Mast climbing work platforms (MCWP)

[edit] Introduction

Mast Climbing Work Platforms (MCWPs), or mast climbers, are a type of construction elevating equipment used to perform work at height. Mast climbers are equipped with a powered drive unit for propelling the work platform up and down a vertical mast structure.

MCWPs are most frequently used in construction but can also be used in other industries where high-level access and maintenance are required. They can offer an alternative to traditional scaffolding and comprise a powered work platform attached to one or more vertical masts. The mechanical drive units are on the masts.

They can lift platforms with people and equipment. In construction, they provide both access and a platform from which to work on tall buildings. They can be used to attach external components such as cladding.

[edit] Types and uses

Mast climbers are typically used in high-rise construction, where they generally come as single mast, small platforms or larger multuple mast platforms for full elevations. The principle is the same, in that the platform uses the masts for ascent and descent, driven by a motor.

Hydraulically-powered ratcheting drive systems are often used a heights below 10 meters, whilst rack-and-pinion systems are typically used at elevations from 10 to 30 metres. Special systems have been designed up to 300 metres, though these are quite rare.

[edit] Health and safety alert

On the 4th of May 2020, the Health and Safety Executive announced a Safety alert directed at construction and all other industry users including employers, dutyholders and anyone else who has responsibility and/or control – directly or indirectly – for the supply, installation, use, inspection, servicing, maintenance, and examination of MCWPs.

Where MCWPs are found in use or available for use without suitable controls to manage the risk, HSE enforcement action will be taken. Regulation 4 of the Provision and Use of Work Equipment Regulations 1998 (PUWER) requires that machinery is constructed or adapted to be suitable for the purpose for which it is provided or used. The relevant standard is BS EN 1495:1997+A2:2009 Lifting platforms – Mast climbing work platforms specifies that the means to prevent the platform falling with overspeed shall be achieved by one of the following systems:

• Safety gear, or
• Two or more independent and identical electric motor direct drive units fitted to each mast.

HSE has discovered that some MCWPs, which rely on two independent motor drive units per mast as the means to prevent the platform falling with overspeed, are not fitted with suitable and sufficient controls to manage this risk.

This means work platforms could fall from height where mechanical faults in drive units go undetected. If not rectified quickly, the fault could cause serious injury, or even death.

Failures in drive units can be such that neither the centrifugal brakes (intended to limit the speed of descent) nor the automatic brakes (intended to engage when powered travel is stopped) within the drive units are able to have an effect.

Malfunctions in drive units which endanger proper function are foreseeable and unless a means of detection of such malfunctions is provided there is a risk of platforms falling with overspeed.

[edit] Immediate action required

Advice is to immediately to check that the necessary control measures are in place for all MCWP in use or available for use at a work. If the control measures are not in place, the MCWPs must be withdrawn from use until those responsible for supply, installation, use, inspection, servicing, maintenance and examination ensure that:

• There is the means to identify a loss of mechanical integrity in each drive unit where this is the system to prevent falling with overspeed.
• Each individual drive unit is fitted with a mechanical device, eg centrifugal brake, that automatically prevents the work platform descending at excessive speed.
• Damage to drive units due to platforms being powered onto buffers/base frames is prevented.
• Platforms and associated equipment are not damaged by physical overloading.
• Thorough examinations, inspections and tests, and visual and functional checks are appropriately planned and carried out.

For further information and detail check the HSE Alert directly here: https://www.hse.gov.uk/safetybulletins/mast-climbing-work-platforms-mechanical-failure.htm

[edit] Related articles on Designing Buildings

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