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The C420 Continuous Air Supply Unit (CASU) is the most widespread design of a blower unit for Powered Air Purifying Respirator (PAPR) mask ensembles. Designed by the Swiss fan and blower company, Micronel AG in close collaboration with the U.S. Army Edgewood Chemical-Biological Center (ECBC) and Soldier Biological and Chemical Command (SBCCOM), the C420 was first developed beginning in 1992 and adopted in 1997 as the 'Lightweight Motor Blower' for the M48 CB Aircraft Mask Program. The blower was one of the first of its kind to be capable of liquid immersion for decontamination and allowed hot-swapping of batteries in a CBRN environment. Its radical design also allowed mounting in a number of positions and configurations and the dual canister design ensured a long service life in use.

The design is IP68 Water and Dust Resistant, could operate in climates ranging between -32 to +49°C (-26 to +120°F), has a shelf life of 10 years, features a wide range of accessories and add-ons to improve job or efficiency, and has been adopted by multiple nations worldwide in all manner of military, law enforcement, industrial, and civilian applications. Despite other blowers being developed and adopted, the C420 CASU to this day remains the gold staple of CBRN PAPR design and continues to see service worldwide.

Development and Early Adoption[]

By the late 1980s/Early 1990s, U.S. SBCCOM had requisitioned for a lightweight blower unit to replace the bulky units in use with the M43/M43A1 CB Aircraft Masks. Initial developments considered the Racal Safety C211 CASU, a rubber sheath with a small integral fan which fit over a standard C2/C2A1-sized Canister and provided a reasonable supply of air. An experimental configuration of these blowers resulted in the M43A2 CB Aircraft Mask, which was nothing more than an M43 Type II General Aviator's Mask with two C211 Blowers hooked up to a single control box (LWPAPR) in place of the standard M43 Blower.

This arrangement proved far too awkward to carry and implement, and so Edgewood Chemical Biological Center continued to work with Swiss Firm Micronel AG, who had also produced the C211 and previously developed the C411, to develop a radical yet simple blower design that would balance both light weight and power. The general design that was settled on was a single 5.2v Induction Blower housed in a triangular Noryl plastic shell with an EPDM rubber gasket between the two halves. The front half featured two RD-40x1/7" Canister ports with seal gaskets as the intake, and a raised pencil-shaped switchbox which housed either a 3-position rotary knob switch or a single rubber sheathed on-off toggle.

The back half of the casing featured two integral belt loop brackets along the diagonal edges for carrying the blower at the waist, as well as multiple threaded inserts along the back for installing a twist-lock adapter for mounting in the cockpit of an AH-64 Apache. The male threaded outlet of the blower protruded out of the top while a long, tubular chamber along the bottom edge of the unit for accepting a standard BA-5800/U Lithium-Sulfur Dioxide battery, which would be sealed off with a RD-40x1/7" Threaded Cap. Opposite of the battery tube opening was a blank plug, which on some models was a second threaded cap for revealing a clansman-type 7-pin Female Connector for accommodating a cable with a CPI K1007 Waterproof Rocker Switch at the end for remotely switching the blower on or off from the swivel end of the breathing tube assembly.

The basic 3-Speed C420 CASU was formally adopted as the 'Lightweight Motor Blower' (NSN 4240-01-442-8415) in 1996 for use with the updated M48/M49 CB Aircraft Mask Programs. Later on, a Single-Speed Toggle version of the blower (NSN 6530-01-543-7916) would also become adopted for use with the Chemical Patient Protective Wrap System.

Proliferation[]

Special Forces[]

The C420 CASU was initially adopted by Apache Aircrews for the M48 CB Mask Program, but the design soon showed its utility and advantages to other specialized units, as the effect of operation greatly reduced breathing fatigue as well as heat stress on the face. The U.S. Special Operations Command was quick to see the tactical advantage of the C420 CASU where maximum combat efficiency in fast-paced engagements while under CBRN conditions was desired and it was quickly paired with USSOCOM-issued masks such as the M45 CB Mask and XM53 Improved Protective Mask. The optional remote cable assembly was commonly seen and utilized within this area of development and a number of commercial pouches were designed to attach the blower to plate carriers, SCBA bottles, etc.

First Responders and Civilians[]

After the September 11 Attacks on the World Trade Center, Pentagon, and subsequent Anthrax letters, the DoD frantically began to organize new standard of protective equipment for first responders, particularly those dealing with terror-related CBRN threats. The C420 CASU was approved by the new NIOSH standard for CBRN PAPR on October 6, 2006, but was already in use well before then for anything from decontamination lines, breaching and hostage rescue, to medical use. Typically, these commercially-intended blowers were single speed units with rubberized toggles and no remote cables. However, some police and federal agencies such as FBI HRT ordered the same 3-speed remote cable-compatible C420 Blowers that were current-issue to USSOCOM.

Typical examples of NIOSH-approved PAPR Configurations include:

Not before long, the C420 also found its way into American civilian hands, being produced by a plethora of companies by this stage and examples becoming increasingly more surplussed, if not outright available for private purchase from safety equipment catalogs and distributors. The benefits of a PAPR are widely acknowledged among those researching tactical CBRN equipment and militias/PMC's alike can on occasion be seen sporting the C420 CASU in their personal gear.

Companies and Distributors[]

Many companies were contracted to manufacture the C420 CASU and several more were subcontracted to market and sell them either alone or as kits. This section will touch base upon each company and list the part numbers of individual components/kits.

Primary[]

Micronel AG, Micronel Safety USA, LLC.[]

As the original contracted developer of the C420 CASU, Micronel has surprisingly little of their own branded units in comparison to other distributors. This is most likely due to the international branches of Micronel being absorbed into the respective domestic counterpart companies, such as SafetyTech International taking over Micronel Safety USA. Micronel AG manufactures the hardware and components while assembly or re-branding is handled by other companies. On occasion, C420 blowers branded by Micronel will appear. The main way to tell them apart from other units, other than the manufacturer's sticker on the back, is a small Micronel logo on the switch position indicator plate (if the unit is a 3-speed). Micronel branding can also sometimes be seen on internal components of blowers that are externally branded to other companies.

It is interesting to note that Micronel was also technically itself a redistributor, as their catalogs sold Kemira M95, M110, M98, and M120 Masks in the short period before Scott Safety bought out Kemira.

SafetyTech International Inc., Immediate Response Technologies, LLC.[]

SafetyTech International was the merged successor of Micronel Safety USA and is the most recognized distributor of the C420 CASU. SafetyTech was the primary contractor for not only the U.S. Government and the Department of Defense, but also for other companies such as MSA, Avon, and Scott for supplying these blowers. Immediate Response Technologies (IRT) would later serve as a distribution company that supplied the U.S. government and federal agencies, reselling blowers for SafetyTech International Inc. as well as Airboss of America before being bought out by the latter.

Airboss Defense Groups, LLC.[]

The Canadian protective equipment company Airboss Defense Group, LLC started as one of the later redistributors of the SafetyTech C420 CASU. Initially, their products were almost entirely distributed through Immediate Response Technologies, LLC, however, ADG eventually purchased out IRT and began to directly handle DoD/Government requisitions for the C420 CASU and their related kits, and may have even handled production of their own units in a similar fashion to SafetyTech [citation needed]. As it currently stands, Airboss is one of the few remaining distributors actively marketing the C420 CASU.

Although Airboss C420 Blowers/Kits are current-issue, units may sometimes be procured aftermarket, although they are not as common as older SafetyTech blowers. They are all most commonly located as Single-Speed Toggle Medical Blowers for the U.S. Army Chemical Patient Protective Wrap (P/N M-60155-001), and others as 3-Speed models (P/N M-60010-001), with some even being found with the remote switch feature (P/N M-60016-001, P/N M-60038-001) when they appear on the market. Once again, aside from the rear manufacturer's sticker, they bear no external difference from SafetyTech blowers.

Known Part Numbers:

Micronel AG, SafetyTech, Immediate Response Technologies, Airboss Defense:

  • N-60198-001 - C420 PAPR System with Promask 2000 (M98) and Hydration
  • N-60199-001 - C420 PAPR System with Promask 2000 (M120)
  • M-60010-001 - C420 Blower, 3-Speed, with Rotary Switch (NSN 4240-01-442-8415)
  • M-60016-001 - C420 Blower, 3-Speed Rotary Switch, with Remote Cable Connection
  • M-60018-001 - C420 Blower, 3-Speed Rotary Switch, with External Power Connection
  • M-60028-001 - C420 Blower, Single Speed, with Rotary Switch
  • M-60034-001 - C420 Blower, Single Speed Rotary Switch, with Remote Cable Assembly
  • M-60035-001 - C420 Blower, Single Speed Rotary Switch, with External Power Connection
  • M-60031-001 - C420 Blower, Single Speed, with Toggle Switch (NSN 4240-01-591-6237)
  • M-60036-001 - C420 Blower, Single Speed Toggle Switch, with Remote Cable Assembly
  • M-60037-001 - C420 Blower, Single Speed Toggle Switch, with External Power Connection
  • M-60067-001 - C420 Blower, Single Speed Toggle Switch, with Remote Cable Connection
  • M-60052-001 - C420 Blower, Single Speed Toggle Switch, with Switch Protector Plate
  • M-60081-001 - C420 Blower, Single Speed Toggle Switch, with Bladder
  • M-60082-001 - C420 Blower, 3-Speed Rotary Switch, with Bladder
  • M-60083-001 - C420 Blower, 3-Speed Rotary Switch, with Bladder and Remote Cable Connection
  • M-60038-001 - C420 Blower, 3-Speed Rotary Switch, with Remote Cable Assembly
  • M-60084-001 - C420 Blower, 3-Speed Rotary Switch, with Bladder and Remote Cable Assembly
  • M-60154-001 - C420 Blower, 3-Speed Rotary Switch, Medical (NSN 6530-01-543-7903)
  • M-60155-001 - C420 Blower, Single Speed Toggle Switch with Rechargeable Cap, Medical (NSN 6530-01-543-7916)
  • M-60039-001 - C420 Remote Cable Assembly, 38" Long, with 90° Connector
  • M-60091-001 - C420 Remote Cable Assembly, 19" Long, with 90° Connector
  • M-60121-001 - C420 Remote Cable Assembly, 27.5" Long, with Straight Connector
  • 2425E-20435 - C420 Remote Cable Connector Jumper Pin (A-C)
  • S-30013-001 - C420 Breathing Tube Assembly with 90° Swivel
  • S-30067-001 - C420 Breathing Tube Assembly with 75° Swivel
  • S-30116-001 - C420 Breathing Tube Assembly, Responder, 30" Long
  • S-30118-001 - C420 Breathing Tube Assembly, Responder, 36" Long
  • M-30073-001 - C420 Breathing Tube Assembly with 75° Swivel and GORE Chempak Ultra Barrier/Cordura (Black)
  • M-30107-001 - C420 Breathing Tube Assembly with 90° Swivel and GORE Chempak Ultra Barrier/Cordura (Black)
  • M-30001-001 - U.S. Army ITAP CASS Hose Assembly
  • M-30105-001 - U.S. Army Advanced Bomb Suit C420 Hose Assembly, 30" Long
  • M-30100-001 - U.S. Army Improved Chemical Protective Patient Wrap Hose Assembly
  • S-30019-001 - Web Belt Assembly, 60" Long x 2" Wide
  • S-30021-001 - Decon Belt Assembly, 70" Long x 2" Wide
  • S-30020-001 - C420 Airflow Indicator (AFI)
  • M-60026-002 - C420 Cartridge Port Gaskets (2)
  • M-20020-001 - LiSO2 (BA-5800/U) Disposable 8-Hour Mission Battery
  • S-20036-001 - NiMH Rechargeable C420 Battery Pack, with Cap
  • S-20036-002 - NiMH Rechargeable C420 Battery Pack (2), with Cap
  • S-20090-001 - NiCD/NiMH 1-Position Rapid Battery Charger
  • S-20038-001 - NiCD/NiMH 4-Position Rapid Battery Charger
  • S-20037-001- NiCD/NiMH 1-Position Rapid Battery Charger (Replaced by S-20090-001)
  • S-20036-001 - NiMH Rechargeable C420 Battery Pack
  • M-30060-001 - Battery Cap Assembly, Rechargeable
  • M-10117-001 - C420 Tactical Belt Loop Plate Kit
  • M-30065-001 - Tester, Lightweight Motor Blower, M48 Mask
  • S-10022-001 - C420 Breathing Tube Assembly Replacement Gasket
  • S-20040-001 - C420 1-Position Rapid Battery Charger with (2) Batteries, Rechargeable, with Cap
  • M-45106-001 - C420 Blower Pouch (Black)
  • M-45107-001 - C420 Blower Pouch (Olive Drab)
  • M-45108-001 - C420 Blower Pouch (Coyote Tan)
  • S-10079-001 - Molded Carrying Case, 19"x14"x7-1/8"
  • S-70018-001 - Cartridge Snap Cap (M96 Cartridge Only) NSN 5340-01-577-5631

Defunct Micronel Safety USA Part Numbers:

  • S65001 - C420 Blower, Single Speed, with Toggle Switch
  • S65011 - C420 Blower, Single Speed, with Rotary Switch
  • S65003 - C420 Blower, Single Speed Toggle Switch, with Rechargeable Battery Cap (NSN 6530-01-543-7916)
  • S65005 - C420 Blower, Single Speed Rotary Switch, with Rechargeable Battery Cap
  • S65014 - C420 Blower, Single Speed Toggle Switch, with Remote Cable Connection
  • S65008 - C420 Blower, 3-Speed, with Rotary Switch (NSN 4240-01-442-8415)
  • S65017-001 - C420 Blower, 3-Speed Rotary Switch, with Bladder
  • S65018-001 - C420 Blower, 3-Speed Rotary Switch, with Remote Cable Connection
  • S65019-001 - C420 Blower, 3-Speed Rotary Switch, with Bladder and Remote Cable Connection
  • S65012-001 - C420 Blower, Single Speed Rotary Switch, with LED/Alarm
  • S65013-001 - C420 Blower, Single Speed Rotary Switch, with LED/Alarm, Bladder, Remote Cable Connection
  • S65015-001 - C420 Blower, Single Speed Rotary Switch, with Remote Cable Connection
  • S35009-001 - Breathing Tube, 36" Long, with 90° Swivel
  • S35011 - Breathing Tube, 42" Long, with 90° Swivel, Heavy Wall
  • S35014 - Decon. Belt, 70" Long x 1-1/2" Width
  • S35027 - Decon. Belt, 60" Long x 2" Width
  • S35016 - Web Belt, 60" Long x 2" Width
  • S65022 - Remote Cable Assembly (For use with S65013, S65014, S65018, and S65019)
  • S25004 - Battery, LiSO2, 6v Non-Rechargeable, BA-5800/U
  • S25001 - Battery, Nickel Metal-Hydride, 4.8v Rechargeable
  • S35017 - Rechargeable Battery Cap
  • S25006 - Rapid Battery Charger, 1-Cell
  • S25001 - Rapid Battery Charger, 4-Cell
  • S25005 - Rapid Battery Charger, with (2) Batteries (4.8v Rechargeable NiMH) and Cap
  • S35013 - Airflow Indicator (AFI)
  • S75001 - Shower Cap, Filter

Secondary[]

Dräger Safety[]

Dräger Safety was the protective equipment distributor branch for German company Drägerwerk AG. Like most companies, they did not produce the blowers themselves, but simply assembled stock hardware supplied by Micronel/SafetyTech and sold them under licensed brand name. Drager appears to have only made Single-Speed Toggle C420 Blowers.

Known Part Numbers:

  • 4059490 - C420 PAPR, Complete Kit
  • 4056916 - C420 PAPR, Blower Unit
  • 4056917 - C420 Battery, LiSO2 (BA-5800/U)
  • 4058934 - C420 Breathing Hose Assembly with 90° Swivel
  • 4056924 - C420 Breathing Hose Assembly with 75° Swivel
  • 4057034 - C420 Battery, Rechargeable
  • 4057037 - C420 Battery Cap Assembly for Rechargeable Battery
  • 4056920 - C420 Flow Measurement Tube
  • 4057591 - C420 Molded Case, Black
  • 4057032 - C420 Single Battery Charger
  • 4057035 - C420 Batteries, Rechargeable (2x) with Cap and Charger
  • 4057036 - C420 Batteries, Rechargeable (2x) with Cap
  • 4056923 - C420 Decon Belt

Scott Aviation, Tyco/Scott, Scott Safety, 3M-Scott Inc.[]

Sometime after Scott Aviation had acquired Finnish Company Kemira and thus the rights to produce the M95, M110, M95, and M120 Masks under the Scott Safety brand, Scott partnered with Tyco International Ltd. (formerly Tyco Fire & Security) began reselling SafetyTech Single Speed C420 Units with the same kits and range of accessories as before, now also offering the AV Series Facepieces along with them. While Scott Aviation has been a military contractor well before the era of the C420 CASU, it is generally unknown to what extent Scott supplied their own blowers to the military (other than the National Guard and various Federal Agencies).

Eventually, Scott took over C420 distribution from Tyco before being taken over themselves by 3M. Tyco/Scott C420 Blowers are another one of the most commonly found on the surplus market, and are easily identified with their boldly presented brand stickers on the front outer shell, similar to the Dräger units.

Known Part Numbers:

Tyco/Scott Technologies C420 PAPR:

(*Consists of Blower Unit, 37" Breathing Tube, 40mm Mask Adapter, Easy Decontamination Belt, and Airflow Indicator)

  • 805371-01 - C420 PAPR Unit*
  • 805633-01 - C420 PAPR Unit* with Lithium Sulfur Dioxide Battery and AV-2000 Facepiece
  • 805636-01 - C420 PAPR Unit* with Lithium Sulfur Dioxide Battery, AV-2000 Facepiece, and AV/NBC Shroud
  • 805358-01 - Spare Lithium Sulfur Dioxide Battery Pack
  • 805665-01 - 40mm Mask Adapter

Scott Safety C420 Plus:

  • 200699-01 - C420 Plus PAPR Blower
  • 200698-00 - C420 Plus PAPR Blower with Decon Belt
  • 200698-30 - C420 Plus PAPR Blower with Decon Belt and 30" CBRN Breathing Tube
  • 200698-36 - C420 Plus PAPR Blower with Decon Belt and 36" CBRN Breathing Tube
  • 200710-30 - C420 Plus PAPR Blower with LiSO2 Non-Rechargeable Battery, Decon Belt, and 30" CBRN Breathing Tube
  • 200710-36 - C420 Plus PAPR Blower with LiSO2 Non-Rechargeable Battery, Decon Belt, and 36" CBRN Breathing Tube
  • 200830-30 - C420 Plus PAPR Blower with Decon Belt and 30" CBRN AV-PAPR Hose
  • 200830-36 - C420 Plus PAPR Blower with Decon Belt and 36" CBRN AV-PAPR Hose
  • 200833-30 - C420 Plus PAPR Blower with LiSO2 Non-Rechargeable Battery, Decon Belt, and 30" CBRN AV-PAPR Hose
  • 200833-36 - C420 Plus PAPR Blower with LiSO2 Non-Rechargeable Battery, Decon Belt, and 36" CBRN AV-PAPR Hose
  • 200700-30 - 30" CBRN Breathing Tube
  • 200700-36 - 36" CBRN Breathing Tube
  • 200829-30 - 30" CBRN AV-PAPR Breathing Tube for approved AV-Facepieces
  • 200829-36 - 36" CBRN AV-PAPR Breathing Tube for approved AV-Facepieces
  • 805359-01 - Decontamination Belt
  • 805374-01 - Airflow Indicator
  • 805358-01 - LiSO2 Battery
  • 31002361 - (Black) End Cap for LiSO2 Battery
  • 31001504 - NiMH Rechargeable Battery Pack
  • 31001506 - (Green) End Cap for NiMH Rechargeable Battery
  • 200703-01 - Single Unit Battery Recharger
  • 200701-01 - NiMH Rechargeable Battery Conversion Kit, (Single Bank Charger, NiMH Battery, (Green) End Cap)
  • 31002221 - PAPR Hard Carry Case

Mine Safety Appliances[]

Mine Safety Appliances (MSA) had been a partner and reseller for SafetyTech to offer the C420 CASU with their Responder line of PAPR Kits, which were the first to receive NIOSH Approval with the C420 Blower. Aside from the manufacturer's sticker on the rear of the blower, there is no distinction from a SafetyTech C420. Due to this, as well as the LEO/Commercial Marketing focus, MSA C420 Blowers are relatively uncommon on the surplus market.

Known Part Numbers:

(*Includes C420 PAPR, Belt, Airflow Indicator, and Breathing Tube)

  • B-60141-030 - C420 PAPR Kit* with 30” Breathing Tube
  • B-60141-036 - C420 PAPR Kit* with 36” Breathing Tube
  • B-20040-001 - NiMH Rechargeable Battery Kit (2 NiMH Batteries, Charger, and Cap)
  • M-20020 - LiSO2 Battery
  • S-30116 - 30'' Breathing Hose Assembly
  • S-30118 - 36'' Breathing Hose Assembly
  • S-20036 - NiMH Rechargeable Battery Pack
  • B-20090-001 - NiMH Rapid Battery Charger
  • B-30060-001 - NiMH Rechargeable Battery Cap Assembly
  • S-30019 - Web Belt Assembly
  • B-10079-001 - PAPR Carrying Case

Survivair, North, Honeywell, Sperian[]

*Note - all 4 companies have merged and offered the same or similar systems throughout their lifespans, so for clarity and lack of information on distinguishing each company's products, all four will be referred to as 'Sperian'.

Survivair Safety -> bought by Bacou Safety Inc. -> bought by Sperian Protection -> bought by Honeywell Safety

North Safety -> bought by Honeywell Safety

Another basic SafetyTech rebrand distributor for the commercial and law enforcement market. Notable as the only company to give the C420 CASU their own designation (SC420). Much like MSA, the Sperian SC420 Blower is identical to SafetyTech Single-Speed Toggle Blowers other than Sperian Labeling on the back and just as relatively difficult to find as surplus.

Known Part Numbers:

(*Includes C420 Blower, Airflow Indicator Tool, Decon Belt, Breathing Tube, Battery Option, 2 CBRN Canisters, 2 Shower Caps, Black Carrying Case, and Approved Environmental Battery Storage Box)

  • 560002 - CBRN PAPR*, LiSO2 Battery Pack
  • 560004 - CBRN PAPR*, D Cell Battery Holder Pack (Batteries not included)
  • 560008 - CBRN PAPR*, NiMH Battery Pack (Includes Charger and Extended Green Cap)
  • 769550 - SC420 Blower, Decon Belt and Airflow Indicator Tool
  • 769519 - SC420 Blower Gasket (2)
  • 769516 - Airflow Indicator Tool
  • 769515 - 38" Breathing Hose Assembly
  • 769549 - Breathing Hose Gasket
  • 769540 - Decon Belt
  • 964869 - D-Ring Kit
  • 769535 - D Cell Battery Holder Pack (batteries not included)
  • 769531 - Nickel-Metal Hydride Rechargeable Battery
  • 769545 - Nickel-Metal Hydride Charger
  • 769533 - Nickel-Metal Hydride Extended Cap
  • 769532 - Lithium Sulfur Dioxide Battery
  • 769584 - Approved Environmental Battery Storage Box
  • 769513 - CBRN Canister Shower Cap

Giat Industries[]

French company Giat Industries is perhaps better known as the manufacturer of the ANP-M53 and the ANP-VP-F1 Masks, however, are also established as a distributor of the Micronel C420 CASU on the European Market. While not much is currently known about the use of their blowers, it is generally regarded that they are intended for use with the French Ephese Respirator, the British Casualty Bag, and potentially other assorted applications. As with other distributors, Giat imported blowers or materials from Micronel/SafetyTech International and either relabeled them, or did their own assembly.

The Giat C420 is a Single-Speed Toggle C420 Blower with the Added low Battery LED/Alarm and Remote Cable Connection - they are the only manufacturer whose blowers can be found with this specific combination of features, and it is unknown if Giat produced any other variations. As of 2020, the Giat C420 is the most commonly found variant C420 CASU on the surplus market, particularly in Western Europe. They are often found with the rubber sheathing over the toggle switch cut off, likely as a demilitarization method.

Other than this and the presence of the low battery alarm feature, Giat C420 Blowers can easily be picked out by the 3 additional multi-position belt loop brackets on the back of the unit, as well as the battery/remote switch connection caps with prominent grip traction 'fins'.

Avon Protection[]

Avon Protection, much like other companies on this list, redistributed Micronel/SafetyTech/Airboss C420 Single Speed Units to supplement their line of protective masks after receiving NIOSH Approval on April 23, 2008. It is unknown when Avon discontinued their resale of the C420, but it is generally known that they have been replaced with Avon's EZAir and MP-PAPR Systems. Avon-branded units are relatively uncommon on the surplus market, likely due to either poor sales, lack of surplused examples, or both.

Known Part Numbers:

  • 70501-245 - C420 PAPR Blower Kit (Includes C420 Blower Unit, 36" Breathing Tube, 60" Waist Belt, and Flow Indicator)
  • 70501-213 - PAPR Hose, 30"
  • 70501-214 - PAPR Hose, 36"
  • 70501-215 - PAPR Waist Belt, 70"
  • 70501-216 - PAPR Waist Belt, 60"
  • 70501-218 - Battery, LiSO2
  • 70501-219 - Flow Indicator
  • 70501-270 - Filter Decon Cover
  • 70501-244 - Rechargeable Battery Cap Assembly
  • 70501-242 - Filter Port Gasket, 10 Pack
  • 70501-243 - Breathing Tube Gasket, 10 Pack
  • 84100-10-1 - Hose Cover, 28"
  • 84100-10-2 - Hose Cover, 34"

Accessories[]

The C420 CASU Blower is but one part of a single, functioning unit. Many accessories are required in order to use and maintain a full PAPR Unit. In this section, each operation-necessary component and feature will be discussed.

Breathing Tube Assembly[]

Arguably, the Hose (or 'Breathing Tube Assembly') is the most essential component to running a PAPR setup. These hoses come in various lengths and designs, but all have the same basic pattern - A 90 or 75-Degree RD40x1/7" Male Threaded Swivel for the Mask, a RD40x1/7" Female Straight Thread for the Blower, a flexible, crushproof, corrugated EPDM Rubber Tube for the main body, and two hose clamps with protective outer shrink-wrap to hold everything together. All hoses are Chemical Warfare Agent and Toxic Industrial Chemical/Material (TIC/TIM)-Resistant.

One must take note that the Breathing Tube Assembly, Nonmetallic (NSN 4720-01-515-9261) is similar in appearance to the 75° Swivel PAPR Breathing Tube Assembly, however, the Nonmetallic Breathing Tubes have a 90°, Non-Rotating Female Thread, which makes for an awkward positioning of the blower and is intended for use with a direct-mounted single canister for the M42 and M45 Series Tank and Aircraft Masks.

Breathing Tube Assembly with 75° Swivel[]

Originally built and procured for USSOCOM using the stock 75° Swivel taken off the M42-M45 Series Nonmetallic Breathing Tube. SafetyTech and Drager are the most common manufacturers for this style of hose, and they along with other manufacturers would soon adopt the subsequently improved 90° Swivel, due to it being less stiff and inconvenient to rotate.

Breathing Tube Assembly with 90° Swivel[]

The second and most commonly-found PAPR Hose, easily identified by its crucifix-shaped thread knob. Hoses may have either segmented or spiraling corrugations depending on the manufacturer.

Batteries[]

C420 Battery Compartment

C420 CASU, with Battery Compartment Illustrated.

The C420 CASU was originally designed for use with the disposable military BA-5800/U GPS Battery, however as these blowers became more common commercially to the public, a number of various adapters and rechargeable batteries have cropped up to supply the need for cost-effective power.

BA-5800/U 6v Lithium Sulfur Dioxide Non-Rechargeable Battery[]

The BA-5800/U is a stock military high performance non-rechargeable Lithium Sulfur Dioxide battery that had already been issued for various military GPS units. Its design consists of a cylindrical, olive drab tube of high impact plastic, with two circular contacts on one end, the outermost annular-shaped contact being the negative terminal and the innermost disk-shaped contact being the positive. A small plastic tab secured under the label is present to discharge the battery before disposal.

The BA-5800/U is engineered and manufactured to meet and exceed US MIL-SPEC and ISO9000 methods and procedures and also meets the requirements of MIL-PRF-49471/11A with reference to MIL-STD810 for Voltage, Electrolyte leakage, and Insulation resistance. These batteries, when used with the C420 have a service life of up to 8 hours in optimal conditions with a cutoff point below 4 volts. Market-wise, these batteries are proprietary, expensive, and their disposable design plus potential risk of toxic material off-gassing contends with the advantage of an 8-hour service life.

Numerous manufacturers offer these batteries.

4.5V and 8.4V Nickel-Metal Hydride Rechargeable Battery[]

Wanting to improve the value of the C420 CASU, companies began marketing rechargeable batteries for their blowers, in order to offer a reusable upgrade to the standard, disposable BA-5800/U LiSO2 6V Batteries. These commercial rechargeable batteries were comprised of several Nickel-Metal Hydride Cells inside a plastic outer tube of appropriate diameter. Due to the limited technology and hardware at the time, these early rechargeable batteries originally had a nominal voltage of 4.8v and had a service life of only 3.5 hours.

In addition to this, the batteries were significantly longer than the BA-5800/U, requiring an extended battery cap upgrade. Eventually, manufacturers such as MSA, Airboss of America, and Avon Protection began to offer an 8.4V Rechargeable Battery, which had the same 8-hour service life as a BA-5800/U. All PAPR rechargeable batteries were frequently offered as upgrade kits with Battery Chargers and Extended 'Green Cap' Battery Caps.

BK-002 Alkaline Battery Adapter Tray[]

Like the BA-5800/U, the BK-002 Battery tray was initially designed to fit in most military GPS systems, however unlike its disposable LiSO2 counterpart, the BK-002 is an extremely improper fit in the C420 due to the square shape and slightly large outer diameter. For this reason, this adapter is only popular among civilians who cannot afford to purchase disposable or rechargeable C420-intended batteries. Some of the modifications users have done to achieve C420 Blower compatibility is to file down the battery retainer clips for an easier fit as well as using a length of cord or a zip-tie to be able to pull the battery tray out of the blower unit again.

SC420 D-Cell Battery Pack[]

One of the more unique battery adapters offered by Sperian/Honeywell (and associated companies) is the SC420 D-Cell Battery Pack, which as the name implies, adapts the C420 CASU to run off four standard 'D-Cell' Alkaline Batteries. They are not often seen on the surplus market due to the awkward belt-mounted pack limiting the position of the blower itself and must be ordered from retailers at full MSRP.

Airflow Indicator (AFI)[]

The Airflow Indicator is a simple tool consisting of a plastic tube with freefloating plastic bead inside to measure the airflow of the C420 CASU to ensure optimal performance. The tube is inserted into the neck of the male-threaded outlet on the blower and the unit is powered on. If the plastic bead hovers below the marking on the outer tube, the battery must be changed and/or the blower must be replaced depending on whether the former improves the airflow rate or not. AFI's typically come boxed with C420 PAPR Kits, but may be purchased on their own.

Pouches[]

There are a great variety of tactical blower pouches designed for the C420 Blower, and each have their own history, warranting a category all its own. In this section, the variants and available part numbers will be broken down for reference.

AWS Inc.[]

Arnold's Welding Shop (later known as 'Advanced Warfighting Solutions') was one of the first companies to design a pouch to hold the C420 CASU. There is very little information regarding these blower pouches, and very few still exist on the surplus market. A large majority of the AWS Blower Covers were contracted specifically for U.S. Special Forces, and used primarily by Delta Force.

The pouch consists of an all-enclosing 1000D Cordura Nylon Shell with individual holes for the switchbox and canister ports. Two hook-and-loop flaps on each diagonal edge allows access to the blower's integral belt loops. The attachment system consists of a two web straps with Fastex Side Release Buckles and a large patch of hook fastener, both of which facilitated attachment to an SCBA bottle cover. This was to integrate the blower as a hybrid system, or 'Combination Unit Respirator'.

The AWS Blower Cover is confirmed to have been offered in U.S. Woodland and 3-Color Daytime Desert Pattern. It is unknown if any other colors or patterns were offered at any point. These pouches are not known to have any other method of installation.

Known Part Numbers/NSN's:

  • P/N 51241 - SCBA BLOWER COVER, DESERT DAY COLOR


London Bridge Trading Inc.[]

London Bridge Trading is a company deeply ingrained in U.S. Special Forces Equipment history, and like AWS, were one of the first companies to offer a pouch to hold the C420 CASU to a vest or SCBA cylinder. One would be hard-pressed to find many functional differences from the AWS Blower Cover, as they both are designed along the same pattern, and LBT's design may be a copy of AWS's. The main design difference comes in the shape of the holes for the switchbox and canister ports, which are hexagonal on the LBT pouch as opposed to circular of the AWS.

The LBT pouch also adds two small patches of '10-speed' elastic at each edge of the opening where the blower is inserted, likely to retain it better. As previously mentioned, the LBT Blower Pouches were offered in a standard MOLLE/PALS Attachment (designated with an 'A' after the part number), and a variant with several quick release buckles and a large patch of hook fastener material on the back for securing to a special cover for SCBA cylinders (designated with an 'B' after the part number). These pouches, despite being an 'oldgen' design, were still somewhat prevalent on the surplus market as late as 2018, however are starting to become rare.

LBT would go on to copy the subsequent Paraclete Blower Pouch with the LBT-6062C, but not much is known of this model and no physical examples are known to exist.

Known Part Numbers:

  • LBT-6062A - Modular Blower Pouch, Olive Drab
  • LBT-6062A - Modular Blower Pouch, Black
  • LBT-6062A - Modular Blower Pouch, Coyote Tan
  • LBT-6062B - Modular Blower Pouch, Olive Drab
  • LBT-6062B - Modular Blower Pouch, Black
  • LBT-6062B - Modular Blower Pouch, Coyote Tan
  • LBT-6062C - Enhanced Modular Blower Pouch, Olive Drab
  • LBT-6062C - Enhanced Modular Blower Pouch, Black
  • LBT-6062C - Enhanced Modular Blower Pouch, Coyote Tan

*Note - Examples of LBT-6062A are only known to exist in Black and Olive Drab and LBT-6062B has only one known specimen in black. Specimens of other mentioned colors or variations are not known to exist at this time. There is also reference of an earlier LBT-2181A and 2181B Blower Pouch that the 6062 Series replaced, however neither stock photos nor physical examples have been found and identified at the present moment.

Paraclete Armor & Equipment Inc.[]

Paraclete Inc. was a company that provided a major breakthrough in tactical equipment design of the period, and C420 Blower Pouches were no exception. The Paraclete Blower Pouch was a radical breakthrough from previous designs, this being that the Paraclete Pouch fastened with a Y-shaped flap over the front of the blower, rather than the blower needing to be inserted from the widest end at the bottom. This design not only make the blower easier to insert, but the blower could also be removed while the canisters and hose were still installed.

In addition to all of these advantages, the Paraclete Blower Pouch also allowed the use of Rechargeable Battery Caps and Remote Cable Assemblies, as the tolerances were much looser than previous designs, however the batteries still could not be replaced while the blower was in the pouch. The Paraclete Pouch was made in a wide variety of patterns and colors, as well as having two amendments to its part number over the years. The Paraclete pouch is also currently the cheapest and most common pouch on the market, however Coyote Tan and 'Smoke Green' (Ranger Green) seem to be the only commonly available colors on the surplus market.

Known Part Numbers:

  • MBP0019-BK - POUCH, BLOWER, M-45 PAPR, BLACK
  • MBP0019-CB - POUCH, BLOWER, M-45 PAPR, COYOTE BROWN
  • MBP0019-DC - POUCH, BLOWER, M-45 PAPR, DESERT CAMOUFLAGE
  • MBP0019-MC - POUCH, BLOWER, M-45 PAPR, MULTICAM
  • MBP0019-SG - POUCH, BLOWER, M-45 PAPR, SMOKE GREEN
  • MBP0019-UN - POUCH, BLOWER, M-45 PAPR, UNIVERSAL CAMO (UCP)
  • MBP0019-WC - POUCH, BLOWER, M-45 PAPR, WOODLAND CAMO

*Note - The Part Designations changed over time from 'POUCH, BLOWER, M-45 PAPR,' to 'BLOWER POCKET' and finally 'BLOWER POUCH'. These designation changes likely had little impact on the timeline of available patterns. Physical examples are only known at the time of Paraclete Blower Pouches in CB, MC, SG, and WC.

Blackhawk! Tactical Gear Inc.[]

The Blackhawk STRIKE MOLLE Gas Mask Blower Pouch is little more than a Paraclete clone with the difference that the MOLLE/PALS Webbing on the back panel is of the standard 'Natick' type with Scovil DOT Fasteners rather than Paraclete's Patented 'Soft Snap'. Despite this, the Blackhawk Blower Pouch remains one of the most popular designs being used by SOF and EODMU alike, and it is still in use with Army Chemical Battalions to this day, despite being a discontinued item. There was also a variant with belt loops, rather than the typical MOLLE webbing.

Known Part Numbers:

  • Blackhawk 37CL50BK - STRIKE Gen-4 Molle System Gas Mask Blower Pouch, Black
  • Blackhawk 37CL50CT - STRIKE Gen-4 Molle System Gas Mask Blower Pouch, Coyote
  • Blackhawk 37CL50OD - STRIKE Gen-4 Molle System Gas Mask Blower Pouch, Olive Drab

*Note - there does not appear to be any known part number distinction between MOLLE and Belt Loop Pouches.

TAG: Tactical Assault Gear[]

This pouch, whose part number is unknown and does not appear on any past or present catalogs found, was manufactured by Tactical Assault Gear, potentially on custom order for U.S. Naval Special Warfare Command. While an undoubtedly rare pouch, it is one of the most famous for being seen in photographs of U.S. Navy Explosive Ordinance Disposal Mobile Unit Eleven (EODMU-11) during exercises in 2009, and may have also potentially been used by Navy SEAL and VBSS Teams as well [citation needed]. The pouch has not yet been fully confirmed as being a production item, however given the lack of documentation and photographs of the pouch in use, it is hard to determine either way.

The pouch consists of a stiffened back panel as previously referenced, which rather than having the walls and flaps that would comprise an encapsulating pouch, instead this design opts for two 1" Web Straps, which cross over each other, loop through two ITW LoopLoc Rings along the diagonal edges, and fold over to fasten with hook-and-pile fastener. On the back of the panel, there is a row of PALS Webbing used to secure the assembly to a plate carrier or tactical vest, however the PALS is placed in such a way that the panel can really only be installed so that the hose outlet points downward. It is an extremely simple, effective, yet perhaps somewhat underbuilt pouch.

*Note - the designation "MOLLE C420 Blower Panel" is an approximation based on other product designation patterns. Only one known surviving example exists and there is no company part number or catalog reference material currently known regarding this panel.

Eagle Industries Inc.[]

*Note - Almost nothing is known about the Blower Pouch that Eagle Industries developed. Further citations are needed regarding the current information featured in this article.

This experimental pouch developed by Eagle Industries has no known history, service photographs, or record of existence in available Eagle Industries Catalogs. It is a very robust and well-functioning pouch which functions on similar design principles as the older AWS and LBT Pouches, except that unlike older pouches, it allows hot-swapping of the battery while in the pouch as well as allowing the use of remote cable switches, thanks to its open-ended bottom flap, which secures with a patch of hook-and-pile fastener and a 3/4" fastex buckle.

Of additional noteworthiness is the curious design of the switchbox being completely shrouded by the upper flap and the strange tab of 2" Webbing which is held captive to the pouch with a single DOT Fastener Snap and brandishes a loop of elastic shock cord on one end. It is currently believed this feature was meant to be looped around the toggle switch of a single-speed C420 CASU [which EODMU-11 is also known to use over the SOF-preferred 3-Speed Blowers], which presumably would have allowed user to switch the blower on while it was off and being worn on the back - a simple rip on the tab would flick the blower into action.

As implied before, there only known specimen and it is unknown in what quantity these were produced, if and in what other colors were potentially produced, or even down to what specific branch contracted or tested the design. Eagle Industries is not known to have any other blower pouch designs.

Known Part Numbers:

  • MBP-C420-M5 - [Description Unknown], Khaki

Crye Associates, LLC.[]

An experimental C420 Blower Pouch of unknown designation appears as part of a Personal Air Ventilation System (PAVS) Ensemble for the Kokatat AP-PPE CB Overgarment during Future Force Warrior trials. It is believed to have been custom-made by Crye Associates LLC. for testing and experimentation, due to their heavy involvement as the designer of multiple other experimental uniforms and pieces of armor, field equipment, helmets, weapons systems, and more which saw use during the Future Force Warrior trials. Due the blower pouch being a prototype item, it is unlikely very many survive, and none are known to physically exist as of current.

Ministry of Defence/Unknown[]

While most C420 Blower Pouches are U.S.-designed and manufactured, there exists one pouch for the C420 CASU developed for the British Government. It is generally known who manufactures the aforementioned pouch, nor how it was intended to be used, as the pouch has no accommodations to thread on any form of filter canister. Markings defer that it was intended to be used in conjunction with a 'Casualty Bag', presumably in a similar sense to the U.S. Chemical Protective Patient Wrap, but the similarities end there.

The pouch opens with a large flap on the front with hook and pile strips and several 'Pull-The-Dot' fasteners. It is constructed of an olive drab nylon material and Instead of canister ports, the pouch has two inlets of 7 eyelets that allow air to pass through the pouch, making the blower impossible to use for CB protection while in this pouch. Two large pockets along each edge serve an unknown purpose, a clear vinyl window is present to observe the blower's battery life alarm LED, and a 93 Pattern PLCE Web Belt Adapter is present on the back, similar to that seen on the S10 Haversack.

NATO National Stock Number:

  • 6532-99-869-3213

FirstSpear Inc.[]

FirstSpear is a modern tactical equipment company known for their innovative laser-cut plate carriers, pouches, and other gear. While it does not appear on any of their product lists or catalogs, FS does have one C420 Blower Pouch in their history. They are not obtainable through FirstSpear themselves and are entirely custom contract for Airboss to supply with their C420 Kits. It is unknown if they are still produced.

The construction pattern follows a similar profile to the original AWS Inc. Blower Cover - an all-encapsulating cordura pouch that surrounds the entire body of the blower with the only openings being a hook-and-pile closure flap at the bottom and round, individual cutouts for the canister ports, the hose thread, and the switchbox. However, the similarities end here, as the FS C420 Pouch is built of noticeably thinner-grade material, lined with with nylon taffeta and loop fastener material, and of course, being entirely laser-cut templates to eliminate the need for edge finishing. This reduces production cost and gives a precision appearance, but also substantially weakens the integrity of the pouch, making it much more prone to tearing.

The attachment system consists of two lines of First Spear's 6/9 Laser-Cut MOLLE System, with belt loops on either side. This design, while saving cost, effectively makes the pouch self-destructive, as stress on the 1-ply material will warp, widen, and eventually tear through over time. Only one specimen is known to exist in black, and it is unknown if other colors exist.

Known Part Numbers:

  • 10-00889 - C420 PAPR Pouch (Black)

Tyr Tactical Inc.[]

Another modern gear company, Tyr Tactical is the main and current producer of C420 Blower Pouches, supplying the U.S. Government as well as Law Enforcement and Civilians with a modern, simple pouch based on proven designs. The Tyr Blower Pouch is based on the Paraclete design, but with several improvements - the outer flap does not cover the ends of the battery compartment, allowing for extended rechargeable battery caps as well as remote switch pouches to not only be installed, but changed/removed while the pouch is in place. The outer flap is secured with not only two patches of hook-and-loop fastener, but also a DOT Durable Line 24-style Snap Fastener on each 'wing' for extra retention security.

The back panel of the pouch is plastic-reinforced and uses a simple but very effective MOLLE/PALS webbing matrix that does not need improvement. Tyr also offers their Blower Pouch in the form of a Zip-on Back Panel for their PICO line of plate carriers.

Known Part Numbers:

  • TYR-ODC420-BLK - Ordnance/ Breaching Pouch - C420 PAPR, Black
  • TYR-ODC420-CYT - Ordnance/ Breaching Pouch - C420 PAPR, Coyote Brown
  • TYR-ODC420-RG - Ordnance/ Breaching Pouch - C420 PAPR, Ranger Green
  • TYR-ODC420-MC - Ordnance/ Breaching Pouch - C420 PAPR, Multicam
  • TYR-CBZP420-DA-BLK - Direct Action Zip On Platform Chem Bio C420 - Black
  • TYR-CBZP420-DA-CYT - Direct Action Zip On Platform Chem Bio C420 - Coyote Brown
  • TYR-CBZP420-DA-RG - Direct Action Zip On Platform Chem Bio C420 - Ranger Green
  • TYR-CBZP420-DA-MC - Direct Action Zip On Platform Chem Bio C420 - Multicam

International Distribution, Issue, Copies[]

Other major nations soon saw the utility and advantage of the C420 CASU and began to procure small quantities of the blowers for similar purposes. Many countries, such as Romania, use the blowers for strictly decontamination purposes, mostly as a ventilation system for heavy impermeable protective suits. Other nations, such as Australia, Germany, France, and the United Kingdom issue it to their special forces and law enforcement agencies in a similar doctrine to the United States.

People's Republic of China - FNM010[]

The Chinese PLA FNM010 (or SV001) PAPR Blower is a direct clone of SafetyTech/Airboss P/N M-60010-001 - C420 Blower, 3-Speed, with Rotary Switch (NSN 4240-01-442-8415) and has little differences other than markings. Details of performance are relatively unknown, but it can be deferred from photographs that in terms of external layout and function, it is a near-exact copy with the primary structural difference being the lack of external belt loops molded into the outer casing. These blowers are featured with the FMJ10 Protective Mask quite frequently as part of a PAPR kit.

References[]

  1. TM 3-4240-342-10 - Operator's Manual, Mask, Chemical-Biological Aircraft: Apache Aviator, M48 (December 12, 1998) (PDF)
  2. SpecWarGear - M45 Chem-Bio Gas Mask and C420 Powered Air Purifying Respirator (PAPR)
  3. SpecWarGear - M45 Chem-Bio Gas Mask (Standard & PAPR version)
  4. Chemical Patient Wrap Demo (YouTube)
  5. Scott C420 Powered Air-Purifying Respirator (PAPR) © Brooke Clarke 2015
  6. U.S. Patent #US6929226B1 - Twist Lock Mounting System
  7. Micronel Part Numbers (PDF)
  8. SafetyTech Part Numbers (PDF)
  9. Dräger Part Numbers
  10. Tyco/Scott Part Numbers
  11. Scott Safety Part Numbers (PDF)
  12. North/Honeywell Part Numbers (PDF)
  13. BA-5800/U Battery Specs (PDF)
  14. MSA Responder CBRN PAPR
  15. TYR Tactical® Ordnance/ Breaching Pouch - C420 PAPR
  16. TYR Tactical® Direct Action Zip On Platform Chem Bio C420
  17. Collection of honggildong29
  18. Avon Protection Receives CBRN NIOSH Approval for Advanced Face Masks with C420 PAPR Unit
  19. Powered Air Purifying Respirator SV001
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