Scaffold safety: Mast climbing work platforms
Mast climbing work platforms are becoming increasingly common on construction sites. Contractors began substituting mast climbers for conventional framed scaffolds in the 1990s for a number of reasons: they were quick to erect and dismantle, they had a very large load capacity, they could position workers precisely at the right height, and they had capability to reach much higher than traditional scaffolds.
But the advantages of mast climbers over conventional scaffolds also raise the safety risks for workers who are unaware of their hazards.
Essentially, a mast climber is a power-driven platform that climbs a vertical tower. Mast climbers, which can be set up as a single tower or as multiple towers braced together, are associated with high-rise construction (they can go as high as 1,000 feet) but they're typically used on "medium-rise" buildings up to six stories high. Uses include brick and masonry work, glazing and drywall applications, painting, window installation, architectural covering, and mechanical work.
When installed and used correctly, mast climbers are as safe as other scaffolds. But, a mishap can be catastrophic when their hazards are overlooked.
What are the hazards?
- Platform failures. Platform failures often happen when the manufacturer's erection, dismantling, use, or bracing procedures aren't followed. Ensure that the work platform, which is supported on a cantilevered beam, is capable of supporting its own weight and at least four times the maximum load applied to it after the final brace is removed during the dismantling process.
- Insecure anchorage points. A building's exterior, such as thin brick veneer, may not support the scaffold's anchors. Always secure the scaffold to the building following the manufacturer's instructions.
- Poor communication between manufacturers and users. Manufacturers must ensure that those who buy, lease, or use their equipment know about any product recalls or updates. Distributors, suppliers, and leasers must also stay informed about equipment updates and provide the information to those who use, maintain, and inspect the equipment.
- No escape from disabled platforms. A disabled platform can put workers at risk if there is no way to get off the platform safely. Make sure that workers know what to do in an emergency. A best practice is to ensure that escape procedures meet the requirements in ANSI A92.9 (Mast Climbing Work Platforms).
- Untrained operators. Erecting, operating, and dismantling mast climbers require a different skill set than other scaffolds. And being trained on a model from one manufacturer does not mean that an operator knows how to operate a model from a different manufacturer. It's essential that users be trained on the specific equipment that will be used at a site.
- Power lines. Extended-boom forklifts and cranes are often used to move mast climbing tower sections. Make sure that workers and all equipment – including the mast climber – are at least 10 feet away from power lines. Failure to do so puts workers at risk of electrocution.
- Falls. Hazards that increase the risk of falls aren't unique to mast climbers. They include unguarded platform ends, removed guards, climbing from the platform to a building opening, and uncovered holes in the platform.