The Canadian produced Respirator, Anti-Gas, General Service, Mark IV (or just the Mark IV General Service Respirator) is an Interwar and Second World War Respirator. Being an almost exact copy of the British Mk. IV General Service Respirator, this mask was one of the many starts to the modernization of the Canadian Armed Forces equipment pre-WW2. This design would see use alongside the Mk. V General Service Respirator and Light Anti-Gas Respirator until the end of the Second World War.
This article will likely be prone to change as more is resarched on it's production and usage. If you have any information that could benefit the article, please contact hungryforgsr on Reddit or Discord (simplisticname1), or if you make changes to the article please ensure you cite and format them correctly. Thank you!
History & Development[]
In the years leading up to the Second World War, personnel within the Canadian Armed Forces were lacking in modern equipment, still training with First World War technologies. This included Canada's anti-gas equipment, with them still likely relying on the dated Small Box Respirator. However, with tensions slowly rising in the thirties and the effects of gas still being fresh on the minds of Canadians, it was quickly realized that Canada needed to prepare themselves with up-to-date equipment for a potential conflict, including their respirator design.
A particular officer in the Canadian Armed Forces, Major G.P. Morrison, was tasked with finding newer alternatives to Canada's aging anti-gas equipment. Initially, it was thought an easy solution to this problem would be to simply import British made anti-gas equipment, but the Department of National Defence shut this idea down as they had a greater interest in being able to produce equipment domestically. A problem quickly arose with this interest however, which was that Canadian rubber companies lacked both the tooling to manufacture faceblanks, as well as the mixing recipe and vulcanizing method for making service grade rubber, primarily due to British rubber companies not being keen on sharing these techniques. [1]
Eventually, Morrison had partnered with a Canadian industrial mining and industrial safety equipment company in 1932, Safety Supply Company, where Morrison would supply the manufacturing details on the Mark IV G.S. Respirator, while Safety Supply Company would figure out a recipe and vulcanization method for the rubber. Safety Supply Company initially had difficulties finding a plant suitable for producing rubber that would match serviceable standards, but would make a deal with Stokes Rubber Company. Unfortunately, after contacting them again at a later period of time, Stokes Rubber Company had come up with little to show for their efforts.
Their reason for coming up with so little was due to them having difficulties with the molding process and concluding that press machine molds should be used more freely over hand-molding [2], but upon the plant being visited by Morrison, it had been concluded their plant was entirely unsuited for large scale manufacturing of faceblanks. [3] Safety Supply Company would later partner with B.F. Goodrich Company instead, with Morrison also stating a new interest in manufacturing the rubber connecting tubes seen on G.S. Respirators in addition to the faceblanks. Unsurprisingly, the mold needed for the hoses had yet to exist in Canada, so this was left up to B.F. Goodrich to manufacture. [4]
Finally, proof of concept faceblanks were developed and submitted to the Department of National Defence for review, which although having defects were good enough to warrant continued production after refinement. Morrison would later supply B.F. Goodrich with additional specifications on making the stockinette material for the faceblank and hose. Unfortunately, production would be delayed again after some engineering drawings would be misplaced. [5]
The Canadian Armed Forces would later approve an additional 10,000$ in 1935 - 1936 to the development of these respirators, with the intent of having them be ready as soon as possible [6]. This would also attract another Canadian rubber company, Gutta Percha & Rubber Limited, with a representative from Gutta Percha stating that their production equipment would be able to meet specifications, and upon being inspected, was found to be true. The only catch was that Gutta Percha had only been outfitted with the capacity to make rubber footwear, but this was easily fixable [7].
Another issue had arose, which was the lack of suitable manufacturers for the smaller pieces of hardware (i.e. eyepieces, head-harness components, etc.) in the Ontario area (where most of the discussed rubber plants up to this point were based) [8]. It was concluded that companies from across the country would have to assist in the manufacturing, with components being sent to Dominion Arsenal for final assembly. After final prices had been arranged and approval was made by General McNaughton (president at the time of the National Research Council) on the rubber components of the respirator [9], limited orders for production were made.
Containers at this point had yet to be researched and developed properly, but the War Office stated they would send specifications for them eventually. In the meantime, 3,550 containers would be imported from the U.K. for use on Canadian G.S. Respirators [10]. Canada was finally approaching self-sufficiency for production of anti-gas equipment, but as of 1936 - 1937, B.F. Goodrich was the only company capable of manufacturing faceblanks since Gutta Percha was still undergoing changes to be capable of producing anti-gas equipment [11]. After a sampling was made on 340 completed Canadian facepieces in 1936 - 1937 however, it was found only 125 were acceptable, with the rest having defective eyepieces, porosity, and uneven rubber thickness [12].
The troubles had yet to end however, as the government then stalled on approving an initial order of 11,000 facepieces. In addition to this, the estimated $32,000 that was needed to complete this order was withdrawn, further pausing mass production until 1938 [13]. Finally, by mid-1938, production had started with more than a dozen companies manufacturing needed components [14].
Container Development[]
As stated prior, container development had yet to be researched and developed properly, as facepiece production was still being finetuned. Eventually in 1938 - 39, Canada had made detailed investigations on domestic production of containers, specifically the Type E [15]. Fortunately, production of these containers when compared to facepieces are much more straight-forward, allowing for easy production.
Ontario Metal Specialties would be the first Canadian company to manufacture No. 4A housings, but General Steel Wares would later produce a much higher amount of them. At this point, the filling materials to these canisters was still moderately unknown to Canadian manufacturers due to the War Office not sharing details, and had to be imported from the U.K.
It also been noted that Canada produced a specialized version of the Type E Mk. VI filter, referred to as the "green dot" container. These were made when chemical warfare experts found the Type E Mk. VI to be lacking in protection against cyanogen chloride and hydrogen cyanide, so they were upgraded to be able to filtrate these chemicals. This variation in container is still undergoing research.
Design, Component Designations & Identification[]
Facepiece Designations[]
Mark IV[]
Similar to British examples, the Canadian made Mark IV facepiece is coated in stockinette, alongside earlier produced connecting tubes. Later produced connecting tubes lack this stockinette cover. A difference noted in Canadian facepieces when compared to British facepieces is the thickness, as the rubber faceblanks seen with Canadian Mark IV G.S. Respirators seem to be thicker than their British counterparts.
The faceblank itself is referred to as the "No. 4 Rubber Mask", and it is currently unknown if Canadian facepieces were ever made with gum rubber, but it is highly unlikely.
Sizes Available: Small, Normal, Large
Mark IV Special T[]
The Mark IV Special T utilized increased pressure at the temples to allow for easier wearing of spectacles while having the respirator donned, as well as to ensure a proper seal. The faceblank was referred to as the "No. 4 Special T Rubber Mask".
Sizes Available: Small, Normal, Large
Mark IV Special T-Mic[]
The Mark IV Special T-Mic added a microphone port onto the left cheek of the mask to allow for easier communications over radio. The faceblank was referred to as the "No. 4 Special T-Mic Rubber Mask".
Sizes Available: Extra Small, Small, Normal, Large, Extra Large
Guards, Valve, Checkplate & Seating[]
Mark II Valve Guard:[]
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An example of a Canadian made Mark II Valve Guard - Pender Islands Museum
The earliest pattern of valve guard that can be found on Canadian produced Mk. IV General Service Respirators is the Mk. II valve guard. This pattern is rare likely due to it only being produced in small amounts during 1936 - 1937 before being replaced by the more common Mk. IV & V valve guard upon mass production being resumed later in 1938.
Mark IV Valve Guard:[]
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An example of a Canadian made Mark IV Valve Guard - Unknown Collector
Although very uncommon to find on Canadian made Mark IV G.S. Respirators, the Mark IV pattern of valve guard does exist. This looks visually close when compared to British made Mark IV valve guards with the 20 larger holes, but seems to differ as it doesn't utilize wire gauze and has a checkplate. The dimensions of the captive nut also don't seem to differ greatly, so it is unclear what differentiates this valve guard in comparison to Canadian Mark V valve guards besides the "IV" marking.
Mark V Valve Guard:[]
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An example of a Canadian made Mark V Valve Guard - hungryforgsr
Being the most common type of valve guard found on Canadian examples, the Mark V looks the exact same as the Canadian variant of the Mark IV valve guard. Every example seems to be also paired with a checkplate, unlike some British examples where the outlet valve can be seen.
Mk. I Checkplate[]
Designed to keep the outlet valve protected and secured, Canadian made Mk. I Checkplates appear to be no different visually than British made ones (besides manufacturer markings). However, an interesting thing to note is that, unlike British Mk. IV GSRs, Canadian made Mk. IV GSRs almost always will have a checkplate (not including Canadian made Mk. IVs with Mk. II Valve Guards), making them easier to distinguish.
Mk. I Seating:[]
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Valves, Inlet/Outlet[]
Inlet Valves[]
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Outlet Valve No. 2 Mk. I[]
One of the many parts of the valve assembly, the outlet valve is responsible for allowing the wearer to exhale without breaking the seal of the mask. The Outlet Valve No. 2 Mk. I is extremely uncommon on Canadian masks, likely only being found with Mk. II Valve Guards/earlier made Mk. IV Valve Guards (speculative), but can be characterized by its red colouration.
Outlet Valve No. 2 Mk. II[]
Being the most common type of outlet valve on Canadian made Mk. IVs and Vs, the No.2 Mk. II Outlet Valves can be characterized by its green colouration.
Valve Holders[]
No. 4 Mk. II[]
The No. 4 Mk. II Valve Holder appears to be the only kind used on Canadian Mk. IV GSRs, unlike its British counterpart that has multiple. Potential Canadian alternatives are still currently being researched.
Eyepieces[]
Most of the information seen below is taken from the Mk. IV General Service Respirator article due to similarities in British and Canadian eyepiece designs.
"Snap-On" Eyepieces:[]
Being present on very early Canadian Mk. IV GSRs (possibly only 1936 manufactured examples), these eyepieces were presumably of a two-piece design, with connection occurring by locking the pieces into one another through pressure. This type of eyepiece was likely made in limited amounts as by the time production had restarted in 1938, the Mark III Eyepieces were available. (pictures to be inserted soon)
Mark III Eyepieces:[]
The Mark III Eyepieces are the most common type of eyepiece seen on Mark IV G.S. Respirators, with them being seen on examples from approximately 1938 all the way up until the end of the war. The Mark III Eyepieces can be found in two variations, which will be referred to as "Mark III Eyepieces A" and "Mark III Eyepieces B" due to lack of clarification between the two designation-wise and for distinguishment.
"Mark III Eyepieces A" are comprised of the lenses, gum rubber seal/ring, and threaded outer caps. The eyepieces made this way to allow for easy removal of damaged lenses and replacement while in the field. To remove the lenses, expose the outer ring and rotate counter-clockwise, which will expose the lens in its entirety, where it can be popped out (which will break the gum rubber seal around the lens).
"Mark III Eyepieces B" were likely made to succeed the original "Mark III Eyepieces A" due to them being seen much more often on late war produced Mark IV & V G.S. Respirators, with the primary difference being in the removal of the outer threaded cap and addition of a more secure threaded eyepiece. Removal of these eyepieces would be achieved through a specialized tool that would be inserted into the slots, and then would be turned counter-clockwise which would allow for removal. This type of eyepiece would later be reused (and redesignated) with the Light Anti Gas Respirator.
Head-Harnesses[]
A comparison between both a British and Canadian made No. 4 Mk. III Head-harness - hungryforgsr
There was only one type of head-harness used with Canadian made Mark IV G.S. Respirators, which was the No. 4 Mark III. Like the British naming system, the full technical name for a Canadian head-harness would be in the format "Buckles, Loop" or in this case No. 4 Buckles, Mk. III Loop.
No. 4 Mk. III:[]
Head-harness No. 4 Mk. III consists of a rubberized skullpad and features individual elastic webbing (straps) fed through a system on the skullpad, all reaching 6 points on the respirator faceblank. Canadian made No. 4 Mk. IIIs differ visually with markings than British made ones, with the font typically being yellow and larger with Canadian examples.
Tubes, Connecting[]
Short-Type:[]
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Containers, Anti-Gas[]
Type E:[]
The only domestically produced containers made by Canada were all apart of the Type E series, with examples of Canadian made Type E Mk. Vs and Type E Mk. VIs existing. It is currently under research if Canada made Type E Mk. IVs. Taken from Greenlizard56's section on the Mk. IV General Service Respirator page: "Type E filters consisted of a filtering matrix of fibre pads and activated charcoal. The fibrous pad section of the filters was comprised of Merino-Wool noils and asbestos fibres. The rationale behind the two-fibrous constituents was based on the fact that asbestos, whilst possessing inherently satisfactory filtering abilities, tended to mat (and consequently decreasing filtering efficiency and increasing breathing resistance), so the wool noils served to keep the asbestos fibres separate. Whilst the generally accepted ratio of 80% noil to 20% asbestos gave satisfactory filtering ability, Green (1936), notes that particularly fine asbestos ('fine' meaning its fibres are more fully opened) could potentially constitute only 5% of the filtering medium. Green also states that if the asbestos is poorer quality its ratio inside the filter should be increased, but must not exceed 30%. Crocidolite (blue asbestos) was preferred for military filter application as its fibres are much smaller, leading to less breathing resistance."
Type E Mk. IV
The Type E Mk. IV Container of the Type E series can be identified by its use of a brown paint. As with other containers in this series, the identification "E IV" will be bossed into the bottom plate of the container. It is possible Canada produced this variation of Type E Container, but this information is currently being researched.
Type E Mk. V
The Type E Mk. V can be identified by the "E V" marking on the base of the container and also by its "buff" colouring. Canada didn't produce many examples of the Type E Mk. V, likely due to the newer Type E Mk. VI design being avaliable, but examples do exist.
Type E Mk. VI The Type E Mk. VI is the most commonly seen canister with Canadian Mark IV G.S. Respirators, and can be identified by it's brick red colouring. This design would be used until the end of the Second World War. It isn't uncommon to find stamped P(X) markings on top (i.e. P2, P3, P4), and it is unknown what the significance of these markings is.
Type E Mk. VI "Green Dot"
As stated prior, sometimes Canadian made Type E Mk. VIs can be found with a painted green dot on top. These were made when chemical warfare experts found the Type E Mk. VI to be lacking in protection against cyanogen chloride and hydrogen cyanide, so they were upgraded to be able to filtrate these chemicals. It is unknown how these filters were updated to protect against these chemicals, however.
Haversacks[]
Mk. Va:[]
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Mk. VI:[]
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Mk. VII:[]
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Accessories[]
Container Sleeve (unknown designation)[]
It appears that the ARP had at one point produced sleeves for use with their Type E Containers. The amounts made and reason behind its production is unknown.
Known Manufacturers of Components[]
| Manufacturer: | Known Components Made: |
|---|---|
| B.F. Goodrich Rubber Company | Facepieces, Connecting Tubes, Outlet Valves, Skullpads, Inlet Valves |
| Gutta Percha & Rubber Company | Facepieces, Eyepiece Washers |
| Kaufman Rubber Company | Facepieces, Skullpads |
| Coulter Copper & Brass Company | Eyepiece Retaining Rings, Valve Guards, Fasteners |
| Dominion Steel & Coal Corporation | Binding Wire |
| St. Lawrence Steel & Wire Company | Head-harness Buckles, Loops |
| Canadian Die Casters | Valve Holders |
| W.E. Phillips Company | Lenses |
| Penmans Limited | Stockinette |
| Dominion Rubber Company | Eyepiece Washers, Rubberized Tape, Facepieces |
| Woods Manufacturing Company Limited | Haversacks |
| Belding Corticelli | Elastic Harness Webbing |
| Russell Manufacturing Company | Elastic Harness Webbing |
| Duplate Safety Glass Company of Canada | Lenses |
| Aluminum Company of Canada | Valve Holders |
| Byers Company Limited | Head-harness Buckles, Loops |
| General Steel Ware | Valve Guards, Eyepiece Retaining Rings, Container Housings |
| S.S. Holden Limited | Haversacks |
| Ontario Metal Specialties | Container Housings |
References[]
A good chunk on the production history of Canada's Mk. IV G.S. Respirators was taken from Andrew Iarocci's "A Unique Art"
- ↑ Morrison to NDHQ, 4 October 1934, HQ 56-23 (vol.1), LAC RG 24 vol.5918
- ↑ 18 December 1936, File 56-23 (vol.4), LAC RG 24 vol.5919
- ↑ “Visit to the Stokes Rubber Company,” February 1933, HQ 56-23 (vol.1).
- ↑ Carr to Morrison, 22 March 1934, HQ 56- 23 (vol.1)
- ↑ Morrison to NDHQ, 4 October 1934; Memorandum, Inspector Artillery Stores, 2 October 1934; Safety Supply Company to DND, 3 December 1934, HQ 56-23 (vol.1)
- ↑ Pearkes to CGS, 4 December 1934; Carr to CGS, 11 April 1935, HQ 56-23 (vol.1).
- ↑ Morrison tour report, 13 May 1935, HQ 56-23 (vol.1)
- ↑ Dominion Arsenal to DND, 13 August 1936, HQ 56-23 (vol.2)
- ↑ Table of Components for Face Piece No. 4 for Immediate Order from the Trade in Canada, October 1936; La Flèche to McNaughton, 15 August 1936, HQ 56-23 (vol.3), LAC RG 24 vol.5918.
- ↑ Memorandum to La Flèche, 18 January 1937, HQ 56-23 (vol.3)
- ↑ Carr to Master General of Ordnance, 20 April 1937, HQ 56-23 (vol.3)
- ↑ Memorandum to Director of Mechanization and Artillery, 25 February 1937, HQ 56-23 (vol.3)
- ↑ Pricing of components for Mark IV and IVa respirators; Morrison to DEOS, 20 July 1937; DEOS to Carr, 23 August 1937, HQ 56-23 (vol.5)
- ↑ HQ 56-23 (vol.6); Suppliers of Components for Canadian-Made Respirators, July 1939, HQ 56-23 (vol.8)
- ↑ Bode to CIAA, 19 April 1939, HQ 56-23 (vol.8), LAC RG 24 vol.5920