Killer HDB lifts – What’s going on?

Saw a disturbing headline today: Dog killed in lift accident after leash gets trapped in lift door (Warning: Disturbing Picture)

It was not long ago when a video circulated showing another dog’s leash getting caught in the lift’s door, but it was a small pug and it managed to escape the death trap.

Yes, the owner of the golden retriever is technically at fault, but I won’t put all the blame on her, plus, you have to remember she’s in her 50s. Blur cocks come from all walks of life. I’m not going to put blame on HDB and their lifts either. It’s not like anybody had malicious intentions to choke the life out of their beloved pet.

What I want to do, is to focus on the problem and find suitable solutions for it.

What Contributed to the accident

1. Physical Sensors

Practically all lifts, new and old, use a bar to sense obstructions between doors. You usually see it as a metal bar in between the moving doors. Obstructions would give the sensors a ‘push’ when the door closes, causing the lift doors to open again.

2. Leashes are Loose Fabrics

Here’s the problem – Leashes, at the end of the day, are usually loose fabrics or lengths or plastic. Unless pulled taut, it will conform to the shape of the door and the sensor and not trigger the auto door opening sequence.

3. Old Lifts close fast

I remember visiting some old estates and noticing that the lifts don’t open for long before wanting to close on you. Slowing it down should help prevent such things from happening. In the latest incident however, it was one of the newer lifts that contributed to the accident.

4. No Laser/Infra-Red (IR) sensors, even in newer lifts?

Modern lifts usually include beam sensors of some sort, often based on Infra Red or Laser. So, instead of only relying on the door closing on your leg to realise that there’s an obstruction, most lifts nowadays have the ability to sense an obstruction even before it starts to close. A leash crossing the paths of one of these sensors will prevent the door from closing.

One problem here is the position of the sensors. If, say, the sensors are only at the top and the bottom, the a leash dangling somewhere near the waist height would not trigger it. There is no set standard and different manufacturers would have implemented this safety feature in any number of ways.

And then there’s another problem – what if the newer, modern lifts procured by HDB didn’t even have these sensors at all?

Based on the picture (which is disturbing, you’ve been warned), it should be one of the newer lifts, that should have been equipped with a laser based sensor. The lift at my HDB block looks similar, so I decided to check it out. Guess what? There weren’t any:

Modern HDB Lift Sensor Module Slot

As you can see, the lift’s design allows for a IR/Laser based sensor module to be installed

Here’s a quick video as well: HDB Killer Lifts – Why Didn’t the Door Safeties Trigger?

So, if HDB weren’t such cheapskates and installed the beam based sensors, would this have prevented the death?

No… or very unlikely.

The problem is that in this lift’s design specification, even if the beam sensors were in place, it would only be able to sense feet-level obstructions.

The only way this would have worked is if while going into the lift, the leash became very loose and movement between the pet owner and the dog caused it to move up and down near the floor, which, if you’ve owned a dog before, you’ll know that that’s very unlikely to happen. You don’t have to be a genius to realise this, but the leash would tend to stay between the hip level (where the hands usually are, casually holding the leash) and the height of the dog’s neck. It doesn’t help that the golden retriever would have its neck way above the sensor opening’s height.

HDB Lift Sensor Height Expectations

We have to imagine the height at which the leash would be present. Existing sensor module position would be too low to detect a moving leash.

How Can We Prevent This?

1. Don’t be blur  

Speaks for itself. Be aware of your surroundings.

2. Let the dog in first (No pun intended)

This practically negates the problem. If you’re a sharp-ish person but, for whatever reason, you’re damn sway or you have problems at home/work and your mind isn’t working at that time, then it would be you that is at risk of being left outside and you’d be able to react accordingly. A dog has no hands and wouldn’t know what to do.

3. Install IR/Laser obstruction sensors – At the right height

The first 2 are changes we can implement immediately to prevent such a catastrophe from happening. This however, doesn’t being down the risk to zero. There will always be the blur cocks, or the old people, which would not really be fair if we were push all the blame on them. At the end of the day, we’ll still need a form of insurance, like the seat belt and air bags in cars, to prevent unexpected deaths from happening.

This is where HDB comes in. Put in the sensors. If you pay attention to lifts used in offices buildings and shopping centres, you’ll notice that a lot of them have the beam sensors in the middle, and quite a few even have sensors running down the length of the door, which is ideal. Unless HDB decides in all its wisdom that people should be safer while working and shopping than when they’re near their homes (a decision that they’re very capable off), I don’t see why we shouldn’t have similar safety features in HDB lifts.

I’m not expecting them to upgrade all the existing lifts around Singapore overnight, but at least start start with the upcoming estates and perhaps install the sensors on those that already have the specifications to accept them.

At the end of the day… we can’t all just put all blame on the lady or HDB for negligence or being cheapskates. We’ll just have to accept it for what it is – an accident – albeit an easily preventable one – and move on from there.

So everyone, I hope you guys found this useful and while we wait for the powers to be to hopefully address this and not sweep it under the carpet, we as pet owners will have to do our part and make the world an awesome place for our pets, if only because they’ve made life awesome for so many of us, yea?

By Aaron Loy

This was first published at

This entry was posted in Commentaries.
This entry was posted in Commentaries.