Government must monitor safety of green roofs

Those responsible for collapse at City University will be brought to book but that does not absolve the authorities of their obligations

PUBLISHED : Wednesday, 15 June, 2016, 12:02am
UPDATED : Wednesday, 15 June, 2016, 12:02am

City University dodged a bullet when a green roof collapsed at a sports centre. The incident left three people injured, but if it had happened days earlier the roof would have fallen on a hall full of examination candidates, or a day later on hundreds of dinner guests. It is therefore important that investigations reflect the potential gravity of the incident and spell out clear lessons that will help prevent such a thing happening again. The addition of rooftop vegetation to old buildings is, after all, increasingly popular in Hong Kong and is promoted by the Environment Bureau.

Roof collapse at City University in Hong Kong blamed on wrong loading data

The internal investigation committee tasked with finding out what went wrong has found that the roof was probably overloaded because contractors relied on inaccurate and outdated data when adding green features. It has recommended that the institution seek legal advice on suing those responsible, believed to include a surveyor and the contractor, and foreshadowed disciplinary action against several senior campus development and facilities staff over poor supervision and lack of diligence in dealing with contractors and professionals. This meets public expectations as far as it goes. The next step is now up to the Education Bureau and the Buildings Department, which will take into account the results of its own investigation. The internal probe also recommended the school get independent opinions for similar projects in future and strengthen safety inspections.

Hong Kong City University green roof collapse contractor faces possible lawsuit

University president Professor Kuo Way rightly says the collapse is a valuable lesson for organisations that undertake green-roof projects. The university is on the right track. Pursuing legal responsibility with the relevant professional adviser and the contractor and initiating internal disciplinary action are necessary steps to show accountability and to restore confidence.

That said, the government, too, may need to be more vigilant to safeguard against overloading. In that respect, design, construction and maintenance of the original roof structure had been ruled out as contributing factors. University vice-president and investigation chairman Professor Paul Lam Kwan-sing cited as core factors the design of the greening works and especially the loading assessment, while other factors included the impact of rain and the efficiency of roof drainage.

Since the promotion of green features is not only well-intentioned but official policy, officials need to ensure awareness of risk and monitoring to enhance their safety.