HOUSING AND DEVELOPMENT BOARD FLATS (Shattering of shower room tempered glass doors)

Miss Penny Low asked the Minister for National Development, in view of the recent incidents of shattered shower room tempered glass doors installed by the Housing and Development Board (HDB), what are (i) the measures being taken to prevent such a recurrence and (ii) the number and percentage of these incidences in HDB flats.

The Senior Parliamentary Secretary to the Minister for National Development (Assoc. Prof. Koo Tsai Kee) (for the Minister for National Development): Mr Speaker, Sir, HDB has identified three possible causes for the breakage of tempered glass shower screens in HDB flats.

(1) Rough usage and improper renovation works by the flat-owner, which may cause chipping of the glass. Over time, the chips may develop into cracks, causing the glass to break suddenly when they widen to a certain crack width;

(2) Deterioration or damage of the fitting accessories, such as the hinges or sliders, which may cause the glass panel to detach and break; and

(3) Presence of minute impurities within the glass that render the glass more susceptible to breakage. Based on current technology, the formation of such impurities during the manufacturing process cannot be totally eliminated.

Though the causes of the breakage cannot be ascertained conclusively, HDB's building contractors have replaced, and will replace, the glass doors within the defects liability period.

Also, as a precautionary measure, HDB contractors have started to inspect all HDB flats that were installed with tempered glass shower screens. The glass doors and other fittings will be replaced, if necessary, at no cost to the lessees. Lessees of these units have also been provided with a usage and maintenance guide to advise them on the safe and proper usage of the shower screen. In addition, they are given the particulars of the original installer of the shower screen to facilitate future maintenance of their shower screen, if necessary.

Since May 2000, 58 incidents of shattered tempered glass shower screens in HDB flats have been reported. This constitutes less than 0.2% of the total number of sets of shower screens installed.

Dr Teo Ho Pin (Holland-Bukit Panjang): Mr Speaker, Sir, may I ask the Senior Parliamentary Secretary what are the tender specifications for this tempered glass? Are the specifications for HDB shower screens different from those for private condominiums? Why are there fewer cases of shattered glass screens in private condominiums? Secondly, are there any safety standards which these tempered glass screens must comply with? If there are, is there a breach of these standards? Thirdly, will the HDB replace not just the glass screens which have shattered but all those in the same batch of the contract as well?

Assoc. Prof. Koo Tsai Kee: Mr Speaker, Sir, the hon. Member asked three questions. Let me take the last one first.

HDB started putting in glass shower screens since 1999. We have installed something like 30,000 shower screens in 15,000 flats. Usually, there are two showers in each flat. We will inspect all the 30,000 shower screens, every single one - the fixtures and the glass doors - before the end of October this year. Improper fixtures will be replaced. If we can detect any glass impurities within the expertise of the contractor, we will replace the tempered glass doors at no cost to the lessee. So, I hope Members are reassured of that. And we are replacing them expeditiously, as fast as we can.

Secondly, I think the hon. Member is under the misguided notion that private condominiums do not suffer the same fate. They do. In fact - without mentioning names - in a condominium somewhere in north-east Singapore, we have a 1% breakage of glass doors; HDB's record is 0.2%. The contractors kept quiet. Of course, I can give Members the list of names, etc, privately.

Shattering of glass screens is not uncommon. HDB is late in the game. It only started building glass shower curtains in 1999, and tempered glass screen doors only came in lately. We did a search of the Internet and found that this subject is something that has been published in the New Scientist. I will circulate it later on. It shows that such things happen. Even high quality tempered, hardened glass doors shatter in different parts of the world randomly.

Are there any standards imposed? HDB, of course, has the specifications. I do not have the detailed specifications. The specification is that they must stand up to a certain usage. And the contractors who supply these glass doors to HDB, supply the same glass doors to many of the condominiums in Singapore. But I will give the hon. Member the specifications.

Miss Penny Low (Pasir Ris-Punggol): Sir, may I know what is the warranty period for these shower screens in HDB flats? If the residents prefer not to install tempered glass shower screens but prefer plastic or any other type of material because they have senior citizens or children at home, is that also permissible? Will HDB replace them, also at no cost?

Assoc. Prof. Koo Tsai Kee: If the glass shatters within the defects liability period, ie, one year after taking possession, we will replace them with no questions asked. If it happens after the one-year period, please let us know and we will see what we can do. So far, all the shattered glass screens have been replaced at no cost.

The second question was that if the lessees want a different kind of replacement, eg, a plastic door, yes, we are accommodating. But sometimes there is a cost differential. So, if it is cheaper than a glass door, of course, no charge - FOC. If it is more expensive, then it is reasonable for the lessee to top up the difference.

Dr Teo Ho Pin: Mr Speaker, tempered glass is not supposed to shatter, that is why it is called tempered glass. It has certain reinforcements in the glass. It is supposed to just have a crack, unless some direct force is applied. So, I do not understand what are the causes for the shattering of tempered glass in those units. Also, knowing the activities, normally the specifications will specify the thickness and whether armour-shield or tempered. So, if the cause is due to impurities, that means that the whole 30,000 glass doors may shatter, and that could be a safety problem.

Secondly, how can the HDB check the integrity of these glass doors for the shower rooms? It is very difficult to check the impurities in glass.

Thirdly, as to the 1% breakage in private condominiums, the private developer concerned may be one of the not-so-up-to-quality developers. The HDB should not use that as a benchmark.

Assoc. Prof. Koo Tsai Kee: Mr Speaker, Sir, I do not know which discipline the hon. Member comes from, but he does not know much about tempered glass. I hate to give a technical presentation on how tempered glass comes about, but I will just read a paragraph from the New Scientist. It reads:

"Tempered glass is found everywhere from cars and bus shelters to the windows, walls and roofs of thousands of buildings around the world. It is easy to see why. This glass has five times the strength of standard glass, and when it does break, it shatters into tiny cubes rather than large razor-sharp shards. Architects love it because large panels can be bolted together to make transparent walls, and turning it into ceilings and floors is almost as easy."

What is it made of?

"It is made of heating a sheet of ordinary glass to about 620oC to soften it slightly, allowing its structure to expand, and then cooling it rapidly with jets of cold air ..."

It goes on and on. I can give a copy of the article to the hon. Member.

"The problem starts when glass contains nickel sulphide impurities. Trace amounts of nickel and sulphur are often present in the raw materials used to make glass ...."

It is inherent in the glass. What is glass made of? Nickel and sulphide. And they are impurities.

The second question is how is it possible to detect glass doors which might crack? We do our best. The percentage of shattering is very miniscule. We will carefully check for fine cracks. Many of the glass doors shatter not because of impurities. Some of them are due to wear and tear. We do not know. Once it is shattered, we cannot trace whether it is wear and tear or whether it is due to impurities. So, we look for fixtures - whether they are properly installed. We know it can. The contractors have experienced installing hundreds of thousands of glass doors throughout Singapore, and HDB is actually a small player in this game.

Dr Teo Ho Pin: Mr Speaker, Sir, may I ask the Senior Parliamentary Secretary what is the purpose of installing tempered glass in shower screens? What is the tempered glass supposed to perform in the shower screens? He still has not given the answer as to what are the causes of the glass shattering. If you look at the photograph in the Straits Times, they were really shattered. Maybe he can explain how HDB inspectors or contractors inspect the rest of the shower screens and give an assurance to the residents that after inspection or testing by the checkers, they will be all right and they will not shatter.

Assoc. Prof. Koo Tsai Kee: My answer is: trust us. We have to trust the contractors because they have the experience. Will the glass door shatter after inspection? Unlikely, but it can happen. There is no 100% assurance. But we will do our best. We must remember that there are potentially thousands of defects in a building due to wear and tear and we cannot guarantee that none of these defects will occur at all.

Mr Low Thia Khiang (Hougang): Sir, my question is: will tempered glass shatter? We have an engineer by training here who says that tempered glass should not shatter but the fact is that it has shattered. So will tempered glass shatter?

Assoc. Prof. Koo Tsai Kee: Tempered glass should not shatter but because of the intrinsic traces of nickel and sulphur, it can shatter in a small number of cases. It does not happen just in HDB flats. It happens in private condominiums. It happens all over the world, in Britain, Australia and America.

Dr Teo Ho Pin: Sir, I think the Senior Parliamentary Secretary has not answered my question on what is the purpose of tempered glass as shower screens. What is it supposed to do? Why not ordinary glass? Why tempered glass? He has not answered the question.

Assoc. Prof. Koo Tsai Kee: In fact, tempered glass is safer than ordinary glass because when ordinary glass cracks, it cracks in fairly huge pieces with sharp razor corners. If you are not careful, when you lean on to it, it cracks and it can pierce you. In the case of tempered glass, when it cracks, it cracks into thousands of pieces. Of course, it can still hurt you once in a while but it is safer. It is hard, it is safe. When it does crack, it shatters into thousands of pieces, just like your car windscreen. Why do the car manufacturers not use ordinary glass? Because in an accident, they will shatter and it will not pierce you. You might still be hurt by the shattered pieces, rather than sharp triangular pieces that will pierce your face. That is the answer. In fact, tempered glass is safer than ordinary glass.

Assoc. Prof. Ngiam Tee Liang: Mr Speaker, Sir, in view of what we have heard in the House now, would the HDB reconsider future installation and use other alternative means until this issue can be resolved?

Assoc. Prof. Koo Tsai Kee: For the new contracts, we are using a new kind of glass called framed, laminated safety glass. We will frame the outside so that the edges will not crack and we will laminate it. So if it does crack, the thousands of pieces will be held together by the lamination. We are also reconsidering the use of glass per se. We may move on to acrylic. Acrylic is expensive, and also over time, it loses its transparency, it becomes yellowish. We have to weigh all these consequences.

Dr Teo Ho Pin: Sir, can I check whether HDB has done any test on tempered glasses before they were actually installed at the units? Were they tested by SPRING or any other authorities?

Assoc. Prof. Koo Tsai Kee: HDB's specification is no different from the specification of private contractors. In view of these incidents, HDB, as I have said, will review the use of tempered glass altogether.

Miss Penny Low: In view of the introduction of this framed, laminated glass, is it possible to replace those glasses in the 30,000 units that have been mentioned earlier on with this framed, laminated glass instead of the usual tempered shower glass? The other question is I read in the Straits Times yesterday that they had some tests for this kind of glass. I think it is a kind of stress test. Does HDB also conduct stress tests on some of these products? Because it appears that some contractors, to reduce costs, actually import sub-standard products and some of these products may get into the HDB flats.

Assoc. Prof. Koo Tsai Kee: Shattered glass screens henceforth will now be replaced with heat-soaked tempered glass. We soak the plates in the water for a few days and those containing even minute traces of impurities will crack. We will then know it is defective. But it does not eliminate completely the presence of nickel and sulphur altogether. In other words, the possibility of cracking will be reduced. That is the test she is talking about. That is the test that she read in yesterday's papers - the heat soaked test.

Mr Speaker: Before this goes on and on, Dr Teo, can you ask your last supplementary question? After this, we will go to the last Question.

Dr Teo Ho Pin: I know there are no known Singapore standards for tempered glass shower screens. I still would like to find out what HDB has specified in the contracts for these shower screens. There is an American, Australian or Indian standard or whatever standards. What sort of standard has HDB specified which the contractor must comply in order to make sure that the tempered glass can perform? What sort of compliance standards were specified in the contract?

Assoc. Prof. Koo Tsai Kee: I do not have the details of HDB's tempered glass specifications. I can find that out for him. But HDB has told me that the specification is the same as those specified for private condominiums. I will find out for him.