Any business that has staff members working at height has both a legal and an ethical obligation to ensure the safety of those workers through the provision of proper height safety equipment, adequate training for new employees, and a well structured safety plan that allows for continuous monitoring and improvement. The goal for all companies should be to prevent falls from height. Worksafe NZ expect that all work at height is actively managed to keep people from harm. According to work safe, Factors contributing to injuries sustained from working at height include:
- lack of or inadequate planning and hazard assessment
- inadequate supervision
- insufficient training for the task being carried out
- incorrect protection or equipment choices
- incorrect use or set-up of equipment including personal protective equipment
- unwillingness to change the way a task is carried out when a safer alternative is identified suitable equipment being unavailable.
- More injuries happen on residential building sites than any other workplace in the construction sector.
Allround Safety provide a wide range of height safety equipment including temporary anchor points for roofers, as well as a wide range of roof safety kits, scaffold height safety kits, construction height safety kits, grab ropes, fall arrestors and energy absorbing blocks. Worksafe recommends that "a harness system enables a person to be positioned and safely supported at a work location for the duration of the task being undertaken at height. Harness systems are used for gaining access to, and working at, a workface where there is a risk of a fall. The most common harness systems include:
- total restraint systems
- fall arrest systems
- work positioning systems
- industrial rope access systems
- safety lines, lifelines, prescribed or proprietary (engineered) systems."
Total restraint system
A Total restraint system is the recommended harness system for working at height. These systems prevent a worker from reaching an unprotected edge, thus preventing any chance of a fall occurring. The system should consist of safety equipment rated for a fall. For example a full body harness that's connected by a lanyard or alternatively a safety line to a suitable anchorage point or horizontal lifeline.
Fall arrest system
Fall arrest systems are designed to catch a worker in the event of a fall. They are not work positioning systems as there job is not to support a worker while performing a job at height. Fall Arrest Systems should only be used where a total restraint system in not practical. Fall arrest systems are a injury minimisation tool NOT a fall prevention tool. Fall prevention is always the preferred method where possible. They require more training for workers as a higher level of competence is required and supervision is considered essential. Fall arrest systems are made up of a number of components usually including a harness which is connected to an anchorage point with a lanyard and an energy absorbing block. They may be utilised where staff are required to perform their work close to an unprotected edge. Safety helmets must be worn when using a fall arrest system.
Work positioning systems
These systems allow an employee to work while in a harness under tension in such a way that a fall is not possible. This system should allow the worker to stay in a stable position and have both hands free to perform the task required. The harness system can't let them fall more than 60 cm. Typically this would be ensured through the use of a short lanyard.
A permanent anchor point should be designed by an engineer. Both the manufacturer and the designer should make sure each (permanent) anchor is given a unique identifier allowing proper tracking of installations well as maintenance and testing throughout its life. Permanent anchor systems will inevitably be exposed to corrosion and stress from usage. They also rely on the structural integrity of the material they are connected to. As such, testing and inspection should check all possible sources of failure and if there is any doubt they should be replaced. The engineer that designs the anchor point must specify the design life of the anchor and the testing regime required. All anchors must have a rated load of 15 kN. Fall arrest and abseil anchors must be tagged and re-certified each year to ensure compliance with AS/NZS 1891.4.
Temporary anchor points may include specially designed fittings or an arrangement consisting of strops and ropes. Temporary anchors must be set up by a competent trained person. When using a temporary system comprised of a specially designed fitting it must be used in accordance with the manufacturer’s instructions. Prior to installing a temporary anchor point the roof or structure on which it is going to be installed must be checked by a suitably competent expert. All anchors should be positioned above the head height of the worker. This limits the free-fall distance. It is critical when an inertia reel is used. This will stop the line from contacting obstructions and reduce the free fall distance.
Harness work requires training. Only trained and competent personnel are allowed to install and use harness systems on job sites. People not correctly trained should not be allowed to use the system until they have been properly inducted. During induction they must be supervised by a experience worker who is trained and competent. Worksafe recommends that for "workers who are to complete basic work while under total restraint, a recommended means of achieving competence is NZQA Unit Standard 23229 – Use a safety harness for personal fall prevention when working at height, or an equivalent or higher qualification. A recommended means of obtaining competence for workers who are involved in planning, installing, operating fall arrest systems and supervising staff is NZQA Unit Standard 15757 – Use, install and disestablish proprietary fall arrest systems when working at height or an equivalent or higher level of qualification. NZQA Unit Standard 23229 is a prerequisite for achieving NZQA Unit Standard 15757."
Minimising the potential fall distance
Care should be taken when using a fall arrest system to ensure the potential free-fall distance is less than two metres. Do not use energy-absorbing lanyards with inertia reels as this can result in an longer fall before the fall is arrested increasing the risk of injury or death.
Maintain minimum of slack in fall arrest line
For a fall arrest system to work safely there must not be to much slack in the line between the user and the attachment point. Anchorage points should be as high as possible. Workers should not be working above the anchor point as this will increases both the fall distance and the chance of serous injury
Positioning the inertia reel anchor points
Anchor Inertia reels above the head height of the worker. This limits the chance of the line becoming entangled and reduces the free fall distance.
The pendulum effect occurs when a workers free fall potentially involves them either swinging back into another object or down to the ground. Worksafe recommends the following to "prevent the pendulum effect from occurring:
- place the anchorage point at a right angle to the position of the line at the perimeter edge; a mobile anchorage is of assistance here
- use secondary anchor points and/or anchor lines
- use a perimeter guardrail to prevent any fall over the perimeter edge.
Where the pendulum effect is possible, it is better to use a work positioning system or another means of access such as an elevating work platform."
You should have a rescue plan in place prior to installing a harness system. It's vital that suspended workers can be rescued quickly and safely. Workers stuck for to long in a safety harness can die as a result of blood pooling in the legs. Having a pre-rigged system is a good way to ensure a prompt rescue. Rescue plans should include:
- the rescue method, such as a crane or cherry picker.
- all available rescue equipment
- training and clear demarcation of responsibilities
- medical requirements
- provision to involve emergency services.
- Workers using fall arrest systems must never work alone.
A recommended means of achieving competency for rescue planning is NZQA Unit Standard 23232 – Develop a rescue plan for recovery of a suspended individual after a fall or equivalent or higher standard. NZQA Unit Standard 23229 is a prerequisite for achieving NZQA Unit Standard 23232.
Industrial rope access
Industrial rope access is a highly specialised work method. For further guidance google:
- AS/NZS 1891 Industrial Fall Arrest Systems and Devices Series (Parts 1–4)
- Industrial Rope Access in New Zealand Best Practice Guidelines
- AS/NZS 4488.1 Industrial rope access systems – Specifications
- AS/NZS 4488.2 Industrial rope access systems – Selection, use and maintenance
- The Approved Code of Practice for Arboriculture
- IRAANZ Best Practice Guidelines Industrial Rope Access in New Zealand.
Australia/New Zealand Standards that apply are:
- AS/NZ1891.4:2009 – Industrial fall-arrest systems and devices – Part 4: Selection, use and maintenance
- AS/NZ4488.1:1997 – Industrial rope access systems – Part 1: Specifications
- AS/NZ4488.2:1997 – Industrial rope access systems – Part 2: Selection, use and maintenance.