Rigging

Guidelines for safe and proper rigging procedures.

Definitions

  1. Approved Person: A competent / qualified individual familiar with the running of DSC events, capable of working at a senior level.

  2. Characteristic Load: the maximum force applied to the system resulting from normal intended operating conditions while the system is at rest or in motion.

  3. Competent Person: a person who is capable of identifying existing and predictable hazards in the workplace and who is authorized to take prompt corrective measures to eliminate them.

  4. Design Factor (DF): specified by a designer or manufacturer; this defines the factor applied to the minimum breaking strength (MBS) to determine the maximum load acceptable for a component (i.e. the working load limit).

  5. Dynamic Load: is any load that changes over time. These types of loads exert forces onto a structure that are often much greater than their static equivalents.

  6. Factor Of Safety (SF): the ratio between the designated working load limit (WLL) and the load the equipment is expected to fail at. A common SF for performer flying (suspension) is 10.

  7. Load Bearing Hardware: purchased elements, such as fasteners, rigging components, and equipment, which are part of the load path.

  8. Load Path: all contiguous mechanical elements that support the suspendee, up to the supporting structure.

  9. Mechanical Advantage (MA): a measure of the ratio of output force to input force in a system.

  10. Minimum Breaking Strength (MBS): refers to the maximum amount of force a material can withstand before it breaks completely under a straight pull.

  11. Peak Load: the maximum force applied to the system resulting from abnormal conditions, or irregular operation.

  12. Qualified Person: a person who, by possession of a recognized degree or certificate of professional standing, or who by extensive knowledge, training, and experience, has successfully demonstrated the ability to solve problems relating to the subject matter and work.

  13. Rigger: See Roles and Responsibilities.

  14. Static Load: the force that results from an unmoving suspended load. It is a constant force produced during a lift when the load is stationary.

  15. Three-Sigma Testing: used throughout the climbing and rescue industries to determine a level of accuracy in breaking strength numbers.

    A 3-sigma rating is much more reliable than, say, an average strength where 50% of a sample could be below that strength. 3-sigma ratings are based on a statistical analysis of the breaking strengths of a given sample. Statistically speaking a 3-sigma rating means that 99.9% of the products are stronger than the reported MBS rating. What this means is a 3-sigma rated MBS is three standard deviations below the average breaking strength. Standard deviation helps to define the spread in the distribution of a given test sample. It is not the mean.

    Reporting 3-sigma ratings more accurately represents an item’s strength to be at least the MBS reported.

  16. Working Load Limit (WLL): the maximum weight as defined by the manufacturer that a user is allowed to apply to a lifting medium in the performer flying system.

Roles and Responsibilities

  1. Head Rigger: responsible for the overall rigging of the suspension event - all rigging is to be checked off by the head rigger prior to any suspension commencing. Any and all matters pertaining to rigging can be brought to the head rigger.

  2. Top Rigger: responsible for the rigging of the hard point of the suspension and attaching all equipment of the load path from the ceiling to the bottom block.

  3. Ground Rigger: responsible for spotting the top rigger on the ladder and must remain at the bottom as a support until the top rigger has concluded their work and is safely back on the ground. They are also responsible for identifying any hazards that may be present under and around the area to be rigged.

  4. General Rigger: responsible for the general checking and oversight of any rigging in place, being vigilant to ensure the safety of everyone involved with the suspension(s).

Connecting The Load Path

Ladder Safety

  1. Secure the ladder at the top and the bottom to prevent it from slipping sideways or outwards.

  2. You must wear a climbing helmet at all times when working at height.

  3. Don’t overload yourself with equipment, anything being taken up must not exceed the safe working load of the ladder (150kgs).

  4. Don’t overreach, stop at the third step from the top of the ladder.

  5. Do not rest anything on the rungs.

  6. Attach any tools/items to a harness or tool belt.

  7. Ideally, try to keep three points of contact on the ladder at all times.

  8. For every 4m the ladder is extended, it is to come out 1m (4:1 ratio).

Mechanical Advantage (MA) Over Suspendee

  1. Once the ladder is carefully secured against the steel beam, the top rigger is to climb the ladder with a protective layer (carpet) and round sling, while the bottom rigger secures the ladder.

  2. The top rigger sets up a protective layer (carpet) over the beam checking first for any potential rough areas or abnormalities — specifically burrs or sharp edges, anything that may compromise the hardware. This layer can be taped down if needed.

  3. A round sling is then wrapped around the beam by the top rigger over the protective layer using a girth hitch. Ensure this is secure and the girth hitch is at the lowest point of the wrap.

  4. The top rigger returns to the floor, collects remaining hardware (delta rapide, reeved pulley system) and climbs the ladder with the additional gear, while the bottom rigger secures the ladder.

  5. The top rigger attaches delta to the round sling then attaches the pulley system to the delta. Ensure there is no tension on the delta when threading the gate closed (remember to thread down).

  6. Once all hardware is attached, have a competent rigger double check all the attachment points in the load path and attach a green tag with a zip tie, ensuring the tag will not interfere with the operation of the system.

  7. It is the responsibility of the head rigger to ensure the load path is set up correctly. This checklist includes — but is not limited to:

    • Protective Beam Covering: make sure it is not moving around and is covering all of the edges

    • Round Sling: check it is evenly wrapped and not bunched

    • Connector: ensure the gate is closed properly

    • Pulley Shackle: check pin is threaded properly and moused with a red cable tie

    • Pulley Side Plates: check they are engaged and secured

    • Pulley Sheaves and Pivot: ensure these are moving freely

    • Termination To Becket: check knot is tied correctly and secured

Mechanical Advantage (MA) Over Operator

  1. Disconnect wall attachment for desired rigging point.

  2. Check any knots and ensure the attached swivel is moving freely.

  3. Attach the pulley system to the swivel using a connector.

  4. Have another rigger check all connections then attach a green tag.

  5. Hoist the point up to the desired height, then terminate to appropriate termination.

  6. Have another rigger double check all connections.

Attaching Beam Clamps (Gravlocks)

  1. Once the ladder is carefully secured against the steel beam, the top rigger is to climb the ladder with the gravlocks and torque wrench, while the bottom rigger secures the ladder.

  2. The top rigger attaches gravlock clamp to one side of the flange, threading the bolt down to appropriate torque. Match this on the other side with the other gravlock, ensuring the openings are opposing and tighten with torque wrench.

  3. The top rigger returns to the floor, collects the pipe and runner (nylon sling).

  4. Fix the pipe between the two gravlock clamps, ensuring the clamps are lined up and the pipe sits flush. Tighten the pipe clamps to appropriate torque.

  5. Wrap the runner in a round turn and a choke ensuring the pipe is smooth and is not in contact with the gravlock clamps (these are galvanized and the surface can be abrasive).

  6. The top rigger attaches a connector to the runner then attaches the pulley system to the connector.

  7. Once all hardware is attached, have a competent rigger double check all the attachment points in the load path and attach a green tag.

  8. It is the responsibility of the head rigger to ensure the load path is set up correctly. This checklist includes — but is not limited to:

    • Runner: check it is evenly wrapped around the pipe

    • Connector: ensure the gate is closed properly

    • Pulley Sheaves: ensure these are moving freely

    • Pulley Side Plates: check they are engaged and secured

    • Termination To Becket: check knot is tied correctly and secured

Portable Aerial Rig

  1. Lay all the pieces of the rig out and ensure they are all in good working order.

  2. Piece together on one side, with 1-3 helpers.

  3. Hardware to be attached to the top spreader bar while partially assembled.

  4. The top rigger attaches either to the eyebolt or a runner can also be wrapped around the bar and used as a connection point.

  5. The top rigger attaches a connector to the eyebolt or runner then attaches the pulley system to the connector.

  6. Once all hardware is attached, have a competent rigger double check all the attachment points in the load path and attach a green tag.

  7. It is the responsibility of the head rigger to ensure the load path is set up correctly. This checklist includes — but is not limited to:

    • Runner: check it is evenly wrapped around the spreader bar

    • Connector: ensure the gate is closed properly

    • Pulley Sheaves: ensure these are moving freely

    • Pulley Side Plates: check they are engaged and secured

    • Termination To Becket: check knot is tied correctly and secured

    • Termination To Rig Leg: ensure this is set up correctly and secured.

  8. Attach accessory cord to shackles on the spreader bar (to later attach to the bottom of the legs, once set up).

  9. Complete the setup of the freestanding rig by attaching the remainder of the legs, ensuring they are securely fixed in place.

  10. Attach accessory cord lengths to eyebolt with a truckers hitch, then twist legs to tighten line.

Cord Use

When selecting an appropriate cord for use with body suspension, a safety factor of 10 needs to be employed. This safety factor takes into account dynamic forces and unknown variables but not terminations. The MBS of the cord needs to be derated by 50% for class 1 fibers and 70% for class 2 fibers, to account for knots/terminations.

Factors that should be considered when selecting cord:

  • The cord’s strength
  • The cord’s diameter
  • What the cord is made from
  • How well it holds knots, bends & hitches
  • How well the cord cuts / melts
  • How much friction the cord creates through eyelets
  • How durable the cord is

Cord used by DSC:

  • 1/8” Amsteel Blue (UHMWPE) — MBS 2300 lbs
  • 7/64” Amsteel Blue (UHMWPE) — MBS 1400 lbs
  • 1/8” QNR Polyester Cord with Kevlar Core — MBS 825 lbs
  • 1/8” Polyester Cord — MBS 400 lbs

Cord Calculator

Terminations

There are many knots/hitches/bends that can be utilized for body suspension. Below are the most commonly used ones. As a general rule, it is widely agreed that knots derate rope by up to 50% — this should be factored in when choosing a cord or mainline.

Videos:

Hardware Selection and Use

When selecting hardware for suspension, it is important to take into consideration its intended use and how it will work for your application. Certain hardware is designed for specific uses.

Understand how they are designed and ensure their strength is suitable for your specific use. As a general rule, any single component in the load path should have an MBS of at least 1500 kgs (15kN).

  1. Round Slings: Round and synthetic generally — how it is used affects the strength so make sure you read the label and derate accordingly.

  2. Sewn Runners: Smaller, lighter and more compact than round slings and generally of a lower MBS — good for connecting to rigs but can also be used at a structural point.

  3. Connectors: Popular connector options are aluminum carabiners, steel carabiners, maillon rapides and shackles.

  4. Pulleys: Many pulley systems are available. Marine styles are quite popular due to their high strength to weight ratio as well as their durability. Aluminum climbing pulleys are also a popular option as they too are lightweight and designed specifically with live loads in mind.

  5. Mainline Rope: Different applications may require different rope types. Commonly used are semi-static or low-stretch ropes made from nylon or polyester. Common sizes are 10mm / 11mm / 12mm.

  6. Swivels: These have at least 24kN MBS — check also the intended use of the swivel before purchasing.

  7. Rig Plates: Aluminum climbing plates are most suitable as these are rated for human load, are lightweight and are well finished. Custom steel and aluminum rigs can also be made to a suitable strength for human load.

  8. Custom Fabrication: This is something that needs very careful consideration. All custom fabrication needs to be engineered by a professional who understands the intended use of the custom piece, therefore made in such a way to withstand the forces imposed on it.

  9. Hooks: Different hooks are available for different uses. The style of suspension will determine the desired hook type. Open gape hooks are primarily for static/semi-static suspensions; semi-locking hooks for multi directional static or dynamic loads; and locking hooks for dynamic loads.

Belay Ascent / Descent

  1. The purpose of the belay (or in the case of body suspension, modified belay) is to be able to raise and lower the suspendee in a safe and controlled manner.

  2. The belayer should have an attachment point on their person, usually a well fitted harness, fit for purpose. Alternatively, utilizing a fixed point may also be appropriate. This is usually venue and situation dependent — see MA over Operator.

  3. A suitable descent device should be used. Ensure the rigger/belay is trained in its use.

  4. Rigger’s gloves should be worn to ensure hand safety.

  5. The belayer is to keep their attention on the suspendee throughout the whole duration of the suspension.

Mainline

  1. Care should always be taken with the mainline.

  2. Follow the mainline inspection guide prior to use.

  3. Unravel the mainline in such a way that it is free from any kinks or unnecessary twists.

  4. Never stand on the mainline at any time as this can damage the rope.

Gear Inspection

To be visually carried out before, during and after use. For specific inspection guidelines, always read manufacturer’s instructions.

Round Slings
  • Inspect for any damage, irregularities, or signs of wear and tear, specifically nicks & cuts. Check the stitching also.
  • Check to make sure the safety tag is readable and intact
Maillon Rapides
  • Ensure there are no deformities or irregularities
  • Check there are no nicks and wear is less than 10%
  • Ensure the gate threads smoothly
Pulleys
  • Check the sheaves are free moving
  • Check the body is free from any deformities
  • Check the side plates move and engage properly
  • Check the swivel shackle head is moving freely
  • Ensure the shackle is in working order
  • Ensure the becket pin is secure
Mainline
  • Rope should be inspected by passing through hands, meter by meter, feeling for any changes in the flex/shape.
  • Check for any bunching of the sheath
  • Check for any pulls in the sheath
  • Ensure there are no cuts or abrasions
  • Ensure the core is not exposed
Carabiners
  • The gate mechanism should operate freely
  • The gate should close straight so that it cleanly engages
  • The body of the carabiner should be free of any cracks, marks and deep scratches
  • There should be no corrosion evident
  • Locking mechanisms should operate freely
  • Wear should be no more than 10%
Swivels
  • Check all parts are moving and spinning freely
  • Check for any cracks, deformation, wear and corrosion
  • Ensure there are no unusual noises when spinning
  • Check the axle screw has not loosened
Rig Plates
  • Check for any burrs, scratches and wear
  • Eyelets should be free from any nicks that may damage cord
  • Ensure there is no deformation of the plate
  • Wear on the anchor points should be no more than 10%
Belay / Descent Devices
  • These can be prone to excessive wear given the friction from rope
  • Ensure the device is functioning properly
  • Check the rope surface is free from any nicks, burrs or abrasions
Shackles
  • Check for wear on the surface
  • Check the pin is still straight and threads into the body freely
  • Check there are no signs of the body opening
  • Ensure the pin is well seated
Hooks
  • Ensure hooks are not deformed in any way
  • Check hooks for any signs of damage
  • Locking hook parts should all still align and bolts should thread freely
Harnesses / Restraint Belt
  • Check all stitching, buckles and attachments for any sign of damage or wear
  • Ensure harness webbing is dressed and not twisted
Helmets
  • Inspect the helmet for any cracks or deformations
  • Ensure the straps are not twisted and the clip is working properly
  • Check any stitching to ensure there is no wear or damage

General Rigging Guidelines

  1. All cord is single use and disposable.

  2. Inverted suspensions are to be fitted with a harness / restraint belt and a disposable line attached.

  3. All knots and connections are to be double checked by a competent rigger.

  4. A visual check of all hardware should be carried out before and after each use.

  5. Full hardware inspections are to be carried out and recorded at least every 12 months and recorded in Asset Tiger.

  6. Only approved people are allowed to change, add or remove equipment and/or apparatus at our events/workshops. These people may not appoint another person to change, adjust or modify any piece of rigging gear unless competent to do so.

  7. An approved person may allow a volunteer to clip gear onto the eyelet end of the pulleys however you must double check their work.

  8. Wherever possible when you have attached anything onto the pulley, get a competent person to double check your work.

  9. Only approved riggers may modify, move, adjust any rigging that directly connects to the structure.

  10. You must wear a climbing helmet at all times when working at height.

  11. Ensure tools are secured when working at height.

  12. It is the responsibility of all riggers to each have safety shears and a butane torch on their person in case of emergency. An LED torch should also be made available for checking of overhead rigging and/or hook shifting.

Sources / Credits

  • ANSI e1.43 — Entertainment Technology — Performer Flying Systems
  • Safe Rigging Practices for the Entertainment Industry in New Zealand
  • Circus Safe New Zealand
  • Physics for roping technicians 2020 — Richard Delaney
  • Hall Rigging Academy
  • Eden Thomson