Basic principles of working-at-height anchorage systems
By Working at Height Association (WAHA)
Tuesday, 06 October, 2015
Working at height — whether on maintenance and cleaning operations on high-rise buildings or on new construction work — has been, and always will be, a risk activity.
How many times have you looked up in the city and seen workers hanging from ropes down the side of a high-rise building?
How many times have you looked down from a high-rise building to see people working along the edge of roofs on warehouse-style buildings or lower-rise apartments?
How many times have you passed a construction or worksite and seen workers perched up in the structure carrying out construction work?
A closer look at those workers would reveal that they are wearing specialist fall arrest equipment and are 'anchored' to the structure in a way that allows them to both move about the work area but would arrest any accidental fall in a safe distance.
However, recent accidents from working-at-height activities reported from both Queensland and New South Wales highlight the need to re-enforce the basic principles that must be observed to ensure that the risks from falls are to be minimised through the correct design, installation, testing and recertification of working-at-height anchorage systems. A summary of these principles is detailed below.
1. Safety system design
The overall safety system must be designed to suit the specific tasks that will be required to be undertaken. This will include consideration of all aspects of the system — from safe access, personal protective equipment to be worn, the anchorage system to be used, the work methods to be used to move around the task area, safe egress on completion of the work and a rescue plan in the event that something unforeseen happens. The system should be designed by a person deemed to be competent in such work. This will include engineering skills to ensure that the parts of the building structure used for the fitting of anchorages are capable of bearing the loads resulting from arresting a fall.
2. Clearances under work areas
The system design must take into consideration what is below the work movement area, including access and egress. This is to ensure that there are adequate clearances so that, if a worker falls, they will not hit any object or protrusion before the fall is arrested. Clearances need to take into consideration the lanyard length, shock absorber extension, possible harness stretch and anchorage extension (particularly on lifeline systems). AS/NZS1891.4 – Section 7 gives good guidance on this subject. Consideration should also be given to protecting the area below from possible falling material and ensuring tools are tied off to prevent them falling.
3. System access and egress
Without safe access, a worker can be exposed to a fall before he or she reaches the designated work area. With this in mind, safe access to and from the anchorage system must be considered as an integral part of the overall work method and the overall safety system. Fall hazards getting to the work area can be minimised by the use of stairways and ladders for getting to height, and the use of walkways and guardrails for horizontal access. Vertical anchorage systems may be required on ladders — with particular care taken in the transfer of personnel anchorage from vertical to horizontal activity.
4. System attachment equipment and personal protective equipment
The correct equipment to be used for the task needs full consideration. The correct harnesses, attachment hardware, lanyards and shock absorbers need to be specified with particular reference to the design of the connection of that equipment to the anchorage. This is to ensure proper connection compatibility such that the possibility of dynamic rollout at the attachment connection is eliminated. All harnesses and lanyards should be certified in compliance with AS/NZS1891.1 and should be well within their lifecycle dating.
There are a variety of anchorage possibilities. Where movement across a work area is required, lifeline and rail systems can offer continuous connection for the operator whereas single-point anchor systems generally require connection and disconnection using twin tail lanyards to move over the work area. All types of anchors must be rated and tested to sustain the loads from arresting a fall. Lifeline and rail systems and single-point anchorages can be rated for single-person or two-person use. It is therefore critically important that appropriate labelling and signage is clearly visible. Lifeline and rail systems require specialist design, and that design should only be undertaken by persons certified by the lifeline manufacturer as competent to do so. Those systems should be certified to comply with AS/NZS1891.2. Similarly, single-point anchors systems should only be designed by persons certified by the anchor manufacturer as competent to do so. The anchors themselves should be certified to comply with AS/NZS5532.
Image courtesy of RIS (Roofsafe Industrial Safety).
6. Installation and testing
As with the design of the anchor systems, their installation must be undertaken by persons certified as competent to do so. It is normal practice for the installation company to carry certification confirming the training and subsequent accreditation provided by the anchor system/point manufacturer. The installer is required to undertake testing required by the manufacturer on the system, ensure all appropriate labelling is in place and provide all necessary system documentation for both user instruction and use recording, as well as for future inspection and recertification purposes. It is essential that this system documentation is retained and that ongoing system usage records are maintained by the system owner/manager to assist with the ongoing system recertification requirements.
7. User training
Before allowing any access to the system, the system owner/manager must ensure that workers have been suitably trained for the type of work at height to be undertaken. This training should include appropriate emergency rescue training and first aid training. Training currency and operator experience should be checked to ensure that refresher training to maintain competency is not required. It may be necessary to check the credentials of the training provider if competency doubts exist.
8. Inspection and testing
Competent operators understand the need for proper pre- and post-use inspection of all equipment. However, there is an additional requirement for formal inspection and recertification of anchor systems. The frequency of inspection and testing requirements varies by state and is between 6 and 12 months as a minimum for anchorage systems. Load testing and compliance inspections should be carried out on time and to the manufacturer's product installation testing specification. This requires the engagement of suitably trained and qualified inspectors.
The designed work method statement — including access and egress — for the work to be undertaken, anchorage layouts (single points or lifelines), installation certificates and testing records, usage records and emergency rescue plans are essential parts of a harness-based safety system. All this information must be readily available on-site. This enables workers to be induced to use the system as intended at the design stage.
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