Green for danger: how a trend to put vegetation on Hong Kong’s roofs ended in a tangled mess
Luckily no one was killed when the ceiling collapsed at a City University sports centre – but the drama has exposed major flaws in oversight and responsibility for greening work
It was shortly after 2pm on a normal Friday afternoon when Fung Ping-yan was notified that water was leaking from the roof of the Hu Fa Kuang sports centre at City University’s Kowloon Tong campus.
Accompanied by a colleague from the maintenance unit, the veteran security manager came across a frightening scene at the Chan Tai-ho multi-purpose hall on the fifth floor of the complex: water gushing from burst pipes and alarming sounds from all directions.
He immediately sensed something was wrong. More than a dozen people were still going about their activities in the hall: students were playing badminton on the courts, while canteen workers prepared for a banquet for the sports team the next evening, to be attended by hundreds.
There was no time to think. Fung rushed everyone out in a split-second decision. Making sure no one remained in the facility, the 56-year-old manager shut and locked the door of the complex. As soon as he turned to leave, a thunderous noise erupted from behind and a blast of air sent him and his colleague flying. The roof of the complex had come crashing down.
Fung’s decisive action in avoiding a tragedy earned him widespread praise.
CityU’s management, on the other hand, was in for a rough ride over how something like this could happen at one of Hong Kong’s top educational institutes.
The incident sent shock waves, not just across the university community, but throughout a city that has the highest number of skyscrapers in the world and takes much pride in its exacting safety standards.
Most of the focus in the wake of the collapse at CityU has been on the greening elements that were retrofitted onto the sports centre roof only months ago. The suspicion is that the added soil and vegetation exceeded the loading capacity of the roof and triggered its eventual cave-in.
Finding out what exactly went wrong has been left to an investigation committee set up by the university, which is scheduled to publish its preliminary findings on June 6.
The much bigger issue here, however, is whether Hong Kong has bitten off more than it can chew by embracing the concept of greening buildings.
The collapse has exposed a mess when it comes to oversight and responsibility. The government has left it to the end users to interpret guidelines and regulations instead of keeping proper tabs on the popular practice of incorporating green elements into buildings.
Professor Jim Chi-yung from Hong Kong University’s geography department recalls it was about 10 years ago when he started pitching the concept of greening buildings to government departments. A long-time advocate of urban afforestation, he admits public reception was rather cold at the beginning as few people knew what benefits such projects could bring.
The turning point came in July 2007, when Jim submitted a proposal to the Hong Kong Bank Foundation to install green roofs for schools around the city. A HK$5 million grant was secured to fund the construction of lawns and irrigation systems on the roofs of 14 schools within the next two to three years.
The project earned public recognition and encouraged others to adopt green principles in new building designs. The concept gained further traction when then-chief executive Donald Tsang Yam-kuen pledged in his 2009-10 policy address to “increase the greening ratio of all new public rental housing estates to at least 20 per cent”, while providing green roofs in low-rise buildings and vertical greening in pilot projects “wherever feasible”.
A Development Bureau circular in 2012 specified a 30 per cent “greenery coverage” for sites of 20,000 square metres or more, and 20 per cent for sites of less than 20,000 square metres for all government construction projects.
While a greening ratio has never been adopted into law, it has become an increasingly important factor for town planning bodies when vetting construction projects. The term is often floated in proposals submitted to the Town Planning Board, while government land sale programmes demand developers achieve a certain greening ratio from time to time. The 320-hectare Kai Tak development in Kowloon East even boasts greening ratios of up to 85 per cent in certain areas.
But Jim says environment conservation is much more than fiddling with numbers. The greening ratio – the percentage of land reserved for agriculture, forest, grassland and parks – is only a “raw” indicator of vegetation at a particular site, and does not reflect its true ecological value, he points out.
He laments the general perception that green roof installations are merely “amateurish enterprises” that do not require professional practitioners.
“There are many factors to be considered. The soil structure and porosity, as well as the drainage system all need to be calculated to suit the types of vegetation to be planted – everything is science,” Jim explains.
A prime example is the Sky Woodland project at a CLP Power substation in Tseung Kwan O. Rather than potted plants and shrubs, the roof of the facility houses 80 trees of 32 species, even offering shelter to wildlife. Jim says the loading limit of the roof was specifically designed to withstand more than two tonnes of weight per square metre.
A common practice for owners to retrofit green gardens or vertical walls on their buildings is to hire certified contractors through tenders. But owners often accept the lowest bid instead of the firm with the most expertise. The lack of a qualification system for contractors to undertake greening projects may have contributed to the problem, Jim says.
But not all building owners have the financial clout or freedom to conduct extensive research and trials when adding green landscapes, especially when the projects are smaller in scale. As a result, many owners take short cuts by hiring contractors to do all the work, paying little attention to building safety.
The Hong Kong Green Building Council specifies that the advice of authorised persons or registered structural engineers should be sought before embarking on any greening project. It is then up to the professionals to decide whether there is a need to submit a plan to the Buildings Department for formal approval when green modifications may affect the structural integrity of a building.
Professor Bernard Lim Wan-fung says this is where the root of the problem lies. The former president of the Hong Kong Institute of Urban Design says minimising costs has become something of a culture among Hongkongers. Often a single contractor is responsible for an entire project, he explains, as owners are reluctant to hire an additional party to act as a check and balance.
“Everybody takes a chance to save money,” he says. Lim estimates seeking professional advice will only add 10 per cent to the project’s overall costs, but everyone seems to have adopted the profit-maximising mentality of big developers.
“But there will be consequences,” he warns.
The architect admits there is a grey area when deciding whether a building plan needs to be submitted to the government for greening projects, as many factors, such as size and loading requirements, come into play.
Another reason is bureaucracy – the lengthy waiting time for such plans to receive the green light. He reveals it usually takes the Buildings Department three to five months to vet a plan, and that may deter some owners who perform smaller-scale fittings.
Lim says the Leisure and Cultural Services, Lands, and Highways departments all have their own tree management or greening units, but a lack of coordination often frustrates industry practitioners when trying to clear legal hurdles.
He says the government should form an inter-departmental body to provide concrete guidelines, not just for building owners, but also developers when undertaking greening works.
Peter Cookson Smith shares similar views. A renowned urban planner who has worked in Hong Kong since 1977, he says comprehensive guidelines need to be published to detail the technical aspects of greening projects, which are often neglected.
The lack of criteria means even professionals sometimes find it difficult to decide whether a plan needs to be submitted. He says the problem is exacerbated when developers in Hong Kong tend to make open space in buildings – podiums, decks or rooftops – as “usable” as possible.
But who is ultimately to blame for violations?
At CityU, the management is pointing the finger at veteran surveyor Kenneth Chan Jor-kin, saying he had approved the greening of the roof that collapsed. Chan, a former chairman of the Professional Green Building Council himself, has denied responsibility. No one can say for sure who should be blamed.
But a hint was dropped at an emergency Legislative Council session on May 25, when development undersecretary Eric Ma Siu-cheung said the Buildings Ordinance clearly stated a building owner was the ultimate responsible party. He was asked if the government planned to assign criminal and civil liability to accredited professionals when something goes wrong.
At the same meeting, education minister Eddie Ng Hak-kim revealed that 66 schools had been fitted with green roofs, with 62 funded by the Environment and Conservation Fund.
Established in 1994, the fund has granted non-profit organisations hundreds of millions of dollars for Environmental Education and Community Action projects. A HK$5 billion injection was approved in 2013.
Separately, the Environmental Campaign Committee has organised the Green School Award since 2000 to promote environmentally friendly policies at educational institutions. As far as promotion is concerned, it seems the government has done enough on this front.
What it lacks, however, is a database with all the details of green roofs and structures in Hong Kong. That would that would keep the public informed and make it simple for the authorities to keep an eye out for potential trouble. And pinpoint blame when something goes wrong.
When asked if such a database would be set up, Ma said the government would consider it.
Following the CityU collapse, the Buildings Department clarified that plans must be submitted for all building works unless they are “exempted or considered as minor” by authorised persons, without elaborating.
“I don’t see where one would be able to draw a line,” Cookson Smith says.
While the city tries to sort this out, the word “green” is now starting to be associated with “danger” in Hong Kong.