What it is
STANAG 4666 is the NATO Standardization Agreement on assessing how cast-cured polymer bonded explosives (PBXs), using an inert or energetic binder, change with ageing, in its first edition, promulgated 16 November 2016. Like some of the STANAGs it cross-references, it carries its own technical content directly: four annexes covering scope, principles and methodology, an accelerated ageing procedure, and a set of test procedures, rather than pointing to a separate Allied Publication for the specification. What a nation ratifies and what a laboratory runs to assess ageing are the same document.
Why a common approach matters
The agreement's own aim is to standardise "accelerated ageing and testing protocol" so that aged PBX samples "can be assessed and compared," wherever in NATO the work is done. That is a comparability problem, not an acceptance one: nothing in the document sets a limit for what an acceptable result looks like, and nothing in it evaluates how long a PBX-filled munition remains serviceable in storage. The scope is explicit on that second point: "This STANAG does not cover the evaluation of the service life of PBXs but only the characterization of ageing of PBXs." Deciding what a given change means for a munition's service life sits outside this agreement.
Four annexes, one specification
Annex A fixes the scope: procedures for accelerated ageing and testing that "allow assessment and comparison of PBX compositions," and nothing beyond that. Annex B sets out, in general terms, the principles behind how ageing changes a PBX and the categories of method used to track that change. Annex C sets out the accelerated ageing procedure a laboratory follows to age a sample under controlled conditions ahead of testing. Annex D lists chemical, mechanical, thermal and other test methods used afterwards to characterise what ageing has done to the material, several of which draw their own apparatus and procedure from a separate NATO STANAG (see below), together with a reporting sheet used to record and exchange each test's results. This page does not describe the conditions, apparatus or specific test methods those annexes set out; a laboratory needs them from the STANAG itself, not from a summary of it.
How it binds
A STANAG binds a nation, not a company. It "is promulgated by the Director NATO Standardization Office under the authority vested in him by the North Atlantic Council," and a nation implements it once that nation "has issued instructions that determination of ageing characteristics of PBXs shall be performed by the test procedures described in this STANAG." None of this reaches a supplier or a laboratory directly: it reaches one only when a contract, a tender, or a national requirement calls for an ageing assessment carried out under this STANAG.
What it does not cover
STANAG 4666 does not itself evaluate service life, set a numeric acceptance limit, or certify anyone. It standardises an accelerated ageing procedure and the test methods used to characterise the result, so that a laboratory in one nation and a laboratory in another are comparing like with like; what a national authority or a customer then does with that characterisation, including any judgement about remaining service life, is outside the agreement. The document also carries a plain warning: it "calls for the use of substances and test procedures that may be injurious to health if adequate precautions are not taken," and this "in no way absolves the user from the statutory obligations relating to health and safety at any stage during use."
Standards it references
Most of the sixteen documents on STANAG 4666's cover are STANAGs supplying the apparatus and procedure for one of Annex D's test methods: sensitivity tests draw on STANAG 4487, STANAG 4488, STANAG 4489 and STANAG 4490, with STANAG 4491 named as an alternative for one further property; mechanical tests draw on STANAG 4506 and STANAG 4540; thermal and stability tests draw on STANAG 4515, STANAG 4525, STANAG 4556, STANAG 4582 and STANAG 4147. STANAG 4170 is cited for comparability with qualification testing rather than as a procedure source for Annex D. STANAG 4507 is named on the cover without further elaboration in the text, and STANAG 4581 is the equivalent agreement for a different explosive type, composite propellants with an inert binder. AAP-03 is the administrative format STANAG 4666 itself was produced under, not a technical reference. Three further references named on the cover sit outside our catalogue: the UN Orange Book recommendations on dangerous goods, a US military packaging-material specification, and a commercial ASTM test-method standard.