AEP-2902 non-ballistic test methods for combat helmets

What it is

AEP-2902, Non-Ballistic Test Methods and Evaluation Criteria for Combat Helmets, is a NATO Allied Engineering Publication, Edition A Version 1, promulgated in February 2019. It sets out how combat helmets are tested and scored for everything except ballistic performance: blunt impact, penetration by sharp objects, structural rigidity, retention and stability, coverage of the head, the helmet cover and mounting points, snag hazard, ageing and environmental durability, marking, flammability, primary blast durability, combat identification, human factors, and paint adhesion. Nations record their agreement to use it through STANAG 2902, the Standardization Agreement that covers this publication, in the same way every Allied Engineering Publication rides on the STANAG that ratifies it.

The document speaks to National Authorities and test facilities rather than to a helmet manufacturer directly. A National Authority decides which chapters and sample sizes apply to a given helmet programme, based on the role the helmet will fulfil - dismounted, mounted, parachutist, public order, engineering or maritime - and a test facility carries out the testing and signs the resulting report. A manufacturer meets the document only through whatever a specific tender or contract requires.

What is deliberately excluded

Ballistic test standards and methods, Behind Helmet Blunt Trauma, Back Face Deformation, and visual pattern or camouflage emissivity are all out of scope here. The ballistic testing lives instead in STANAG 2920, so a helmet accepted against AEP-2902 alone has said nothing about how it performs against bullets or fragments; camouflage emissivity is left to each nation's own requirements.

Blunt impact, penetration and structural tests

Blunt impact protection (Chapter 4) offers nine alternative test methods for the helmet shell, each borrowed from a different civilian standard - BS 6658, EN 397, ECE R22.05, FMVSS 218 - with its own drop height, anvil shape and pass threshold; a National Authority chooses the method that matches its own risk assessment. Visor and mandible guard impacts get their own dedicated rigs and criteria. Rotational blunt impact has no agreed test method yet: the document says plainly that it is not currently possible to define one reliably, and points instead to ongoing civilian research. Resistance to penetration (Chapter 5) drops a striker onto a helmet mounted on a headform wired to detect contact, using either a mountaineering-derived or a vehicle-helmet-derived method; the vehicle Type B standard is the one recommended. Structural rigidity (Chapter 7) cyclically loads the shell and checks afterwards for cracking, delamination and permanent deformation; any crack or delamination that runs through the shell thickness is an automatic failure.

Retention, coverage and mounting

Retention and stability (Chapter 8) uses three separate chin-strap tests - a dynamic drop-mass test, a static test with a simulated jaw, and a static test that clamps the helmet directly to simulate a blast pulling at the strap - plus a stability test and an ease-of-release test measuring the force needed to open the buckle under load. Coverage (Chapter 9) is assessed against anatomical landmarks - the nasion, the external auditory meatus, the superior nuchal line - comparing full-shell, high-cut, mid-cut and low-cut designs, and the additional facial coverage a visor or mandible guard provides. The cover must fit securely, resist tearing and fading in accordance with STANAG 2333, and be flame resistant (Chapter 10); mounting points must conform to STANAG 4694 or one of two rail designs set out in Annex B (Chapter 11).

Ageing, marking and blast durability

Age and environmental testing (Chapter 13) sets a minimum storage life of 10 years and a minimum service life of 5 years, and covers heat distortion, temperature shock, altitude and vibration - helmets in operational use or during storage and transport via wheeled vehicle, rail, air, or ship may experience vibration that loosens or causes de-bonding and fracture between attachment points or mechanical interfaces, which is the rationale for the vibration test even though it is optional. Every helmet is marked with its name, manufacturer, size, origin, date of manufacture, NATO stock number, contract, serial and batch numbers (Chapter 14). Flammability testing (Chapter 15) checks for liquid traps, self-extinguishing behaviour and flame spread on the cover material. Primary blast durability (Chapter 16) stands a dressed mannequin at set distances from a PE4 charge and visually scores whether protective items stayed attached and effective; a score of 1 or 2 is unacceptable.

Human factors

Chapter 18 is the longest in the document and covers head-size anthropometry against a sizing table, fit and adjustment, stability, ease of donning with gloves, physical and thermal comfort, mass, centre of mass, inertia, and situational awareness - field of view, auditory awareness, speech intelligibility - plus integration with body armour, eyewear, hearing protection, respirators, vehicles, weapons, load carriage and gloves. Most of it is subjective, rating-scale testing with representative users rather than instrumented pass/fail criteria; where a number does appear, such as the recommended upper threshold of 1.5 kg for user acceptance of a helmet's mass, the document is explicit that it is a recommendation rather than a hard limit.

What a National Authority actually checks

There is no accredited or NATO-awarded certification of a helmet or a company here, and the document is explicit that passing it proves only what it tests: compliance with this STANAG does not certify the adequacy of helmets to meet regulations for use on public roads or competitive events, by vehicle users. What happens instead is that a National Authority selects the chapters and sample sizes relevant to its own procurement, a test facility runs them, and the final report is dated and signed by an authorised representative of the test facility, referencing the chapters and tests conducted for the helmet's selected role.

Standards it references

AEP-2902 is covered by STANAG 2902, the Standardization Agreement nations ratify to use it. It points to STANAG 2920 for the ballistic, Behind Helmet Blunt Trauma and Back Face Deformation testing it deliberately excludes, to STANAG 4694 for one of its two accepted mounting-rail designs, and to STANAG 2129 and ATP-91 together for where combat identification patches sit on the helmet and cover. AECTP-400 is one of several vibration test methods the age and environmental testing chapter allows. Outside the catalogue, the document leans on civilian test standards it does not attempt to replace - STANAG 2333 for cover material properties, BSI BS 6658:1985 for blunt impact and penetration rigs, EN 960:2006 for headforms, EN 397:2012 and ECE R22.05 for alternative impact methods, and the EN 13087 series for retention, stability and field-of-view testing - none of which are catalogued here, so none are linked. As with all NATO documents, AEP-2902 is free of charge and not sold; it is retrieved from the NATO Standardization Document Database or through a national standardization authority, never from a third-party copy.

Standards it references

• STANAG 2920Background
• STANAG 4694Background
• STANAG 2129Background
• ATP-91Background
• AECTP-400Background