Ten Years of UXO Risk Management | What a Decade of Projects Teaches About Planning
UXO risk should be assessed before intrusive works begin on any construction, infrastructure or ground investigation project in the UK.
Unexploded ordnance (UXO) can remain buried for decades. Disturbing it during excavation, piling or drilling can pose a serious risk to site personnel and others nearby. An unexpected encounter can also stop work, delay programmes and add unplanned costs.
Over the past ten years, Brimstone UXO has delivered UXO risk management across a wide range of construction, infrastructure and ground investigation projects. That work has shown us that the projects which manage UXO risk most effectively are those that identify it early, respond proportionately and build mitigation into the wider project plan.
Why early planning makes a difference
UXO risk is rarely obvious from a site’s current appearance. A site may have a long history of redevelopment, show no visible trace of its past use, or sit in a location that raises no immediate concern. However historical land use, wartime activity and post-war development all influence the potential for UXO to be present.
If suspected ordnance is encountered once works are underway, work stops while the situation is assessed and specialist advice is obtained. Decisions are then made under time pressure, with fewer mitigation options available.
Assessing UXO risk during early planning establishes whether further measures are needed and allows them to be built into the programme and budget. Early assessment does not mean extensive investigation on every site. It means understanding the potential risk and using the evidence to decide on an appropriate course of action.
Five lessons from a decade of projects
1. Every site has its own story
No two sites are alike. Locations within the same town, or even the same development area, can have very different histories and risk profiles.
A UXO risk assessment considers historical aerial photography, military records, previous land use and the nature of the proposed groundworks together. It does not rely on a site’s current appearance or on findings from neighbouring developments.
The planning lesson: understand the site’s history before deciding what measures are appropriate. A site-specific assessment provides a stronger basis for decisions than a generic approach or guesswork.
2. Early assessment creates more options
Mitigation options differ in cost, complexity and programme impact. Assessing UXO risk at the feasibility and design stages allows time to compare those options and schedule the most suitable approach before contractors mobilise.
As a project progresses, the options narrow. Contractors are committed, plant and resources are on site, and additional requirements are harder to accommodate. A more costly or disruptive option can become the only practical one.
The planning lesson: assess UXO risk as early as practicable. Where mitigation is required, allow enough time to identify, plan and schedule it before construction is imminent.
3. Proportionate risk management is essential
Effective UXO risk management matches the response to the evidence. CIRIA C681 sets out a staged approach for this reason.
On some sites, a preliminary UXO risk assessment establishes that the potential risk is low and no further UXO-specific measures are required. On others, the findings indicate that a detailed risk assessment, survey or on-site support should be considered.
The right approach depends on the evidence, the proposed activities and the potential consequences of encountering UXO. A proportionate approach avoids both unnecessary expenditure and inadequate preparation.
The planning lesson: let the evidence guide decisions. The objective is to implement measures that are appropriate to the risk, no more and no less.
4. UXO management works best when it is integrated into the wider project
UXO risk can affect ground investigation strategies, piling, excavation, drilling, utility installation and other intrusive activities. It also shapes contractor briefings, site procedures and programme planning.
Integrating UXO into project planning gives clients, contractors and specialist advisers a shared understanding of their responsibilities. This matters most on complex projects involving multiple contractors, phased construction or changing groundworks requirements.
Communication is as important as the plan itself. Procedures only work if the people carrying out the work understand them. UXO safety briefings and toolbox talks give site teams the knowledge to recognise the hazard, follow the agreed controls and respond correctly if a concern arises.
The planning lesson: integrate UXO risk management into the wider project safety and risk management process. Make responsibilities clear and brief site personnel on the risks and procedures that apply to their work.
5. Good planning accounts for change
Projects rarely stay as first envisaged. Designs evolve, site boundaries change, ground conditions are clarified and construction methods are adapted.
An assessment or mitigation plan that suited one scope of work may not cover a later change. A revised piling layout, a deeper excavation or an extension into a previously unassessed area can all introduce new considerations.
UXO risk management should respond to project development. Reviewing the assessment and planned mitigation when there are material changes to the site, scope or groundworks ensures any additional requirements are identified before affected activities proceed.
The planning lesson: build review points into the project programme and assess changes before they introduce new or unmanaged risk.
From uncertainty to informed decisions
The clearest lesson from ten years of UXO risk management is that uncertainty is easier to manage when it is addressed early.
A UXO risk assessment establishes the potential hazard, evaluates the available evidence and recommends a way forward. Sometimes this confirms that no additional UXO-specific measures are required. In other cases, it identifies further assessment or mitigation to complete before intrusive works begin. Both outcomes give project teams a clearer basis for decisions.
No risk assessment can guarantee that UXO is absent. As with other areas of risk management, the aim is to reduce risk to a level that is as low as reasonably practicable (ALARP). This means implementing appropriate controls and ensuring that any remaining risk is understood and managed.
Ten years on, the lesson remains the same
Construction and infrastructure projects balance programme, budget and delivery objectives against the responsibility to protect everyone on and around site. UXO risk management supports both by identifying potential hazards before work begins, informing the choice of mitigation and reducing the likelihood of unexpected encounters.
A decade of projects comes back to the same fundamentals:
- Understand the site.
- Assess the evidence.
- Take a proportionate approach.
- Integrate risk management into the project programme.
- Review decisions when circumstances change.
Proactive planning does not remove every uncertainty. It gives project teams the information they need to manage risk responsibly and deliver projects with confidence.
Discuss your project with Brimstone UXO
Brimstone UXO can help you understand the potential UXO risk on your site and identify appropriate next steps. Contact our team to discuss your project and how early UXO risk management can support safer, more effective planning.
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