Sight & Sound
over people’s heads. Many hoists are not rated for overhead lifting, which means that they place your celebrant, choir or performers in danger. The hoists you choose must be designed for theatrical use, and the control system must be fail-safe. At the minimum, ask the supplier if the system meets NFPA-79, the Electrical Standards for Industrial machinery regulation. Enlist the assistance of a theatre consultant— someone who works with performance spaces on a regular basis, who can bring his or her expertise to your facility. Above all, do not attempt to cobble together a system with hardware store components—nothing you’ll find at the DIY store is appropriate for hanging heavy weight over people’s heads. Remember that the liability rests with your church if someone gets hurt.
As most houses of worship have counterweight rigging, perhaps installed many years ago, let’s look at the manually operated system to fully understand its use and to move toward its safe operation.
What is counterweight rigging?
Counterweight rigging operates on simple principles of physics: The load over the stage is counter balanced by an equal amount of steel weights called “counterweights” backstage. When properly counter- weighted, this manual rigging is easy to operate—but when the set is out of balance, the system has the potential to be very dangerous. That’s why it’s so important to understand your system, and to be properly trained to run counterweight sets.
The information provided here will familiarize you with the parts of the system and its basic operation, but every system is installed and configured differently, to fit the space in which it is used. To fully under- stand your system and its operation, bring a professional trainer with Entertainment Technician Certification Program (ETCP) training to your facility, both to train your operators and to inspect your system to be sure it is in perfect working order.
Batten: The pipe or truss to which the scenery, curtains or lights are attached over the stage Lift lines: The wire ropes that suspend the batten from the loft blocks Loft block: A pulley mounted to the gridiron of a performance space or to the building’s support steel, to support the lift lines and change their direction between the load (on the batten) and the head block. There are several loft blocks for each batten, and each supports a portion of the total load. Head block: The pulley, or block, mounted to the building’s support steel, that guides the wire rope between the arbor (see below) and the loft blocks. The head block bears the full load of the set, and changes the direction of the lift lines. Arbor: The carriage that holds the weights that counterbalance the load on the batten. Hand line (also called Operating Line): The rope that allows the operator to control the movement of the set. Rope lock: This lever holds the batten in position when the load is balanced. A rope lock is not intended to hold a load that is heavily out of balance while you load or unload the arbor. It is also not intended as a brake, or to slow the speed of a set. Locking rail: A horizontal metal rail, with a row of rope locks—one for each coun- terweight set. Tension floor block: The return pulley for the hand line, which is weighted to keep tension in the hand line.
1 = Batten 2 = Lift Line 3 = Loft Block 4 = Head Block 5 = Counterweight Arbor 6 = Rope Hand Line 7 = Rope Lock 8 = Locking Rail 9 = Tensioning Floor Block
Everyone working backstage at your house of worship should use the same vocabulary when talking about your rigging system. The diagram will help you define the parts of your system, and the purpose of each piece of equipment.
Rigging Safety Basics
Using counterweight rigging is a process of understanding some basic laws of physics— especially the ones involving gravity—and taking every precaution to ensure that the load is in balance, so it won’t come crashing down when you least expect it. Remember that you are hanging heavy weight over people’s heads, both onstage and backstage. In houses of worship, it’s common to have children involved with services, pageants and holiday celebrations, so treat the rigging as if your own children were standing beneath it.
The key is to counterbalance the load with
September 2009 / Church & Worship Technology