Personal Fall Arrest System
PFAS is a collection and arrangement of components that work in conjunction to arrest a user in the event of a fall from height. It typically consists of an anchorage, connecting device and full body harness. The system may also include components such as a lanyard, deceleration device, lifeline or a combination of these.
Components of a Personal Fall Arrest System
In general, a complete PFAS consists of three main components — “Anchorages”, “Body Support” and “Connections”. In order to provide the desired level of protection, each of the components must be in place and properly used.
“A-B-C” of a Personal Fall Arrest System
A brief introduction to the “A-B-C” (i.e., anchorage, body support and connections) of a PFAS.
Anchorage
- An anchor is a fixture or place for the secure attachment of lifelines or persons (e.g., an eyebolt is a fixture and a steel beam is a place).
- An anchor point (also known as anchorage) is a part of an anchor for other equipment in a PFAS to be attached to.
- An anchor device is an element or series of elements or components of a personal PFAS, which incorporates one or several anchor points.
With reference to SS570:2011 Personal protective equipment for protection against falls from a height – Single point anchor devices and flexible horizontal lifeline systems, an anchor device or anchor with a minimum static strength of 12kN (2697 lb-f) should be used In order to arrest a fall for a single person. Anchorages must always be located at a higher securing point; high enough for a user to avoid hitting a lower level should a fall occur.
Note: Refer to WSH Guidelines: Anchorage, Lifelines and Temporary Edge Protection Systems for more information on the selection, application and usage of anchorages.
Body Support
A full body harness is a body support device that distributes fall arrest forces across the shoulders, thighs and pelvis of its wearer.
It has a center back fall arrest attachment for connection to the fall arrest connecting device; and may have other D-rings for use in worker positioning, fall prevention, suspension or ladder climbing.
Note that the only form of body wear acceptable for fall arrest is the full body harness.
Connections
The connection sub-system is a critical link between the body support and the anchorages or anchor devices. It can be an energy-absorbing lanyard, self-retracting lifeline (SRL), rope grab, or a retrieval system.
The means of connection will vary depending on whether the user is equipped for a personal fall arrest, work positioning or travel-restraint system.
I. Personal Fall Arrest Connection Means
The connection means for personal fall arrest is often a lanyard equipped with an energy absorbing element to limit the arresting force to 6 kN in the event of a fall.
SRLs can also be used as a connection to reduce free fall distance and energy loads from a fall.
Refer to Section 4.2 for details on connectors.
II. Work Positioning and Work/ Travel-restraint Connection Means
The means of connection for work positioning and travel restraint is often a simple lanyard (with length adjuster) made from rope, web or wire rope. These may also include specialised work positioning assemblies for rebar work, they are constructed from chain or webbing.
All work positioning devices are intended to reduce the potential for free fall; and restraint lanyards need to be specific in length to prevent the user from reaching a fall hazard zone.