Quick Search

899 Glazing design and horizontal barrier loading

Report ID: 899

Published: Newsletter 59 - July 2020

Report Overview

A reporter shares problems they have encountered with barrier loading requirements on a curtain walling glazing system.

Report Content

A reporter has experienced problems in relation to evidence of compliance with barrier loading requirements on a curtain walling glazing system in an entertainment building subject to crowd loading. Enquiries made into the design of the glazed units found that the glass installed on the inside of the panels was unable to withstand the required horizontal loading, whereas the glazing on the outside of the panels could. The reporter found it difficult to obtain comprehensive design information justifying the system that was to be installed.

The deficiencies were addressed by the introduction of additional transoms at barrier height. This issue calls into question how glazing is designed and the level of scrutiny that systems are being subjected to. It is clear that the way in which critical elements are being procured and the responsibilities that are being put in place in relation to design are not being properly defined, leaving grey areas or gaps.

On the project in question, extensive use of glazing has been used along escape corridors. These corridors would be required to convey large numbers of people to safety in the event of an emergency, yet, says the reporter, the capacity for the glazing to withstand the critical load case was found to be in question. Some of the corridors and escape routes are on upper floors of the building, and on the perimeter, meaning that any failure could result in a fall from height.

Comments

This is another example of problems with complex interfaces where management of the design, procurement, and construction processes must be linked. Particularly important are the boundaries of responsibilities for connection design and detailing between specialist subcontractors and the design team.

Elsewhere, there is some evidence that adequate design and detailing of critical safety structures such as balustrades is given secondary attention during the design process. It is fortunate that the reporter identified the issues before the units were subject to live crowd loading. In the past, there have been devastating failures with multiple fatalities due to inadequate barriers in sporting venues.

Glazing is quite capable of taking crowd loading if designed correctly. Glass design is however a specialist area and often the detailed design is left to the specialist contractors. The type and thickness of glass are important, but so are details such as glazing beads, sealants and gaskets. It must always be recognised that glass is a brittle material, and where it is in a safety critical location, this should be explicitly taken account of, normally by the use of laminated glass.

A useful reference is the Institution of Structural Engineers guide on Structural use of glass in buildings (Second edition).

 

CROSS depends on you for reports. If you have experienced a safety issue that others can learn from, please Submit a CROSS Report which is treated as confidential

If you have any comments regarding this CROSS report, please Submit Feedback

View other CROSS reports published in Newsletter 59


Previous page

Email Updates

How to Report

Online submission:
Submit by post: