Falls from height continue to be a major cause of accidents across industry, and the number one killer within the construction sector – in the UK, at least. Falls from height accounted for 50% of all fatal accidents on UK construction sites in 2000. Bad as they are, the official accident statistics may only be the tip of the iceberg, as the workforce in some industries such as construction and entertainment can be casual, freelance or subcontracted which can result in many accidents not being reported.

There is nothing inevitable about this toll. With correct training and supervision these deaths can be avoided.

Principles of working at height

In addressing the issues surrounding working at height, it is important to gain an understanding of the main principles involved.

Protection from falling is needed where there is any unprotected side or edge with a risk of falling more than 2m. There are a variety of ways of applying the fall protection needed, but the first consideration must always be that of safety and the risks involved to workers. As such, in all cases where working at height is involved a risk assessment should be carried out to establish what safety measures need to be adopted to avoid or reduce risk. Consideration should be given to the:

• physical condition of the people involved

• activity

• equipment to be used

• location – is it near water, close to power lines etc.

• condition and stability of the work areas and surfaces

• environment – temperature, lighting, wind etc.

• duration of the work.

In addition to the above process, a manager will establish what is the best method to adopt to carry out the work. The individual must weigh up the practicalities involved and balance this against the risk presented to the worker by the chosen means of access. There exists what is termed as a ‘hierarchy of risk’ based on risk and practicality. The higher up the hierarchy a method of access is considered to be, the lesser the risk associated with it.

Permanently installed access is at the top of the hierarchy as it has the least amount of risk associated with it. This involves the installation of walkways and gantries, and is appropriate where a site must be accessed regularly for routine maintenance.

Next in the hierarchy is temporary working platforms such as scaffolding, cradles and mobile platforms. This method requires the staff using them to be trained in their use.

Bottom of the hierarchy and therefore most risky is the use of personal protective equipment (PPE) and fall arrest techniques. This involves the use of PPE to catch a falling worker and prevent serious injury. In addition, PPE is also used in work positioning and work restraint techniques. As the majority of accidents occur during the application of these methods, these areas will be examined in detail.

Fall arrest techniques

Work restraint is a technique that involves the use of PPE to prevent a worker entering an area where there is a risk of a fall from height. This means that a worker is effectively restrained to an anchor point and is a technique often used when working on flat roofs or open decks. Careful placement of the anchor point can mean that a single point can cover a large safe working area.

Work positioning is a technique for supporting a person working using a PPE in tension, to prevent a fall. This is opposed to fall arrest where the PPE is used to catch the worker in the event of a fall.

Where the worker’s weight is supported primarily by the structure, such as when climbing scaffolding or a ladder, then a single line system will provide backup should the worker fall from the structure. Where the worker’s weight is being totally supported by the PPE, then a separate backup system is necessary to prevent a fall, should the primary system fail.

Apart from preventing falls, a work positioning system can be used by a worker to help maintain balance and can be seen as a ‘third arm’, leaving the worker’s hands free to carry on with the work.

Fall arrest is a technique that makes use of items of PPE to stop a falling person under safe conditions.

As a worker falls and is caught by the fall arrest equipment, it is important that any force applied to the worker must not be in excess of 6kN (600kg). This can be achieved through the use of a shock absorber, such as tear-out lanyards, and ensuring that lanyards are always anchored above head height to reduce the impact forces of a fall.

The fall factor is a figure used to express the seriousness of a fall. It is the relationship between the length of the fall and the length of rope available and can be calculated as:

fall factor = length of fall ÷ rope in system

The fall factor is influenced by the relative position of the anchor and the worker. The maximum possible fall factor in normal conditions is two – where the climber falls twice the length of his attachment. See illustration above.

Personal protective equipment

Incorrect application of personal protective equipment (PPE) is just as bad as not using anything at all. PPE used in the wrong application can prove fatal, so it is worth knowing about the various types of equipment and for which applications they are most suitable.

Harnesses

One of the most important and critical pieces of PPE is the full body harness. In particular, the choice of connection points is an important consideration when using harnesses. Rear or chest connection points, for example, can only be used in a fall arrest application, and if a harness has an integral waist belt with side connection points they must only be used for work positioning or work restraint.

Lanyards

Another key part of the PPE used in fall arrest is lanyards. The length of a lanyard should not exceed 2m, and when used for fall arrest in conjunction with a full body harness, the lanyard should incorporate an energy absorber. Consideration must always be given to the height at which you are working, plus your own height and the length of the fully extended lanyard should a fall occur. Clearly if it is too long, you will hit the ground before the system has functioned.

Fall arrestors

Arrestors come in a variety of forms including self retracting. They are designed to work in vertical or near vertical applications only. They should not be used in horizontal applications, as in the event of a fall the user would swing back to a vertical position exposing themselves to an unacceptable length of fall and the risk of striking something on the way.

Inspection and care of PPE

For PPE to work effectively, it needs to be in good condition and operating as the manufacturer intended. Regular inspection, and careful use and storage, will help ensure its safe use. Before use, each piece of equipment should be checked for signs of damage or excessive wear. Check the locking mechanisms on connectors and inspect webbing for cuts, burns, frays and chemical attack. If any defect, excessive wear or corrosion is found, the item must not be used. Ideally, harnesses and lanyards should be dealt with in a similar way to slings – they should be tracked and records kept of inspections.

And the need to avoid cutting corners when buying PPE cannot be stressed strongly enough.

Many companies gain their knowledge of safe working at height only after an accident. Usually these accidents were totally avoidable, through the use of the correct techniques and equipment. The ideal is to reduce the need to work at height. If a safer alternative means of working can be found then this is always preferable.

In the real world, however, it must be accepted that there are instances where working at height is necessary and unavoidable. In these cases, a thorough assessment of risk should be undertaken, with competent, trained personnel, using the right equipment to perform the work. Under these conditions, work at height can be undertaken in complete safety, as long as the right procedures are implemented and an appropriate degree of care is taken.