It essential that products designed to protect people and property undergo thorough testing. The staff at SJH Projects have carried out many explosive trials in the process of product development. We can help you exploit this experience to bring your own products to market.
The process starts with a consultation in which the end use and market sector requirements are discussed. Advice is then given on what level of testing, and where necessary, what formal test specifications should be followed. Liaison with the test ranges is then undertaken and all the planning other than test item manufacture is carried out on behalf of the customer. If required, the test footage/photos and data can be edited into a short movie or clips for presentations to potential customers.
Since 2007, SJH Projects has developed experience in the use of the draft NATO publication, AEP55 Vol 2. The function of this document is to define the conditions for testing vehicles against the effects of landmines. By closely following the protocols laid down within, researchers around the world can directly compare results. This will lead to a wider acceptance of test results and cut down on the need to repeat tests for different national authorities.
The document is exhaustive in its detail, controlling factors such as the ground conditions, composition of the surrogate landmine, the settings for Hybrid III crash test mannequins, the data acquisition and injury criteria to be employed.
The links forged with test ranges and facility providers has resulted in a team that is now used to working to this complex document and can deliver comprehensive results in a timely fashion.
Explosive blast testing is a highly specialized field of empirical science used to validate the resilience of structures, materials, and security equipment against the devastating effects of a detonation. Unlike computational fluid dynamics (CFD) modelling, which provides theoretical predictions, physical blast testing offers ground-truth data on how protective measures, such as blast-resistant glazing, doors, or vehicle barriers, behave under extreme, high-strain-rate loading. There is also a need for testing blast containment systems and the protection rating offered by armoured vehicles.
The core objective of a blast test is to replicate a specific Design Basis Threat (DBT) and measure the resulting interaction between the blast wave and the target.
The primary destructive force of an explosion is the shock wave, a thin zone of highly compressed air traveling faster than the speed of sound. Testing focuses on two main metrics: Peak Overpressure (the maximum pressure above atmospheric levels) and Impulse (the area under the pressure-time curve).
To capture this, engineers utilize piezoelectric or piezoresistive pressure transducers. These sensors are placed in two configurations:
Incident (Free-field) Pressure: Sensors placed parallel to the blast wave to measure the pressure of the wave itself.
Reflected Pressure: Sensors placed directly on the face of the target. When a blast wave hits a solid surface, it reflects, often magnifying the pressure by a factor of two to eight
Beyond the pressure wave, many explosive threats involve fragmentation—either from the weapon casing itself (primary) or from debris displaced by the blast (secondary). Assessing how protection measures stop or contain these high-velocity projectiles is critical for life safety.
In a test environment, fragmentation is often monitored using “witness screens” (typically made of plywood or thin aluminium) placed behind the target. By analysing the perforation patterns and the depth of penetration in these screens, testers can determine if the protective measure successfully prevented “spalling”—the lethal ejection of material from the rear face of a barrier.
Because an explosive event occurs in milliseconds, standard videography is only part of the solution and is used for wide view general effects shots. Blast testing relies on High-Speed Cameras (HSC) capable of frame rates ranging from 2,000 to over 100,000 frames per second for proper analysis.
High-speed filming allows engineers to:
Observe the exact moment of structural failure or deformation.
Track the velocity of fragments and how stable they are in flight.
Verify that the “stand-off” distance was maintained throughout the dynamic loading phase.
The validity of a blast test is entirely dependent on the precision of the setup. Small deviations in geometry can lead to massive variances in results. Documentation must include:
The Charge: The exact mass, shape, and type of explosive (e.g., TNT, ANFO, or C4), as different explosives have different “equivalency” factors.
Atmospheric Conditions: Temperature and humidity can affect the speed of sound and shock wave propagation.
Positioning: The precise “Stand-off Distance” (the distance from the centre of the charge to the target) and the “Height of Burst” (HOB).
There is no “one size fits all” for blast testing. The principles are applied through various international standards depending on the asset being protected:
ISO 16933/16934: Often used for glazing and windows, categorizing performance based on the level of glass fragments entering a room.
ASTM F2927: The standard for testing doors and frames under blast loads.
GSA/ISC Criteria: Specific to government buildings, focusing on protection levels (e.g., “Protection Level 1” for no damage vs. “Protection Level 4” for significant but non-lethal damage).
AEP55 Volume 2 & 3 examine the protection against blast for buried landmines and form IEDs.
By adhering to these rigorous principles, security engineers can ensure that when the unthinkable happens, the protective equipment functions as a life-saving barrier rather than a point of failure.
A discussion at the DSEI defence show in London posed the question on the possibility of adapting our Detsafe technology to safely contain an array
We have recently completed the design phase for a novel blast/pressure containment vessel. This will allow the customer to perform research and proofing of their
Steve Holland of SJH Projects participated in PASS 2025 ( The Personal Armour Systems Symposium) in Bruges in September. PASS is the premier technical event
