1.5 million HDB lift buttons have been coated with a disinfectant that can last for months – here’s why it’s so powerful

Called sdst, the disinfectant lasts for 90 days and does not need to be reapplied in that time.
Changi Airport Group

A powerful long-lasting disinfectant is now being used to coat lift buttons in Singapore’s public housing estates.

Called sdst, the disinfectant lasts for 90 days and does not need to be reapplied in that time.

In a press statement on Thursday (Apr 2), Changi Airport Group’s (CAG) philanthropic arm, Changi Foundation, said it had donated 650 litres of the coating to all 16 town councils in Singapore.

Already used to coat frequently-touched surfaces in Changi Airport, the coating has now also been applied on about 1.5 million lift buttons in Singapore’s 26,000 HDB lifts, CAG said.

According to CAG, sdst is a broad-spectrum coating comprising a modified quaternary ammonium compound. It is also said to be eco-friendly and works to safeguard against viruses, bacteria and fungi.

The product’s official website, where it is also sold, described it as a “high performance self-disinfecting coating with antimicrobial active which physically controls and ruptures the target organism’s cell membrane on contact”.

This is possible as it has a needle-like structure that ruptures the outer membrane of viruses, bacteria and fungi, and reduces their ability to infect, CAG said.

By neutralising microbes on treated surfaces, the solution prevents germs from breeding on the surface, sdst’s website said.


Bonding agents in the coating also allow it to adhere tightly to surfaces at a molecular level, so that it remains effective even with repeated scrubbing and cleaning.

But Dr Teo Ho Pin, co-ordinating chairman of PAP Town Councils, also urged lift users not to press lift buttons with pointed objects such as keys, as hard objects could still scrape the coating off.

An ATP reading of the bacteria count before (left) and after sdst is applied to the lift button.
Changi Airport Group

According to sdst’s website, the product – which retails at S$34.90 – is safe to use at home and on personal items such as laptops and mobile phones.

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