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STANAG 4155
NATO member and partner nations ratifying AEP-4155, and the mask and filter canister suppliers who meet its thread requirement through a contract
STANAG 4155 is NATO's agreement committing member nations to implement AEP-4155, the screw thread dimensions that make CBRN protective masks and filter canisters interchangeable across NATO forces; it binds nations, not suppliers, directly.
STANAG 4155 is a NATO Standardization Agreement, currently Edition 2, promulgated 6 February 2019. It is not a technical specification. It is the agreement by which NATO nations commit to implement AEP-4155, Edition A, the Allied Engineering Publication that sets out the screw thread dimensions for CBRN protective masks and filter canisters. The document's own aim is to respond to an interoperability requirement: "to provide for full mechanical interchangeability between CBRN protective masks and filter canisters for NATO forces irrespective of national origin of masks and canisters" - so a filter canister made in one nation screws onto a mask made in another. Read on its own, STANAG 4155 requires nothing of a mask or filter canister manufacturer. Its obligations run to nations and to NATO bodies, and the thread dimensions themselves sit in AEP-4155, not in this cover.
STANAG 4155 is explicit that it binds nations rather than organisations. Its letter of promulgation describes the enclosed agreement as one "which has been ratified by member nations, as reflected in the NATO Standardization Document Database (NSDD), is promulgated herewith." Under "Agreement," participating nations agree to implement AEP-4155, Edition A - a national commitment, made by ratification, not a duty a supplier signs up to by reading this document. Ratification and implementation stay separate steps: nations that have not already done so are invited to "examine their ratification of the STANAG and, if they have not already done so, advise the NSO of their intention regarding its implementation." So "is STANAG 4155 mandatory" has no single answer: it depends on whether a given nation has ratified and implemented it, and this cover names no manufacturer, supplier or test house at all.
The STANAG states it "is effective upon receipt and ready to be used by the implementing nations and NATO bodies" - a NATO-wide mechanism, with partner nations separately "invited to adopt this STANAG." It is considered implemented once nations "have equipped the forces with CBRN protective masks and filter canisters with rolled threads conforming to AEP-4155; and by incorporating the provisions of this AEP into their national procurement specification." Nations are invited to "report on their effective implementation of the STANAG in accordance with AAP-03," and partner nations to report their adoption the same way.
The agreement states: "It is agreed within NATO, to retain the ability to use an RD 40 mm threaded canister in extremis on all negative pressure air purifying devices." It also records that "NATO recognizes alternative connectors (e.g. bayonet joints) between the mask and the canister have been developed and can be used alternatively." A nation that fields an alternative connector must still "equip at least the mask with the ability to convert the joint into an RD 40 x 3.63 mm (female) thread," a conversion the document says "needs to be performable." Once converted, "the requirements regarding tightness and protection factor according to AEP-71 and AEP-73 are to be achievable." Beyond that fallback dimension, STANAG 4155 prints no thread table of its own: the full geometry and tolerances sit in AEP-4155.
A reader who only has STANAG 4155 in hand does not yet have the thread dimensions it points to. Those sit in AEP-4155, Edition A, the publication named under "Standard." The STANAG also names STANREC 4727 (covering AEP-73, on protective mask operational characteristics and evaluation), STANREC 4725 (covering AEP-71, on fit and protection testing for negative-pressure respirators), and STANREC 4548 (covering AEP-38, on CBRN protective clothing), plus two civil standards outside our catalogue: EN 148-1 and ISO 17420-3, both on respiratory-device thread connections. Edition 2, 6 February 2019, supersedes an earlier edition of STANAG 4155 (the source text names the prior document but prints no edition number for it).
National responses on ratification and implementation are recorded in the NATO Standardization Document Database. The STANAG itself "is to be reviewed at least once every five years," with the result recorded in the NSDD, and "nations and NATO bodies may propose changes, at any time, through a standardization proposal to the tasking authority (TA)." The agreement is supervised under CNAD, AC/225 NAAG (the NATO Army Armaments Group) and JCBRND CDG (the Joint CBRN Defence Capability Development Group), with Germany named as custodian through Bundeswehr research into protective technologies.
STANAG 4155 names no thread dimension or tolerance table beyond the RD 40 mm fallback and its RD 40 x 3.63 mm (female) conversion requirement - the full specification sits in AEP-4155, which this agreement covers but does not reproduce. It also names no test method for tightness or protection factor: those sit in AEP-71 and AEP-73. And it names no assessment or certification scheme: the only stated check is that the STANAG itself is reviewed periodically, not that a nation, an organisation or a piece of equipment is certified.
STANAG 4155 itself gives a mask or filter canister manufacturer nothing to implement in software: it is an agreement between nations, and the thread dimensions sit in AEP-4155. Where this reaches an organisation is through a tender, contract or national procurement specification that has incorporated AEP-4155's thread requirement - and that work is physical, done on a lathe or thread roller and checked with a gauge, not in a compliance tool. ComplyTrain's usual footprint applies around it: holding the procedure describing which thread specification and edition of AEP-4155 a given programme is built to, as a controlled document; the training record showing the people cutting or rolling those threads know the specification they are working to; the design and inspection records held with their revision history; and the corrective-action trail if a gauging result comes back short.
ComplyTrain does not machine or gauge a thread, does not decide which connector configuration a programme uses, and does not certify a mask, a canister or a nation against this STANAG - NATO itself recognises no such certification. Our standards explorer shows what else sits alongside STANAG 4155, including AEP-4155 and the related fit, protection-factor and clothing standards it names - if you're weighing up what a tender or quality clause is actually asking of you, we're glad to talk it through.
Tell us how you need to work with STANAG 4155 and what you need from it. We will come back to you about what ComplyTrain can do.
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Not on its own. A STANAG binds a nation once that nation has ratified and implemented it, and this cover names no manufacturer, supplier or test house at all. Whether it touches a given organisation is a question for the tender or contract in front of you, not for this page.
STANAG 4155 is the cover agreement: it commits nations to implement AEP-4155 but contains no thread dimensions itself. AEP-4155, Edition A is the Allied Engineering Publication that sets out the actual screw thread dimensions for CBRN protective masks and filter canisters.
This cover names only one dimension directly: nations fielding an alternative connector, such as a bayonet joint, must still be able to convert it into an "RD 40 x 3.63 mm (female) thread." The full interchangeable thread specification and its tolerances sit in AEP-4155, Edition A, which this document covers but does not reproduce.
No. STANAG 4155 describes no certification or accreditation scheme. Its only stated check is a periodic review of the agreement's own currency, at least every five years, recorded in the NSDD. NATO does not certify a nation, an organisation or a product against a STANAG.
Edition 2, promulgated 6 February 2019, which supersedes an earlier edition of STANAG 4155 (no edition number for that earlier document is printed in the source text).
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