In agriculture, roughly half the deaths and serious injuries caused by falls involve work on fragile roofs. These are roofs sheeted with materials that will not safely support a person's weight and can shatter without warning, for example fibre cement roof sheets (commonly referred to as 'asbestos cement'), corroded metal sheets, and many roof-light sheets.
Replacing old asbestos cement roof sheets
Problem
A farmer died after falling through a fragile roof. He went onto the roof to clean moss from old asbestos cement sheets and inspect them before replacing them with new metal sheets. The roof gave way under his weight and he fell approximately 3m onto a concrete floor, suffering serious head injuries. He died five days later.
Solutions
- Always assume that roofs are fragile unless you can confirm otherwise.
- Never go onto any part of a fragile roof without using platforms to support your weight and means to reduce the consequences of a fall.
- Fit appropriate warning signs to buildings that have fragile roofs, particularly at roof access points.
- Consider doing the job from underneath the roof, using safe access equipment.
Repairing damaged roof sheets
Problem
A farm worker was killed when he fell 4m through the roof of a farm building. He was one of two experienced employees who were finishing some roofwork repairs started the day before. He was using a single scaffold board to walk on the roof and had been standing on this while he cut away some damaged fibre cement roof sheets with a disc cutter. As he stood up on the board after cutting the sheets, he lost his balance and fell backwards through the roof to the concrete floor below.
Solutions
- Make sure that working platforms are:
- wide enough to allow you to work safely and to get to and from your workplace with any tools and equipment;
- long enough to provide adequate support across roof members; for example, they should span at least three purlins. On a sloping roof you may need a purpose-made roof ladder.
- Make sure that enough platforms are provided on the roof. Do not simply use a pair of platforms to 'leapfrog' across a roof.
- Protect against falling through the fragile roof adjacent to the platform by providing:
- a properly installed safety net, scaffolding or similar; for example, a suitable stack of bales close to the underside of the roof; or
- suitable guard rails and toe boards or similar at the edges of the platform; or
- further suitable coverings over all fragile materials.
- Never walk along the line of the purlin bolts. It is like walking a tightrope and gives no protection at all.
- Raise and lower tools and materials safely to and from the roof so that nothing can fall from or through it.
Repairing a leaking roof on an animal shed
Problem
The farmer and two of his employees were repairing a leaking roof on a cow shed. The men went up a ladder (not tied and with no handrails at the top) and along the roof. The workmen were told to walk on the sheet joints because there were trusses below. In the course of attaching new sheets, first the farmer fell, then one of the employees. No handrails, edge protection, crawling boards or other means of preventing a fall had been provided.
The investigation of the accident indicated that a timber purlin – having suffered decay as a result of water leaking and soaking through the roof – had probably fractured beneath some of the roof sheets.
Solutions
Take steps to provide a means of preventing or minimising falls, eg:
- a combination of stagings and nets tied tight up to the roof is the safest method;
- a visual examination from the building floor for obvious distress or decay would be reasonable.
Roof gives way while 'walking the purlins'
Problem
A farm worker fractured a lumbar vertebra and badly bruised his ribs after falling through a fragile roof while cleaning the gutters. He had cleared an edge gutter by riding in a grain bucket while the farmer drove the tractor along next to the gutter. He then moved on to clean a valley gutter. The asbestos cement sheeting on the adjacent roof was fragile. The farmer had examined the work area from a ladder and told the worker to 'just walk on the bolts and you won't go through'. The farmer then left the worker on his own to clear the gutter and carry the waste to the grain bucket, which was left raised at the end of the valley. At some point, he slipped and fell through the roof to the concrete floor below.
Solutions
- Provide protection against falls whenever anyone works on or near fragile materials. Suitable protection will normally include a combination of coverings, guard rails, safety nets and safety harnesses.
- Never walk the line of the purlins.
- For many tasks carried out at height, the use of a suitable, purpose-built work platform attached to a suitable forklift or materials handler will provide greater protection against falls than the use of a ladder.
- Never lift people on alternatives such as grain buckets, potato boxes or pallets.
Cleaning valley gutters on a farm building
Problem
A farm worker fell over 3m through the fragile roof of a farm building during the cleaning of valley gutters. He was one of a team of two who had been lifted onto the roof by a telescopic handler and then began to walk along the valley gutters. The valley gutter was too narrow and the men could not get their feet beside each other in the gutter. They were moving along with one foot in the gutter and the other on the nail line of the fragile roof sheets. As they were cleaning and moving along the gutter, one of the roof sheets gave way and he fell to the concrete floor below. He suffered head injuries and cuts to his feet.
Solutions
- Provide suitable protection against falls whenever anyone works on or near fragile materials. Suitable protection will normally include a combination of coverings, guard rails, safety nets and safety harnesses.
- Never allow workers to walk the line of purlins.