Spreading the pressure of powered access platforms

Working with powered access platforms often means operating on a wide range of surface types, uneven or sloping ground so a strong and stable foundation is essential.

Using spreader plates with boom lifts and outriggers saves lives by minimising the risks of falls which are a result of overturning and instability – still the major causes of serious injury and death involving access equipment.

Spreader plates reduce the weight and pressure at the point of contact between a boom lift or stabilizer leg and the ground, by spreading the load through a wider area. They must be of suitable strength and appropriate material to prevent distortion when a load is imposed upon them and spread the load evenly across the whole area of the spreader plate

The size and thickness of spreader plates will depend on the ground conditions. Assessing ground conditions is very important and should be carried out by a competent, responsible person and recorded in the risk assessment documentation. A visual inspection is usually all that’s required but, occasionally, the job may need a full geotechnical survey to assess ground stability.

As a rough guide, it is recommended that spreader plates up to 600mm square or diameter are at least 25mm thick and spreader plates up to 900mm square or diameter should be a minimum of 50mm thick.

Choosing spreader plates
Selecting the right size and type of spreader plate for specific locations and access equipment is important. Spreader plates should be big enough, stiff enough and strong enough  to cope with the necessary pressure and weight of the access platform.

Plate size should reduce load-bearing pressure, provide a stable footing and not sink into the ground. They should be strong enough to bear the access platform weight without breaking. Spreader plates are manufactured from a range of materials including timber, aluminium or plastics and resins. When ground conditions are particularly poor, additional foundations, such as timber mats, proprietary mats, steel grills or concrete pads can also be used.

Support for access platform users
The International Powered Access Federation (IPAF) has a number of resources to support access platform users to select spreader plates. The ‘Spread the Load!’ campaign aims to encourage the use of spreader plates with powered access platforms and prevent accidents resulting from inadequate ground assessments and incorrect set up of access equipment.

IPAF also has an online Ready Reckoner – a simple interactive tool designed to offer guidance to operators and those involved in determining the size of spreader plates to be used when setting up a boom-type access platform. It calculates the minimum area of spreader plate required, based on the gross weight of the machine, and the minimum sizes of spreader plates required for differing ground types and strengths.

Spreader plates save lives and can improve the speed and efficiency of jobs at height in differing ground conditions. For more information or to access the free IPAF resources, go to www.ipaf.org.

MEWPs can be stabilised and perform safely and effectively on most surfaces and gradients provided a few basic things are taken into consideration. Make sure you know how to use the individual machine, what it is capable of, and what it is telling you. This applies to both road towable and vehicle mounted platforms. Assess the ground conditions that you are working on to ensure you can use the machine to its optimum performance. This will prevent avoidable tip overs or subsidence accidents that can put lives at risk.