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Working At Height [June 2011]

Published: 01st Jun 2011 in OSA Magazine

The Work at Height Regulations 2005 came into effect on April 6, 2005. The regulations apply to all work at height where there is a risk of a fall liable to cause personal injury.

They place duties on employers, the self employed and any person that controls the work of others - for example facilities managers or building owners who may contract others to work at height.

Since the regulations were amended in 2007, they now apply to the provision of paid instruction or leadership in caving or climbing by way of sport, recreation, team building or similar activities.

As part of the regulations, duty holders must ensure:

• All work at height is properly planned and organised

• Those involved in work at height are competent

• The risks from work at height are assessed and appropriate work equipment is selected and used

• The risks from fragile surfaces are properly controlled

• Equipment for work at height is properly inspected and maintained

There is a simple hierarchy for managing and selecting equipment for work at height. Duty holders must:

• Avoid work at height where they can

• Use work equipment or other measures to prevent falls where they cannot avoid working at height

• Where they cannot eliminate the risk of a fall, use work equipment or other measures to minimise the distance and consequences of a fall should one occur

The regulations include schedules giving requirements for existing places of work and means of access for work at height, collective fall prevention?(e.g. guardrails and working platforms), collective fall arrest (e.g. nets or airbags), personal fall protection (e.g. work restraints, fall arrest and rope access) and ladders.
There are a variety of activities that involve working at height which include:

• The erection of the structure which may be steel frame, concrete, timber frame or traditional brick-built

• The placing of facade panels, curtain walling, glazing, beam and block or concrete plank flooring

• All roof work, whether traditional tile or slate or industrial type

• Lifting operations which may include tower cranes, piling work, hoists, powered access platforms and elevators

• Working over water, rivers, docks or sinks

In addition, falls can result from work
on demolition or excavation sites, or in confined spaces.

The main cause of fatal accidents

These often occur due to:

• Inadequate scaffolding

• Lack of edge protection

• Unprotected openings in buildings

• Lack of edge protection in roof work

• Dangerous demolition work

• Inappropriate use of ladders and hoists

All activities in construction are potentially hazardous; however, the largest single problem is falls from height. Over the years, this has always been the main accident causation and has remained fairly constant. Realistically, so much work is undertaken at height that this is inevitable, though not acceptable.

The potential for harm becomes greater as the height of the fall increases, so there is a requirement under the Construction, Design and Management (CDM) Regulations 2007 to implement specific control measures, such as guard rails, wherever there is a danger of any person falling from a height.

It is also necessary to consider who actually has the accidents, e.g. analysis by occupation, to give an indication of the more hazardous activities.

It is interesting to note that labourers have the most accidents but, as they represent a large percentage of the workforce, there may not be a correlation with the number of accidents. However, if you consider that most of the trades in the construction industry work at height, this does balance the figures slightly.

Where there is a risk of injury from a fall, then suitable and sufficient precautions should be taken, e.g. if a person could fall 1.2 metres and land on protruding reinforced steel starter bars, it may be that protection can be achieved by covering them with a length of timber, or providing proprietary protectors (mushroom caps) - but this would not prevent the fall in the first place, and there would be a good case to provide guard rails in this instance.

Other hazards in this situation could be from falling onto packs of bricks, pipe work or valves, falling onto a concrete plinth or other equipment, such as a mechanical pump or generator.

Erection of structures

The erection of structures presents a high risk of falling to those involved in the work, with the potential for broken limbs and fatality.

Other hazards could be the collapse of the structure, which could crush persons. This type of accident is often caused by not following the correct erection sequence.

As with any work at height, material falling presents another risk. Segregated areas will often resolve this problem. However, the sequence of work should reduce the likelihood, e.g. sheeted material secured down, good housekeeping, tools connected to the operator by cord.

The wearing of safety harnesses also provides protection against the risk of falling.
However, a safe place of work should always be the first priority.

Steel-framed structures

With steel-framed structures, there have been considerable advances in the provision of a safe place of work.

It is common practice on many portal frame buildings for access at height to be achieved with the use of power-operated mobile work platforms.

On taller structures, the progressive introduction of the floors as the structure rises helps to reduce the effective fall height for steel erectors, although in these situations the use of riding cages would be appropriate.

At times, it may be possible to walk along the top of beams, provided they are a minimum of 430mm wide, or 600mm wide for the passage of materials, if there is a continuous running line or anchorage for a safety harness.
Beam straddling may also be acceptable, providing the steel cross section allows for sufficient foothold and handhold and a safety harness is worn.

The use of and reliance on safety harnesses should only be considered as a last resort - but it is, nevertheless, vital that such PPE is available when needed.

When needs must

Falls account for a great number of accidents in the construction industry. All too often, the correct equipment may have been provided but not properly used.

An important point to remember is that the regulations require that a safety barrier must be used where it is possible to fall two metres or more. This includes stairwells, scaffolding, tower systems, including mobile tower systems, roof perimeters and excavations.

The safety rules you might consider for the prevention of falls would include:

• No work at height unless it is essential

• If work at height is unavoidable, ensure that the working platform, of whatever type, is safe and secure, checking that:

1. It is strong enough to support the weight of the worker(s) and any equipment that they may be using
2. It is stable and will not overturn (for example: all types of scaffolding needs to be tied to a supporting structure)
3. The ground is stable and will support the structure

• Provide guard rails and barriers at all openings on floors, close to edges on roofs on working platforms

Edge protection

Both the edge and any openings need to be protected. It will often be more appropriate to securely cover openings rather than put edge protection
around them.

Any protection should be:

• In place from start to finish of the work

• Strong enough to withstand people and materials falling against it
Where possible, the edge protection should be supported at ground level, e.g. by scaffold standards, so that there is no obstruction. If the edge is too high for this, the surrounding structure can support the edge protection, provided it is strong enough.

Edge protection can also be supported by frames, counterweights or scaffolding. The protection should be in place at all times. Guarding systems are widely available that enable repair work or alteration to carry on without removing any guard rails.

Safe working platforms

Working platforms should be adequately supported and provided with guard rails or barriers.

General access scaffolds

Any scaffold must be planned, erected, altered, dismantled and checked by persons who have the appropriate competence.
It is vital to ensure that the scaffold, of whatever type is:

• Based on a firm, level foundation, taking care of basements, drains, or patches of soft ground, which could collapse when loaded

• Braced and tied into a permanent structure or otherwise stabilised

• Capable of supporting loads likely to be placed on it

When independent, the scaffold is a complete structure in its own right; the tied scaffold is firmly attached to the building by making use of openings such as doors and windows.

This type of scaffold will probably be used for work on an existing building - the scaffold being erected alongside the building and ‘holding on’ very firmly via the ties.

Tower scaffolds

Tower scaffolds are widely used and are involved in numerous accidents each year. These usually happen because the tower is not properly erected or used. Aluminium towers are light and can easily overturn. Towers rely on all the parts being in place to ensure adequate strength. They can collapse if sections are left out.

Erecting the tower

A wide range of prefabricated towers are available. The manufacturer or supplier should provide an adequate instruction manual which should give advice on the erection sequence?and bracing requirements. If the tower has been hired, the hirer should provide this information. This information should be passed on to the erector. 

The person erecting the tower should be competent.

Stability

Make sure the tower is resting on firm, level ground with the wheels or feet properly supported. Do not use bricks or building blocks to take the weight of any part of the tower.

The taller the tower, the more likely it is to become unstable. As a guide, if towers are to be used in exposed, outdoor conditions, the height of the working platform should be no more than three times the minimum base dimension.

If the tower is to be used inside, on firm level ground, the ratio may be extended to 3.5. Using this guide, if the tower base is 2m by 3m, the maximum height would be 6m for use outside and 7m for inside.

Always check the safe height to base ratio in the instruction manual.
Remember, the stability of any tower will be affected if it is:

• Sheeted and/or likely to be exposed to strong winds

• Loaded with heavy equipment or materials

• used to hoist heavy materials or support rubbish chutes

Access

There must be a safe way to get to and from the work platform. It is not safe to climb up the end frames of the tower except where:

• The frame has an appropriately designed, built-in ladder

• A purpose-made ladder can be attached safely on the inside

Edge protection

Provide suitable edge protection on platforms from which a person could fall. Guard rails should be at least 910mm high and toe boards at least 150mm high.

An intermediate guard rail or suitable alternative should be provided, so the unprotected gap does not exceed 470mm.

Brick guards or other barriers may be used instead of the intermediate guard rail, as long as they are strong enough and placed so no one can fall through.
Tower scaffolds must be inspected by a competent person:

• Before first use

• After substantial alteration

• After any event likely to have affected its stability
If the tower remains erected in the same place for more than seven days, it should also be inspected at regular intervals (not exceeding seven days) and a written report made. Any faults found should be put right.

Tower scaffolds can be erected quickly and - used properly - can give good safe access. However, they have been involved in numerous accidents because they have not been erected or used correctly - manufacturer’s instructions must always be followed.

If the scaffold is owned by the company using it, a copy of the instruction manual must be available. If the scaffold has been hired, the hirer must provide this information.

For all types of tower scaffold, the requirements are to ensure that:

• The tower is vertical

• The legs are resting properly on firm, level ground and all wheels and outriggers are locked

• There is a safe means of access, for example, an internal ladder

• Edge protection is provided for platforms
In situations where the tower will be subject to extra stresses (for example if the tower is protected by weather-proof sheeting, used for grit blasting or lifting heavy loads), it will be necessary to provide additional support which might include tying to the structure being served.

Mobile and suspended access equipment

There will be many occasions when it will not be possible to work from an existing structure and the use of a scaffold-based working platform would not be appropriate. A range of mobile access equipment can be used, including:

• Mobile elevated working platforms (MEWPs)

• mast platforms which are, in essence, transportable lifts which are brought to the required place of work

It is essential that personnel who are going to use such equipment should be well trained and competent to operate it.

They should also learn emergency and evacuation procedures so that they know what to do; for example, if the power supply to the platform fails or fire breaks out in the building where the work is taking place.

Safety harnesses

For work at heights, providing a safe place of work and system of work to prevent falls should always be the first consideration.

However, there may be circumstances in which it is not practicable for all - or any - of the requirements for guard rails, or other systems, to be met; for example where guard rails have to be taken down for a short period of time to (un)load materials.

Where people may still approach an open edge from which they would be liable to fall, other forms of protection will be needed and in such cases, a suitably attached harness and line could allow safe working.

It is important to remember that a harness will not prevent a fall - it can only minimise the risk of injury; the person who falls may be still be injured when the line goes tight and/or by striking parts of the structure during the fall. 

Author Details

Andrew Taylor is currently a Chartered Safety Practitioner working with Sheilds Ltd as a support tutor on the NEBOSH National Diploma Course. He has extensive experience in Health, Safety and Environmental Management, most recently in consultancy and construction environments.

For further information on this topic and other areas in Health, Safety and Environmental Management contact:
E: safety@sheilds.org
T: 01482 806 805
W: www.sheilds.org

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Published: 01st Jun 2011 in OSA Magazine

Author


Andrew Taylor


Andrew Taylor is currently a Chartered Safety Practitioner working with Sheilds Ltd as a support tutor on the NEBOSH National Diploma Course. He has extensive experience in Health, Safety and Environmental Management, most recently in consultancy and construction environments.


 


Andrew Taylor

Website:
http://www.sheilds.org

Email:
safety@sheilds.org

Phone:
01482 806 805

safety@sheilds.org
http://www.sheilds.org
01482 806 805

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