Fall Arresters – “Rope Grabs”

by Enzo Garritano, P.Eng., Manager, Technical Services, CSAO

 

Fall arresters, also known as “rope grabs,” are used for travel restraint and fall arrest. Section 26.1(3) of the construction regulation (Ontario Regulation 213/91) requires that rope grabs meet standard CAN/CSA Z259.2.1 M98 Fall Arresters, Vertical Lifelines, and Rails.

Described in the CSA standard, the following are typical classes of fall arresters used in construction.

 
Class AD – a device, such as a rope or cable grab, that travels freely, or automatically (A), and is intended to be connected to the back or dorsal (D) attachment point of a harness.
 

  Class ADP – same as an AD with an added “panic” (P) feature that allows the device to remain engaged on the lifeline if released or held beyond its non-engaged position, and in the event of a fall will lock so as to arrest the fall. See “Panic Grab” box.

Class AS – same as the AD except the device is intended to be connected to the chest or sternal (S) attachment point of a harness.

MDP – a rope or cable grab that must be operated manually (M) to move in one or both directions on a lifeline and is intended to be connected to the dorsal (D) attachment point of a harness. This device is also equipped with the panic (P) feature.

Class AD and ADP are typically used in construction. An amendment to the CSA standard in August 2002 now requires Class AD fall arresters to have an integral connecting linkage (attaching to the D-ring on the back of the harness) that is between 0.3 metres and 0.6 metres long. Because this class of device does not have the panic feature, keeping the connecting linkage short makes it very difficult for a worker to grab the device in the event of a fall.

“Panic Grab” – the user grabs the arrester during a fall, inadvertently holds it “open,” prevents the device from working properly, and slides to injury or death below.

As a safety feature, and part of the CSA standard, rope grabs must not come off the line unless at least one deliberate action by the user allows the device to be removed. Rope grabs often have a thumbscrew or other latch to keep the device on the line. Bumping the device in normal use or disengaging a connecting device should not allow the rope grab to come off the line. Remember to tie a knot in the lifeline at the farthest point where you need to travel. The knot ensures that the device will not run off the free end of the line.

For use in a travel-restraint system, ensure that a knot is tied in the lifeline at a point that allows you freedom to work without reaching a fall hazard. The rope grab will be stopped from travelling through this point by the knot. Alternatively, if the rope grab is equipped with a parking feature, lock the device at a point on the lifeline that will not allow you to reach a fall hazard.

In fall-arrest applications on vertical lifelines, always adjust the rope grab or other fall arrester to a point as high as possible above your D-ring to minimize free fall. Ensure adequate clearance beneath the working surface since some classes of rope grabs (AD and ADP) may move on the lifeline as much as one metre before completely arresting a fall.

Always ensure that the directional arrow on a rope grab is pointing along the lifeline to the anchor point. After putting the rope grab on the lifeline, give it a firm tug in the direction of a fall to make sure it engages. Fall arresters are designed to work with certain types and diameters of lifelines. Make sure the appropriate lifeline is used.

The CSA standard requires that fall arresters come with permanent markings. The following are the eight required marks on each certified fall arrester:

    1. manufacturer’s name or logo
    2. Class AD, ADP, AS, MDP, or FRL (frontal-fixed rail-ladder)
    3. type(s) and size(s) of lifeline/rigid section with which the device may be used
    4. an arrow, permanently stamped, etched, or cast on the fall arrester, indicating the UP position on the device, relative to the support, unless the device can function properly in any possible orientation
    5. model number, if applicable
    6. lot, serial number, or date of manufacture
    7. CSA logo and standard number
    8. warning to follow manufacturer’s instructions before use.

When using fall arresters, follow three simple steps.

  1. Inspect your fall arrester before each use to ensure that parts move as they should, are not distorted, do not have sharp edges, and are free from cracks, rust, or other defects.
  2. Remove from service any rope grab involved in a fall arrest, along with the rest of the system. Do not use any of these components again until they are certified safe by the manufacturer.
  3. Ensure that lifelines are free from ice, grease, or any other material that may affect the fall arrester’s performance.