from ASA 93-6
FOCUS ON RESPIRATORS: THE SWISS TYPE SM-90 & SM-3
by Christopher Carey
One highly regarded aspect of the Swiss Confederation is the existence of a very sophisticated defense establishment. As if to remind us of this fact, just prior to the outbreak of hostilities in the Arabian Gulf (1991), the Swiss Gruppe fur Rustungsdienste (Defense Technology and Procurement Agency) announced the latest example of Swiss NBC protection technology to the world by introducing its newest chemical and biological (CB) military respirator.
The new mask, designated ABC Schutz-maske 90, has recently been joined by a modified version of the same design known as the SM-3. While the SM-90 model uses a front-mounted filter configuration, the SM-3 mask has been redesigned so as to be able to take the same filter canister on either cheek as well as in the snout position, giving it a far greater range of ergonometric utility. The new Swiss NBC protective masks, manufactured by Huber & Suhner AG of Pfaffikon, are the most recent evidence of a strong tradition of CR warfare protection awareness which has its roots in the decades immediately following the First World War.
In examining the latest modem Swiss military respirator family (SM-90 and SM-3), it is perhaps appropriate to take a brief look at the precursor Swiss CBW protective respirator designs, and review a bit of the history of previous individual protection efforts.
Despite the fact the Swiss Confederation does not maintain a conventional standing army, their policy of relying entirely upon an exceptionally well organized defensive militia has resulted in a concentrated emphasis on specialized regional defense that has long included CBW protection. Early in the decade following the First World War, heightened awareness of the importance of developing CR protection equipment resulted in the production of the first Swiss standardized field protective respirator for individual use.
This respirator, known as the ‘Gasmaske 33’, featured twin circular glass eye-pieces inset into a rubber face-blank covered with a cotton textile gauze. As the power of Hitler’s Third Reich grew, the lessons of CW use in the First World War were not lost on the Swiss Confederation. By the mid-to-late 1930’s and in anticipation of the possible use of CW in the event of war, this ‘Gasmaske 33’ became the standard for use by all elements of the Swiss national defense.
After years of continued reliance upon the Gasmaske 33 and as the additional threat of atomic weapons loomed in the late 1940s, the Swiss recognized that new developments were required. This led to the development of the Gasmaske 53, which incorporated the nuclear requirements as well as the requirement for updating the somewhat obsolescent face-piece. Additionally, the advent of new nerve agents mandated Swiss advances in filter compositions.
The Gasmaske 53 featured an entirely new rubber face-blank without a textile outer surface layer but that again used circular twin glass eye lenses. It used a simple front-mounted, mushroom type expiratory valve and the same 5 strap head harness arrangement of the earlier mask. It featured a twin Tissot-type interior air flow arrangement to facilitate lens demisting and it used a new filter canister with similar external dimensions to the previous model. As with earlier models there was no voicemitter, and drinking devices were yet to be introduced as a standard NBC respirator feature.
In the early 1970’s the system was reviewed for the purpose of up-dating. While the black rubber face-blank was kept essentially unaltered with its Tissot demisting channels and non-reversed, flat lip seal (there was no interior oronasal cup), the older cylindrical canister on a long hose was replaced by a snout-mounted metal filter canister manufactured by Luwa AG that was screwed directly to the lower front of the mask. As an aside, Luwa AG ceased filter canister production in 1989. The 5 strap head harness was of elasticized fabric, and although somewhat different from the earlier style, not entirely dissimilar to the original mask retention system. With the later model masks, two alternative carrier satchels were in common usage. One was a proofed olive colored nylon satchel which could be worn in a number of ways and the other was of the older snout type carrying satchel design of canvas worn with a shoulder strap.
These early Swiss masks and their accessories were manufactured by Huber & Suhner, Lonstroff, Detwyler, and Maloya which were all major rubber products manufacturing corporations in Switzerland.
By the middle of the 1980’s, advancements in NBC protection technology as well as a better definition of the NBC threat, made it clear to the Swiss Gruppe fur Ruistungsdienst’s (GRD) chemical defense section that a new generation protective respirator was needed. In the design of the new respirator, consideration was given to the increased world-wide acceptance of advanced features such as the reversed peripheral face seal and inner oronasal cup for positive control of interior air movement. Additionally the importance of the need for improvements in the visual fields as well as an integrated drinking device and redesign of the lenses for weapons systems sighting use was recognized. The result was the development of the ABC Schutz-maske 90; a standardized design for use by all elements of the Swiss Confederated Defense Forces.
The SM-90 mask is today replacing the earlier SM-74 model as standard NBC issue. The plan calls for the transition from the SM-74 to the SM-90 to be fully completed in 1995. As mentioned previously, both the SM-90 and the new SM-3 variant share essentially identical design configuration and component features. An exception is that the SM-90 may only use a front mounted canister while the newer SM-3 mask allows for use of a canister mounted in either of three ports, one frontal and two lateral which provides for the maximum user convenience.
Both masks are very comfortable for extended wear. The new 6-strap 'mesh-net' head harness which the masks use is exceptionally well conceived to promote secure, comfortable face sealing and use of protective helmets without interference from buckles, etc. The elasticized fabric straps are joined to a non-stretching perforated nylon mesh panel which accommodates ventilation as well as adjustments quite well. This harness also allows rapid (9 second) donning with precision. It should be also noted that the incorporation of a 'mesh-net' head harness system was practically an original Swiss innovation; it has since become almost universally adopted in CBRN respiratiors
Whereas the SM-90 mask was developed by the GRD, exclusively, the newer variant SM-3 respirator is actually a proprietary Huber & Suhner design. It was engineered and produced in a cooperative venture with the GRD as a logical and innovative modification to the existing SM-90 design.
The face blank of both masks is made from polymeric compound rubber, a complex formulation of butyl/ethylene propylene diene monomer (EPDM). The wearer is provided excellent resistance to penetrative chemical agents. The filter canister screw thread conforms to current NATO (STANAG 4155) standards which means any NATO type filter may be used with the respirators. However, the current standard filter (as opf 1992-3) for the SM-90 and SM-3 masks, as used by Swiss Defense Forces, is manufactured by Protector Company, Ltd. of the United Kingdom.
A new carrying satchel fabricated from olive colored, proofed nylon is normally used with the SM-90/SM-3 masks. The satchel case features a quick release fastener on the top opening flap and is provided with a shoulder strap. Other types of custom fabricated carrying satchels may be made to suit the procurement requirements of international clients. These masks come with a pair of protective dark plastic eye outserts, as well as a special plastic fluid bottle to be used with the mask’s drink device.
Cold weather characteristics of the new mask include good internal demisting through controlled oronasal air movement. Additionally and with careful attention to design of components and face blank subassembly junctures, the possibilities for decontamination of the mask have been greatly facilitated.
As with most modern respirators, side-mounted accessory voicemitter devices (on the SM-3) may be used to enhance interface with telecommunication devices and blanking caps are provided to secure unneeded filter canister attachment ports. A strong suite of the SM-90 and SM-3 respirators is their functional simplicity and sturdy fabrication. The quality in the design and manufacture of this series is evident and characteristic of the well-known reputation for product excellence for which all Swiss designed and manufactured goods are famous.
At present, the SM-90 and SM-3 respirators are being export-marketed by both the Inter-CB Corporation of Bern and the Huber & Suhner Cpmpany of Pfaffikon through a joint agreement.
Further substantiation of the design integrity of the new Swiss masks may be found in the selection of the SM-90 by the South Africans for license production. Protechnik Laboratories (Pty) Ltd., based in Randburg and one of the largest scientific laboratories in Africa, conducted an extensive two year evaluation of most of the world’s modern protective NBC respirators. This Protechnik evaluation determined that the Swiss design was the best for meeting the South African requirement, ranking it among the very best available ion the entire world at that time.
Overall, the impression created by the new Swiss SM-90 and SM-3 protective respirators is excellent. With quality of design and development, high-grade component fabrication and assembly and above all superb fit and wearer comfort, these Swiss respirators rank among the very best of the new generation military NBC protective masks which are being produced today. The SM-90 and SM-3 do warrant serious consideration by all who may be interested in procuring a very high quality, well-engineered and sturdy military NBC respirator.
Today, due to the fact that only a very small pre-production run of the SM-3 was produced, the Swiss Huber & Suhner SM-3 CBRN respirator ranks is today ranked among the rarest of the rare by collectors.