A rational explanation has not been given as to why older Housing Board flats have not been upgraded with proper air-con ledges and railings, even where there are known vulnerabilities.

I find HDB's reply unhelpful. (Safety measures in place for HDB air-con installers; June 30).

While it listed all the current legislation and guidelines, it was quiet about the extremely dangerous and hazardous situations that air-con tradesmen have to deal with while installing the split-type condensing unit outside older flats.

In fact, the multi-split system is currently the most commonly used in Singapore.

I invite all who are concerned about personal safety to watch the video titled Dangerous Air Con Installation in HDB on YouTube, which demonstrates that just a misstep in such extreme conditions could be fatal.

But it shouldn't take a tragedy for us to tap our natural humanity.

In the absence of physical fall-prevention measures, can the relevant public agencies and businesses share with us about how we, as residents, can help to assure the safety of the tradesmen we engage?

Manfred Lin