Stage 1

What is a Stage 1 Preliminary UXO Risk Assessment (PRA)

(Also known as a UXO PRA, Stage 1 UXO report, UXO hazard assessment or similar)

A preliminary risk assessment serves as an initial qualitative screening exercise to evaluate the potential presence of UXO at a given site.  This process involves considering fundamental factors that influence the likelihood of UXO being present and the probability of any associated hazards occurring.

The primary objective of the PRA is to determine whether there is a need for more in-depth research, in the form of a detailed risk assessment, to further clarify the risk from UXO.  By identifying or discounting the necessity for a detailed assessment, the preliminary assessment helps streamline the risk management process, ensuring that resources are allocated efficiently.

The preliminary UXO risk assessment examines various elements, such as the historical use of the site, previous military activities, and any evidence of ordnance disposal.  This common-sense approach allows for an informed decision on the next steps, making it an essential first step in the comprehensive UXO risk management strategy.

By obtaining a preliminary UXO risk assessment, project managers can make early assessments of UXO risks, enabling proactive planning and mitigation measures.  This initial screening ensures that any potential UXO hazards are identified and addressed promptly, contributing to a safer project environment and reducing the likelihood of costly delays.

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What does a Preliminary UXO Risk Assessment include?

A preliminary UXO risk assessment conducted by Igne harnesses a wealth of in-house information sources to place a development project within the broader context of domestic military and conflict history.

This assessment delves into various critical factors to ensure a comprehensive evaluation of potential UXO risks.

The preliminary report examines the extent of the proposed works, evaluating the scope and scale of the development to understand its potential impact on and interaction with any existing UXO hazards.   It also investigates the conflict history of the area, including specific enemy actions that may have contributed to the presence of UXO.

In addition to historical conflicts, the preliminary assessment considers domestic military activities, encompassing aerial, naval, and land-based operations.

By analysing these operations, the assessment can identify areas that were subject to intensive military actions and, therefore, might have a higher likelihood of containing UXO.

Furthermore, the preliminary report takes into account any existing risk mitigating factors that could reduce the potential hazards associated with UXO.  These might include prior UXO clearance efforts, post-war site redevelopment, or other conditions that could influence the presence and stability of UXO.

Igne’s preliminary risk assessment process begins with an in-depth analysis of its extensive internal database, which includes bombing density maps, bomb plot mappings, and detailed records of British and Allied military activities.

This robust data foundation is crucial for identifying potential UXO risks.  Subsequently, Igne consults additional publications and historical documents to expand on specific details and ensure the accuracy and thoroughness of the assessment.

A general overview of the area is also conducted, incorporating broader historical and geographical context into the PRA.  This holistic approach ensures that all relevant factors are considered, providing a detailed and reliable assessment that guides further risk mitigation strategies and ensures the safety and success of the development project.

Stage 1

What is a Stage 2 Detailed UXO Risk Assessment (DRA)

(Also known as a UXO DRA, UXO desktop report, UXO threat assessment or similar)

A detailed UXO risk assessment is a tailored and thorough report evaluating the potential risk posed by unexploded ordnance (UXO) to your proposed project.  This detailed UXO report investigates the potential extent of contamination, identifying both the source and nature of likely explosive contaminants.  It also assesses the likelihood and potential consequences of encountering UXO in relation to the intended use of the site.

Often carried out in the early stages of project planning, a desktop risk assessment ensures cost and time efficiency within the broader project scope.  Conducting the assessment before any intrusive on-site work begins is key.

Many clients may choose to proceed directly with a detailed risk assessment, bypassing the preliminary risk assessment, if they are already aware that their site is in a heavily bombed area or was previously used by the military, such as an airfield, training area, or firing range.  This approach allows for the swift development of a detailed mitigation strategy based on the findings of the report.

The risk assessment process involves several stages of research, encompassing all available historical and modern records.  This comprehensive approach provides clients with a clear understanding of the risks present on the site and outlines strategies to mitigate them effectively.  The goal is to ensure that all potential hazards are identified and addressed, promoting the safe and efficient progress of the project.

What does a DRA include?

The primary objective of a detailed risk assessment is to evaluate the likelihood of encountering and potentially detonating explosive ordnance during intrusive activities at a project site.  If the assessment identifies an elevated risk, it will recommend appropriate risk mitigation measures in accordance with CIRIA C681 guidelines.

These measures are designed to minimise the risk of UXO detonation and the associated potential for harm and damage during the planned works, ensuring that the risks are managed to ‘as low as reasonably practicable’ (ALARP).

A detailed UXO risk assessment is considered a dynamic document that must be updated whenever there are changes to the proposed works or if UXO is discovered during the project.  It is crucial for maintaining the accuracy and relevance of the risk management strategy throughout the project lifecycle.

The report will incorporate all available and pertinent historical information related to the site and its surrounding area.  This includes detailed historical context to help both the risk assessor and the client understand the site’s background.

Additionally, the assessment will integrate relevant modern information, including post-WWII mitigation efforts that might impact the current risk evaluation.

Igne’s detailed risk assessments are comprehensive and include visual aids such as maps, images, and other data that help to contextualise the information.  These resources are available in GIS formats upon request, enhancing the utility and accessibility of the data.

The report will also provide general information about the types of ordnance commonly found on UK construction sites, offering further insight into the types of hazards that may be encountered.

This thorough approach ensures that all aspects of UXO risk are considered and managed effectively.

 

What UXO issues will be addressed?

Igne’s detailed UXO risk assessments will comprehensively address several critical issues related to UXO at a project site.  The assessment will evaluate the following factors:

• Likelihood of site contamination: the report will assess the probability that the site was previously contaminated with UXO.  This involves examining historical records, past military activities, and other relevant data to determine the likelihood of UXO being present.
• Presence of UXO: the assessment will determine the probability that UXO remains on the site.  This involves analysing available evidence to estimate whether unexploded ordnance is still present and poses a risk to ongoing or planned activities.
• Risk of encountering UXO: the report will evaluate the likelihood that UXO may be encountered during any planned works.  This includes assessing the potential for UXO to be uncovered or exposed as a result of the construction or excavation activities.
• Potential for UXO detonation: the assessment will consider the probability that any UXO encountered could be detonated.  This involves evaluating factors such as the stability and condition of the UXO and the nature of the planned works that could trigger a detonation.
• Consequences of UXO encounter or detonation: the report will analyse the potential consequences of encountering or detonating UXO, including the risk of harm to personnel, damage to equipment, and environmental impact.  This assessment is crucial for understanding the full implications of UXO hazards on the project.

In addition to addressing these key issues, the assessment will provide recommendations for appropriate risk mitigation measures to reduce the risk to ‘as low as reasonably practicable’ (ALARP).  These recommendations will be tailored to the specific risk rating, the characteristics of the site, and the nature of the planned works.

By offering targeted mitigation strategies, the report ensures that all identified risks are managed effectively and that safety measures are in place to protect personnel, equipment, and the environment.

What sources of information does Igne use for its detailed UXO risk assessments?

When conducting a detailed UXO risk assessment, Igne undertakes a thorough examination of a broad spectrum of historical and contemporary sources to obtain a comprehensive understanding of the site’s context.  This approach ensures that all relevant and available information is considered, which can vary depending on the project's location.

Igne possesses one of the largest UXO databases in the country, a valuable resource that includes datasets accumulated since the 1990s and continuously updated.  This extensive database encompasses information from a variety of sources such as national and local archives, public records, military archives, academic publications, and other relevant materials.

Each project benefits from this rich repository of data, which is consulted to provide a solid foundation for the risk assessment.

In cases where certain datasets are lacking or information for a specific location is limited, the Igne team will make site visits to local archives to gather additional data.  This proactive approach ensures that any gaps in the information are filled, providing a more complete picture of the site's history and potential risks.

Additionally, Igne collaborates with trusted suppliers to obtain historical maps and photographs, which are crucial for understanding changes to the project site over time.  These visual resources can reveal significant details such as the presence of bomb craters or ruins, contributing to a more accurate risk assessment.

Beyond these sources, Igne also consults geological databases, museums, heritage assessments, archaeological studies, and other relevant references.

By integrating information from these diverse sources, Igne ensures that the assessment is as thorough and precise as possible, allowing for effective risk management and informed decision-making for the project.

Quantitative vs qualitative risk assessing

To establish risk ratings and recommend suitable mitigation measures, Igne employs a semi-quantitative assessment approach.  

This method is designed to evaluate the level of risk associated with the planned activities at a project site.

The assessment process involves identifying potential hazards, investigating the possible receptors that could be impacted, and analysing the pathways through which these hazards might affect the site.  This relationship is commonly described using the Source–Pathway–Receptor model.

The risk rating for a site is determined by several key factors: the likelihood that UXO remains on the site, the probability of encountering or initiating UXO during the proposed activities, and the potential consequences of an accidental detonation.

Each factor is assigned a numerical value on a scale of 1 to 5, and these values are analysed using a risk matrix to derive the overall risk rating.

The result is categorised into risk levels—Low, Medium, or High—based on the total score.  This rating is applied to each identified weapon type (source) that poses a potential threat to the project.

This semi-quantitative approach offers a clear and structured explanation of the risk rating, as it integrates both numerical and qualitative assessments.  It provides a more comprehensive understanding than a purely qualitative approach, which might leave readers to interpret the rationale behind the risk rating themselves.

Conversely, a purely quantitative approach would be inadequate for UXO risk assessment, as it relies heavily on variable data that may not capture the full complexity of the situation.

By combining both quantitative and qualitative elements, Igne’s method ensures a more accurate and transparent evaluation of UXO risks.

Recommendations

Effective UXO risk management is an important aspect of any construction or development project.  UXO, originally designed to cause harm, continues to pose a significant residual risk long after its initial use.  This risk is not only a safety concern but also carries substantial commercial implications.

The potential for UXO incidents can lead to severe delays and disruptions in project timelines, which in turn can result in increased costs.  These disruptions can affect various stages of a project, from initial planning and excavation to construction and completion.  The financial repercussions of such delays are significant, often impacting project budgets and profitability.

In addition to the immediate operational impacts, UXO risks can also affect the long-term financial value of the land.  Properties with unresolved UXO issues may experience decreased market value due to the perceived or real hazards, affecting the land’s desirability and financial return.

Land and building owners bear the responsibility for managing residual UXO risks.  This obligation includes ensuring that proper risk assessments and mitigation strategies are in place to address any potential threats.  Failure to manage these risks effectively can result in legal liabilities and further financial burdens, making proactive risk management an essential part of property and project management.

Overall, addressing UXO risks comprehensively is vital for safeguarding both the safety of personnel and the financial viability of projects, ensuring that potential hazards are managed efficiently to minimise their impact on development activities and property values.