Horizontal vs. Vertical Fall Protection. Whats the Difference?

The hit 90s television show America’s Funniest Home Videos has always been a testament to several things about American culture:

1. Americans are clumsy creatures
2. Americans enjoy filming their clumsiest moments for national television
3. Americans know many different ways to fall

Even though there is unabashed clumsiness displayed on television, there are several lessons to be learned about fall protection. Although it may seem obvious, it is important to remember that people tend to fall in either a horizontal or a vertical direction.

Horizontal falls occur on the level upon which a person is standing or moving (i.e. running and tripping). Meanwhile, a vertical fall is typically something that occurs between two different levels (i.e. falling from a roof to the ground).

Fall arrest in horizontal and vertical scenarios needs to be handled in different ways. Due to the nature of those types of falls, there are specific criteria that need to be met when attempting to arrest that type of fall. ANSI defines the type of lifeline based upon the type of fall that it is designed to arrest.

ANSI Z359.0 Fall Protection Code defines the following:

~2.78-Horizontal Lifeline – A component of a horizontal lifeline subsystem, consisting of a flexible line with connectors or other coupling means at both ends for securing it horizontally between two anchorages or anchorage connectors

~2.79-Horizontal Lifeline Subsystem – An assembly, including the necessary connectors, comprised of a horizontal lifeline component and, optionally, of: (a) an energy absorber component or, (b) a lifeline tensioner component, or both. This subsystem is normally attached at each end to an anchorage connector and may also contain one or more intermediate anchorages. The end anchorages have the same elevation.

~2.167-Vertical Lifeline – A component, element or constituent of a lifeline subsystem consisting of a vertically suspended flexible line and along which a fall arrester travels.

~2.168-Vertical Lifeline Subsystem – An assembly, including the necessary connectors, comprised of a vertical lifeline component and, optionally, an energy absorber and a lifeline tensioner component.

The equipment described above does not utilize a rigid track fall arrest system. It’s important to remember that those definitions pertain more to cable lifeline systems. When using a cable lifeline system, the cable will either need to be attached at three points or two, depending purely upon the angle. Horizontal work will want to use three attachments—two anchorages on the building and one on the person. Meanwhile, a vertical job will only truly want two attachments—one anchor on the object that is being scaled and one on the person. The use of a cable system instead of a rigid track system has both advantages and disadvantages. When working with a cable lifeline system, it’s important to remember the following points.

Cable lifelines will sag and deflect during a fall event. When someone falls on a cable lifeline system, the cable will bend at the point where the most weight is being placed. As a result, the person who is at the mercy of the cable will be forced to bounce and droop with their flexible lifeline. Then, from a fiscal perspective, cable lifeline systems require a comprehensive replacement of all parts involved after a fall event has occurred. This can cost a company money due to having worker downtime and overall expenses for the new materials.

On a positive note, the cable lifelines allow for maximum worker mobility without requiring them to officially disconnect from the line. And, cable lifelines have proven to dramatically reduce the amount of swinging that occurs during a fall event. Also, cable lifelines cost less, holistically, to purchase than a rigid track system. Cable lifelines are also helpful because they are portable and can be installed and removed in an efficient manner.

There are many different ways to provide fall protection for workers. And regardless of the system that an employer chooses to use on a site, the important thing is that there is a fall arrest system in place for the worker. Both rigid and cable systems have advantages and disadvantages, however, having at least one system is better than having no system.

Think safe, be well!

Hannah Addison