeginning of the chapter to provide easy access to its content. Each chapter is divided into sections. Chapter 1 containsgeneral information pertaining to location of forms, destruction of Army material, how to store and ship the mask, proceduresfor reporting any improvement recommendations you may have, as well as, corrosion prevention and control. Chapter 2gives unit maintenance instructions and includes four types of maintenance activities. These are: Service Upon Receipt;Troubleshooting or location of faults by symptoms you can detect; Preventive Maintenance Checks and Service (PMCS);and Maintenance Procedures that are used to correct faults and replace failed parts. Within the Troubleshooting andmaintenance portions of this manual, you will find the material in functional group code order like the Maintenance AllocationChart in Appendix B of this TM. This allows the TM to be aligned with its applicable Repair Parts and Special Tools List(RPSTL). For information on how to use the RPSTL, refer to the introduction in Appendix C.

Each section in this manual is further divided into three parts. The first addresses procedures which are the same regardlessof which mask you are using. The second part addresses those tasks which are peculiar to the M40A1 and the thirdaddresses those peculiar to the M42A2. Therefore, depending on which mask you are using, you must follow theinstructions in the general part and the part which is peculiar to your mask.

For instance, if you have the M40A1 mask, you must do the Before PMCS checks under COMMON and those checks listedunder M40A1 PECULIAR Those tasks listed under M42A2 PECULIAR are not required.

Those tasks which are considered to be COMMON and apply to either mask are illustrated using the M42A2.

However, the differences between the M40A1 and M42A2 do not impact on the task, and, in many cases, you willnot be able to tell from the illustration which mask is being illustrated.

HOW TO FIND PROCEDURES

If you're using the manual to perform Troubleshooting, go to Section IV, and read TROUBLESHOOTING PROCEDURESand proceed according to the instructions there. If you're going to do Scheduled Maintenance, you can turn directly toPreventive Maintenance Checks and Services (PMCS), Section V, and proceed according to the instructions there.

If you are using the manual to perform repair or replacement of a part that you already know is bad, you would start bylocating the part to be replaced in the Alphabetical index located at the back of this manual. Look in the Alphabetical Indexfor a key noun from the mask system or part nomenclature. The Alphabetical Index lists each task under one or moreheadings also giving the location for the installation and removal of some part. For example, the procedure for CLEANINGAND SANITIZING would be listed under "C" for Cleaning.

Once you've located the correct procedure, read through it to determine if you have everything you need to perform the job.Make sure all the Equipment Conditions have been met. Familiarize yourself with the potential hazards described by theWARNINGS and CAUTIONS. You must familiarize yourself with the entire maintenance procedure before beginning themaintenance task.

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HOW TO USE A MAINTENANCE PROCEDURE

The first page of a maintenance procedure lists everything you will need to perform that procedure. The followingparagraphs describe all the blocks of information you will find there.

TOOLS. Individual tools from your mechanic's tool kit will not be listed under this heading. If any tools from this kit arerequired, the tool kit itself will be listed as the first item. Special tools, and tools from any other source will be listed with areference to a specific item and appendix number. The referenced appendix will provide you with the necessary informationto find or make the tool.

SUPPLIES. If any expendable or consumable supplies are needed to perform the task, they will be listed under this headingalong with the quantity in parentheses and a reference to a figure item and appendix in the back of the TM. The referencedappendix will give you the detailed information necessary to requisition the supply if you don't have it on hand. Replacementparts are not normally listed under this heading. The inspection steps in the removal or disassembly procedure will tell youwhich parts to replace. Mandatory repair parts ( parts that are destroyed in disassembly or not normally reused, such asgaskets and lock washers) are listed under this heading by their nomenclature only. Refer to Repair Parts and Special ToolsList (RPSTL), Appendix C for information you need on repair parts.

iv (v blank)

TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

CHEMICAL BIOLOGICAL MASKS

M40A1

M42A2

1-0

TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

CHAPTER 1INTRODUCTION

SECTION I. GENERAL INFORMATION

1-1. SCOPE

a. Type of Manual. Unit maintenance.b. Model Numbers and Equipment Name. Chemical-biological (CB ) mask: field M40AI, and CB mask combat vehicle

M42A2.c. Purpose of Equipment. Protects the face, eyes, and lungs from field concentrations of CB agents, toxins, and

radioactive fallout particles.

1-2. MAINTENANCE FORMS, RECORDS, AND REPORTS

a. Department of the Army forms and procedures used for equipment maintenance will be those prescribed by DAPAM 738-750, The Army Maintenance Management System (TAMMS), as contained in the MaintenanceManagement update.

b. Marine Corps forms and procedures used for equipment maintenance are prescribed in TM 4700-15/1_.

1-3. DESTRUCTION OF ARMY MATERIAL TO PREVENT ENEMY USE

Refer to TM 43-0002-31 for methods of destruction.

1-4. PREPARATION FOR STORAGE OR SHIPMENT

Refer to Chapter 2, Section IX, for preparation for storage or shipment.

1-5. REPORTING EQUIPMENT IMPROVEMENT RECOMMENDATIONS (EIR)

a. If you have ideas on how the M40A 1 or the M42A2 masks can be changed or maintained more effectively, let usknow. Send us an EIR. You, the user, are the only one who can tell us what you don't like about your equipment. Letus know why you don't like the design. Put it on an SF 368 (Quality Deficiency Report). Mail it to us at Director, USArmy Armament and Chemical Acquisition and Logistics Activity, ATTN: AMSTA-AR-QAW-A (RI), Rock Island, IL61299-7630. We'll send you a reply.

b. Marine Corps users shall submit a Standard Form 368 (SF368) in accordance with MCO4855. 10 directly to:Commander, Marine Corps Logistics Base (Code 856), 814 Radford Blvd., Albany, GA 31704-5000. We will sendyou a reply.

1-6. CORROSION PREVENTION AND CONTROL (CPC)

a. CPC of Army material is a continuing concern. It is important that any corrosion problems with this item be reportedso that the problem can be corrected and improvements can be made to prevent the problem in future items.

b. While corrosion is typically associated with rusting of metals, it can also include deterioration of other materials suchas rubber and plastic. Unusual cracking, softening, swelling, or breaking of these materials may be a corrosionproblem.

c. If a corrosion problem is identified, it can be reported using a Quality Deficiency Report, SF 368. Use of key wordssuch as "corrosion", "rust", "deterioration", or "cracking" will assure that the information is identified as a CPCproblem.

d. The form should be submitted to Director, US Army Armament and Chemical Acquisition and Logistics Activity,ATTN: AMSTA-AR-QAW-A (RI), Rock Island, IL 61299-7630.

e. Marine Corps Units report CPC problems using SF 368 and procedures prescribed in TM 4700-15/1_.

1-1

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SECTION II. EQUIPMENT DESCRIPTION AND DATA1-7. EQUIPMENT CHARACTERISTICS, CAPABILITIES, AND FEATURES.

COMMON

The lightweight, CB masks (M40A1 / M42A2 ) are easy to assemble for transport and storage. The mask assembly is keptdry, when required by climate and mission, by a waterproof bag and stored in a carrier made of mildew-resistant, waterrepellent, coated nylon.

The facepiece is made of silicone rubber with an inturned sealing surface so it can provide protection to face, eyes, andrespiratory tract from CB agents, toxins and radioactive particles. The mask assembly is not intended for use in an oxygendeficient environment. Nor is it intended to provide protection against carbon monoxide or ammonia It forms a comfortableseal on a soldier's face as it protects against adverse elements. The mask assembly is equipped with both front and sidevoicemitters for ease of communication and an outlet valve body with a drinking system. To ensure a comfortable fit, themask assembly is issued in three sizes: small, medium and large which are marked with S, M and L on the forehead toshow sizing. It is also equipped with clear and neutral gray outserts to protect the eyelens from scratches, reduce sun glareand prevent fogging in cold weather.

The masks have a second skin, universal second skin, or universal second skin (USMC) which fits to the facepiece andprotects the facepiece from liquid agents, and a quick doff hood made of lightweight, butyl rubber-coated fabric, whichprovides protection to the head and neck from liquid toxic chemical agents. The second skin, universal second skin, oruniversal second skin (USMC) is issued in two sizes: small and medium/large which are marked S and M/L on the exteriorleft cheek.

M40A1 PECULIAR

The CB mask, M40A1, consists of a facepiece and filter canister.

M42A2 PECULIAR

The CB mask, M42A2, consists of a facepiece, canister carrier and hose assembly . The M42A2 masks has microphonecommunication capability that can couple with on board communication systems, through the Combat VehicleCommunications (CVC) helmet.

1-8. LOCATION AND DESCRIPTION OF MAJOR COMPONENTS

COMMON

a. FACE PIECE ASSEMBLY

FACEPIECE (1). The following components are molded/assembled into the silicone rubber facepiece: buckle tabs,facepiece openings for eyelens, nosecup, voicemitters, outlet valve, and filter canister/hose connectors.

HEAD HARNESS (2). Constructed of elastic webbing sewn to a rectangular head pad and buckled to facepiece.The ends of the head harness straps have metal strap end clips to prevent fraying of the elastic webbing. Ends ofthe head harness straps pass through buckles at the two forehead, temple and cheek positions. Elastic webbingconnects the two forehead straps and holds them in proper alignment when the mask assembly is worn. Headharness straps attached to buckles at the ends of the tabs permit adjustment to obtain proper fit of the maskassembly.

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

NOSECUP ASSEMBLY (3). Made of soft rubber, fits over the soldier's nose and mouth. Diverts exhaled air towardthe outlet valve to reduce fogging of the eyelens.

NOSECUP VALVE SEATS (4). Each of two nosecup valve seats holds silicone rubber NOSECUP VALVE DISK (5),which allows filtered air to enter nosecup and prevent moist exhaled air from fogging the eyelens in cold weather.

INTERNAL DRINK TUBE (6). Allows the soldier to drink while wearing the mask assembly.

AIRFLOW DEFLECTOR (7), located inside the mask assembly, directs inhaled air over eyelens to reduce fogging.The airflow deflector also supports the inlet valve disk and the inlet valve body.

INLET VALVE BODY (8) and INLET VALVE DISK (9), fits into the airflow deflector, allows filtered air to enter themask assembly and prevent moist exhaled air from entering the filter canister.

OUTLET VALVE COVER (10). Protects outlet valve disk and outlet valve housing from damage.

RETAINER (11). Holds external drink tube quick disconnect coupling.

OUTLET VALVE DISK (12) and OUTLET VALVE HOUSING (13). Located behind outlet valve cover; releasesexhaled air and closes on inhalation to prevent contaminated air from entering mask assembly.

FRONT (14) AND SIDE VOICEMITTERS (15). Transmits the soldier's voice outside the mask assembly.

EXTERNAL DRINK TUBE (16). The External Drink Tube is used to connect the mask assembly to the M1 Canteencap for drinking. It consists of a length of hose and a quick disconnect coupling half (17) that fits into the externaldrink tube retainer.

DURABILITY ENHANCEMENT BAND (18). Band placed around outlet valve housing to ensure seal is maintained.

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1-8. LOCATION AND DESCRIPTION OF MAJOR COMPONENTS (CONT)

COMMON (CONT)

b. FILTER CANISTER (19) filters out CB agents and other particles from contaminated air.

NOTEThe soldier may be issued either the one piece hood OR the quick doff hood andsecond skin OR universal second skin and quick doff hood or hooded over-garment OR the universal second skin (USMC) and hooded overgarment. Theyare identical in function and effectiveness. However, the one piece hood may notbe removed during decon operations.

c. ONE PIECE HOOD (20). Provides protection to the head and neck against liquid toxic chemical agents encounteredin field operations. Made of lightweight butyl rubber-coated fabric. It is attached to the mask assembly during useand stowed in mask carrier.

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d. QUICK DOFF HOOD.

QUICK DOFF HOOD (21). Is made of butyl rubber-coated fabric, which protects area of neck and head that is notcovered by mask assembly against CB agents, toxins, and radioactive fallout particles.

ELASTIC AROUND OPENING (22). Attaches quick doff hood to the second skin. It enables easy removal of thequick doff hood.

ELASTIC AROUND NECK (23). Draws quick doff hood close to the neck to protect from CB agents.

UNDERARM STRAPS (24). Retain quick doff hood on the shoulders. Plastic fasteners (25) are used to attach thestraps.

e. UNIVERSAL SECOND SKIN (26). Is made of butyl rubber and covers the mask assembly. It provides additionalprotection against liquid agents. (Rubber catches and ridges are no longer needed because the universal secondskin is now larger.)

Interfaces with hooded overgarments.

Extends beyond the mask assembly.

Interfaces with QDH..

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1-8. LOCATION AND DESCRIPTION OF MAJOR COMPONENTS--(CONT )

COMMON (CONT)

f. SECOND SKIN ( M40A 1/ M42A2).

SECOND SKIN (27). Is made of butyl rubber, and covers the mask assembly. It provides additional protectionagainst liquid agents.

RUBBER CATCHES (28). Used to retain the quick doff hood on the mask assembly.

The RIDGE (29) is also used to retain the quick doff hood.

g. UNIVERSAL SECOND SKIN (USMC only) (30). Is made of butyl rubber and covers the facepiece. It providesadditional protection against liquid agents. (Rubber catches and ridges are no longer needed because the universalsecond skin is now larger.)

Interfaces with hooded overgarments.

Extends beyond the mask facepiece.

Interfaces with the QDH.

h. Outserts have RUBBER RINGS (31) that fit over mask assembly eyelens rings to secure outserts to maskassembly. The CLEAR OUTSERTS (32) and NEUTRAL GRAY OUTSERTS (33) prevent scratching of eyelensfrom scratches and reduce fogging of eyelens in cold weather. The neutral gray outserts are used to reduce sunglare.

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i. M1 WATERPROOF BAG (34). The folded waterproof bag and a small envelope containing the RUBBER BANDS(35) are packed in carrier. The waterproof bag keeps the mask dry when required by climate and mission.Instructions for use are printed on the waterproof bag.

j. FACEFORM(36)

Holds mask assembly in proper shape when stored longer than 30 days.

M40A1 PECULIAR

NOTEThe soldier may be issued either mask carrier. Major differencesare size and accessory stowage locations.

k. Mask Carrier is made of mildew-resistant, water-repellant fabric. It has adjustable straps. It is closed with a flap heldby hook and pile material.

IMPROVED FIELD MASK CARRIER (37) is designed to serve the field mask only. It has a larger velcro closingsurface, the AQD opening has been eliminated, the ID area is now camouflaged, the stiffeners have been removed,it is wider and not as deep, and the interior pockets are larger.

FIELD MASK CARRIER (38) was designed to serve field and combat vehicle masks.

1-7

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1-8. LOCATION AND DESCRIPTION OF MAJOR COMPONENTS--(CONT )

M42A2 PECULIAR

I. DETACHABLE MICROPHONE (39). Located in the recess of the front voicemitter.

j. CANISTER CARRIER Improved (40) - Original (41)

NOTEYou may have been issued the original canister carrier or theproduct improved model of the canister carrier. They areinterchangeable.

The IMPROVED CANISTER CARRIER (40) is larger and interfaces with the a C2/C2A1 filter canisters, as well as, avariety of North Atlantic Treaty Organization (NATO) filter canisters. The cover now screws on rather than attachingwith lug bolts, there is now a slip ring within the cover and the AQD is detachable and rotates.

The ORIGINAL CANISTER CARRIER (41) interfaces with the C2/C2AI filter canisters only.

ARMOR QUICK DISCONNECT (42). Attached to the canister cover (43) and permits the filter canister to be coupledto a vehicle's Gas Particulate Filter Unit (GPFU).

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c. HOSE ASSEMBLY (44). The hose assembly connects the filter canister and canister carrier to the mask assembly.

M42A2 - The hose assembly is attached to the mask assembly with the STAR KNOB (45). The hose assembly isremovable and can be relocated on left or right side of the mask assembly.

NOTEThe soldier may be issued either mask carrier. Major differencesare size and accessory stowage locations.

d. Mask Carrier is made of mildew-resistant, water-repellant fabric. It has adjustable straps. It is closed with a flap heldby hook and pile material.

COMBAT VEHICLE MASK CARRIER (46). This mask carrier has been redesigned. It is now shaped to aid instowing the filter canister and hose, the velcro closing area has been enlarged to prevent dirt from entering themask carrier, the exterior pouch has been removed, the ID area is now camouflaged, the stiffeners have beenremoved and the interior pockets are larger. It was designed to serve the combat vehicle mask only.

FIELD MASK CARRIER (47) was designed to serve field and combat vehicle masks.

1-9

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1-9 DIFFERENCE BETWEEN MODELS

This chart shows major equipment and differences between the M40A1 and M42A2.

Table 1-1. Differences Between Models

MASK FEATURESCHEMICAL

BIOLOGICAL MASK

M40A1 M42A2

Facepiece

Filter canister is connected to end coupling of hose assembly

Detachable star knob hose assembly

Filter Canister attached directly to facepiece

Hood (One-Piece)

Quick Doff Hood

Second Skin

Universal Second Skin

Universal Second Skin (USMC only)

Clear/Neutral Outserts

Detachable Microphone (External)

Front and Side Voicemitter

Field Mask Carrier

Improved Field Mask Carrier

Combat Vehicle Mask Carrier

Operation Capabilities:

Combat Vehicle

Transportable and stored in carrier

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

1-10

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1-10EQUIPMENT DATA

a. Tabulated Data

Weight (with carrier and accessories):

M40A1 mask. 3.8 lbs. (1.73 kg)

M42A2 mask. 4.5 lbs. (2.05 kg)

Dimensions:

M40A1 mask Mask with carrier...12 x 14 x4.5 in. (30.5 x 35.6 x 11.4 cm.)

M42A2 mask Mask with carrier...12x 14 x4.5 in. (30.5 x 35.6 x 11.4 cm.)

b. Shipping and Storage Data.

Shipping and Storage Data is identical for the M40A1 and M42A2 masks.

Number and type of pack: 10 per fiberboard container, 1 per fiberboard box.

Fiberboard container:

Dimensions: 34.375 x 22 x 16.75 in. (87 x 55.9 x 425 cm)

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SECTION III. PRINCIPLES OF OPERATION

1-11PRINCIPLES OF OPERATION

a. M40A1 PRINCIPLES OF OPERATION

(1).Air enters the FILTER CANISTER (1), which is screwed into the side of the mask. The filter canister filters out CBagents, toxins, and radioactive fallout particles from contaminated air. Air then passes over the AIRFLOWDEFLECTOR (2) which is located inside the facepiece and on the same side as the filter canister. The air thenmoves into the eye area of the facepiece.

(2).From the eye area, air enters the NOSECUP (3) through NOSECUP VALVES (4). Filtered air from the nosecup isinhaled by the soldier. Exhaled air is passed through the nosecup area and out through the OUTLET VALVE (5).The OUTLET VALVE COVER (6) protects the outlet valve from contamination and damage, and provides a retainerfor the external drink tube.

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b. M42A2 PRINCIPLES OF OPERATION

(1). Air enters the filter canister, which is held in the CANISTER CARRIER (7). The filter canister filters out CB agents,toxins, and radioactive fallout particles from contaminated air. Air then passes through the HOSE (8) andDEFLECTOR (9) which is located inside the mask assembly and on the same side as the hose assembly. The airthen moves into the eye area of the mask assembly.

(2). From the eye area, air enters the NOSECUP (10) through NOSECUP VALVES (11). Filtered air from the nosecup isinhaled by the soldier. Exhaled air is passed through the nosecup area and out through the OUTLET VALVE (12).The OUTLET VALVE COVER (13) protects the outlet valve from contamination and damage, and provides aretainer for the external drink tube.

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CHAPTER 2 UNIT MAINTENANCE INSTRUCTIONS

Table of Contents

Para. Page

SECTION I. REPAIR PARTS, SPECIAL TOOLS, TMDE, AND SUPPORT EQUIPMENT ...............2-3

2-1. COMMON TOOLS AND EQUIPMENT...................................................................................................................2-3

2-2. SPECIAL TOOLS, TMDE, AND SUPPORT EQUIPMENT......................................................................................2-3

2-3. REPAIR PARTS.....................................................................................................................................................2-3

SECTION II. SERVICE UPON RECEIPT ..........................................................................................2-3

2-4. GENERAL..............................................................................................................................................................2-3

2-5. SERVICE UPON RECEIPT OF MATERIAL............................................................................................................2-3

2-6. IDENTIFYING AN INDIVIDUAL'S MASK..............................................................................................................2-18

SECTION III. EQUIPMENT/USER FITTING INSTRUCTIONS........................................................2-19

2-7. ADJUSTING MASK ASSEMBLY AT INITIAL FITTING..........................................................................................2-19

2-8. CHECKING MASK ASSEMBLY FOR PROPER FUNCTION.................................................................................2-23

2-9. CHECKING DRINKING SYSTEM FOR PROPER FUNCTION..............................................................................2-28

SECTION IV. TROUBLESHOOTING..............................................................................................2-29

2-10. TROUBLESHOOTING PROCEDURES..............................................................................................................2-29

SECTION V. PREVENTIVE MAINTENANCE CHECKS AND SERVICES (PMCS) .......................2-39

2-11. INTRODUCTION TO PMCS TABLE...................................................................................................................2-39

2-12. PMCS PROCEDURES.......................................................................................................................................2-39

SECTION VI. CONVERSION PROCEDURES................................................................................2-45

2-13. LEFT/RIGHT FILTER CANISTER/HOSE ASSEMBLY CONVERSION................................................................2-45

2-14. M40A1 TO M42A2 CONVERSION.....................................................................................................................2-51

2-15. M42A2 TO M40A1 CONVERSION.....................................................................................................................2-52

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Table of ContentsPara Page

SECTION VII. MAINTENANCE PROCEDURES ............................................................................2-53

2-16. GENERAL..........................................................................................................................................................2-53

COMMON TASKS

2-17. INTERNAL DRINK TUBE...................................................................................................................................2-54

2-18. QUICK DISCONNECT COUPLING, EXTERNAL DRINKTUBE...........................................................................2-56

2-19. HEAD HARNESS...............................................................................................................................................2-57

2-20. NOSECUP VALVE DISKS.................................................................................................................................. 2-58

2-21. AIRFLOW DEFLECTOR, INLET VALVE, AND VALVE BODY............................................................................2-59

2-22. OUTLET VALVE COVER AND OUTLET VALVE DISK.......................................................................................2-63

2-23. SIDE VOICEMITTER, VOICEMITTER RETAINER, AND GASKET.....................................................................2-65

2-24. INTERNAL DRINKTUBE NIPPLE.......................................................................................................................2-66

2-25. OPTICAL INSERT KIT.......................................................................................................................................2-68

M40A1 PECULIAR TASKS

2-26. M40A1 FACEPIECE...........................................................................................................................................2-73


2-27. M42A2 FACEPIECE...........................................................................................................................................2-74

2-28. CLAMP COVER.................................................................................................................................................2-75

2-29. PORT GASKET..................................................................................................................................................2-76

SECTION VIII. CLEANING AND SANITIZING...............................................................................2-77

2-30. CLEANING M40A1.............................................................................................................................................2-77

2-31. SANITIZING M40A.............................................................................................................................................2-81

2-32. CLEANING M42A2.............................................................................................................................................2-85

2-33. SANITIZING M42A2...........................................................................................................................................2-91

SECTION IX. PREPARATION FOR STORAGE OR SHIPMENT ...................................................2-95

2-34. PREPARATION FOR STORAGE OR SHIPMENT..............................................................................................2-95

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CHAPTER 2UNIT MAINTENANCE INSTRUCTIONS

SECTION I. REPAIR PARTS, SPECIAL TOOLS, TMDE, AND SUPPORTEQUIPMENT

2-1. COMMON TOOLS AND EQUIPMENT

For authorized common tools and equipment, refer to the Modified Table of Organization and Equipment(MTOE) applicable to your unit.

2-2. SPECIAL TOOLS, TMDE, AND SUPPORT EQUIPMENT

Special tools, TMDE, and support equipment required are listed in Appendix C-Repair Parts and Special ToolsList (RPSTL) and Appendix B-Maintenance Allocation Chart (MAC).

2-3. REPAIR PARTS

Repair parts are listed and illustrated in Appendix C of this manual.

SECTION II. SERVICE UPON RECEIPT

2-4. GENERAL

This section contains instructions and procedures for services to be performed upon receipt of a new mask.These services include unpacking and checking the mask.

2-5. SERVICE UPON RECEIPT OF MATERIAL

a. Table 2-1 contains instructions for performing the services required upon receipt of the M40A 1 mask.b. Table 2-2 contains instructions for performing the services required upon receipt of the M42A2 mask.

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2-5 SERVICE UPON RECEIPT OF MATERIAL

Table 2-1. Service upon receipt -- M40A1 Mask

LOCATION ITEM ACTION REMARKS

UNPACKING

1. OUTER BOX,FIBERBOARD OFWOOD, ASAPPLICABLE

2. INNERFIBER-BOARDBOX

Flaps (fiberboard box) ortop (wood box)

a. Facepiece/second skinassembly.

WARNINGAfter removing the top of a woodbox, remove nails or bend nails toprevent injury.

NOTEIf possible, retain shipping boxesfor possible future turn-ins.

Open box by cutting tape andbanding on fiberboard boxes orremove top by cutting bandingand prying open top of woodboxes. Remove nails or bendnails over to prevent injury.Remove inner fiberboard boxes.Remove barrier bar aroundfacepiece folder.

NOTESecond skin is packaged on top ofthe facepiece in the facepiece/second skin or universal secondskin assembly.

Open inner box (1). Remove thefacepiece/universal second skinor second skin assembly (2). Takethe facepiece/universal secondskin or second skin assembly outof the sealed bag and discard thebag. Remove universal secondskin (3) or second skin (4).

NOTEMasks stored more than 30 daysshall be stored with faceform infacepiece. Keep all faceforms. DoNot Discard.

Loosen head harness straps offacepiece (5) and removeclamshell (6) and faceform (7).Cut tabs (8) where indicated.Store at organization level.Discard clamshell.

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UNPACKING (CONT)

2.INNER FIBER-BOARD BOX (CONT)

b. Fiberboard separator:hood assembly, filtercanister, outserts.

Remove protective polycovering(9) from eyelenses (10) by pullingcovering away from eyelens tostretch, then forward to remove.Discard protective covering.

Remove fiberboard separator(11).

Take quick doff hood (12) out ofheat-sealed bag and discard bag.

Store unopened canisters (13)until issued. Record lot number ofcanister in accordance with unitSOP.

Take clear (14) and neutral gray(15) outserts out of heat-sealedbags and discard bags.

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2-5 SERVICE UPON RECEIPT OF MATERIAL (CONT)



UNPACKING (CONT

INSPECTION

c. Poly-bag Mask Carrier

d. Waterproof bag

e. Heat sealed bag-manual

Take improved field mask carrier(16) out of bag and discard bag.Take field mask carrier (17) out ofbag and discard bag.

Remove waterproof bag (18) inself-sealing plastic bag. Checkthat three rubber bands (19) areincluded.

Take manual (20) out of heat-sealed bag. Bag may be retainedto protect manual.

Inspect equipment for damageincurred during shipment. Ifequipment has been damaged,report the damage on SF 364,Report of Discrepancy (ROD).Check equipment against packingslip to see if shipment is complete.Report all discrepancies inaccordance with the instructionsof DA PAM 738-750.

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PREPARINGTO STOWTHE MASK CARRIER

a. Universal second skin orsecond skin

b. Clear outserts

c. Mask Assembly

d. Mask Assembly (22)(mask assembly, hood,head harness andfaceform).

e. Mask Assembly (23)(mask assembly, headharness and faceform). (Foruse with hoodedovergarments.) (USMConly)

Install universal second skin (3) orsecond skin (4) on facepiece (seeOperator's Manual).

Install clear Outserts (15) onfacepiece (see Operator'sManual).

Record alphanumeric number (21)in a property book or log IAW unitSOP.

Place faceform (7) into maskassembly. Place neatly foldedquick doff hood ( 12) into back offaceform. Tighten head harness tohold quick doff hood.

Place faceform into maskassembly. Tighten head harnessto hold facefom

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

2-5 SERVICE UPON RECEIPT OF MATERIAL (CONT)



STOWING IMPROVEDFIELDMASK CARRIER

a. Waterproof bag

b. Neutral gray outserts

c. Operator's manual

d. Mask Assembly

a. Install waterproof bag (18 )inside left end pocket.'

b. Install neutral gray outserts (14)in left back pocket.

c. Pack operator's manual (20) inthe right back pocket.

d. Store the mask assembly (22).

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2



STOWINGFIELDMASKCARRIER

a. Waterproof bag


c. Operator's manual

d. Mask Assembly

a Install waterproof bag (18 )inside left back pocket.

b. Install neutral gray outserts (14)in back middle pocket.

c. Pack operator's manual (20) inthe right back pocket.

d. Store the mask assembly (22).

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

2-5. SERVICE UPON RECEIPT OF MATERIAL (CONT)



UNPACKING

1. OUTERBOX,FIBERBOARD ORWOOD, ASAPPLICABLE

2. INNER FIBER-BOARD BOX

Flaps (fiberboard box) ortop (wood box)

a. Facepiece fiberboardfolder, outserts, and secondskin or universal secondskin.

WARNINGAfter removing the top of a woodbox, remove nails or bend nails toprevent injury.

NOTEIf possible, retain some shippingboxes for possible future turn-ins.Open box by cutting tape andbanding on fiberboard boxes orremove top by cutting bandingand prying open top of woodboxes. Remove nails or bendnails over to prevent injury.Remove inner fiberboard boxes.Remove barrier bar aroundfacepiece folder.

NOTESecond skin, or universal secondskin is packaged on top of thefacepiece in the facepiece holder.

Take clear (1) and neutral gray (2)outserts out of bags and discardbags.

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UNPACKING (CONT)

2. INNER FIBER-BOARDBOX (CONT)

a. Facepiece fiberboardfolder, outserts, and secondskin, or universal secondskin. (Cont)

b. Facepiece and faceform.

c. Mask Carrier

NOTEMasks stored more than 30 daysshall be stored with faceform inmask assembly. Keep allfaceforms. Do Not Discard.

Remove facepiece folder (3).Remove facepiece (4) anduniversal second skin (5), orsecond skin (6) and discard bothfolder and bag.

Loosen head harness straps offacepiece (7) and removeclamshell (8) and faceform (9).Cut tabs (10) where indicated.Store faceform at organizationlevel. Discard clamshell.

Remove protective poly-covering(11) from eyelenses (12) bypulling covering away fromeyelens to stretch, then forward toremove. Discard protectivecovering.

Take combat vehicle mask carrier(13) out of bag and discard bag.

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Table 2-2. Service upon receipt -- M42A2 Mask (Cont)


UNPACKING (CONT) d. Mask Carrier.

e. Quick doff hood(M42AI/M42A2).

f. Detachable microphone(M42A2).

Take field mask carrier (14) out ofbag and discard bag.

Take quick doff hood (15) out ofbag and discard bag.

Take detachable microphone (16)out of bag and discard bag.

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2



UNPACKING(CONT)

h. Canister Carrier

i. Vacuum sealed cancontaining filter canister.

j. Hose assembly

k. Waterproof bag

l. Heat sealed bag-manual

Take canister carrier (17) out ofbag and discard bag.

Store unopened can (18) until is-Sued. Record lot number of filtercanister in accordance with unitSOP.

Take hose assembly (19) out ofbag and discard bag.

Remove waterproof bag (20) fromplastic bag and discard plasticbag. Check that three rubberbands (21) are included.

Take manual (22) out of bag. Bagmay be retained to protectmanual.

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INSPECTION

PREPARING TO STOWTHE MASK CARRIER

a. Universal second skin orsecond skin

b. Clear outserts

c. Detachable Micro-phone (M42A2).

Inspect equipment for damageincurred during shipment. Ifequipment has been damaged,report the damage on SF 364,Report of Discrepancy (ROD).Check equipment against packingslip to see if shipment is complete.Report all discrepancies inaccordance with the instructionsof DA PAM 738-750.

Install universal second skin (5)(see Operator's Manual) orsecond skin (6) (see Operator'sManual) on facepiece.

Install clear Outserts (1) onfacepiece (see Operator'sManual).

Attach detachable microphone(16) to front voicemitter opening offacepiece (see Operator'sManual).

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PREPARING TO STOWTHE MASK CARRIER(CONT)

d. Mask assembly

e. Hose Assembly

f. Mask assembly (24)(mask assembly, hood,head harness and face-form).

g. Mask assembly (25)(mask assembly, hood,head harness and face-form). (For use with hoodedovergarments.)(USMC only)

Record 13 digit alphanumericnumber (23) in a property book orlog IAW unit SOP.

Attach the hose assembly (19) tothe mask assembly (4) (seeOperator's Manual).

Place faceform (9) into maskassembly. Place neatly foldedquick doffhood (15) (M42A1/M42A2) into back of faceform.Tighten head harness to holdquick doff hood.

Place faceform into maskassembly. Tighten head harnessto hold faceform.

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STOWING THECOMBAT VEHICLEMASK CARRIER

a. Waterproof bag


c. Manual

d. Canister Carrier

e. Mask Assembly

Store waterproof bag (20) in rightpocket.

Store neutral gray outserts (2) inleft pocket.

Store operator's manual (22) inthe middle pocket.

Store the canister carrier (17).

Store the mask assembly (24).

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Table 2-2. Service upon receipt -- M42A2 MaskLOCATION ITEM ACTION REMARKS

STOWING THE FIELDMASK CARRIER

a. Waterproof bag


c. Manual

d. Canister Carrier

e. Mask Assembly

Store waterproof bag (20) ininside left end pocket.

Store neutral gray outserts (2) inleft back pocket.

Store operator's manual (22) inthe right back pocket.

Store the canister carrier (17).

Store the mask assembly (24).

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

2-6. IDENTIFYING AN INDIVIDUAL' S MASK

Although a mask will be used only by the soldier to whom it is issued and fitted, do not make permanent identificationmarking on either mask or mask carrier (AR 700-84). A card may be placed in the exterior side pocket with the soldier'sname or a code number for identification purposes. The date the mask was tested and fitted to the soldier along with the IDcode will be recorded in accordance with local SOP. Include the lot number of the canister and the mask assembly.

Each unit will devise its own code to ensure operational security. Take care not to include any designations that may identifythe parent organization.

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

SECTION III. EQUIPMENT/USER FITTING INSTRUCTIONS

2-7. ADJUSTING MASK ASSEMBLY AT INITIAL FITTING

THIS TASK COVERS: a. Putting on mask assembly b. Adjusting mask assembly c. Checking mask assembly for fit

INITIAL SETUP:

Personnel Required:NBC NCO or other trained personSoldier to be fitted

Applicable Configurations:M40A1/M42A2

Materials/Parts:M41 Protection Assessment Test System (If Available)ORn-Amyl acetate (banana oil) (item 11, app D)ORStannic Chloride (tube smoke) (item 16, app D)

References:TC 3-41

WARNINGBefore putting on and adjusting mask assembly, soldiers shallremove all hairpins, combs, hair knots, buns, or braids that willinterfere with mask assembly seal. Soldiers must be cleanshaven to prevent mask assembly leaks.

DO NOT wear contact lenses (soft or hard) while wearing CBProtective Masks. Inadequate oxygen supply to the cornealsurface, exposure to dust, dirt, and smoke/ gas may causeserious vision loss or eye damage. Soldiers requiring visioncorrection are provided optical inserts for their protective masks.

NOTEInitial mask assembly fitting should be performed by the unit NBC NCO or other trained person.There is no special tool for sizing with the M40A1/M42A2 masks. You will have to use yourjudgement and the guidelines found in this paragraph on size selection. Initial fitting is donewithout the hood installed.

The protective mask fit may be checked by the following equipment/tests. The order of preferencefor mask fitting and testing is the M41 Protection Assessment Test System (PATS) if available, n-Amyl acetate (banana oil), or stannic chloride (tube smoke).

Detailed instructions for checking the fit with the M41 PATS is found in the M41 operator'smanual and in TC 3-41. Detailed instructions for checking the fit with banana oil is in para 2-8 ofthis manual.

After initial fitting of soldier's mask, determine if soldier fires from right or left. Convert maskaccordingly (para 2-13). Determine if soldier requires vision correction and install as required(para 2-25).

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2-7. ADJUSTING MASK ASSEMBLY AT INITIAL FITTING (CONT)

a. PUTTING ON MASK ASSEMBLY

WARNINGEdges of open can are sharp.

1. Use attached key (1) to open canister can (2) and remove filter canister (3).

NOTEOptical inserts should be installed, if required.

2. Install filter canister on mask assembly (4) (M40A1 only).

3. Feed hose end connector (5) through canister carrier (6) (M42A2 only).

4. Install filter canister on hose connector and secure canister carrier cover (7) (M42A2 only).

5. Loosen head harness (8) so that strap ends are approximately 1 in. (2.5 cm) from buckles.

6. Pull head harness over front of mask assembly (9).

7. Hold hair back from sealing area and place chin in the chin pocket (10).

8. Have soldier slip head harness over head while holding mask assembly against face.

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

b. ADJUSTING MASK ASSEMBLY

1. Have soldier hold mask assembly (9) tightly against chin.

2 (NBC NCO) Center head harness pad (11) on back of soldier's head and have soldier hold in place.

3. (NBC NCO) Place finger or thumb under buckle (12) of forehead strap (13). Then give strap end short, sharp tugsuntil buckle feels snug. Adjust other forehead strap in same manner.

4. (NBC NCO) Place finger or thumb under buckle (14) of cheek strap (15) and adjust cheek strap until it feels snug.Adjust other cheek strap in same way.

5. Have soldier release mask assembly. Mask assembly should not slip down. If mask assembly slips, readjustforehead straps and cheek straps until mask assembly remains in place.

6. (NBC NCO) Place finger or thumb under buckle (16) of temple strap (17) and adjust temple strap until buckle feelssnug against finger. Repeat adjustment on other temple strap.

CAUTIONImproperly adjusted internal drink tube may irritate lips if ittouches them while wearing mask assembly.

7. Ask if internal drink tube touches soldier's lips. Adjust length of internal drink tube if necessary (para 2-17).

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

2-7. ADJUSTING MASK ASSEMBLY AT INITIAL FITTING (CONT)

c. CHECKING MASK ASSEMBLY FOR FIT

WARNINGSoldier's safety depends on proper fitting mask assembly.

NOTEWhen doffing mask, only loosen the cheek straps.

1. Edge of mask assembly (9) comes up on forehead but not into hairline and within 1 in. (2.5 cm) of ear.

2 Temple straps (17) and cheek straps (15) do not cut into ears.

3. Soldier's pupils are within the center one-third area (vertical) (18) of the eyelens (19). Adjust optical inserts ifrequired (para 2-25).

4. Mask assembly does not press flesh so tightly that eyes are partly closed.

5. Bottom of mask assembly does not cut into throat.

6. Skin in front of ear is not wrinkled.

7. Nosecup (20) does not obscure vision.

8 If mask assembly still does not meet above standards, try another size mask.

NOTEFOLLOW-ON MAINTENANCE: Check the mask assembly for Proper Function. (para 2-8).

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

2-8. CHECKING MASK ASSEMBLY FOR PROPER FUNCTION

THIS TASK COVERS: a. Testing mask assembly with M41 PATSb. Testing mask assembly with n-Amyl acetate

INITIAL SETUP:


Personnel Required:NBC NCO or other trained personSoldier to be tested

Materials/Parts:M41 PATSApplicator (item 1, app D)n-Amyl acetate (banana oil) (item 11, app D)Rubber gloves (item 8, app D)

References:

TM 3-4240-346- 10/TM09204A/09205A-10/1.TC 3-41Commercial Manual (M41)

NOTEPMCS should be conducted and verified prior to proper function testing.

The order of preference for mask fitting and testing is the M41 Protection Assessment Testsystem (PATS) if available, n-Amyl acetate (banana oil), or stannic chloride (tube smoke).

COMMON

a. TESTING MASK ASSEMBLY WITH M41 PATS

1. Have soldier put on and adjust mask assembly (para 2-7).

2. Refer to TC 3-41 and Commercial Manual for instructions on the use of the M41 PATS.

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2-8. CHECKING MASK ASSEMBLY FOR PROPER FUNCTION (CONT)

COMMON (CONT)

b. TESTING MASK ASSEMBLY WITH N-AMYL ACETATE

WARNINGN-amyl acetate is flammable. DO NOT touch skin (or the soldier)with n-Amyl acetate. It could irritate the skin. Wear rubbergloves. DO NOT smoke around n-Amyl acetate. Keep n-Amylacetate away from an open flame. DO test mask assembly in awell-ventilated room. N-Amyl acetate may be toxic if inhaled inquantity.

NOTESoldier should breathe deeply through nose only. If soldier smells n-Amyl acetate just beforemasking, test results will be inaccurate.

1. Dip applicator in n-Amyl acetate (banana oil).

2. Move applicator approximately 1 to 2 in. (2.5 or 5.1 cm) from mask assembly as follows:

a. Have soldier turn head to left and move applicator completely around outer edge of mask assembly.

b. Have soldier turn head to the right, again move applicator around outer edge of mask assembly.

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

c. Have soldier tilt head upward and turn head from side to side, move applicator under chin around outer edge ofmask assembly.

d. Have soldier tilt head forward, move applicator around outer edge of mask assembly.

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

2-8. CHECKING MASK ASSEMBLY FOR PROPER FUNCTION (CONT)b. TESTING MASK ASSEMBLY WITH N-AMYL ACETATE (CONT)

M40A1 PECULIAR

e. Have soldier smile and frown while looking straight ahead. Move applicator around both eyelenses (1), frontvoicemitter (2), side voicemitter (3), filter canister (4) and outlet valve cover (5).

f. Instruct soldier to press palms firmly over filter canister, but not so firmly that mask assembly is distorted andloses its seal. Have soldier breathe in, creating a vacuum and collapsing mask assembly. Move applicatoraround outer edge of mask assembly before having soldier breathe out.

M42A2 PECULIAR

g. Have soldier smile and frown while looking straight ahead. Move applicator around both eyelenses (1), frontvoicemitter (2), side voicemitter (3), star knob (6), and outlet valve cover (5).

h. To test seal integrity for the connector at each end of the hose assembly, check the clamp cover (7) on eachend of the hose (8).

i. Move applicator around the canister carrier (9).

j. Instruct soldier to press palm firmly over Armor Quick Disconnect Opening (10). Have soldier breathe in,creating a vacuum and collapsing mask assembly. Move applicator around outer edge of mask assembly beforehaving soldier breathe out.

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

NOTEIf soldier being tested smells n-Amyl acetate (banana oil) during initial fitting and testing,a 5-7 minute odor sensitivity recovery period is required before retesting.

4. If soldier can smell n-Amyl acetate, readjust head harness to improve fit (para 2-7) and repeat above check.

5. If soldier cannot smell n-Amyl acetate, have him unmask and smell the applicator to be sure that his sense of smellis not impaired. If soldier's sense of smell is impaired, the mask assembly must be tested in a CS (irritant) chamberor using a smoke tube (item 16, app D) and an aspirator bulb (item 4, app D) containing stannic chloride, whichproduces an irritating acid smoke. The smoke tube test should be conducted in still air in an area that can beventilated.

NOTEFOLLOW-ON MAINTENANCE: Remove mask assembly and stow in carrier in accordancewith TM 3-4240-346-10/TM 09204A/09205A-10.

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

2-9. CHECKING DRINKING SYSTEM FOR PROPER FUNCTION

THIS TASK COVERS: Testing Drinking System

INITIAL SETUP:


Personnel Required:NBC NCO or other trained personSoldier (mask wearer)

TESTING DRINKING SYSTEM

a. Steady mask assembly (1), withdraw quick disconnect coupling half (2) from retainer (3) and let it hang freely.

b. Grasp internal drink tube (4) between your lips.

WARNINGIf resistance is not felt when checking drinking system, the drinking system leaks.

c. Blow into internal drink tube. If resistance is not felt, drink system is leaking.

d. A more positive test may be done on the external drink tube quick disconnect by the following procedure:(1) Fill cup (5) full of water.(2) Place mask assembly on face.(3) Dip quick disconnect in cup filled with water.(4) Blow into internal drink tube.(5) Watch for bubbles in water. If no bubbles, quick disconnect is operational. If bubbles are detected, the

quick disconnect is not operational. (Refer to para 2-18).

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SECTION IV. TROUBLESHOOTING

2-10. TROUBLESHOOTING PROCEDURESa. Perform functional test first. Then use the symptom index for quick access to the troubleshooting procedures.b. The following describes the use of the troubleshooting procedures.

SYMPTOM INDEX PAGE

COMMON

1. Eyelens Fog Excessively.....................................................................................................................2-30

M140A1 PECULIAR

2. Insufficient Air to User.........................................................................................................................2-31

3. Mask Assembly Fails To Seal..............................................................................................................2-32

M42A2 PECULIAR

4. Insufficient Air to User.........................................................................................................................2-35

5. Mask Assembly Fails To Seal..............................................................................................................2-36

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2-10. TROUBLESHOOTING PROCEDURES - (CONT)

COMMON

2-30

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M40A1 PECULIAR

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M40A1 PECULIAR (CONT)

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2-34

TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

M42A2 PECULIAR

2-35

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

2-37

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SECTION V. PREVENTIVE MAINTENANCE CHECKS AND SERVICES(PMCS)

2-11. INTRODUCTION TO PMCS TABLEa. General. Unit PMCS is performed semiannually (every 6 months). The soldier may perform semiannual PMCS

under supervision of NBC NCO or other trained person. Unit PMCS is performed to assure that the moreexperienced NBC NCO regularly checks that the soldier is properly doing daily PMCS. This allows the NBCNCO to perform his responsibilities to assure that: 1. The soldiers are properly performing their daily PMCS; 2.The soldiers are properly performing their monthly PMCS; and 3. That the soldiers are involved in performingthe semiannual PMCS. In addition the NBC NCO is responsible for assuring that those checks identified areperformed on a weekly basis during combat situations. Semiannual PMCS and initial and mandatory fitvalidation M41 test will be scheduled and will be recorded on DD Form 314, Preventive Maintenance Scheduleand Record. The Semiannual PMCS will be completely performed in accordance with the applicable operator'smanual (TM 3-4240-346-10/TM 09204A/09205A-10) and this TM. Marine Corps Users will perform and recordsemiannual maintenance in accordance with procedures prescribed in TM 4700-15/1_ and unit SOP.

b. Inspections. The most detailed inspections and PMCS of the mask is performed when it is first received, aftereach use, semiannually and during the annual fit test. The NBC NCO is involved in all of these inspections. Thisallows the NBC NCO to assure that the operator is properly doing the daily PMCS.

c. WARNINGS and CAUTIONS. It is vital to the safety of the operator and the Unit Maintenance personnel that allWARNINGS and CAUTIONS are followed. It is also the responsibility of the NBC NCO to make sure theoperator understands their importance and follows them very carefully.

d. Training Materials. Training materials are available (see Appendix A).

NOTEConduct an initial and annual fit test of all assigned masks using the ProtectionAssessment Test System (PATS M41), if available, banana oil, or stannic chloride.

2-12. PMCS PROCEDURES

The following paragraphs describe the information presented in each column of the PMCS table.a. Item Number Column. Numbers in this column are for reference. When completing DA Form 2404 (Equipment

Inspection and Maintenance Worksheet), include the item number for the check/service indication at fault. Itemnumbers also appear in the order that you must do checks and services for the intervals listed. Record anyfaults that you discover before, during, or after operation. You DO NOT need to record faults that you fix.

b. Interval. This column of your PMCS table tells you when to do a certain check or service.c. Item to be Inspected Column. This column identifies the item to be checked or serviced.d. Procedure Column. This column briefly describes this procedure for performing the check or service. Whenever

replacement or repair is recommended, reference is made to para number for the applicable maintenanceInstruction.

e. Not Fully Mission Capable If: Column. Information in this column only tells you what deficiencies will keep yourequipment from being capable of performing its primary mission safely. DO NOT use your mask if a check andservice shows a fault listed in this column. Shortcomings or minor discrepancies which DO NOT limit operationalcapability or safety of use may require corrective surveillance, but does not "deadline" the mask.

f. Other Table Entries. Be sure to observe all special information and notes that appear in your table.

NOTEAll PMCS tasks are common to both the M40A1 and the M42A2. Therefore, all PMCStasks must be performed regardless of which mask you have. Please note that all tasksare illustrated with the M42A2 mask, however, the procedures indicated are common.

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2-12. PMCS PROCEDURES (CONT)

Table 2-3. UNIT PREVENTIVE MAINTENANCE CHECKS AND SERVICES

ITEMNO.

INTERVAL ITEM TO BECHECKED OR

SERVICED

PROCEDURE NOT FULLYMISSION

CAPABLE IF:

1 SemiannualSchedule(PMCS)*

Mask Assembly

CAUTIONDO NOT use a high pressure hose toclean mask. It may damagecomponents.

NOTESanitizing will be done prior to reissueto another soldier or prior to turn-in asexcess.

Make sure finish covers all metalsurfaces. Coat all bare metal surfaceswith lacquer (item 10, APP D).

a. Check mask assembly (1) for dirt orpermanent set which may affect fit orconformance to the face. Signs ofpermanent set are:1. Mask assembly is difficult tospread open.2. Unusual stiffness in sealing areaof mask assembly.

b. Check rubber next to eyelens (2) tobe sure neither eyelens will pull awayfrom mask assembly.

Mask Assembly Maskassembly is dirty enoughto affect mask assemblyseal or function.Mask assembly has apermanent set, orstiffness.

Eyelens will pull awayfrom mask assembly.

COMMON

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ITEMNO.


SERVICED


CAPABLE IF:

c. Pull head harness (3) over front of mask.Pull chin flap (4) forward so you cansee under it. Look around the twoholes (5) in the chin cup (6) for cutsor tears.

d. Hold nosecup chin flap (4) back soyou can see the internal drink tubeconnection (7).

e. Check the internal drink tubeconnection, inside the maskassembly to see if it is broken. If theconnection looks like the leftillustration, replace the facepiece(para 2-26, M40A1; para 2-27,M42A2). If the connection looks likethe right illustration, replace theinternal drink tube nipple(para 2-25).

The black silicon has anycuts or tears.

Internal drink tube nippleis broken and cannot bereplaced.

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Table 2-3. UNIT PREVENTIVE MAINTENANCE CHECKS AND SERVICES (CONT)

ITEMNO.


SERVICED


CAPABLE IF:

1 SemiannualSchedule(PMCS)*

Mask Assembly (Cont)

f. Place thumb on sideport (8) andfingers inside mask (1). Push upgently with thumb while pullinggently with fingers until mask snapsup to reveal inside of mask area (9)around sideport.

g. Fold back nosecup (10) so view ofarea around sideport is clear.Inspect area around sideport forholes, cuts or tears. Forreplacement see para 2-26, M40A1or para 2-27, M42A2.

Mask has any holes, cutsor tears.

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COMMON

TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2



ITEMNO.


SERVICED


CAPABLE IF:

WARNINGDo nut push up hard on side voicemitterretainer. The retainer could cut thefacepiece and cause leaks.

h. Place thumb on side voicemitter(11) and fingers inside mask (1).Push up gently with thumb whilepulling gently with fingers until masksnaps up to reveal inside of maskarea (12) around side voicemitter.

i. Fold back nosecup ( 10) so view ofarea around side voicemitter isclear. Inspect area around sideportfor holes, cuts or tears. Forreplacement see para 2-26, M40A1or para 2-27, M42A2.

Mask has any holes, cutsor tears.

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Table 2-3. UNIT PREVENTIVE MAINTENANCE CHECKS AND SERVICES (CONT)

ITEMNO.


SERVICED


CAPABLE IF:

2

3

SemiannualSchedule(PMCS)*

Front voicemitter

Side voicemitter

a. Check Front Voicemitter (13 ) fordamage, cracks or distortion thatmay affect voice transmission.

a. Remove side voicemitter retainer(14) by unscrewing counterclockwise with the D-ring (15) onthe carrier. Inspect retainer forcracks or distortion. Forreplacement see para 2-23.

b. Remove side voicemitter (16) andinspect for holes, cracks, orwarping. For replacement seepara 2-23.

c. Remove gasket (17) and check forsplits, sticky, or compressed areas.For replacement see para 2-23.

Front Voicemitter iscracked, damaged ordistorted.

Side voicemitter retainerhas cracks or distortion.

Side voicemitter retainerhas cracks or distortion.

Gasket is split, sticky orcompressed.

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

SECTION VI. CONVERSION PROCEDURES

2-13. LEFT/RIGHT FILTER CANISTER/HOSE ASSEMBLY CONVERSION

THIS TASK COVERS: Conversion Instructions

INITAL SETUP:

Applicable Configurations:

M40A1/M42A2

Equipment condition:

Quick Doff Hood removed. (See Operator's Manual)

CONVERSION INSTRUCTIONS

1. Remove filter canister (I) by turning counterclockwise (M40A1 only).

2. Remove hose (2) by turning the star knob (3) counterclockwise (M42A2 only).

CAUTIONBe careful when disconnecting buttons. The mask assembly maybe damaged if care is not exercised.

3. Disconnect the airflow deflector (4) from mask assembly (5) by carefully pulling the silicon rubber housing (6) awayfrom the airflow deflector buttons (7).

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2-13. LEFT/RIGHT HOSE ASSEMBLY CONVERSION (CONT)

4. Grasp a tab (8) on inlet valve body (9) and pull toward center of inlet valve body until unsealed from sideport (10).

5. Tuck unseated portion of inlet valve body into the mask assembly. Remove airflow deflector from mask assembly.

6. Remove side voicemitter retainer (11) by unscrewing counterclockwise using the D-ring (12) on the mask carrier.

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7. Remove side voicemitter (13) from mask assembly by pressing from inside of mask assembly (5). Remove gasket(14) from sideport (10) housing on mask exterior.

WARNINGBe sure the inlet valve body is installed on the post of the airflowdeflector with the tabs of the inlet valve body away from the inletvalve disk. If it is installed improperly, the mask will leak.

8. Check that inlet valve body (9) is installed on the post of the airflow deflector with the tabs (8) of the inlet valve bodyaway from the airflow deflector (4).

9. Position airflow deflector in pocket on opposite side of mask assembly.

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

2-13. LEFT/RIGHT HOSE ASSEMBLY CONVERSION (CONT)

CAUTIONDO NOT pull on spokes of valve body while installing. This will break the spokesand require replacement of the valve body.

10. With one hand push inlet valve body (9) through sideport (10). With other hand pull on thick outer rim (15) of valvebody until valve body is completely through sideport.

11. Push buttons (7) on sides of airflow deflector (4) into button holes (16) in mask assembly pocket.

12. Press lightly around thick outer rim of valve body until the valve body seats in the sideport.

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13. Install filter canister (1) by turning clockwise.

14. Install hose (2) by turning star knob (3) clockwise.

WARNINGBe sure the side voicemitter is installed with the flange and fourbeads facing out. If installed incorrectly it could cause the maskassembly to leak.

15. Position gasket (14) in sideport (10).

16. Install side voicemitter (13) with four beads (17) facing out..

17. Position side voicemitter retainer (I 1) in sideport.

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2-13. LEFF/RIGHT HOSE ASSEMBLY CONVERSION (CONT)

18. Tighten voicemitter retainer (11) by turning clockwise with the D-ring (12) on the mask carrier strap.

19. Check for proper function (para 2-8).

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

2-14. M40A1 TO M42A2 CONVERSION


INITIAL SETUP:


M40A1



Materials/Parts:

Detachable MicrophoneHose AssemblyCanister CarrierCombat Vehicle Mask Carrier


1. Remove filter canister (1) (see Operator's Manual).

2. Install hose assembly (2) (see Operator's Manual).

3. Install filter canister in canister carrier (3) (see Operator's Manual).

4. Install detachable microphone (4) (see Operator's Manual).

5. Stow mask in combat vehicle mask carrier and turn in field mask carrier.

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2-15. M42A2 TO M40A1 CONVERSION


INTIALSETUP:


M42A2



Materials/Parts:

Field Mask Carrier


1. Remove hose assembly (1) (see Operator's Manual).

2. Remove filter canister (2) from canister carrier (3) (see Operator's Manual).

3. Remove detachable microphone (4) (see Operator's Manual).

4. Install filter canister by turning clockwise (see Operator's Manual).

5. Stow mask in field mask carrier and turn in combat vehicle mask carrier, detachable microphone, and canistercarrier.

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SECTION VII. MAINTENANCE PROCEDURES

2-16. GENERAL

a. The maintenance procedures in this section are to be performed by a unit NBC NCO or by the user under unitNBC NCO supervision.

b. This section is divided into those tasks which are common to the M40A1 and the M42A2, those tasks whichare peculiar to the M40A 1, and those tasks which are peculiar to the M42A2. Common tasks are illustratedwith the M42A2.

c. This section contains detailed instructions for replacing the following components.

Para. Page

COMMON TASKS

2-17. INTERNAL DRINKTUBE.......................................................................................................................................2-54

2-18. QUICK DISCONNECT COUPLING, EXTERNAL DRINK TUBE.............................................................................2-56

2-19. HEAD HARNESS..................................................................................................................................................2-57

2-20. NOSECUP VALVE DISKS.....................................................................................................................................2-58

2-21. AIRFLOW DEFLECOR, INLET VALVE, AND VALVE BODY..................................................................................2-59

2-22. OUTLET VALVE COVERAND OUTLET VALVE DISK...........................................................................................2-63

2-23. SIDE VOICEMITTER, VOICEMlTTER RETAINER, AND GASKET........................................................................2-65

2-24. INTERNAL DRINK TUBE NIPPLE........................................................................................................................2-66

2-25. OPTICAL INSERT KIT..........................................................................................................................................2-68


2-26. M40A1 FACEPIECE..............................................................................................................................................2-73


2-27. M42A2 FACEPIECE..............................................................................................................................................2-74

2-28. CLAMP COVER....................................................................................................................................................2-75

2-29. PORT GASKET.....................................................................................................................................................2-76

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

COMMON

2-17. INTERNAL DRINK TUBE

THIS TASK COVERS: a. Removal b. Installation c. Checking for Fit

INITIAL SETUP:


Materials/Parts:Shears (item 14, app D)

a.REMOVALCAUTION

Do not scratch plastic eyelens while performing maintenance procedures.

NOTEThere are two types of internal drink tubes. The original drinktube and a revised drink tube which is used only when the drinktube nipple has been replaced. Both are illustrated.

1. Lay mask assembly (1) face down on nonabrasive surface.

2. Grasp internal drink tube (2) at drink tube coupling (3) and pull internal drink tube away from coupling.

b.INSTALLATION

1. Lay mask assembly face down on nonabrasive surface.

2. Install internal drink tube on drink tube coupling and press internal drink tube until it bottoms fully against drink tubecoupling.

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c.CHECKING FOR FITCAUTION

Internal drink tube will irritate lips if it touches them while wearing maskassembly.Internal drink tube must be removed from mask assembly prior to adjustinglength to prevent damage to mask assembly.

NOTESlight pressure on the top of the outlet valve body shouldenable the internal drink tube to be grasped by the soldier'slips.

1. Have soldier put on mask assembly and check to see if internal drink tube touches lips.

2. If internal drink tube (2) touches soldier's lips while wearing mask assembly (1), adjust length of internal drink tubeas follows:

a. Remove internal drink tube from mask assembly.

b. Cut internal drink tube behind first barb (4).

c. Install internal drink tube.

CAUTIONDO NOT remove the last barb, as this is needed for proper function.

3. Repeat steps 1 and 2, if necessary, to achieve proper fit.

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COMMON (CONT)

2-18. QUICK DISCONNECT COUPLING, EXTERNAL DRINK TUBE

THIS TASK COVERS: a. Removal b. Installation

INITIAL SETUP:


a. REMOVAL

1. Lay mask assembly (1) face up.

2. Remove quick disconnect coupling (2) from retainer (3).

3. Grasp external drink tube (4) where it joins the quick disconnect coupling , with one hand, and with the other, graspthe quick disconnect coupling and pull away with a twisting motion, disengaging the external drink tube from thequick disconnect coupling.

b.INSTALLATIONNOTE

Quick disconnect tube connection may be moistened with waterto aid in coupling it with the rubber tubing.

1. Lay mask assembly face up.

2. Insert quick disconnect coupling into the external drink tube and, with a twisting motion, press drink tube in place.Ensure tube extends over the nipple end of the quick disconnect by 5/8 - 3/4 inch.

3. Verify drink system for leaks in accordance with para 2-9.

4. Reinstall quick disconnect coupling in retainer.

5. Check for leaks in accordance with para 2-9.

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TM 3-4240-346-20&PTM 09204A/09205A 20&P/2

2-19. HEAD HARNESS


INITIAL SETUP:


a. REMOVAL

CAUTIONDo not scratch plastic eyelens while performing maintenance procedures.

Work head harness straps (1) out of buckles (2).

b. INSTALLATION

NOTEElastic webbing that joins the two forehead straps must be onoutside to avoid hot spots on head.

1. Position head harness (3) in mask assembly (4) with head harness straps next to buckles and tab (5) down.

2. Work head harness straps into buckles and pull through approximately 1 in. (2.5 cm) so that head harness strapends are outside.

3. Stretch head harness away from mask assembly and check that buckles hold head harness straps tightly.

4. Perform Initial Fitting Procedures. (para 2-7)

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/

COMMON (CONT)

2-20. NOSECUP VALVE DISKS


INITIAL SETUP:


a. REMOVAL


To avoid tears, do not stretch rubber more than necessary to remove or installparts.

1. Pull head harness (1) over front of mask assembly (2).

2. Curl back lip of nosecup (3) to expose nosecup valve seat (4) and valve disk (5).

3. Pull nosecup valve disk out of each nosecup valve seat from inside of nosecup.

b. INSTALLATIONNOTE

It may be necessary to pull on nosecup valve disk stem fromoutside of nosecup while pressing it into the nosecup valve seatfrom inside of nosecup.

Moisten the stem of nosecup valve disks with water to aid ininstallation.

1. Press nosecup valve disk into nosecup valve seat from inside of nosecup until nosecup valve disk is flat againstnosecup valve seat and the stem (6) slips completely through the hole (7) in the nosecup valve body.

2. Gently rotate nosecup valve disk to make sure it is completely seated.

3. Repeat steps 1. and 2. to install remaining nosecup valve disk.

4. Return head harness to its original position.

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TM 3-4240-346-20&PTM 09204A/09205A - 20&P/2

2-21. AIRFLOW DEFLECTOR, INLET VALVE, AND VALVE BODY


INITIAL SETUP:


Equipment Condition:Hose removed (M40A1/M42A2)Canister carrier removed (M40A1/M42A2)Quick Doff Hood Removed (M40A1/M42A2)

a. REMOVAL


Be careful when disconnecting buttons. The mask assembly may be damaged ifcare is not exercised.

1. Disconnect the airflow deflector (1) from mask assembly (2) by carefully pulling the silicon rubber housing awayfrom the airflow deflector buttons (3).

2. Grasp a tab (4) on inlet valve body (5) and pull toward center of inlet valve body until unseated from sideport (6).

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COMMON (CONT)

2-21. AIRFLOW DEFLECTOR, INLET VALVE, AND INLET VALVE BODY (Cont)

a. REMOVAL (Cont)

3. Tuck unseated portion of inlet valve body (5) into the mask assembly. Remove airflow deflector (1) from maskassembly (2).

4. Grasp inlet valve body with thumb under two spokes (7). Pull and peel off airflow deflector post (8).

5. Pull inlet valve disk (9) from airflow deflector post.

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b. INSTALLATION

WARNINGBe sure the inlet valve body is installed on the post of the airflowdeflector with the tabs of the inlet valve body away from the inletvalve disk. If it is install improperly, the mask will leak.

NOTEThere are two sizes of deflectors. Ensure that the deflector sizematches the mask size.

1. Position inlet valve disk (9) on lower groove (10) of airflow deflector post (8).2. Position the inlet valve body (5) on the airflow deflector post. Be sure that the tabs (4) of the inlet valve body face

away from the inlet valve disk.3. Position airflow deflector (1) in pocket on side of mask assembly.

CAUTIONDO NOT pull on spokes of inlet val

Documents

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