SJH Projects can assist you in conducting a blast vulnerability study of your building or facility. Utilizing our experience in testing building elements such as glazing and combining this with blast overpressure prediction software, we can help you determine the necessary safe stand-off distances or what additional blast mitigation measures should be considered.
We have conducted such blast vulnerability studies in the UK and abroad for both commercial and government facilities.
With this information, we can recommend actions to mitigate the threat. These may include alterations to limit the proximity of a potential threat, as well as changes to the facade and structure of the building. Additionally, procedural changes can be implemented to aid prevention and minimize potential casualties.
The predicted blast overpressures can be aligned with the widely used specification performance levels utilized by governments and manufacturers for testing and qualifying their products.
Much of the advice provided by SJH Projects is driven by a focus on business continuity and minimizing both actual and reputational damage.
A building vulnerability assessment refers to the susceptibility of structures to damage or failure when subjected to explosive forces. Understanding these principles is essential for architects, engineers, security professionals, and urban planners who aim to design buildings that can better withstand blasts, protect occupants, and reduce damage. Various factors influence a building’s vulnerability, including its structural design, materials, layout, and proximity to potential blast sources.
When an explosion occurs near a building, it produces a rapid release of energy in the form of a blast wave. This wave consists of a high-pressure shock front followed by a sudden drop in pressure. The blast wave impacts the building’s exterior, creating intense overpressure loads that can cause structural damage. Secondary effects include fragmentation from flying debris, fire, and ground shock transmitted through the foundation.
The vulnerability of a building depends on how well it can absorb, resist, or deflect these forces. The following principles outline key factors that determine building blast vulnerability:
A building’s structural system, comprising beams, columns, walls, and floors, plays a critical role in its blast resistance. Rigid, continuous load paths that distribute forces evenly are vital to prevent progressive collapse. Structures with weak connections or brittle materials tend to fail catastrophically under blast loads.
Reinforced concrete and steel frameworks generally offer better resistance than unreinforced masonry or lightweight construction. Buildings designed with redundancy, where multiple load paths exist, are less vulnerable because if one part fails, others can carry the load.
The shape of a building influences how blast waves interact with its surfaces. Flat, smooth surfaces tend to reflect blast waves, potentially intensifying pressure on certain areas. Conversely, curved or angled facades can help deflect blast energy away from the structure.
Orientation relative to the blast source is also important. Buildings with their narrowest profile facing the potential threat may experience less force compared to those with broad, flat surfaces exposed.
Materials’ strength, ductility, and energy absorption capacity affect vulnerability. For instance, reinforced concrete can absorb significant energy before failing, whereas brittle materials like glass and unreinforced masonry shatter easily.
Windows and curtain walls are typically the most vulnerable parts of buildings during a blast. Glass breakage causes flying debris, leading to injuries. Using laminated or blast-resistant glass, protective films, and window frames designed to contain fragments can reduce this risk.
The intensity of the blast wave decreases rapidly with distance from the explosion. Buildings closer to the detonation point experience higher pressures and are more vulnerable. The amount and type of explosive material, along with the environment (open space versus confined urban settings), also influence blast intensity.
Designing buildings in high-risk areas requires acknowledging these variables and implementing enhanced blast-resistant features accordingly.
The function of a building affects its vulnerability considerations. Critical infrastructure, government facilities, hospitals, and public assembly buildings require higher blast resistance standards because of their occupancy and importance.
Incorporating safe rooms, blast-resistant glazing, and reinforced structural elements helps protect occupants. Additionally, designing for controlled failure modes and safe evacuation routes mitigates casualties if a blast occurs.
The way a building interacts with the ground affects how blast waves and ground shock impact the structure. Soft soils may amplify ground motion, while rock or firm soil can reduce it.
Foundations must be designed to resist uplift and lateral forces caused by blasts. Isolation techniques, such as base isolators or shock-absorbing materials beneath foundations, can reduce transmitted forces.
Non-structural components, such as cladding, ceilings, lighting fixtures, and mechanical systems, often suffer significant damage during blasts, creating hazards for occupants. Securing these elements and selecting blast-resistant designs can reduce injuries and maintain functionality post-blast.
Architectural features that create recesses, overhangs, or narrow corridors can inadvertently concentrate blast pressures, increasing vulnerability in those areas.
Martyn’s Law is a proposed UK legislation aimed at enhancing the security of public venues and crowded places against terrorist attacks, particularly focusing on preventing and mitigating the impact of such incidents. Named after Martyn Hett, a victim of the 2017 Manchester Arena bombing, the law seeks to impose clear security responsibilities on owners and operators of public venues, including buildings, stadiums, concert halls, shopping centres, and other places where large numbers of people gather.
The core objective of Martyn’s Law is to ensure that venues adopt proportionate and effective security measures tailored to their specific risk profiles. This includes conducting thorough risk assessments, implementing appropriate physical security controls (such as screening or surveillance), training staff in security awareness and emergency response, and collaborating with law enforcement agencies. The law encourages a proactive approach to threat detection and prevention, emphasizing the importance of preparedness and resilience.
For buildings and venues, Martyn’s Law means a heightened focus on safeguarding occupants from threats like bombings, shootings, or other attacks. It drives the integration of security into building design, operational protocols, and event management. Ultimately, Martyn’s Law aims to create safer public spaces by fostering a culture of vigilance and accountability, reducing vulnerabilities, and enhancing emergency preparedness across the UK’s diverse range of public venues.
See the SJH Projects article on ‘Blast Mitigation in Public Spaces’ in ‘Collected Articles’ by clicking here
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Steve Holland of SJH Projects participated in PASS 2025 ( The Personal Armour Systems Symposium) in Bruges in September. PASS is the premier technical event
