15.07.2009

Mast climber drops UPDATED

A twin masted mast climbing work platform, working on a tower block in Wolverhampton, UK, gave two painters a fright earlier today, when one side of the platform dropped around 30 metres, from the ninth floor to the fifth before jamming.
The left hand of the platform dropped from the ninth to the fifth floor

The painters apparently managed to get off onto a balcony on the eighth floor according to the West Midlands Fire Service spokesman which was called to the block this morning along with the police.

A spokesman said: “They have been rescued by firefighters who forced entry into the flats to make sure they could be safely retrieved. No injuries have been reported but I’m told they are possibly suffering from shock.”

The painters were sub-contractors to Wolverhampton Homes, which said that it was looking into what happened and that a number of tenants had been evacuated. The Health & Safety Executive is investigating.
The failed left hand drive motors


The mast climber is built by AS Climber, the Spanish based manufacturer, and was working for contractor Frank Haslam Milan (FHM), part of the Keepmoat group which specialises in the refurbishment of social housing. We do not currently know who owns the platform or who is responsible for its maintenance.
The right hand motors held but the mast and frame is badly twisted


UPDATE:
A spokesperson for Frank Haslam Milan West Midlands said last night: “As a precautionary measure, tenants have been evacuated from the bottom nine floors of the building into a community centre across the road while we work to make the site safe.”

This morning the FHM spokesperson said that all tenants have now been fully informed by letter and “we are pleased to announce that the majority will be let back into Longfield House tonight.”

“We have, however, made arrangements for the tenants of four flats to stay overnight in alternative accommodation. We are also asking tenants in 101 flats to vacate the premises tomorrow, between 9am and 5pm, and attend the Heath Town community centre where drinks and refreshments will be made available while we continue to work on site.

“FHM is currently working alongside the Health and Safety Executive to determine the cause of the incident and we’re not in a position to comment any further at this stage.”



Vertikal Comment

This type of accident is not unknown, although it is very rare, this particular model is one that uses a twin drive motor/braking system. One of which tends to provide the main drive while the other operates as a back up, simply following until the unlikely event that the lead motor or brake fails, it then comes into play.

However if by chance the back up motor or brake is not functioning or out of adjustment, then in the event of a main motor or brake failure the platform will either be stranded or if it is the brakes that have failed it can drop or as possibly happened in this case slip down the mast.

The masts and the platform connections on tis unit seem to have held up well to the failure and given that the two men were able to climb out the speed of descent was probably not rapid.

On a twin mast arrangement the platform will drop until it breaks something or, as in this case, it jams. Some mast climbers are fitted with overrun/overspeed or centrifugal brakes, which one assumes, would have behaved differently in such an incident. This unit appears to have had one fitted in addition to the twin motor set up, if so a steady, relatively slow descent would explain why it did not click in and stop the platform, assuming the required speed of descent to operate it was not achieved.

Either safety braking system works and is inherently safe as long as it is maintained and regularly inspected.

If this had been a single mast set up the painters might have experienced a bit more of a shock than they did?


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