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Following is a question by the Hon Wong Kwok-kin and a written reply by the Secretary for Transport and Housing, Ms Eva Cheng, in the Legislative Council today (July 7):
Question:
I have recently received complaints from members of the public about the rusting problem of the hinges of the aluminium windows in quite a number of units in Upper Ngau Tau Kok Estate and Lam Tin Estate, which were completed for occupation for less than a year, necessiting the replacement of nearly 100,000 hinges. It has been reported that results of laboratory test have indicated that the quality of those hinges fails to meet the standard specified by the Housing Department (HD) in the contracts. Regarding the quality of fixtures in public housing estates (PHEs), will the Government inform this Council:
(a) which parties bear the costs for replacing the hinges;
(b) of the number of complaints received by the authorities in the past five years about problems involving public housing fixtures in PHEs completed for occupation for less than a year, which required maintenance arranged by HD;
(c) of the respective current numbers of PHEs completed and under construction the aluminium windows of which were/are supplied by the contractors which provided the aforesaid problem hinges, and whether such contractors also supplied other public housing fixtures in addition to aluminium windows; if they did, of the fixtures involved and progress of such projects;
(d) whether a set of criteria is in place at present for contractors to follow when HD awards contracts for installation of aluminium windows, to ensure that the materials provided by the contractors meet the requirements of HD; whether projects are followed up and inspected by qualified works staff of HD upon completion; if not, of the reasons for that; if so, whether the authorities have reviewed the inspection criteria and procedures subsequent to the occurrence of the aforesaid incident; whether the authorities will draw up a list to preclude contractors with poor records from bidding for works contracts of HD again; and
(e) given that there have been repeated problems with the quality of public housing fixtures recently, whether the authorities will carry out detailed reviews and studies on the quality of public housing; if they will, whether they will consider setting up an ad hoc group to follow up the matter and review the problems brought by the use of pre-cast units in building public housing, with a view to preventing the recurrence of similar problems; if not, of the reasons for that?
Reply:
President,
My reply to the question is as follows:
With regard to the incident of defective window hinges at Upper Ngau Tau Kok Estate and Lam Tin Estate, the root of the problem lies in the deviation in chemical composition of the raw material for stainless steel. The current set of comprehensive monitoring procedures on the construction of the aluminium windows including stages such as design, supply and installation, etc, is effective. But this incident reflects the importance of quality assurance of building materials in the upstream of the supply chain.
(a) Under the Hong Kong Housing Authority (HA)'s building contracts, responsibility to ensure material compliance rests with the contractors. In this incident, the concerned contractors have admitted responsibility and will be responsible for the entire replacement cost for window hinges of all flats in Upper Ngau Tau Kok Estate and Lam Tin Estate. The HA does not need to bear any cost.
(b) According to records, over the past five years, there have been a small number of complaints or reports on defects from tenants in public rental housing (PRH) estates within one year of completion. An average of about 0.2 defect per flat was recorded. The problems were mainly related to wall finishes, plumbing and drainage, and ironmongery, etc. These were minor in nature. Once complaints or reports on defects are received, the Housing Department (HD) will take prompt follow-up action and arrange for the maintenance works to be carried out at a time convenient to the tenant in order to minimise the possible nuisance and disturbance.
(c) In the past five years, the supplier of the defective aluminium window hinges in the incident took part in three building projects for the HA, namely Upper Ngau Tau Kok Estate Phases 2 and 3, Lam Tin Estate Phases 7 and 8, and Lei Yue Mun Estate Phase 2. The concerned supplier is not taking part in any project currently under construction.
In February 2010, we took six aluminium window hinges by random sampling from Lei Yue Mun Estate for laboratory tests. Results revealed that only one sample contained a carbon content slightly higher than the specification requirement. The chemical compositions of all other samples fully complied with the specified requirements. Although no rusting and breakage problem have been found in Lei Yue Mun Estate since its population intake three years ago, we will closely monitor the situation there. If there are any abnormalities, we will take immediate follow-up action.
(d) The HD has been exercising stringent control over the aluminium window quality through inspection, close supervision on workmanship and checking. The scope of windows inspection is in line with the industry practice. In the contract specification, we clearly set out the performance requirement of the aluminium windows. Under the contract, the contractor is responsible for the design, supply and installation of the aluminium window. The current inspection procedures in relation to aluminium window are as follows:
(i) submission of sample, shop drawing and structural calculation to ensure the design, proposed materials, components and structural strength comply with specification requirement;
(ii) carry out performance test to ensure satisfactory performance in the areas of water penetration, air infiltration and structural adequacy;
(iii) on-site delivery verification including documentation, visual and measurement checks;
(iv) periodic inspection during installation to ensure that workmanship complies with specification requirement;
(iv) perform water-tightness test to ensure no seepage; and
(vi) carry out final inspection by visual and functional test to all flats to ensure proper installation and smooth operation of all windows. All hinges are checked for proper fixing and with no missing screws.
The overall inspection and checking process is undertaken by professional and qualified staff. We followed this process in Upper Ngau Tau Kok Estate and Lam Tin Estate. All window hinges were inspected at the time of completion. However, the defects in material composition which resulted in rusting and breakage could not be detected under normal inspection procedures and did not surface until some time after occupation. We have uploaded the incident of defective window hinges to the Material Database at the HA's intranet, notifying colleagues of the details.
(e) The defective window hinge incident in Upper Ngau Tau Kok Estate and Lam Tin Estate reinforces the importance of managing the quality of raw materials in the upstream part of the supply chain in the construction industry. To avoid a recurrence of the problem, the HA is now actively working with the stakeholders in the construction industry to extend the product certification scheme to aluminium window and 4-bar hinge assembly. This scheme can further strengthen the monitoring of product quality and deliver better assurance.
In the interim, the HD would take the following immediate steps to strengthen control of the quality of windows supplied for HA's construction sites:
(i) requiring contractors to submit mill certificates and manufacturer's test reports for stainless steel window components;
(ii) carrying out surveillance tests on the mechanical and chemical properties of 4-bar hinges;
(iii) carrying out surveillance tests on the endurance of fasteners and other hardware; and
(iv) carrying out random checks on the workmanship of the hinge pivots to ensure they are squarely pinned for smooth movement.
Ends/Wednesday, July 7, 2010
Issued at HKT 11:35
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