Legislative Council Panel on Economic Services



At the meeting on 25 January 1999, Members discussed a paper from the Administration on the safety of gas water heaters. The Administration agreed to conduct a review of further measures to be taken, including the possible prohibition of the use of flueless gas water heaters, with a view to minimizing the occurrence of accidents related to the use of such heaters.

2. The review has been undertaken by the Gas Authority (the Director of Electrical and Mechanical Services) in consultation with the Gas Safety Advisory Committee. This paper reports on the outcome of the review.


Present position

3. The Gas Safety Ordinance, which came into effect in 1991, allows flueless gas water heaters to be installed other than for serving a bathroom or shower, provided that the installation is well ventilated and the heater is affixed with a warning label to advise that it is not to be used for more than five minutes continuously. Notwithstanding this provision, it has been the advice of the Gas Authority since 1991 (in the relevant code of practice) that the use of a room-sealed or fanned draught model is to be preferred. Hence most of the flueless water heaters still in use were installed before 1991.

4. Currently, there are -

  1. some 20,000 flueless water heaters serving bathrooms and showers (this figure takes into account heaters replaced since January 1999 under the gas supply companies' current inspection and replacement programmes); and

  2. some 59,000 flueless water heaters installed in kitchens.

Flueless water heaters serving bathrooms and showers

5. Regulation 35 of the Gas Safety (Installation and Use) Regulations, which came into operation in 1991 and does not have retrospective effect, provides that no person shall install a flueless sink gas water heater to serve a bathroom or shower. This prohibition recognises that such heaters are not designed for providing a continuous supply of hot water to a bathroom or a shower. Being flueless, they have no means of discharging the products of combustion to the outside air. There will be a build-up of such products in the room atmosphere when there is inadequate ventilation and the heater is used continuously. Such heaters will be rendered potentially unsafe in those situations.

6. Gas suppliers were informed in 1991 that, where owners declined to replace old bathroom or shower installations using flueless sink gas water heaters, there should be at least one fully louvered window permanently open to the outside air next to the heater so as to provide an uninterrupted means of ventilation. There should also be a warning label affixed to the heater to indicate that this means of ventilation must not be blocked.

7. In light of recent incidents involving flueless sink gas water heaters serving bathrooms and showers and in view of recent public concern over the safety of these pre-1991 installations, the Gas Authority has sought the advice of the GSAC as to whether the use of all flueless water heaters connected to bathrooms or showers should be prohibited, on the grounds that such action would eliminate future dangers arising from some tenants blocking essential ventilation openings, enclosing previously open balcony areas, or missing important safety inspections.

8. It was recognised during the discussion at the GSAC meeting that, despite the fact that most of these flueless water heaters were over 15 years old and increasingly subject to repair and frequent maintenance, the enforcement of a ban on their use could be problematic, in that there would almost certainly be some resistance from owners, despite the safety risk. To overcome this, legislation would be needed to permit, in extreme cases, the shutting off of the gas supply to a dwelling if proper enforcement of the ban was to be ensured. It was also noted that many of the remaining flueless units were installed in older dwellings in public housing, which may be scheduled for demolition anyway. On the other hand, past incidents have indicated that there is no guarantee that owners will follow the safety requirements in the use of such heaters at all times and public safety cannot be fully ensured under the present arrangements. After lengthy consideration, the GSAC supported the Gas Authority's proposal that the gas safety legislation be amended to prohibit the use of all flueless water heaters serving bathrooms and showers.

Flueless water heaters in kitchens

9. The Gas Safety (Installation and Use) Regulations allow the installation of flueless sink gas water heaters for kitchen use provided that there is adequate ventilation and a warning label is affixed advising that the maximum continuous period of use should not be more than five minutes. The Gas Authority has considered in the light of recent incidents whether there is justification for a prohibition on the use of such heaters in kitchens.

10. The restriction of five minutes on continuous use takes into account that this type of heater is designed only to provide an intermittent supply of hot water to a kitchen sink for washing purposes and that, although the heater discharges combustion products into the room, kitchens are normally well ventilated places. Publicity by the Gas Authority emphasises the importance of good ventilation when using this type of heater.

11. Since the late 1980s, flueless sink gas water heaters have been available with an oxygen deficiency sensor, which monitors air quality in the vicinity of the water heater and shuts off the heater before the surrounding atmosphere becomes hazardous. About 9,000, or about 15%, of the 59,000 flueless water heaters installed in kitchens have this safety device. It is now standard for this type of water heater on the market to have an oxygen deficiency sensor.

12. The Gas Authority introduced new gas water heater installation requirements in 1998. These facilitate the use of a new generation of gas water heaters. Innovative designs will allow the installation of small, room-sealed models of heater inside kitchens, for example located within kitchen cabinets. This option is favoured by architects and for the first time in Hong Kong provides a range of gas alternatives to the flueless sink model. An amended Building Practice Note has already been issued to this effect and the Gas Authority's code of practice on installation of gas water heaters is being revised accordingly. It may be expected therefore, that market demand for flueless sink gas water heaters will diminish further over time. It would be in the public interest to encourage this process.

13. Taking into account points in paragraphs 9 to 12 above, the Gas Authority considers that the situation does not call for the immediate prohibition of the use of flueless sink gas water heaters in kitchens, but does call for action to be taken to prohibit the new installation and replacement of such heaters in kitchens. Accordingly, he has sought the advice of the GSAC as to whether the sale of flueless water heaters should be discontinued within a reasonable timescale. While some members of the GSAC supported the proposal, some other members felt that the emphasis should be on further public education on gas safety in the home.

Way forward

14. Following consideration of the GSAC's advice, the Gas Authority intends to -

  1. proceed with a view to the introduction of legislation to prohibit the use of flueless sink gas water heaters to serve bathrooms or showers; and

  2. in view of the absence to date of a consensus within the GSAC as to whether the sale and the new installation and replacement of flueless sink gas water heaters should be discontinued, pursue further with the GSAC the proposed prohibition of such sales and new installations.

15. As regards timing, the Gas Authority's aim is to have the proposed prohibition in (a) above in place as soon as possible. It will be brought into force about six months after enactment of the amending legislation, so as to allow time for the industry to replace the existing heaters. The timing for (b) above will be considered after further discussion by the GSAC.

16. In parallel, the Gas Authority will discuss with the gas supply companies the practical aspects of implementing the proposed prohibitions, including publicity arrangements, and undertake more public education on gas safety.

17. We welcome Members' views on the proposed approach.


18. The following paragraphs update Members on other action in hand on matters related to the safety of gas water heaters.

Gas suppliers' inspection and replacement programme for flueless water heaters

19. The Gas Authority is continuing to monitor the gas supply companies programmes to visit and inspect all flueless gas water heater installations and to replace, upgrade or disconnect, as necessary, any units considered to pose an immediate risk to the household concerned.

20. As at 18 March 1999, the Hong Kong and China Gas Company had visited all of the 15,856 towngas flueless water heater installations connected to showers on its records. Of these, 15,443 visits have been successful and 7,421 installations were found to require safety enhancement measures. The company's programme to enhance the safety of the unsafe installations is continuing.

21. As at 13 March 1999, the LPG suppliers had recorded a total of 15,837 LPG flueless water heaters installed in bathrooms and kitchens. A total of 13,095 visits have been made to these installations, of which 5,411 visits have been successful and 3,281 installations were found to require safety enhancement measures. The LPG suppliers' programmes to visit the remaining installations and enhance the safety of the unsafe installations are continuing.

Control of the import and manufacture of domestic gas appliances, including water heaters

22. The Gas Authority and the GSAC are taking steps to improve and control safety standards of imported domestic gas appliances, including water heaters.

23. In November 1997, GSAC agreed that a detailed code of practice stipulating appliance safety requirements and approval procedures should be prepared prior to introducing legislative controls. A code entitled "Approval of Domestic Gas Appliances" (GU05), prepared by the Gas Authority in conjunction with the industry, was published in June 1998. Safety requirements contained within GU05 include, among other things, the provision of a protection device on all domestic gas appliances to shut off the gas supply to the appliance automatically in the event of the gas flames being extinguished, for example, during windy conditions.

24. In November 1998, the GSAC supported a proposal by the Gas Authority for legislation to regulate the import and manufacture of domestic gas appliances. The new legislation would require in particular that new gas appliances for use in Hong Kong, including water heaters, must be in compliance with international safety and quality standards and be approved by the Gas Authority. Preparatory work for this legislative amendment is in train. The purpose of the legislative amendment is to give code of practice GU05 statutory backing.

Regulation of the activities of gas distributors

25. At the GSAC meeting held in November 1998, members considered a proposal to strengthen the regulation of the activities of gas distributors. The GSAC agreed that a new code of practice detailing the duties and responsibilities of gas distributors should be prepared. In this connection, the day-to-day responsibilities of gas distributors and their operating procedures, and the adequacy of corresponding areas of existing legislation, are being examined in detail. In particular, attention is being focused on whether gas distributors should also have to be registered gas contractors, as a means of ensuring that they are able to provide the necessary technical back-up services to their customers and that they maintain proper customer records. Possible means of improving control of distributors by gas supply companies through elimination of multi-brand distributorships and sub-dealer networks are also being explored. A draft code of practice is expected to be presented to the GSAC around July 1999 and thereafter there will be consultation with all parties involved over the legislative amendments.

Gas Standards Office
Electrical & Mechanical Services Department
March 1999