Demolition work at a building project in Sham Shui Po is creating less noise and non-recyclable waste than traditional methods. The Housing Society and the Urban Renewal Authority, in their first joint redevelopment project, are using an hydraulic crusher instead of a breaker to bring down buildings. A breaker uses a hammer to punch through walls, while a crusher has a hydraulic clamp that crushes the concrete and separates it from metal foundations. Chum Hon-sun, the society's general manager for project management, said the breaker noise level was 120 decibels, while the crusher created about 85 decibels. The project, launched in 2003, involves tearing down 40-year-old buildings in Wai Wai Road and putting up 348 flats by 2010. Weekly checks found the noise level for nearby residents was 65 to 68 decibels when the crusher was used, while the breaker would record a level of 80 decibels. Busy traffic at a distance of 5 metres away creates 70 decibels. The crusher also allows debris to be handled separately, which significantly increases the amount of waste being recycled instead of being dumped in a landfill. More than 85 per cent of waste created at the site can be recycled and used for reclamation, while 10 per cent goes to the landfill. The figure is better than the target of the society, which demanded contractors have no more than 50 per cent of the waste sent to the landfill. The use of the crusher also decreases the use of oxyacetylene - usual in operations with the breaker - thus minimising the fire hazard. Thomas Wong Kam-chuen, managing director of project contractor YSK2 Engineering, said while a breaker cost about HK$100,000, a crusher cost HK$300,000. Mr Wong said he had imported the technology from Japan. He said the technology was not new, but his company had managed to find the right configuration to use it in demolition work. This is the first time the Housing Society has used the system, although it has been used on other developments in Hong Kong. Mr Chum said the technology would be used in six other redevelopment projects on which the society was co-operating with the Urban Renewal Authority.