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3. Rigging-Strength Ratings, Safety
Factors, and Special Safety Considerations
3.1 Working-Load Limit and Safety Factor Definitions:
The structural ratings for all of the X-Line rigging components and complete loudspeaker systems
are based on test results in which parts were stressed to failure. Manufacturers typically present
the structural-strength ratings of mechanical components or systems as either the working-load
limit (WLL) or the ultimate-break strength. Electro-Voice chooses to present the structural-load
ratings of the X-Line loudspeaker systems as the working-load limit. The working-load-limit rating
represents the maximum load that should ever be applied to a mechanical component or system.
THE USER SHOULD NEVER APPLY A LOAD THAT EXCEEDS THE WORKING-
LOAD LIMITS OF ANY OF THE RIGGING COMPONENTS OR COMPLETE
LOUDSPEAKER SYSTEMS DESCRIBED IN THIS MANUAL.
The working-load limits for the X-Line rigging components and complete
loudspeaker systems described in this manual are based on a 5:1 safety factor. The safety factor
is defined as the ratio of the ultimate-break strength divided by the working-load limit, where the
ultimate-break strength represents the force at which a part will structurally fail. For example, if a
part has working-load limit of 1,000 lb (454 kg), it would not structurally fail until a force of at least
5,000 lb (2,268 kg) was applied, based on a 5:1 safety factor. However, the user should never
apply a load to that part that exceeds 1,000 lb (454 kg). The safety factor provides a margin of
safety above the working-load limit to accommodate normal dynamic loading and normal wear.
CAUTIONS for Working-Load Limits and Safety Factors:
The working-load limits defined by the manufacturer of any rigging component should never be
exceeded. Electro-Voice bases the working-load limits of its X-Line products on a 5:1 safety
factor. A 5:1 safety factor is fairly common amongst rigging manufacturers because many
regulatory agencies call for a minimum safety factor of 5:1.
The user is cautioned that some local regulations may require safety factors higher than 5:1. In
that circumstance, Electro-Voice insists that the user maintain the higher safety factor as required
by the local regulations throughout the entire X-Line installation. It is the responsibility of the user
to make sure that any X-Line installation meets any applicable local, state or federal safety
regulations.
3.2 Structural Rating Overview
There are two independent strength ratings that, together, give a complete description of the
overall structural performance capabilities of any X-Line loudspeaker system. They are defined as
follows:
1. The strength of each individual rigging point; which is the combined strength of the rigging
track mounted on the enclosure with the removable rigging-hinge and/or rigging-strap assemblies.
2. The total strength of the overall enclosure; which is a function of the combined forces from
all of the rigging points acting on the enclosure as a whole.
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