THE DIFFERENCE BETWEEN FALL ARREST AND FALL PREVENTION

Discussion in 'Fall Protection' started by Neil Enslin, Feb 10, 2020.

  1. Neil Enslin

    Neil Enslin Moderator

    THE DIFFERENCE BETWEEN FALL ARREST AND FALL PREVENTION

    Section 8 of the Occupational Health and Safety Act deals with the duties of employers to their employees and sub-section 2(b) requires in particular that the employer must take “such steps as are reasonably practicable to eliminate or mitigate any hazard or potential hazard to the safety or health of employees, before resorting to personal protective equipment

    This same requirement applies to working at height. Wherever possible, avoid exposing employees to fall risks by changing the location or position where work has to be performed. If this cannot be achieved, then the best alternative is to make use of “collective safety measures” such as permanently installed guardrails, screens, balustrades or other physical barriers. None of these require employees to wear fall protection harnesses (personal protective equipment).

    When these physical barriers are not practical then the next best solution is to make use of restraint systems that will prevent the employee from entering a fall risk position. In simple terms – secure the person to an anchor point via a fixed length lanyard that stops the person from reaching the edge of an elevated structure. Conclusion: the person cannot fall off the edge. This requires the use of PPE but is considered the safest option when it comes to the use of personal fall protection equipment.

    In certain work situations this protection is simply not practical, and the employees have to be exposed to fall risks in order to do the work at hand. Think of window cleaning on multi-storeyed buildings, the installation of equipment on towers, painting or repair work on tall structures and many more tasks that will expose persons to the risk of falling. This is where lifelines and other forms of fall arrest systems must be employed.

    The basic premise for these systems is to accept that the person can, and might well fall and therefore, the fall arrest system must be designed to save lives.

    So lifelines or anchors are installed to safeguard workers exposed to fall risks and the persons are equipped with fall arrest systems attached to their body harnesses so that when (not if) they fall the combination of the anchor and fall arrest system prevents the person from falling over too long a distance and is designed to gradually absorb the momentum created by the fall and thus reduce the shock load on the person to an allowable level. This “allowable shock load” may not exceed 6,0 kN (± 600 kg force) and is the basis for the design of any fall arrest system catering for a single person.

    For multi-person systems the load changes in accordance with recognised international safety standards. However, this article concerns itself with clarifying the difference between fall prevention and fall arrest without delving into the technical engineering details.

    Herewith three pictograms showing the difference between fall prevention, working in a fall risk environment (attached to a fall arrest lifeline) and fall arrest.

    [​IMG]


    Characteristics of Fall Prevention PPE and anchors


    • Fixed length lanyards – length is determined by the distance from anchor point to the threshold point of the fall risk and can vary depending on application. In some exceptional cases, spring loaded retractable lanyards can be used provided that the lanyard, at its most extended length still prevents the person from reaching the fall risk position.
    • No decelerator fitted between the person and the lanyard. The person must be firmly restraint from reaching a fall risk position.
    • Used with full body harness, normally fitted with centre-back connection point.
    • The anchor points must be clearly marked as fall prevention anchors and the use for rope access / work positioning clearly prohibited on a visible notice / sign.
    • Horizontal lifelines need to be clearly marked and the maximum slack in the rope needs to be such as to prevent the person from reaching the edge of the building / fall risk position.
    • The operating procedure lodged with the responsible person (the duty holder) must spell out the safe use procedures including the type of PPE that must be worn.

    source: saiosh news letter date 24 January 2020 circulated to members