TEST weights for safety harnesses are set to be increased after a survey of construction workers found they were heavier than the average population.
Academics from Loughborough University have weighed nearly 600 builders who work at height during the past 12 months.
And their measurements reveal that tradesmen such as steel erectors are more than 20 per cent heavier than the average man in the street.
The figures mean that Health and Safety Executive experts may have to revise the weight of dummies currently used to test harnesses and lanyards.
A Loughborough researcher said: 'Tests are currently carried out using 100 kg weights.
'Some 95 per cent of the general population fall below that weight but the feeling was that building workers were heavier than that.
'We have finished the research, which backs up that feeling and shows that people working at height are significantly heavier than the general population.'
The results mean that the current test weight of 100 kg (15 and three-quarters stone) should be upgraded to at least nearer 120 kg (19 stone).
The researcher said: 'The actual weights we recorded showed that the average steel erector weighed 91 kg (14 stone 5 pounds) and the heaviest man we found was 139 kg (22 stone).'
Construction workers believe the results are due to bulkiness caused by manual labour.
One steel erector said: 'Everyone knows muscle weighs more than fat and we are a lot fitter than people who sit on their arses in offices all day.
'Sure the lads like a good fry-up in the morning but we work it off. It's hard work up there and you don't survive if you're a fat slob.
'But it's a good thing they have done this. I will feel a lot safer knowing that a harness I'm wearing has been tested using the proper weight.'
A Health and Safety Executive spokeswoman said: 'The next stage will be for a Government committee to take these results into account and it will decide whether the testing standards need to be changed.'
HSE researcher Martin Holden said: 'Workers substantially outside the currently used normal weight should check that the equipment they are using is suitable for their body mass by seeking advice from the original manufacturer or supplier.'