Case Studies

 

Proposed PSPS at New Kowloon Inland Lot 6270, Choi Hung Road

 

 

Notable Features
 
bullet Application of “Ventonit” sprayed plaster
bullet ISO 14000 certification
bullet On-site sorting of waste
bullet Reuse of steel hoarding
bullet Reuse of large timber panels
bullet Recycled waste water

Basic Information
 
bullet Location: San Po Kong
bullet Building Type: Residential 
bullet Contract Period: July 1998 to Jan 2001
bullet Gross Floor Area: 179,100m2 (domestic), 9882m2 (non-domestic)
bullet Client: City Team Development Limited
bullet Architect: Chows Architects Limited
bullet Structural Engineer: Fugro (H.K.) Limited
bullet E&M Consultant: Carnival Consultant Limited
bullet Main Contractor: Hip Hing Construction Co., Ltd
bullet Contract Sum: HK$1,300 million

Overview
 
The following major items were executed under this contract:
 
bullet Demolition of barracks including 12 existing buildings
bullet Foundation, Site Formation Works, Construction of 12 nos. of residential blocks, 1 carport block with shops, 1 elderly centre, 2 footbridge connections, and landscape gardens.
 

Demolition Contract
 
The demolition work was carried out by Hip Hing and commenced on 31 July 1998. There was no requirement for separation of waste. On-site sorting of demolition waste was partially executed. These materials included steel gates, windows, reinforcement, which could be resold in the market for money. Asbestos was also demolished separately according to the building regulations. The rubble and other wastes were disposed to the landfill. As for external works, some trees were required to be preserved in the contract.
 

Building Contract
 
The project mainly involved the construction of 12 towers of residential blocks, a carport block with shops and an elderly centre. Seven towers are 22 storeys and five towers are 30 storeys high. Traditional methods were adopted for this project as the profile of the facades involved construction of A/C hoods, which was not suitable to use steel form.
 

Spray Plastering
 
The low-waste technology, used for this project was “Ventonit” sprayed plaster. For the wall surface, cement sand bedding was applied prior to the application of sprayed plaster. As for the ceiling surface, sprayed plaster was directly applied to the concrete surface. The labour cost of sprayed plaster was HK$53 per square metre and the material cost was HK$27 square metre, as at December 1999 prices. The cost of sprayed plaster is about 30% higher than traditional cement sand plastering. The advantage of sprayed plaster is the guarantee of speed and quality. It is getting popular in Hong Kong.
 

Contact of Contractor
 
Hip Hing Construction Co., Ltd.
29/F, New World Tower, 16-18 Queen's 

Road Central, Hong Kong

Tel: (852) 2525 9251
Fax: (852) 2845 9295
 

   
Waste Management
 
bullet Waste Management Plan
 
For the purpose of identifying opportunities and achieving continual improvement on environmental performance through a systematic approach, Hip Hing Construction Co., Ltd. has documented and maintained an Environmental Management System (EMS) conforming to ISO 14001:96 requirements. They have obtained the ISO 14,000 certificate. Issues related to waste management such as segregation of good and reusable material as well as avoidance of unnecessary wastage resources are also included in the EMS manual.
 
bullet On-site sorting of waste
 
On-site sorting was partially performed. Chemical waste was stored separately as required by regulations. Large rotten timber panels and surplus reinforcement were transferred to the ground floor by tower crane. There was 1 no. of plastic refuse chute for each block. Although plastic refuse chute can reduce noise, it is not durable. There was no separation of papers, cans, lunch boxes, plastic conduits and rubble, etc.
 

 
The problems associated with separation of waste on site are the extra resource and labour required as well as educating the labourers. If on-site sorting of waste was to be carried out, it was preferred to be sub-let to the subcontractor and to be conducted centrally since space was available in the site.
 

 
bullet Material Control
 
The wastage was generally below 5%. The subcontractors were generally required to supply both material and labour so that they reduced the wastage of material as possible as they could. In addition, a mock up floor/flat was used to control the use of material for the remaining typical floors.
 
bullet  Use of recycled materials
 
bullet Waste water was discharged to the waste water treatment plant and then the treated water was distributed to the automatic tire washer.
 

 
bullet

Reusable materials

 
bullet The steel hoarding was used for the demolition contract as well as the building contract.

bullet

Large timber panel was reused for working platform, etc.

 

 

Low-Waste Buildings Technologies & Practices
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