Safety recommendations for installing curtain walls or panels

During a seminar held by the Construction Industry Council on 13 February 2025, I presented a preliminary analysis of the key issues behind two major external scaffolding collapses that occurred last year in the Kai Tak area. Based on the findings, I proposed four recommendations:

(i) Design for Safety

I encourage curtain wall and cladding specialists to conduct further research on the following:

• Is external scaffolding necessary for glass curtain wall and/or cladding panel installation? Can we design those systems and installation methods that eliminate the need for scaffolding?
• If scaffolding is no longer required, it should be dismantled in advance.
• If scaffolding remains essential, can anchor rings be integrated into the primary load-bearing structural members of the curtain wall or cladding system to serve as new anchoring points when modifying the scaffolding ties (putlogs)? A permanent anchoring system is preferable and offers the added benefit of being useful for future maintenance tasks.

(ii) Tripartite collaboration

If external scaffolding remains necessary for curtain wall or cladding installation, it is crucial to implement coordination among the main contractor, specialist sub-contractor, and scaffolder:

• Conduct prior discussions to finalise the practical construction plan; any modifications to the scaffolding (especially the putlog/tie arrangement) must be carried out exclusively by the scaffolder.
• Properly install anchor rings or hooks on the main structural members of the curtain wall or cladding, to serve as alternative anchoring points during modification to the putlogs/ties.

(iii) Enhanced scaffolding management

For large-scale curtain wall or cladding panel installations, inspections of scaffold and the issuance of “SS Form 5” should be conducted more frequently than the statutory interval of every 14 days. Voluntarily reducing this to every seven days, three days, or even after each modification to the tie/putlog systems is recommended.

Employ a scaffolding Competent Person (CP) and two scaffolding workers onsite to assist and verify modifications immediately. However, this could increase daily costs by HK$10,000, amounting to HK$2 million over six months. Naturally, this represents a cost to the contractor(s).

It is advised that curtain wall or cladding specialist contractor designate an additional Technically Competent Person (TCP) at the T1 or T3 level. This technician would be responsible for liaising with the main contractor’s TCP Team throughout the execution of large-scale curtain wall or cladding construction.

(iv) Smart Technology

Place sensors on every putlog/tie, and mount cameras on the external walls to relay all gathered data directly to the appropriate site management and supervision teams. This setup ensures comprehensive monitoring and enables prompt action whenever necessary.

This article is contributed by Ir Dr C M Ho, JP, with the coordination of the Safety Specialist Committee.