Gas Mask and Respirator Wiki
Gas Mask and Respirator Wiki

The GSR (General Service Respirator) is the current issue 5th generation protective mask of the British armed forces and Danish Forsvaret.


Dstl (Defence Scientific and Technical Laboratory) Porton Down was tasked with the concept development and proof of principle to identify, research, devise and develop technologies to meet the requirements of a new respirator for the British armed forces. The protection factors of the new respirator would be well in excess of current US and NATO standards. [1]The Initial business case was approved on 24 July 2002, followed by a competitive procurement between Scott Health & Safety Ltd (Skelmersdale) and Avon Protection Ltd (Melksham). These two contractors were required to further develop these core concept technologies, and provide Proof of Principle Prototype respirators that met the main performance requirements under three main headings of:

  1. Improving protection,
  2. reducing user burden,
  3. and improving equipment compatibility.[2] [3]

The technical performance of these prototypes were independently assessed and validated against the User Requirements Document (URD). The evaluation demonstrated that both contractors had viable solutions that would be compliant against all Key User Requirements (KURs) and the majority of Priority 1, 2 and 3 Individual User Requirements (IURs). [4]

Scott in conjunction with Design Reality came up with a number of designs over 15 months before one was chosen by the British MOD. [5]

The original project timescale was working towards an in-service date of the latter half of 2005, however it was not until 2004 following this 14-month assessment phase and a subsequent competitive selection program, Scott Health & Safety Ltd., (part of Tyco Fire & Security), was awarded the exclusive contract. [1] Scott were selected as the preferred contractor on the basis of the Value for Money that their tender offered, and the Main Gate Business Case was approved in October 2004.[4]

The initial contract was valued in excess of $70 million, with replacements, spare parts, and systems for new recruits, the potential total value of the contract, including the service life of the Scott GSR, was expected to be in excess of $200 million.[1]

Pre Production & Service issue[]

Early Trials masks.jpg

A quantity of 500 pre-production GSRs were manufactured for the User Trials. By March 2006 Common User Tasks, Special to Arms aspects and extreme climatic conditions were complete. A "hot weather" trial was completed mid-April 2006 in Australia confirming the GSR design against specific climatic categories. This trial is was scrutinised by the MoD Ethics Committee to safeguard the interests of the volunteers involved with the trial. The Design Acceptance meeting was set for 3 May 2006 to allow production to commence.[4] Following these trials, various issues where identified and following a parliamentary review in June 2006 [6]components of the mask were further updated and by approximately 2008 the finial production variant would be tested in the Honington trials.

The GSR was officially adopted in August 2010[7] and training was started in the following year, with the first masks going to the British Forces in Germany. It was noted in October 2011 that the production facilities at Scott Safety in Lancashire had been working two shifts a day to meet the demand and that 100,000 respirators had been manufactured to date. Over 30,000 of these had been shipped to Units during the first year of the 4 year roll out.[8] Various issues and production holdups lead to relatively low production volumes until 2012 with the original issue date being pushed back several times. The GSR eventually completely replaced the S10 in 2014 with the British army and by January 2015, 309,228 respirators had been delivered to the British Armed Forces.[9]

Following completion of Scotts contract with the MOD and acquisition by 3M, the British MOD changed their supply chain and awarded Avon Protection a 5-year contract to resupply and in-service support for the GSR in February 2018. Following a year of development work, samples of the GSR were provided to DSTL for laboratory testing and following successful completion of these tests the 'Avon' GSR was accepted into service in September 2019. [10]

It is noted that in service all parts from the two manufacturers are inter changeable with each other, to ensure there are no supply issues.



The chemically hard mask body and twin seal system are made of a proprietary butyl blend material. The facepiece of the inital 2005 test models have a gloss appearance with textured cheeks, that was revised in the 2006 examples to the matt finish as would be seen on the production facepieces. Both face blank and inner nasal cup are available in 4 different sizes. Size 1 being extra Large, 2 Large, 3 Medium & 4 small. The table below indicates the various combinations that are available to provide the best fit characteristics (10 combinations).

GSR Facepiece Compatible inner Nose Cup
1(XL) 1 or 2
2(L) 1,2 or 3
3(M) 2,3 or 4
4(S) 3 or 4

It is noted that size 5 x-small facepieces have been recorded, however these are suspected to be special order as they have not been noted in any trade literature.

In addition to a standard method of fit testing, sizing can be performed using the innovative Advanced Respirator Test System (ARTS) which is advertised to provide unprecedented protection levels supplied by the filtration system.

The visor is a single panoramic lens making it possible to integrate sighting systems, night vision goggles and other associated equipment. Historically the visor/facepiece has been a troubled element of the mask design, with both debonding and cracking recorded during testing. The issues seem to have been resolved with a the introduction of an alternative way of fixing the lense to the facepiece via welding and the introduction of a face former. Although the design issues with the visor where resolved from a performance perspective, cosmetically the welding quality was not really been successfully resolved until Avon took over production in 2019/20.

The Oro-Nasal Cup & Secondary Filter[]

In addition to the filtering capability of the primary canister the GSR has a “mask within a mask” concept incorporating a secondary filter system that provides additional particulate protection against biological and radiological material hazards. The inner oro-nasal mask provides a separate seal, not just an air guide, the respirator filters the air between the ocular (eye space) and breathing zones through the secondary filter which is rated N98. The main facepiece itself also utilizes a self regulating twin seal design that is advertised to provide maximum protection against inward leakage. The secondary filter particulate media is made from a durable hydrophobic polytetrafluoroethylene membrane which is water repellant and can therefore be easily disinfected. The porous PTFE membrane provides a low pressure drop particulate filter with a minimum 98% particulate efficiency.

The secondary particulate filter can be cleaned and reused using the following procedure as circulated by 3M :

  • Visually inspect secondary filter for signs of damage and contamination
  • Wash secondary filter in 1% solution of Trigene or similar non-abrasive detergent and rinse THOROUGHLY
  • Shake excess water from filter
  • Visually check by-pass micro tube is clear and uncontaminated
  • Allow secondary filter to dry naturally. Secondary filters that are wet, from sweating or immersion in water / cleaning fluid, can be air dried and re-used once dry. They should not be dried using artificially heated or forced volume air sources (e.g. hair/ hand dryers). Post cleaning of the FRR and prior to re-assembly, the secondary filter moisture clearance tube must be visually inspected to be clear of any contamination or blockage. If grossly contaminated and/or blocked, replace with a new assembly. Air dry in a non-contaminated area or follow the directions provided in the Operating and Maintenance Instructions provided with the full facepiece.[11]

The oro nasal cup in the 2005 mask is of a light grey colour, with the size number on the left had side of the secondary filter housing. The cup also has an extrusion that mates with a groove in the exhale housing structure. This arrangement was removed in the 2006 mask. The secondary filter in the 2005 dated mask is of a simple rectangular design with a close packed blue particulate membrane enclosed on 5 sides. This element was revised in the 2006 mask to a more wedged shaped filter with a less densely packed particulate membrane. The final production filters are a fan shaped design incorporating a moisture clearance tube.

The Exhale Valve[]

The exhale valve assembly comprises of the valve itself, the valve housing, and a dead space: a partially-enclosed space immediately outboard of the valve. The dead space is needed because all valves leak, and the dead space holds some of the exhaled air next to the valve and ensures that any back leakage is clean. The more clean air that is maintained within the dead space, the better the protection levels will be.[3]There are 3 different exhale structures that can be fitted to the GSR:

1, Fixed negative pressure for APR/PAPR use

2, Fixed positive pressure for AIrline & SCBA use

3, Switchable variable pressure structure operated via a lever mounted on the exhale cover. This option allows the operator to switch between RPE modes seamlessly in the hot zone.

As standard the negative pressure structure is fitted in the GSR, however the other two structures can be fitted for more specialist use and are more commonly associated with either the FRR or GSReS masks.

The Exhale Valve cover & Comms[]

The clip on exhale cover has evolved and there are many variations including standard covers, comms variants and covers with variable switches. As can be noted in the images below the early dated 2005 test GSR cover has 5 horizontal grill louvers, which was revised in 2006 to include 2 holes in the top of the cover which amongst other things allowed for integration of the Bowman PRC 343 microphone adapter. Some time between 2006-2008 the louver was further revised increasing the louvers to 7 number. Covers starting from around 2013/14 included an outline cutout for the variable switch lever. It has also been noted that some of the exhale covers have been cast in one piece and others in two pieces and mechanical fixed together.

The communication louver on the GSR mask is a snap-in replacement for the standard louver. Material construction of the louver has advertised to pass the EN 136 950°C Flame Test.(further citation needed) [10]The standard microphone incorporated into the mask louver is an electret condenser type (dynamic mic) that permits optimum integration with modern communication systems. Integration to the radio is possible, but to date the only dynamic microphones that have been noted seem to be limited to either the two pin Peltor or the Clansman connections. A voice projection unit (VPU) is available and is clipped on in place of the exhale cover. The VPU is compatible with the switchable exhale structure.

The Head harness[]

The 6-point mask harness is provided with the top 4 straps outfitted with adjustable stops that can be set to lock the harness buckles after fit testing to maintain selected fit. Only the bottom two straps need to be tightened when donning the mask and stop bars fitted here allow the fitted user to pull to the same tension every don. The rubber headharness on the 2005 mask does not have the date roundel and all six buckles are the same profile. The buckle roller is alot larger and formed in grey plastic. The 2006 dated mask differs with a date (06) now added to the rubber head harness and the top 4 buckles changing in profile. The rubber tab attaching the buckles to the face piece is also now shorter. Further revisions compared to the early 2008 dated production masks would include changing the grey plastic buckle roller to a metal pin, and the rubber head harness would have a '07' production date. The rubber '07' headstrap seems to have remained in production until 2018. The plastic buckles also where revised with textured ridges sometime around 2014. The only noticeable difference with the Avon manufactured straps is the date roundel with now includes 'A'.

The Drinking System[]

In addition to the standard Osprey 58 pattern canteen adapter, a “universal” adapter is available that will interface with any brand of backpack style reservoir system by incorporating the brand’s own connector. Mask hydration connectors have also been revised to meet the EN 950°C Flame Test requirements.(further citation needed)[12] The drinking system is designed to provide 500 ml/min flow capability. The canteen adapter has had minor revisions over the years and at least 4 variations have been recorded. It must be noted that the GSR canteen adapter is different to the Avon system and therefore a Scott lid is needed for using with the Osprey 58 pattern canteen.

The Filter[]

The filter design on the GSR is vastly different to most military respirators on the market at the current time. The filters have a bayonet lock system which self seals the filter port when the filter is removed, which allows filters to be swapped out more quickly and efficiently than the older 40mm threaded filters. This lock system also gives the user higher levels of protection during the filter changing operation. The CBRN teardrop filters come in a foil vacuum sealed packaging and have a 15 year shelf life when sealed and 4 months unsealed.

TEAR DROP CBRN FILTER Protects against CBRN Agents including Nerve agents: Sarin (GB), Soman (GD), Tabun (GA), VX. Blood agents: arsine (SA), cyanogen chloride (CK), hydrogen cyanide (AC). Choking agents: chlorine, chloropicrin (PS), diphenylchloroarsine (DA) and phosgene. Blister Agents: H, HD and L. Tear Gas (CN, CS, CR, OC) Toxic Industrial Materials – Chemicals (TIMs/TICs). Gases and vapours from organic compounds with a boiling point above 65ºC. Inorganic gases and vapours, e.g. chlorine, hydrogen sulphide, hydrogen cyanide. Acid gases and vapours, e.g. sulphur dioxide. Ammonia and organic ammonia derivatives. Solid and liquid, radioactive and toxic particles and micro-organisms, e.g. bacteria and viruses. Approved for use against: Ammonia, Chlorine, Chlorine Dioxide, Formaldehyde, Hydrogen Chlorine, Hydrogen Fluoride, Methylamine, Organic Vapours, Sulphur Dioxide, Hydrogen Sulphide and all particulate aerosols. Note: Capacity meets NATO Triptych D103 criteria. Tear Drop CBRN Filter also contains NO chromium as an impregnant. PART NUMBER: 7000670 NATO STOCK NUMBER (N.S.N) 4240-99-553-8969.[13]

Further research was completed with the aim of integrating self contained breathing apparatus (SCBA) and toxic industrial chemicals (TIC's).[8] The results of this research led to the development of the civilian Scotts First Responder Respirator (FRR), and the development of the MPRS (Modular Respiratory Protection System). The MPRS kit allows field modifications to the GSR to take the more conventional Stanag 4155/40mm DIN NATO threaded canisters.

The Carrier[]

There are two main respirator carriers (or field packs) associated with the GSR, with a 3rd identified as a possible trials example. Early Production kits where supplied with the Larger DDPM & DPM field packs, to be superseded buy the slightly smaller MTP carrier from around 2012. It is interesting to note that the 2012 Counter CBRN Aide Memoire listed the DMP haversack as the GP (General Purpose) and the MTP as the GM (General Maneuvers) haversack. Both GP & GM field packs would contain stud fasteners to allow for clipping in the GSR face former.

GP(General Purpose) Haversack.[]

The haversack, more properly called a ‘field pack’ ( NSN 4240 99 800 9601)is a large wedge shaped bag made of IRR Cordua nylon. Two patterns of camouflages are noted DDPM & DPM. With the roll out of the GSR in 2010 many service personnel on combat operations were still wearing DDPM uniforms, and where issued DDPM no 1 MK4A CBRN suits. The history is vague, but during this transition period a large quantity of haversacks for the new respirator were produced in the DDPM pattern of camouflage. It is not clear if these were intended for combat troops with the new respirator until MTP came into widespread use, or if they were trials items used during the testing phase of the GSR. Either way large numbers were produced and being obsolete are easily available on the collectors’ market. However although there are plenty of DDPM examples to be found, this would not be the case for the DPM variant, and it is unlikely that it was issued in large numbers due to its rarity today. It also must be noted that the photographed example is void of any NSN codes, and therefore possibly indicating trials use only.

GM (General Maneuvers) Field Pack .[]

By far the most common haversack is the MTP or GM Field pack (NSN 8465 99 434 6734), issued from early 2012 and currently still in service, with British and Danish military. This field pack is also available in Black with a NSN code of 8465-99-383-2959.

Scott Field Pack.[]

This carrier is often miss identified as a S10 haversack. Essentially this field pack is a scaled up S10 carrier, however it shares the same NSN code as the GP Field Pack (NSN 4240 99 800 9601). Although confirmation is needed it is likely that this carrier was produced for the GSR trials. Examination of packaging confirms the Field Pack was produced by Scott Safety in 2008, which would correspond with the 2008 Honington respirators Trials.

Haversack Contents[]

GSR Card[]

The GSR would be issued with a small log book in a fold out layout and contained within a clear plastic sleeve. The log book would record the owners details, including fit test, and corrective lens prescription, respirator harness setting, life Spares record, ARTS test stamps, any maintenance details and a user maintenance section on the back section of the log.

Fullers Earth Decontamination Powders[]

GSR kits contain blotching pads (DKP1) and a small puffer bottle (DKP2) both containing Fullers earth. Fullers Earth, is a naturally occurring sedimentary clay composed mainly of alumina, silica, iron oxides, lime, magnesia and water, in variable proportions. Fullers earth is sprinkled onto a soldier’s equipment to soak up chemical agents. DKP2 is used to force fullers earth powder into places that are inaccessible to the DKP1 pad. These bottles were carried in a soldier’s NBC haversack and can be found with green, black or white stopper cap. Wrapped around the bottle is a paper instruction sheet. The top of the packet has a V-notch to help the user rip open the packet, even when wearing gloves.

Chemical Detector Paper[]

As part of the CBRN kit soldiers have been issued with small sealed packets containing booklets of detector papers. These papers are designed to be stuck to the soldier’s CBRN suits and they will change colour if they come into contact of certain chemical agents. The paper is torn and stuck in a prominent position on your suit. The idea is the paper will detect the liquid chemical agent before you experience, or realise you are under attack by chemical agents. Two sets of detector papers are available:

‘Detector Paper Chemical Agent No2 Mk2 liquid one colour  ’, the most common and identified with a blue spine to the booklet. The paper is grey in colour and any type of liquid chemical agent will cause the paper to turn navy blue.


'Detector Paper Chemical Agent No1 MK2 Liquid three colour' a more sophisticated type of paper that can detect and identify a greater variety of chemical agents, Historically they came in a book with  green or black spines changing to no colour in more recent years. Three-colour detector paper will turn either red, yellow or green to indicate two types of nerve agent and one blister agent. None of the papers will detect vapour or gas attack.  

'Zip Lock Bag'[]

This bag contains the drinking straw, 4 clips to be inserted into the 4 uppermost buckles to fix the head harness once adjustment has been made. 2 clips to be inserted into the rubber head harness in the bottom straps as a sort of stopper. And a comms clip to be added onto the external drinking tube to help hold the Bowman PRC 343 microphone adapter


Often contents of haversack would also contain skin decontamination wipes and lens cleaning wipes.


While the lens itself has been tested to meet the EN 166 standard for safety goggle protection, there is always the need for additional forms of visor enhancement to meet different CONOPS. Tight fitting, rigid shaped lens outserts are available for additional protection against harsh environmental conditions, sunlight, flash and laser blindness. Outserts are easily fitted or removed, even when using gloves.

Corrective vision systems, including progressive lenses, are readily incorporated without affecting the safe and comfortable fit. The height of the Inserts can be adjusted by loosing a screw adjusting position and retighten screw


FRR -First Responder Respirator[]

The civilian version of the GSR designed to accept Stanag 4155 DIN 40mm threaded filter cartridges. Introduced to meet the protection needs of the global civil responder community against CBRN threats. Further information on this mask can be viewed here: FRR

GSRe -General Service Respirator 'Evolution'[]


GSReS -General Service Respirator 'Evolution Specialist'[]

By October 2011 the CBRN Delivery Team at Winterbourne Gunner had begun to investigate how the capability of the GSR could be expanded to meet emerging user needs. Two specific areas of interest were work had already begun was integration of the GSR with Self Contained Breathing Apparatus (SCBA) and the provision of extended duration protection against Toxic Industrial Chemicals (TICS).[8]

The “Evolution” of the GSR respirator to the GSRe / GSReS variants includes the ability to rapidly change between high performance GSR teardrop twin filters to global standard Stanag 4155/DIN 40 mm threaded filters as well as the capability to easily switch between negative and positive pressure operating modes permitting the use of multiple respiratory protection options, including in multi-functional combination respirator ensembles.[14][3]

GSReS Modular Inlet System[]

The modular inlet system is found on GSReS as standard, however a standard GSR can be upgraded with the MPRS kit. As shown in the images optional side fittings are chosen to adapt to a single alternate or two combined respiratory technologies. For example, the user may utilize the two inlet ports for a PAPR and an SCBA. Adapters are also easily configured in the field without the need for tools so that the operating modes can be changed.

GSReS Exhalation Structure[]

In addition to the standard twin valve negative pressure exhalation valve, two alternate structures are available as required for different operating modes. One alternative is a fixed valve usable with airlines or SCBA. Alternatively a variable exhalation valve with lever can be fitted to allow switching  between positive and negative pressures, similar in performance to Avon's FM53/54. For the exhale cover two sizes of levers are available, either long or short. The exhale cover also comes in various configurations  with or without comms plug allowing for integration of a dynamic microphone in either clansman or 2 pin configuration.


Dress States[]

Dress States. As per Counter CBRN Aide Memoire.
State Respirator Meaning
0 Nil Carried Respirator/1st set of IPE within Unit.
0C Respirator/Mask Carried 1st set of IPE within Unit.
1 Respirator/Mask Carried IPE carried or immediately available.
2 Respirator/Mask Carried Suit worn (hood down), boots & Gloves carried.
3 Respirator/Mask Carried Suit worn (hood down) & Boots worn, Gloves carried.
4 Respirator/Mask Carried Suit worn (hood up), Boots & Gloves worn.


Drill for Donning the GSR. as per Counter CBRN Aide Memoire.
1. Remove GSR from haversack, grasping it by the louvre (grille) cover.
2. Insert chin into the respirator, locating into chin cup and roll respirator onto face. With your free hand, grasp the harness.
3. Pull up and over the head firmly and drive harness down back of the head fully.
4. Smooth harness with hands from top to bottom to ensure it is not twisted and that the triangle of the harness is low and central on the back of the head.
5. Locate and tighten the bottom 2 harness straps by pulling the straps rearward until the stoppers are reached.
6. If the face seal requires further adjustment lift respirator from face by grasping PFCs, (filters) re-adjust as necessary. Allow respirator to re-seal on the face.


Drill for Doffing the GSR. as per Counter CBRN Aide Memoire.
1. Locate bottom 2 harness buckles, pull forward and downward until fully slackened.
2. Grasp the respirator by the louvre (grille) cover and pull the respirator 'forward' and 'up' to remove from face.
3. Return respirator to the hackersack, ensuring the harness is located over the front of the respirator. Store Respirator onto the 'former' (face form) inside the haversack ensuring that the witness mark is not visible. Note: When storing, it is imperative that the respirator is located correctly onto the former.





  1. 1.0 1.1 1.2
  3. 3.0 3.1 3.2 ADA452235: The UK General Service Respirator : Defense Technical Information Center : Free Download, Borrow, and Streaming : Internet Archive
  4. 4.0 4.1 4.2
  8. 8.0 8.1 8.2
  10. 10.0 10.1
  14. Cite error: Invalid <ref> tag; no text was provided for refs named :5