Harness Based Work at Height
Harness-based work at height refers to any access undertaken where workers use a webbing full body harness to secure themselves whilst attached to a rope, lanyard, self retracting lifeline or other safety device and place themselves in a position to work, that if they were not wearing such equipment, they could potentially expose themselves to a serious fall.
ABCDs of fall protection
Regardless of the method of harness use, every system involving fall protection should incorporate at least the 4 basic elements of safety when working in a harness:
A = Anchorage – an anchorage point rated for fall arrest is a minimum component of every fall protection system. Anchorages can be certified (engineered to meeting certain requirements) or improvised (created through the knowledge of operators who can set a temporary anchorage system for safe use.
AS/NZS1891.4 specifies performance requirements for anchors to be certified if they are permanently installed. An extract of these anchorage requirements is shown below:
|Purpose of anchorage||Application||Rating|
|Single point anchorages||Free fall-arrest—one person||15kN|
|Free fall-arrest—two persons attached to same||21kN|
|Limited free fall-arrest (including rope access||12kN|
|Restraint technique 12 or 15 (see Note 3)||12 or 15kN|
|Horizontal lifelines||End anchorages||22kN|
|– diversion less than 15°||12kN|
|– diversion 15° or more||12+kN|
- As far as practicable, all single point one-person anchorages should meet the 15 kN requirement regardless of primary purpose.
- Horizontal component of forces induced during a fall-arrest (multiplied by a safety factor of 2.0) is to be added as indicated in Clause 6.2.5.
- Anchorage strengths applicable when using a restraint technique, see Clause 2.2.5, are either 15 kN or 12 kN depending on whether the ultimate fall risk is free fall or limited free fall.
- ‘Ultimate strength’ means that the anchorage may yield at the stated load but must not fail.
AS/NZS5532 provides manufacturers with guidance on testing anchorages for fall arrest systems.
Energy Absorbing Anchor or Static Anchor?
Regardless of whether the anchor is designed to be energy-absorbing or static (non-energy absorbing), the performance requirements are the same. Energy absorbing anchors will technically reduce the energy transferred to the building structure in the event of a fall event. This may offer the reduction in impact of damage to the structure.
Static anchors may be more suitable for other areas where the impact of a load becomes minimal. Either way, a person must still employ an intermediate connecting device that performs the role of reducing energy on the person in a fa fall event and hence the impact on the structure may or may not be relevant to the circumstances of use.
Static anchors are important for use in abseiling/rope access work as energy absorbing anchors will deform under load and will not be suitable for use after this occurs.
B = Body Harness – a full body harness is recommended for all people working in height safety environments. Fall arrest harnesses typically focus on ensuring there is a fall arrest d-ring located at the rear of the harness, as this is the safest place to connect for working in general conditions in a fall arrest environment, such as working in an EWP, on scaffolds, roofs or on structures where a free fall is possible.
For workers in suspension, such as rope access technicians or those working in confined spaces, a frontal connection is often used in practice. For working in locations of limited free-fall and where work activity is better served by frontal connection, this is ideal. Although these same locations are required to be fall-arrest rated, it is highly recommended that these connections be used for work positioning and limited free fall risks due to the higher chance of injury in the event of a fall.
C = Connection Device – The connection device can be a choice of many things. It essentially ensures that the user is connected between the anchorage device and their harness by a device that will secure them in the event of a fall. The device must perform a function of absorbing energy. Therefore the use of a lanyard with a shock absorber, a stand-alone shock absorber or a self restricting lifeline are choice soften made by people to provide their safety.
A shock absorbing system must ensure that the energy transferred to the user is no more than 6kN (approximately 600kg of force) in the instance that a fall event occurs. Many SRLs in the market improve this minimum benchmark by ensuring that no more than 4kN is transferred.
Connection devices include the attachment hardware that is used to secure the user between the energy absorbing device, the anchor and the user’s harness.
Connectors much pass the minimum requirements of AS/NZS1891.1 or AS/NZS1891.3 to be deemed suitable for use in the Australian market.
D = Decent & Rescue – The often forgotten component of a fall protection system is the need for a rescue plan and the equipment required to make this effective. There are significant risks to users who are left suspended and medically untreated in the event of a fall. In this instance the operators should have in place a plan for rescue that does not rely on simply calling 000 in the event of an emergency.
The WAHA recommends contacting suppliers of fall protection equipment and/or training companies in seeking the correct advice on the equipment they may require for fall protection on their sites.
For a point of clarification, recreational climbing (such as rock-climbing, abseiling, high ropes courses, caving and flying fox use is not considered harness-based work at height. Industrial abseiling (specifically those involving twin rope access techniques) to complete work tasks at height, is a work at height activity.
Therefore when assessing products and access solutions where there are fall risks for work purposes, users should refer to the AS/NZS1891.4 series for guidance on both equipment and methodologies for working in a fall arrest environment.
Codes of Practice
Codes of Practice are documents that are produced by the state and territory regulators to provide operational guidance to industry regarding working at height issues. In addition, Safe Work Australia also publishes documents that reflect a Nationally harmonised version of state based equivalents. Documents can be accessed freely from the websites of the regulators.
Accessing these documents directly from the regulator websites or through this site under the ‘Publications’ Tab should be undertaken to provide operational guidance.