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Fall Arrest Systems On Construction Sites
Fall arrest systems are intended to safely prevent workers from falling an uncontrolled distance and reducing the fall’s impact.  The systems should only be used in situations when it isn’t reasonably practical to use higher-level controls or if the higher-level […]

Fall Arrest Systems On Construction Sites

Fall arrest systems are intended to safely prevent workers from falling an uncontrolled distance and reducing the fall’s impact. 

The systems should only be used in situations when it isn’t reasonably practical to use higher-level controls or if the higher-level controls might not be completely effective in stopping a fall by themselves.

All the equipment that is used for fall-arrest systems needs to be designed, selected, manufactured, and used in compliance with the AS1891 series of standards.

When using fall arrest systems, critical safety considerations include:

  • The proper selection, use, and installation of the equipment
  • That the anchorages and equipment are manufactured, designed, and installed to withstand the force applied to them after a person falls
  • That the system is designed and installed to ensure that the person travels the shortest distance possible before the fall is stopped
  • The equipment used for arresting a fall isn’t used again until a competent person inspects and certifies it as being safe for use
  • That workers using fall-arrest systems wear sufficient head protection to protect them in case of a fall.

Catch Platforms

Catch platforms are temporary platforms situated below a work area for catching workers in case of a fall. 

The platforms need to be designed to withstand the maximum potential impact load and should be of robust construction too. 

Scaffolding components can be used for constructing both mobile and fixed catch platforms. Catch platforms should:

  • Always be used with a form of edge protection that’s adequate
  • Be positioned as close as possible to the underside of the work area i.e. the distance a person can fall before they land on the catch platform shouldn’t be greater than 1m
  • Be positioned to ensure that the deck extends not less than 2 metres beyond all the unprotected edges of the work area, except in situations where extended guard railing has been fitted to the catch platform
  • Incorporate a deck that’s fully planked-out.

Industrial Safety Nets

Safety nets can be used for providing a satisfactory means of protection while allowing workers to enjoy maximum freedom of movement. 

They should not be used as a working platform or for entering or exiting a work area. If safety nets are used, you must make sure that:

  • Safety nets are anchored securely before the commencement of any work
  • Safety nets are hung as close as is practicable to the working area’s underside, but no greater than 2m below the working area
  • The material used to make the safety nets is strong enough to catch a falling item or person
  • Perimeter safety nets used in case no edge protection is provided extend not less than 2.5m beyond the working area’s leading-edge
  • Safety nets are properly stored in dry, shaded areas with a good circulation of air
  • Safety nets are regularly inspected, especially after repair, installation, or relocation
  • No oxy cutting or welding is done above the safety nets
  • No accumulation of material is allowed in suspended safety nets
  • The safety net has enough clearance and tension to prevent a falling person coming into contact with any structure or surface below the net

Individual Fall-Arrest Systems

Individual fall-arrest systems comprise of some if not all the components below:

  • Rail System
  • Inertia Reel
  • Anchorages
  • Harness
  • Rope Grabs
  • Retractable Lifelines
  • Fixed-Length Lanyard
  • Lifelines
  • Industrial and Personal Shock Absorbers
  • Rescue Equipment
  • Karabiners (double or triple action for preventing rollout)
  • Snap Hooks (double or triple action for preventing rollout)
  • Wire Grabs

The individual fall-arrest systems depend on workers wearing and using them properly, which is why workers that use such systems must receive training in their safe use. 

Such systems must only be used in situations where using higher-level control measures would not be reasonably practicable.

The relevant New Zealand/Australian Standards for individual fall-arrest systems demand that they be permanently labelled or marked to indicate their correct use, purpose, limitations, along with any other relevant information intended to reduce misuse of the equipment.

Anchorage Points

Anchorage points are required to comply with the requirements in AS/NZS 1891:4. 

A competent person must test and approve all anchorages prior to use – a visual inspection might not be sufficient to determine the anchor point’s structural integrity (i.e. the bolt might have fallen below the concrete surface).

All anchorage points should be located such that the system’s lanyard can be attached to it before the person using the system moves into a position where he/she is likely to fall.

Inspecting The Components Of The System

A competent person must inspect all the system components as well as their attachment to anchorage points:

  • After installation but prior to use
  • At regular intervals
  • Immediately after it has been used for arresting a fall.

Inspecting the components should be done according to manufacturer specifications as well as the relevant standards. 

If the inspection reveals any signs of weakness or wear, the means of attachment or components must be withdrawn from use until they have been replaced with components that are functioning properly.

Limit the Free Fall Distance

Fall-arrest systems that incorporate a lanyard should be installed so that the maximum distance that a person can fall prior to the fall-arrest system taking effect is 2 metres. 

Sufficient distance has to be provided between the surface below and the work surface to enable the system, including the action of any shock absorber to deploy fully.

To determine whether there’s sufficient distance available, you must consider:

  • The height of the worker
  • The lanyard’s length
  • The anchorage point’s position and height
  • Any slack in the horizontal lifeline
  • The length of the energy absorber once extended by a fall
  • The stretching of the horizontal lifeline or lanyard when extended by a fall

Example:

Original lanyard length: 2 metres

Height of person: 1.8 metres

Maximum Energy Absorber Extension: 1.9 metres

Clearance: 1 metre (Allow for dynamic stretch)

The total fall distance for this specific configuration would be effective in stopping a fall is 6.5 metres.

Lanyards must not be used together with inertia reels since this may result in an excessive amount of free fall before the fall is arrested.

Use the Right Harnesses

A full-body harness must be worn in most cases. Harnesses have to be fitted correctly. 

Workers need to connect the fall-arrest line to the attachment point on the harness that offers the best protection in the situation it is used. 

Consideration must be given to the possible fall distance, the possible impact with the structure, the position of the body after a fall as well as the need to interact with equipment such as rope-grabs.

Minimum Slack Should be Maintained in Fall-Arrest Lanyards

Minimum slack should always be maintained in the fall-arrest lanyard between the attachment and user. 

The anchorage point needs to be as high as allowed by the equipment. 

Work should be avoided above the anchor point as it increases the free fall distance in case of a fall, resulting in higher forces on the body as well as higher chances of the lanyard snagging on obstructions.

Use Inertia Reels the Right Way

When considering using inertia reels, keep in mind that they might not always be effective. 

For instance, in case a worker falls from a steeply pitched roof or an inclined surface, the inertia reel line might fail to lock and instead keep extending from the reel.

Inertia reels must never be used as working supports by locking the system and letting it support the user during regular work. 

They simply aren’t designed to provide continuous support. 

Self-retracting and vertical anchorage lines can be used as a measure for controlling risk in connection with work done from ladders and boatswains’ chairs. 

In case such lines are used, just one person may be attached to any one line.

Use Compatible Components

Using components that are not compatible can lead to ‘roll out’ with some carabiner/hook configurations, which may result in the user’s death or injury. 

It is not always possible to avoid this hazard using components from the same manufacturer under one brand name. 

If you are not sure whether a fall-arrest system’s components are compatible, you need to get in touch with the manufacturer for additional information.

Snap hooks should be of the double-action type, which requires at least 2 consecutive deliberate actions to open up. 

Snap hooks must not be connected to each other because this can prevent their safe operation (for instance, roll-out might occur). Double-action hooks might be susceptible to roll-out. 

Hex nut connectors and screw gate karabiners can sometimes be suitable.

Further guidance is provided in AS/NZS 1891

In Case of a Fall, Ensure Prompt Rescue

A person conducting an undertaking or business that implements a fall-arrest system as a control measure needs to establish rescue and emergency procedures. 

Rescuing a worker that’s suspended in a full-body harness must be done promptly to prevent suspension intolerance. 

Workers should not use fall-arrest systems unless there’s at least one more person at the site capable of rescuing them should they fall.

Hazards with Individual Fall-Arrest Systems

If a user of an individual fall-arrest system were to fall, the system can act as a pendulum, and in some instances, such a user might actually hit the ground or swing back onto the structure or building, which is referred to as ‘swing back’.

Swing down may occur in case the lanyard slides back along the roof’s perimeter edge until it is vertical. 

In case this was to happen, the person might hit the ground or the lanyard might break due to its contact with the roof’s edge.

Measures of addressing the ‘swing down’ include:

  • Installing guard rails
  • Installing a second anchorage point and belay devices
  • Placing the anchorage point at a right angle to the lanyard’s position at the perimeter edge (for instance, by using a mobile anchorage).

Anchorage Rails or Lines

Anchorage rails or lines are permanent or temporary fall-arrest systems that can be installed for the purpose of providing continuous fall protection for persons climbing towers or using ladders. 

These can be used on a plant, such as tower cranes along with structures or buildings.

Safety considerations include:

  • The locking device is attached to the harness’s front attachment point and that the lanyard assembly is 300mm long, at most
  • Temporary systems comply with AS/NZS 1891 series of standards
  • Freefall is limited to a maximum of 600mm
  • The point of connection onto the ladder by the climber is close to the base of the ladder to allow the connection prior to the ascension starting and to provide continuous connection to the disconnecting point when at a safe higher level
  • In case of a fall, the system should be removed from service and a competent person should inspect it before it is used again.

Double Lanyards

A double lanyard (also referred to as a ‘Y’ lanyard or twin tail) is an alternative to anchorage rails or lines. 

The unfortunate thing is that double lanyards are incredibly easy to misuse – there must be no back hooking, they shouldn’t be passed between the legs or wrapped around the body, the chest connection must never be higher than the highest attachment point, they aren’t ideal for frequent use (due to the possibility of muscle injury or even misuse), and the structure points or ladder should be capable of arresting forces that the fall generates with a double lanyard. 

Sufficient training should also be provided regarding their use.

If you are looking for knowledgeable and experienced scaffolders, who have leading-hands that work together with you and offer expert advice, please contact us at Skelscaff today on 1300 266 607 or email us at contact@skelscaff.com.au.