CROSS-UK highlights collapse risks across a structure’s full life

by ConstructionFeatured NewsFire Engineering

A famous collapse that was not “technical”

CROSS-UK has published an editorial in Newsletter 79 dated Thursday 11 December 2025, reflecting on how structural failures shape engineering practice and public safety responsibilities.

The editorial was written by Glenn Bell, Director, CROSS-US.

Bell writes that many engineers experience an early-career realisation that mistakes can carry catastrophic consequences.

He links that awareness to his work investigating the Hyatt Regency Hotel walkways collapse in Kansas City, Missouri in 1981.

Hyatt Regency collapse framed as culture

Bell argues that the Hyatt failure is often presented as a single technical issue involving a change in the hanger rod arrangement.

He writes that this is an oversimplification, and that project conditions and culture were central to why the collapse happened.

Bell describes a fast-tracked delivery approach where construction began before design was complete.

He also writes that numerous design changes took place, two key structural engineering staff quit mid-design, the fabricator was overloaded and shop drawing review was rushed.

Missed checks and warning signs

Bell writes that two quality inspection firms were dismissed and not replaced.

He also describes warning signs during construction, including early signs of failure in a structural sunscreen wall and a portion of the atrium roof collapsing.

He writes that two independent rechecks of the atrium structure still failed to uncover the walkway problems.

Glenn Bell, Director, CROSS-US, said: “In short, the project was out of control, with many missed opportunities to catch and correct the conditions that ultimately caused the collapse.”

CROSS reporting and Surfside investigation

Bell describes CROSS as focused on confidential reporting of more frequent “lesser” failures and concerns, rather than catastrophic failures resulting in fatalities.

He writes that, by studying precursors, reporting can help prevent catastrophic failures.

Bell also writes that he is co-lead of the US National Institute of Standards and Technology’s investigation into the Champlain Towers South collapse in Surfside, Florida in June 2021, which he notes claimed 98 lives.

He writes that the investigation is tasked with determining likely technical causes, recommending improvements to building codes and standards and identifying research needed to enhance structural safety.

Recurring themes across failures

Bell writes that structures are vulnerable at every stage of their life, and that survival to date is no guarantee of future safety.

He states that, between 1978 and 1987, the US experienced nine catastrophic failures across building ages, from construction through to decades into service.

He writes that recurring themes include poor quality assurance and quality control, poorly defined responsibilities, lack of redundancy and unheeded warnings.

Readers can view the full article on CROSS-UK’s website.

CROSS-UK examines ageing buildings, structural risk and battery safety considerations

by Building ManagementFeatured NewsResearchSafety

Why battery safety belongs in every ageing building decision

Collaborative Reporting for Safer Structures UK (CROSS-UK) has published a Topic Paper on the ageing built environment in the UK, setting out how existing buildings and infrastructure can be managed, extended in life or repurposed.

The organisation said the paper explains how ageing assets create both challenges and opportunities once structures reach or pass their intended service life.

According to CROSS-UK, the document is based on confidential reports from engineers, asset managers and construction professionals, supported by references to anonymised CROSS Safety Reports.

The Topic Paper describes how older structures may suffer from material degradation, incomplete documentation and historic design approaches that do not align with current expectations.

CROSS-UK frames the publication as guidance for policymakers, regulators, insurers, asset owners, facilities managers and construction professionals responsible for the safety and future use of ageing buildings and other structures.

The paper states that leaving ageing assets unassessed is not an acceptable option and argues for decisions that take safety, sustainability and economic outcomes into account.

Asset knowledge, deterioration and inspection

CROSS-UK places asset knowledge at the centre of decision-making for ageing structures and highlights reinforced autoclaved aerated concrete (RAAC) as an example where incomplete records delayed action.

The Topic Paper notes that many older buildings lack accurate as-built information, have been altered without proper recording or contain materials that were not fully understood at the time of construction.

The report explains that this can leave owners unaware of critical elements and increase uncertainty when problems emerge.

CROSS-UK outlines how steel, concrete, masonry and timber each degrade over time, and how these processes interact with changing conditions such as climate impacts, heavier vehicles, new fire loads and system obsolescence.

The Topic Paper references failures including the Pipers Row car park, the gable collapse at Northwich Station and the Morandi Bridge to illustrate the outcomes of unmanaged deterioration.

CROSS-UK calls for structured inspection and maintenance regimes that combine scheduled and risk-based approaches and give targeted access to hidden or safety-critical components.

According to the paper, examples such as half-joint bridge failures, corroded tendons and concealed steelwork demonstrate how inaccessible details have driven catastrophic collapses.

CROSS-UK argues that maintenance must be treated as a core safety responsibility rather than a discretionary cost that can be reduced when budgets tighten.

Reuse, constraints and changing fire and battery safety risks

The Topic Paper sets out a case for reuse and repurposing as part of a lower carbon built environment, stating that retaining and adapting existing structures can reduce embodied emissions and support resource efficiency.

CROSS-UK explains that safe adaptation requires robust assessment, intrusive investigation where needed and careful review of load paths, fire safety measures and regulatory compliance when a building’s use changes.

The paper warns that poorly planned retrofit measures, such as some insulation approaches, have led to moisture problems and damage in existing structures.

CROSS-UK notes that constraints such as skills shortages, incomplete records, funding pressures and regulatory complexity can limit reuse options or push decisions towards unnecessary demolition.

The Topic Paper also refers to evolving risks, including new fire loads and obsolescent systems, and links to its separate Topic Paper on lithium-ion batteries for those addressing fire and battery safety in buildings that predate current technologies.

According to CROSS-UK, extending the life of structures requires experienced engineering judgement when applying modern standards to historic construction, with decisions based on risk, tolerable performance and the specific context of each asset.

The organisation concludes that collaboration, competence and long-term planning are needed if ageing structures are to be retained safely rather than removed by default.

How ageing asset guidance affects safety and engineering practice

The CROSS-UK Topic Paper has direct implications for asset owners and managers who oversee estates containing older buildings and infrastructure.

For these groups, the emphasis on structured inspection, record-keeping and maintenance describes practical steps that can reduce unplanned failures and support decisions on whether to retain, adapt or deconstruct structures.

Facilities managers in commercial, industrial and public sectors can use the paper’s focus on hidden components and access needs to frame inspection regimes and plan intrusive investigations where safety-critical elements are concealed.

Fire engineering consultants, architects and building services engineers gain a consolidated view of how ageing materials, changing fire loads and retrofit measures interact in older buildings, including references to separate guidance on lithium-ion battery risks.

Regulators and policymakers can draw on the discussion of RAAC, documented failures and maintenance backlogs when considering where to focus oversight, funding and future standards for existing stock.

The Topic Paper also highlights the need for skilled inspection and assessment, which is relevant for structural engineers and surveyors involved in appraising older structures for continued use, conversion or demolition.

Building work obstructs smoke vent function, CROSS-UK warns

by ConstructionFeatured NewsPassiveResearch

Potential safety issues with inoperable smoke vents

CROSS-UK has issued a Red Safety Alert regarding the risk posed by construction activities rendering Automatic Opening Vents (AOVs) inoperable in buildings.

The alert, aimed at fire safety managers, contractors, and building designers, addresses how AOVs, critical for releasing smoke in emergencies, can become ineffective due to building work.

According to the safety notice, these vents are a component of smoke control systems, essential for facilitating occupant escape and supporting firefighting efforts during a fire.

The alert highlights that AOVs, which can resemble ordinary windows, are sometimes inadvertently obstructed.

Incidents where façade materials block AOVs have been reported to CROSS-UK’s confidential system.

In some cases, AOVs were found masked or rendered inoperable when scaffold poles or cladding adjustments interfered with their operation.

Recent cases of obstructed AOVs during building works

CROSS Safety Report 1347 provides examples where AOVs were left inoperative for months following cladding remediation.

The first case involved improper disconnection of AOVs from their electrical components, while another case noted cladding screws fixed into AOV frames, disrupting functionality.

Report 1380 further noted instances where construction workers unknowingly covered AOVs during façade work, inhibiting their emergency use.

These reports underscore the importance of clear identification and consistent accessibility of AOVs in active construction zones.

In response, CROSS recommends the implementation of signage and better training for workers to recognise and protect these fire safety elements.

Fire risk assessments and interim measures advised

CROSS advises that fire risk assessments be updated before and during construction activities that could affect smoke vent function.

Additional interim control measures, such as temporary markings on AOVs to signal their importance, may mitigate risk.

CROSS also recommends evaluating evacuation strategies, especially for buildings with combustible cladding undergoing remediation, as AOVs play a critical role in smoke control and occupant safety.

Contractors and building managers are encouraged to understand the implications of construction activities on fire safety provisions, with special attention given to the operational status of doors, smoke detectors, and AOVs.

Obstructions such as scaffold poles, stored materials, or temporary coverings can easily disable AOVs, leading to potential hazards in a fire.

Guidance on safety compliance and training

CROSS suggests that contractors, especially those working in high-rise residential buildings, ensure all AOVs are identifiable and accessible throughout building works.

As an additional safeguard, CROSS advises signage indicating the presence and importance of AOVs.

Enhanced training is also encouraged for all construction personnel to increase awareness of AOVs’ role in fire safety.

Under the Fire Safety (England) Regulations 2022, any high-rise residential buildings with faulty fire safety equipment must report these issues.

CROSS continues to provide information and support to professionals involved in managing fire safety systems.

Building work obstructs smoke vent function, CROSS-UK warns: Summary

In November 2024, CROSS-UK issued a Red Safety Alert concerning construction work that can inadvertently render Automatic Opening Vents (AOVs) inoperable.

AOVs, which often look like regular windows, are essential in smoke control systems to assist in fire evacuation and firefighting.

CROSS-UK reports cases where AOVs were blocked by scaffold poles, cladding adjustments, or masking during building work.

To address this issue, CROSS-UK recommends updating fire risk assessments and employing signage and training to ensure AOVs remain accessible.