SINGAPORE - A lift company which made some 3,500 lifts in Housing Board estates has been banned from tendering for new HDB projects since October 2015.

This is due to the inability of the firm, Sigma Elevator, to "to fully adhere to the timeline of lift installation for certain projects", a HDB spokesman told The Straits Times on Friday (Jan 13).

The restriction is part of HDB's procedure to stop poor performing contractors from tendering for new HDB projects, so as to allow them to focus their resources on fulfilling their ongoing contract obligations.

"(This is) so that Sigma could focus on completing the installation of lifts and improving the performance of the installed lifts under its current contract," said the HDB spokesman.

"Going forward, HDB will not hesitate to exercise its contractual rights where required, which may also include imposition of liquidated damages and debarment from all public sector works."

There are about 24,000 lifts located in public housing estates, comprising about 20 different brands, including Sigma. To date, about 3,500 of the lifts in HDB estates are Sigma-made lifts.

Sigma is owned by United Technologies Corporation (UTC), an established American conglomerate and reputable international lift manufacturer. Sigma lifts have been installed in HDB flats for the last 10 years since 2007.

HDB's spokesman said that throughout this period, "their lifts have met HDB's performance requirements".

"Indeed, over the 10 year period, the overall performance of Sigma's lifts was comparable with that of some other makes."

The spokesman said the board selects lift contractors through open tenders based on considerations such as the past performance of the lift contractor in supplying and installing the lifts, as well as the contractor's track record and financial capabilities.

The appointed contractors are required to install the lifts and test them in accordance with the prevailing lift code and regulations.

After the installation, the lifts are also subject to independent checks by an authorised examiner - a professional engineer who is registered with MOM - to ensure that the lift is safe and fit for use.

However, the lifts installed by Sigma in the past two years had a higher than usual breakdown rate in the first year of operation, the spokesman added.

HDB's investigation revealed that most of these breakdowns were the result of the alignment of lift doors or lift sensors, resulting in the doors of these lifts being more sensitive to knocks and rough use.

This led to higher breakdowns during the initial period of usage, which typically see heavy lift usage due to renovation and moving activities.

Since then, Sigma has taken steps to rectify the issues in all of these lifts, and to ensure that the door operating devices operate smoothly.

The works for all the lifts are expected to be completed by the end of January.

Said the HDB spokesman: "HDB takes a serious view on the performance of lift contractors and lifts, and our immediate priority is to resolve the inconvenience these faults and breakdown cases have caused residents.

"HDB will continue to do its utmost to ensure that Sigma takes prompt actions to resolve all problems with its lifts."