PPE for Working at Heights

srl

Self retractable lanyard for working below 7m

p47

Webbing single lanyard

PPE FOR WORKING AT HEIGHT

Fall Arrest System.

A fall arrest system is used where there is a risk of free fall from height. The most common accidents are falls from height and the injuries can be caused by trauma and bone fractures to ruptures of internal organs, massive internal bleeding and, ultimately, to death.

To prevent accidents involving falls from heights, priority must be given to having in place appropriate collective fall protection measures. When collective protection cannot be provided or the cost could be prohibitive, PPE must be used, either to prevent the fall or to arrest the fall and to maintain the user in a safe position.

Extremely high forces are generated on the worker’s body at the moment of a sudden arrest of the movement. These forces can exceed 1,500 kg or 15 kN (kilo newton, unit of force) so that falling from a height of about 2 m can produce serious injuries.

working-at-height-training
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Fall arrest systems, components and main characteristics

A fall arrest system includes:

  • A Suitable Body Holding Device, that is a full body harness;
  • An energy absorbing element: energy absorber, retractable type fall arrester, guided type fall arrester including a rigid anchor line; guided type fall arrester including a flexible support;
  • An Anchor Line;
  • An Anchor Point;
  • Connectors/Karabiners/Hooks;
  • Lanyards

The components, except the anchor point, can be separable or inseparably connected. A fall arrest system does not prevent the fall, allowing the user to reach a zone where free fall risk exists, but should a free fall occur, the system stops it, limiting the length of fall to prevent collision with the ground, with the structure from where the worker is falling or other obstacles and it maintains the user in an acceptable ergonomic position until rescue.

Each type of system is intended to ensure that the impact forces on the body of the user during the arrest of a free fall are restricted to the maximum value accepted as non-dangerous, i.e. 6 KN.

Each type of system is characterized by an “arrest distance”, established during the CE type-examination. This value forms the base from which to calculate the minimum ‘free space‘ or ‘clearance’ that is necessary under the legs of the worker to avoid a collision. The ‘clearance’ of a fall arrest system is calculated by adding 1 m to the arrest distance. The decision to use a particular type of fall arrest system needs to take into account the clearance of the disposable energy absorber in balance with the actual clearance at the workplace.

Types Of Fall Arrest Systems And Main Components

h1

Fall Arrest System Incorporating A Lanyard And Energy Absorber

  • Full body harness (B)
  • Lanyard (C)
  • Energy absorber (D)
  • Anchor point – (A)
  • Connectors - optionally, to join the other components.

This type of fall arrest system is used when there is an anchor point above the user and a sufficient high clearance. The arrest distance, H, should be H < 2 Lt+ 1,75 m, where Lt is the overall length of the energy absorber and lanyard. Whatever energy absorber is used, Lt has in any case has to have a value of more than 0,5 m, the arrest distance is over 3 m and the necessary clearance is usually over 4 m.

h2

Fall Arrest System Incorporating A Lanyard And Energy Absorber On A Horizontal Line

  • Full Body Harness (B)
  • Lanyard (C)
  • Energy Absorber (D)
  • Mobile Anchor Point Located On The Flexible Horizontal Anchor Lines (A)

This kind of fall arrest system can be used on platforms without barriers, when it is not possible to have a point of anchorage situated above. The advantage is that such a system allows free movements along the horizontal anchor line, but a limited free movement in front or behind this point, on a distance equal to the total length of the absorber and lanyard.

h3

Fall Arrest System Incorporating A Retractable Type Fall Arrester

  • A Full Body Harness (B)
  • A Retractable Lanyard – Element Of Retractable Type Fall Arrester (C)
  • A Retractable Type Fall Arrester (D)
  • An Anchor Point (A)
  • Connectores

The retractable type fall arrester is a cable or webbing device, which self-retracts inside a housing unit to ensure that the cable or webbing remains taut at all times. It is available in a variety of lengths up to 60m. With a built-in shock absorber, it arrests the falling worker within distances of less than 1m. Extension of the unit is not allowed without the manufacturer’s approval, and the attachment of shock absorbing lanyards is strictly prohibited. This type of a fall arrest system should be used only in the vertical plane, with the anchor point being located above the head. Misuse in ways that ignore above specifications or the use ‘over edge’ can lead to serious, even fatal accidents . The conditions of use stipulated in the instructions manual provided by the manufacturers shall be carefully observed.

h4

Fall Arrest System Incorporating A Guided Type Fall Arrester Including A Flexible Anchor Line

It is assembled out of:ref name=EN 363: 2008

  • An Anchor Point (A In Figure 5);
  • A Full Body Harness (B In Figure 5);
  • A Lanyard (C In Figure 5);
  • A Guided Type Fall Arrester (D In Figure 5);
  • A Flexible Anchor Line (E In Figure 5);
  • Connectors

The flexible anchor line is a lanyard or a wire cable fixed at an anchor point above the head of the worker and is easily tensioned downside. These devices are installed temporarily and should be used in conjunction with a harness with frontal or dorsal attachment elements. Depending on the length of the lanyard, it allows a certain free lateral movement, but the arrest distance, i.e. the clearance increases with the length of the lanyard.

h3

Fall Arrest System Incorporating A Guided Type Fall Arrester Including A Rigid Anchor Line

It is assembled out of:

  • A Full Body Harness (B In Figure 6);
  • A Lanyard (C In Figure 6);
  • A Guided Type Fall Arrester (D In Figure 6)
  • A Rigid Anchor Line (A In Figure 6);
  • Connectors

These devices are permanently installed, usually on very high radio antennas, towers or chimneys. The anchor line is an anchor rail fixed directly to the tower, the edge of a ladder or a wire rope tensioned fixed on a structure, in such a way to limit the lateral movements. The system should be used in conjunction with a front attachment harness directly to a connector with/without lanyard. It allows little free lateral movements of the wearer and is generally characterised by small values of the arrest distance.

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The full body harness is the main component of a fall arrest system, intended to hold and sustain the body of the user during and after a fall. Only full body harnesses must be used in a fall arrest system.

A full body harness is formed of straps made of webbing, buckles, attachment elements and other elements adequately positioned and adjusted on the potential user’s body. It shall have at least a sub-pelvic strap and shoulder straps; it may include thigh strap, chest strap and/or a positioning belt with or without a back support. In order to maintain the body in a safe position after a fall, the attachment elements designed for using in a fall arrest system shall be above the gravity centre of the body, respectively on the chest/stern, on the back or on the shoulders. It can also be incorporated into the clothing.

The full body harness should be adjustable on the user’s body and shall not pose a risk of releasing the body through rupture or elongation. In order that any signs of wear and tear that could affect the mechanical resistance capacity be readily observed, the threads shall have a colour different to the other textile parts.