Like many urban cities around the world, the underground environment of Hong Kong houses complicated and extensive arrays of utility networks. These networks cover sewers, water mains, electricity, gas and telecommunications, etc. To maintain their proper function, it is crucial to conduct regular and effective underground utility (UU) surveys. It is also important to get a precise blueprint of the utility network under a construction site before commencing any underground works.
To improve the quality of underground utility surveys and facilitate planning of underground works, the Hong Kong Polytechnic University has recently developed a series of local test standards that can be utilised for these surveys. The test standards consist of six non-destructive testing methods for surveying, imaging and diagnosis (NDTSID) including (1) electromagnetic pipe cable locating, (2) ground penetrating radar, (3) Laser scanning survey, (4) visual inspection, (5) leak detection by acoustic methods, and (6) flow survey & monitoring for drains/sewers. Conformity assessment bodies may apply these test methods in conducting underground utility survey. To help ensure the quality of these surveys, Hong Kong Accreditation Service (HKAS) has also launched a new accreditation service for NDTSID in November last year. This new programme is based on ISO/IEC 17025 and the supplementary criteria document established by the HKAS Task Force on UU Survey, which is a special expert committee set up under the Accreditation Advisory Board’s Working Party of Construction Material Testing. The supplementary criteria document lays down accreditation requirements specific for NDTSID.
Local government departments, such as those responsible for water supplies and drainage services, are keen on applying NDTSID in their construction projects. They will likely require contractors carrying out these surveys to obtain relevant accreditation. A high demand for such accreditation service is thus anticipated. HKAS has already received some applications for these tests and is actively processing them.