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Rigging Safety
and the Five Deadly Sins
(or if it looks wrong it probably is wrong)

ETCP

The care and maintenance of rigging systems is one of the most important safety concerns in any performance space. Ongoing maintenance must be a process that continues between regularly scheduled inspections. Enclosed is an outline describing the five most common rigging errors and three basic checklists to help spot and correct them. This checklist does not replace annual inspections, which should be completed by an experienced consultant. This overview looks at the three most common rigging systems:

  • Counterweight Systems
  • Motorized Rigging Systems
  • Dead Hung (Stationary Rigging)

As Riggers and Technicians we move equipment and scenic elements overhead on a regular basis. This requires a higher level of diligence and care in a workplace that is often changing and fast paced. The following is a list of the five most common hazards in theatrical rigging. They are meant as guidelines for a comprehensive safety program.

"A lifting device shall be operated in such a way that,
no part of a load passes over any worker"

- Ontario Occupation Health and Safety Act and Regulations
for Industrial Establishments section 51 (2) b (i)

Unrated Hardware

1. Unrated Hardware

It is essential that the Safe Working Load (SWL) of all components in a system are known and that the Safe Working Load for the weakest component is not exceeded. Hardware that does not have the SWL clearly forged into it is a "wild card". Most industrial applications work on a SWL of 5:1. A component that will fail under a load of 5000 lbs. that is given a safety factor of 5:1 has an SWL of 1000 lbs. In the entertainment industry an SWL of 8:1 is the accepted standard.

An unrated "eye bolt" has bent from overloading.

Incomplete Installation

2. Incomplete Installation

Even though a component may have a sufficient SWL rating, it becomes a liability if it is not installed correctly. Installations should be neat and clean with hardware properly terminated. An installation that is neat and orderly allows for easier inspections and ensures that the forces on components, such as pulleys, are within the equipments design limits.

This improperly installed pulley allows the cable to rub on the side of the groove. The fleet angle should not exceed 2 degrees.

Damaged Equipment

3. Damaged Equipment

A piece of damaged equipment becomes the weak link and a liability to the system as a whole. Damaged components must be replaced immediately with ones that are of equal or greater rating. Replacing a broken part, even temporarily, with a substandard piece is putting the integrity of the system at risk.

The thimble on the right has been overloaded to the point of being deformed. The thimble on the left is the correct shape. It is often helpful to compare components to confirm the degree of damage.

Wear and Tear

4. Wear and Tear

Even the best of systems wear out. This is why it is essential for maintenance to be an ongoing process. The Ontario Labour Code requires yearly inspections of all hoisting equipment. The owner must keep a maintenance and repair log. Since we are often lifting over head the operator must be aware of any changes in how the system is running and investigate the cause immediately to ensure that safe operation is not compromised.

Signs of wear from everyday use can be subtle. The stands of the cable shown here began to break from 25 years of use.

Improper Use

5. Improper Use

Using equipment for purposes that it was not designed for, or modifying equipment for other purposes, can easily result in overloading and failure. Many components also have strict guidelines as to how and where they should be used by the manufacturer. For example Spectrum 3 proof coil chain is suitable for suspending stationary loads, but, if the load will be moving a Spectrum 8 chain is required. It is important to ensure that the components are appropriate for the application.

A headblock is being used to divert cables horizontally. This imposes stresses on the bearings that they were not designed for.

Inspection Checklist

Counterweight System

  • Set runs smoothly and quietly
  • Pipe Batten is straight and level over its length
  • Lead cables terminated correctly at batten
  • Lead cables undamaged - no broken strands or birds nesting
  • Lead cables terminated at carriage top
  • Loft blocks securely mounted and lead cables are not rubbing on building structure
  • Carriage square and running true in guides without binding
  • Carriage properly weighted for load
  • Head block secure and fleet angles to loft blocks are under 2 degrees
  • Purchase line not worn
  • Rope lock adjusted and operating properly
  • Floor tension block adjusted and operating properly
  • Bottom stop rail intact
  • Wall frame and T-Channels are straight and plumb with no signs of wear points
  • All fasteners are tightened
  • Loading and fly floors are clear of obstacles and counterweights are neatly stacked

Motorized Rigging Systems

  • Set runs smoothly and quietly
  • Pipe Batten is straight and level over its length
  • Lead cables terminated correctly at batten
  • Lead cables undamaged - no broken strands or birds nesting
  • All fleet angles less than 2 degrees
  • Lead cables terminated at carriage top
  • Loft blocks securely mounted and lead cables are not rubbing on building structure
  • Winch assembly is not leaking lubricant
  • Control and power wiring neat and secure - no exposed conductors
  • Set stops at preset limits
  • All operator stations functioning correctly
  • Emergency stop system operating correctly
  • Power disconnect switch with in reach of winch assembly
  • All fasteners are tightened

Dead Hung (Stationary Rigging)

  • Pipe battens are straight and level over its length
  • Support hardware is rated and correctly installed
  • Support points are not causing any discernable deflection in the building structure
  • All fasteners are tightened

Rigging

Rigging

Rigging

Rigging

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