Theatre Design & Technology - Summer 2003 - 19

Although regular in-house inspection of all rigging components is a necessary practice, here are several reasons for
periodically arranging a professional counterweight system inspection:
* We usually lack the time or staff available to complete the
thorough inspection we want to do.
* We sometimes see what we expect to see when working on
familiar equipment.
* Very few staff technicians can match the years of experience offered by professional rigging safety inspectors.
* A "second opinion" is always in order, especially since rigging mishaps can be catastrophic.
Several expert rigging safety inspectors were interviewed
for this article and asked to discuss approaches to counterweight rigging system safety. These professionals agree that the
inspection process is not a "do-it-yourself" operation, and that
merely reading even detailed information about safety inspections does not qualify theatre technicians for the job. Reviews
of industry and government literature on the subject reveal no
official certification or required training for counterweight
rigging inspectors in the United States, but expert practitioners
strongly advise that extensive experience is the most important
training and preparation necessary for the work. A lengthy,

Upright Head Block

A complete rigging
inspection can take
anywhere from
several hours to two
full days, depending
on the size of the fly
system, the number
of linesets and
building design
factors.
18

S U M M E R

2 0 0 3

successful career as a rigging system installer and operator
may begin to prepare a theatre technician for the safety inspection process.

INSPECTION PROCEDURES AND EQUIPMENT

A counterweight rigging system is relatively easy to operate but
this simplicity can be deceiving. A typical system includes such
diverse elements as Schedule 40 pipe and other steel components, wire rope, copper swaging sleeves and other termination hardware, rope hand lines, several types of sheaves and
other machined equipment. A professional rigging inspector is
thoroughly versed in identifying signs of structural stress or
imminent failure in materials used for rigging system construction. Professional inspections include extensive examination of everything in service from arbor to batten, often paying
special attention to mechanical components such as loft and
head blocks that are sometimes treated as "maintenance free"
by rigging system operators. Rigging inspector Thomas Pettus
feels that every sheave should be manipulated by hand during
a full system inspection to assess bearing wear. Pettus also
notes that some sheave component manufacturers are more
reputable than others, and inspectors consider product quality
when making recommendations for component replacement. Hardware used for
fastening blocks to the building's structural steel must also be inspected, as
Upright Loft Blocks
vibration and system operation movement
can loosen clamping nuts and bolts over
time. Arbor framing, arbor spreader
plates, T-track or wire guides, and tension
blocks must be inspected, along with all
hand line ropes and hand line terminations. Inspection of the operating rail
equipment should include rope locks
and the hardware fastening the rail to
the building. In his book, Stage Rigging
Handbook, Jay Glerum summarizes the
importance of rigorous inspection when
he reminds us that a counterweight
lineset may fail if only one small component of the system fails (Glerum, 117).

Counterweight
Arbor
Rope Lock
Tension Block

TD & T

Upright Head Block

Upright Loft Block

Table of Contents for the Digital Edition of Theatre Design & Technology - Summer 2003