CROSS Safety Report
Large stone panel falls from building façade
This report is over 2 years old
Overview
A reporter witnessed a large stone panel detach from a second floor beam and fall to the ground, narrowly missing a group of school children.
Key Learning Outcomes
For civil and structural design engineers:
- Selecting the correct fixings and corrosion protection for the given environment is important to ensure they perform as expected
- Cladding design and installation should be given the same degree of attention as the primary structure during both design and construction to improve safety, reliability and longevity
- Give attention to the whole design of cladding systems and the safety-critical aspects of their fixings and anchors
- The anticipated life span of the fixings should be noted in the operation and maintenance manual
- Manufacturers' instructions provide helpful guidance on fixings. The Construction Fixings Association (CFA) website and CIRIA publication C778 Management of safety-critical fixings are also useful references.
For building owners/managers:
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The specification of any inspection and maintenance requirements for façade fixings should be considered and recorded in the operation and maintenance manual
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Fixings may require a combination of regular visual inspections with full inspections at appropriate intervals and should
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Fixings should be inspected by a person who is competent to do so
Full Report
Find out more about the Full Report
The Full Report below has been submitted to CROSS and describes the reporter’s experience. The text has been edited for clarity and to ensure anonymity and confidentiality by removing any identifiable details. If you would like to know more about our secure reporting process or submit a report yourself, please visit the reporting to CROSS-UK page.
A reporter was working in Asia on a building with a lobby that was open to the outside between the ground and second floors. One day the reporter was coming down an escalator in this area and witnessed a stone facade tile panel about 1m x 0.5m x 50mm thick detach from the face of the second floor concrete beam and fall to the ground. A group of school children were standing not far from where the panel fell.
The reporter believes that the fixings holding the panel in place had either corroded or failed with temperature variation cycles in fatigue (or a combination of both). They note that the stone panels were slightly eccentric to the face of the concrete beam, which may have caused an increased stress and corrosion rate on the fixings.
The reporter was relieved that no one was hurt. They reported the incident to their manager who they hoped would inform the building owner.
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Expert Panel Comments
Expert Panels comment on the reports we receive. They use their experience to help you understand what can be learned from the reports. If you would like to know more, please visit the CROSS-UK Expert Panels page.
This report adds to the body of evidence which CROSS has on failures of fixings and items falling off buildings, some of which are summarised in the 2010 Standing Committee on Structural Safety (SCOSS) Alert on The Selection and Installation of Construction Fixings.
Facades are important structural systems
The reporter correctly observes that the failure of a fixing in this situation has the potential to cause fatalities or severe injuries. The report also emphasises the value of paying design attention to what might at first seem a minor structural system. In reality, façades are important structural systems whose failure have caused fatalities in other instances, and the attention given to their design should reflect their safety critical nature.
The specification of any inspection and maintenance requirements for façade fixings should also be considered, which may require a combination of regular visual inspections with full inspections at appropriate intervals.
Loads on fixings
The reporter’s comments about eccentricity should alert designers to be realistic about judging the loads on fixings and to ensure that their designs are not sensitive to small changes. Due to tolerance, misalignment and so on, panel loads will most certainly not be shared equally amongst multiple fixings. Slight changes in projection can have dramatic consequences in terms of applied bending.
One of the largest categories for CROSS reports is failed fixings (or anchors) and the advice is always to treat these components very seriously from the perspectives of design, procurement, inspection, testing and installation. As well as manufacturers' instructions, the Construction Fixings Association (CFA) website and CIRIA publication C778 Management of safety-critical fixings are useful references. BS EN 1992-4:2018, which was published in October 2018, is the relevant standard for the design of fastenings for use in concrete. The UK National Annex for this standard was published in March 2019.