Production Rigging

Event Rigging Intro

Welcome to Event Rigging 101 – This is a basic outline of some of the equipment regularly used by Frost Productions. Rigging is the practice of SAFELY suspending objects wherever needed to fulfill the requirements of the event. This regularly includes suspending objects over people and/or in some instances near priceless works of art and therefore, the utmost care must be taken to ensure the safety of everyone involved, start to finish.

Common Terminology

Here are some common terms and markings that you will need to know and recognize.

SWL/WLL

Safe Working Load/Working Load Limit--these are interchangeable terms for the same thing: the maximum allowable load for a given piece of equipment. Although the manufacturer has built in a safety factor ranging from 20-100% of the breaking strength, the SWL/WLL must NEVER be exceeded under any circumstance.

Safety Factor

Refers to the “cushion” given for the loading information. Take care when dealing with multiple parties/persons who might also provide a safety factor, resulting in a severely diminished number.

Lateral force

AKA Side loading. This is any force that acts perpendicular to gravity. Gravity is our friend but must be treated with respect.

Dynamic force

Refers to any load subject to movement. This is an important definition and must be taken into account when figuring loads and lifting capacities. Most manufacturers provide charts for static loading only as this is the simplest, and there are innumerable variables to contend with in the real world.

Equipment

Below is a list of equipment that is used every day, with information on how to use and care for it properly.

Round Slings

Round slings aka "SpanSets" come in various lengths, and there are two main types: Nylon and GAC. Both consist of a strong core surrounded by a woven jacket with a label outlining SWLs and a viewing slit for internal inspection.

Nylon

Lightweight and pliable with a synthetic core but vulnerable to high temperatures.

Galvanized Aircraft Cable (GAC)

Strong and flexible with a core of wire strands surrounded by nylon. Can tolerate higher temperatures and is thus preferred by most venues, particularly if open-flame candles or pyrotechnics are in use.

Care and Use

As shown, a simple knot in a single sling is the easiest way to transport them to and from events. It will also prevent a “pile of spaghetti” in the case and helps when counting for inventory. Slings should always be examined for any fraying, cuts, or other damage before use. Slings should never be exposed to harsh solvents or chemicals.

There are many ways to sling a truss, some reduce the capacity while others enhance it. Check the tag on the sling for these figures, and find the right one for your particular application.

Truss

Aluminum truss is the most versatile and commonly used apparatus in all event rigging. It is durable, strong, and relatively lightweight, making it ideal for temporary event structures. There are many types of truss but the most common are 12x12” box, 20.5x20.5” box, 12” triangle, ladder, and circular.

Lifting truss

Suspending truss typically involves the use of round slings (SpanSets) of equal length at each end of the span. Additional slings add additional spans. There are also manufactured lifting devices such as the Mega Truss Pick. A span of truss should not exceed 40ft to prevent twisting or bowing of the truss under its own weight

When slinging (Choking) a truss, the most effective means is a choke at the panel point on the bottom chords and wrapping the top chords, coming to a triangle, into a shackle.

It is important to refer to load charts provided by the specific manufacturer to get a sense of the SWL of the desired span distance - the greater the span, the lower the capacity. Any overhang outside the span should be considered a cantilever and must be treated differently to the rest of the truss. When making connections between 2 spans of truss using grapples, the load rating of the new span is reduced by 50-70%.

Bolting

Frost uses plated truss joined together by 5/8” - Grade 8 galvanized bolts. Truss manufacturers recommend these bolts be wrenched snug with reasonable force. NEVER use an impact driver on truss bolts . . . this goes for strikes too.

Truss Towers

Towers include the legs of a goal post or box structure or standalone structures with a base plate. Base plates should be completely level and properly weighted.

Inspection

Inspect all truss prior to use for any defects, such as twisting, deflection, missing or damaged members, or gouges deeper than halfway into the aluminum tube wall. If defects are found, the truss must be placed out of commission until repaired or replaced.

Shackles - Screw Pin Bow Shackles

Every shackle, regardless of size, should display the following information or be discontinued from use:

SWL/WLL – Safe Working Load/Working Load Limit.

Manufacturer – CHINA is NOT a manufacturer! CM or Crosby are.

Tracing codes of the batch of steel, should the product fail under normal conditions.

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Each Shackle is forged with a unique pin. DO NOT mix and match pins. This is the most common faux pas. The pin only needs to be hand tight to the body of the shackle. A quarter turn back is a myth!

Below shows the correct and incorrect use of shackles in different scenarios:

Aircraft Cable/Flexible Steel Wire Rope

Aircraft cable refers to thin, often 1/8” wire rope usually with a swaged eye at one or both ends. Grip Locks on 1/16” allow for adjustment in the length using a sliding mechanism, which grips the wire and locks it into place. There are many varieties of Grip Lock and all should state the SWL/WLL on it. It is typically between 200-250lbs.

Beam Clamps

Used to attach loads to I-Beams where a round sling may not be appropriate (closed ceilings exposing only the bottom flanges is commonplace). There are two types: the adjustable “jaw style” and the open-faced clamp.

The jaw style

Screws tight to the beam and needs only to be firmly hand tight. This is the preferred clamp to use when any dynamic forces come into play. A standard clamp should be stamped with the WLL. The center point allows a shackle to attach.

Open-faced beam

These clamps attach to the beam by way of a bolt tightened to the flange and may have an eye bolt or straight bolt attached. These are designed primarily for the running of conduit or HVAC systems in construction. They should only ever be used under static loads.

Neither style should ever experience lateral force.