SITE ENGINEERING EXPERIENCE

WORKING SAFETY AT HEIGHT

Selecting, specifying, & managing mobile elevating work platforms (MEWP)
(a) Vertical ‘scissor’ lift
(b) Self-propelled boom
(c) Vehicle-mounted boom
(d) Trailer-mounted boom



**Photos arranged according to the list



SELECTION CRITERIA:

To decide which MEWP is suitable to be used, the followings should be taken into account:
• What work needs to be done***
• Who is going to operate the MEWP
• At what stage in the job will the MEWP be needed and what will the ground conditions are like at that stage; rough, prepared, poured slab, finished surface, etc.***
• What access is there to the site
• How much base area is available at the work position***
• what is the maximum ground bearing capacity at the work area and along the route to and from the work positions***
• How many people need to be lifted
• What height/outreached is required
• Will the MEWP be expected to move in the elevated position***
• Overhead power lines on site
• Are there any materials to be lifted and if so how heavy/long are they
• What wind loads can be expected***
***Priority



MANAGING THE RISK

Once a suitable MEWP is chosen, look at the hazards associated with using it, assess the risks and identify control measures to develop a safety working method.


Transport and delivery to site:

Think about what size of delivery vehicle or vehicle-mounted MEWP will need access to site or whether a self-propelled MEWP will have to be offloaded on the public highway:

• What time of day will be most appropriate and what additional measures will be required
• Will the MEWP need to be reversed off the carrier or, if vehicle-mounted, reversed onto site
• What size turning circle will be needed***


Storage/charging area:

• Keep MEWP in a secure compound or in a designated area with the engine or motor switched off
• The working platform lowered to its parking position and brakes applied
• The wheels should be chocked


Positioning before and during work:

• What is the ground bearing capacity at the work position and along the route to and from it
• Is there enough space for the outriggers to be deployed and what is the maximum point load (under a wheel, outrigger, or jack pad), are spreader plates required
• Will the MEWP have to operate on elevated floor slabs? Has the risk of the MEWP running off the edge of an elevated floor slab been considered?


Handling materials:

• If MEWPs are to be used directly to install materials, it is essential to know the weight and dimensions of those materials and to properly consider any manual handling and load distribution issues

• Boom-type MEWPs generally have smaller baskets and lower lift capacities than scissor-type MEWPs and their platform can ‘bounce’ at height due to the boom structure flexing. This usually makes them unsuitable to use for installing long or heavy materials, or bulky materials that may obstruct the function controls

• In these cases, consider using a scissor lift, crane or a telehandler of appropriate capacity in conjunction with an appropriate material handling attachment where necessary. This combination reduces the risk of overturning, removes the need to balance materials on the MEWP’s handrails and minimises the risk of injury due to manual handling

• If you plan the work properly the need for outreach may be avoided by, for example, preparing or reinstating the ground conditions in the area directly beneath planned overhead work or by adjusting the work schedule to delay the construction of low-level structures until work overhead has been completed




Hazards during use:

Look out for localised ground features, such as trenches, manholes and uncompacted backfill, which could lead to overturning? If operating on a pre-cast concrete slab, check the slab loading limits and how this compares with the maximum weight of the MEWP. Has enough time been allowed for the concrete to cure? What measures are in place to stop the MEWP running off the edge of the slab onto soft ground?

Think about wet, cold and windy weather:

• What is the manufacturer’s maximum wind speed in which the MEWP can operate safely
• How will the wind speed be checked (usually with an anemometer) and by whom
• Is the MEWP being operated between buildings where increased wind speed and/or turbulence can be a particular problem

On some MEWPs fitted with proportional controls there can be an element of ‘run-on’ when the controls are released. This is designed to create a smoother operation but can mean that the MEWP continues to move after the controls have been released. Therefore particular care must be taken when working close to overhead structures to avoid the risk crushing.

If there are overhead structures against which an operator could be trapped and then pushed onto the MEWP controls causing sustained involuntary operation of the platform, consider selecting a MEWP which has been designed to prevent such accidental contact with the controls. MEWPs with shrouded or otherwise protected controls are available.

Extra care must be taken if MEWPs are used to manoeuvre up through several levels of steelwork as there is a risk of the operator being trapped should the boom or basket strike the steelwork. This risk increases with the number of levels the MEWP operates through and if materials are loaded out onto the lower levels which can reduce clearance.

Look for any overhead hazards such as power lines, pipe bridges, arches or trees.
Think about how the MEWP interacts with other site traffic and personnel:

• Does the operator have limited visibility, particularly during reversing
• What is required in terms of vehicle route signage, pedestrian segregation barriers, cones, crossings etc
• Does any part of the MEWP protrude out of the confines of the site
• Are people below protected from the risk of falling objects
• When working in an area used by other workers or vehicles, the entire MEWP work area (based on reach distances and not just base structure footprint) should be barricaded using cones and warning signs etc.



Maintenance:

The trained operator is responsible for carrying out a basic daily/pre-use inspection and function check and records of these checks should be kept.
The operator should also be fully aware of the procedure you expect to be followed should they identify a fault with the MEWP, i.e. isolate the controls, tag the machine and report the defect to the person in control.
You should request a copy of the maintenance records as evidence that the MEWP and any related materials handling attachments that are going to be used on your site have been properly maintained.



Familiarisation:

Before being authorised to operate a particular make or model of MEWP, the operator should be familiarised with it by a competent person. Familiarisation should follow on from basic training and should cover:
• manufacturer’s warnings and safety instructions
• the control functions specific to the particular MEWP
• the function of each safety device specific to the particular MEWP
• operating limitations such as limiting wind speed, wheel and outrigger loadings, set up requirements, maximum operating slope etc.
• emergency lowering procedures
• safe working loads or load charts
• the maximum number of people who can be carried
• the maximum safe operating speed
** All of the above can be found in the information supplied with the machine

On completion of their familiarisation, the operator should know whether or not that particular MEWP is designed for the operator to travel on with the work platform in the elevated position and whether or not the controls are protected to prevent accidental contact with the operator’s torso.

It is important that you allow enough time for your operator to check, inspect, function test and familiarise themself with every new MEWP.

All familiarisations should be recorded.



Personal protective equipment (PPE):

One of the biggest risks in using boom-type platforms is being thrown out of the basket if the boom swings, jolts or tilts away from the machine’s centre of gravity, or if the operator overreaches (usually by standing on the guard rails).
A hard hat with chinstrap and cold/wet weather high visibility clothing should also be worn.



Emergency and rescue procedure:

The emergency and rescue plan should identify trained, site-based personnel who would be available to lower the work platform using the control panel or emergency descent system situated at ground level. These people should be included in the familiarisation training for the specific machines being used on site.
The plan should also include the call-out details for the service engineer or other person who is competent and authorised to lower the work platform in the event of an emergency.



Job Documentation:

The next stage is to record the planning and communicate it to all those involved with the work.

Before work starts the plan should be reviewed to allow for any changes in circumstances, such as changes in site access, ground conditions, the task to be carried out, the weather conditions etc.

Make a record of who has been briefed and issued with the plan.

Tell those involved in the work to report any problems with the plan immediately. Should they need to deviate from the plan, this should be agreed with the competent person before any changes are made.