Theatre 643 Section II
Entertainment Rigging
Class meets Monday and Wednesday 900--1050
Instructor: Loren Schreiber
Office: DA 203
Phone: 619-370-4858
E-Mail: lschreib@mail.sdsu.edu
Office Hours: 1300 to 1400 MW; other times by appointment
Texts: The Stage Rigging Handbook, 3rd ed., by Jay O. Glerum
Rigging Math Made Simple, 2nd ed., by Delbert Hall
Entertainment Rigging, by Harry Donovan
ESTA Rigging Certification Handbook. Available at:
http://etcp.esta.org/candidateinfo/riggingexams/CandidateHandbook.html
Any comprehensive book of knots and hitches. For example:
The Ultimate Encyclopedia of Knots, by Geofrey Budworth
The Complete Book of Knots, by Geofrey Budworth
The Morrow Guide to Knots, by Mario Bigon and Guido Regazzoni
The Ashley Book of Knots, by Clifford Ashley
Or any other book or resources for knots, (including the Internet)
This class is about rigging of all kinds, but especially the kind of rigging that is performed in the
entertainment industry. Over the course of the semester, we will learn the fundamentals of rigging,
beginning with fibrous rope, knots and splices and progressing through wire rope and wire rope
terminations to full rigging systems. The class is intended to be “hands-on”, so there will be a minimum of
talking and a lot of doing. What talking there is will cover the math and theory of rigging, where
appropriate, and safety factors associated with theatrical and entertainment rigging.
This class will be partial preparation for the Entertainment Technical Services Association’s
Entertainment Technician Certification Program exam. The body of knowledge required of a professional
rigger is extensive and impossible to compress into a single semester. (See attached Body of Knowledge
Outline from the original ESTA rigging working group. This document will provide the basic skeleton for
the content of the course.) But, at a minimum, you will know what you don’t know—which should make
you a better rigger. We will attempt to at least touch on each listed item.
How You Will Be Evaluated
~There will be a quiz each week on assigned reading: 15 points.
~All assigned knots and splices: 10 points.
~There will be a Mid-term Exam: 15 points and a Final Exam: 25 points.
~This is a hands-on class. Participation: 25 points.
~Graduate student reports: 10 points.
Undergraduate Grade Schedule*:
81—90 points = A; 72—80 points = B; 63—71 points = C; 54—62 = D; 53 or less = F
Graduate Grade Schedule*:
91—100 = A; 81—90 = B; 71—80= C; 61—70 = D; 60 or less = F
*Lower third of each tier = minus, upper third of each tier = plus, e.g., 81 = B-; 90 = B+
Graduate Lecture Topics
Possible topics for Graduate Lectures include:
~Performer flying
~Fall Arrest/OSHA regulations
~Fire Curtains/Smoke Doors
~What Went Wrong: Rigging Disasters
Other topics subject to approval of the instructor.
Rigging Body of Knowledge Outline
From the ESTA Rigging Safety Working Group, 2004
Summary Outline
1. Physics, Mechanics & Engineering
1.1. Physical Principles & Basic Formula
1.2. Materials Science
2. Entertainment Rigging Systems
2.1. General Rigging Principles
2.2. Rigging Systems
3. Formulas and equations / Specific Principles
3.1. Load Calculation
3.2. Calculation of Reactions Acting on Structure
3.3. Force Calculation
3.4. Beam Formulas
3.5. Load Increase Factors
3.6. Specific Principles
4. Fall Protection
4.1. Know the Three Specific Types of Fall Protection
4.2. The rigger must have an understanding of the design requirements of a PFAS
4.3. The rigger must know the following pertaining to the use of PFAS
4.4. Design requirements of most PFAS
4.5. Basic regulations pertaining to the use of PFAS.
4.6. Regulation locations regarding Fall Protection & PFAS
5. Principles relating to the use of equipment, facilities & techniques
5.1. General Principles
5.2. Dynamic loads and shock loads
5.3. Center of Gravity
5.4. Deadhangs
5.5. Breastlines
5.6. Bridles
5.7. Block and Fall
5.8. Shackles
5.9. Wire Rope
5.10. Fiber Rope
5.11. Rings, Hooks & Eyebolts
5.12. Roundslings
5.13. Aluminum Truss
5.14. Hitches
5.15. Padding
5.16. Facilities
5.17. Testing
6. Risk
6.1. General Risk
6.2. Misc.
Knowledge List (full outline)
1. Physics, Mechanics & Engineering
1.1. Physical Principles & Basic Formula
1.1.1. Mathematics
1.1.1.1. Units
1.1.1.1.1. Length
1.1.1.1.1.1. Must know the following Imperial units of length and be able to convert
from any unit to any other unit.
1.1.1.1.1.1.1. Inch
1.1.1.1.1.1.2. Foot
1.1.1.1.1.2. Must know the common abbreviation for the following Imperial units of
length.
1.1.1.1.1.2.1. Inch
1.1.1.1.1.2.2. Foot
1.1.1.1.1.3. Must know the following SI units of length and be able to convert from any
unit to any other unit.
1.1.1.1.1.3.1. Millimeter
1.1.1.1.1.3.2. Centimeter
1.1.1.1.1.3.3. Meter
1.1.1.1.1.4. Must know the common abbreviation for the following SI units of length.
1.1.1.1.1.4.1. Millimeter
1.1.1.1.1.4.2. Centimeter
1.1.1.1.1.4.3. Meter
1.1.1.1.1.5. Must be able to convert back and forth from SI to Imperial units of length.
1.1.1.1.2. Angles
1.1.1.1.2.1. Demonstrate an understanding of the unit “degree”
1.1.1.1.2.2. Know the abbreviation for degree
1.1.1.2. Formulas
1.1.1.2.1. Algebra
1.1.1.2.1.1. Be able to handle basic algebraic operations
1.1.1.2.1.1.1. Addition, subtraction, multiplication, division
1.1.1.2.1.1.2. Squares and square roots
1.1.1.2.1.1.3. Order of operations, parentheses and nested parentheses
1.1.1.2.1.1.4. Signed numbers
1.1.1.2.1.1.5. Transpositions and equation manipulation (solving for an unknown)
1.1.1.2.2. Geometry
1.1.1.2.2.1. Must be able to define a/an:
1.1.1.2.2.1.1. rectangle
1.1.1.2.2.1.2. parallelogram
1.1.1.2.2.1.3. triangle
1.1.1.2.2.1.4. right triangle
1.1.1.2.2.1.5. circle
1.1.1.2.2.1.6. arc
1.1.1.2.2.2. Determine the area of a rectangle
1.1.1.2.2.3. Find the length of the hypotenuse of a right triangle given the length of the
two sides
1.1.1.2.2.4. Construct a right angle by the 3:4:5 triangle method
1.1.1.2.2.5. Be able to determine the size of an angle
1.1.2. Forces
1.1.2.1. Force / Weight
1.1.2.1.1. Must understand that a force has a magnitude and a direction
1.1.2.1.2. Must be able to convert the following imperial units from one to any other
unit.
1.1.2.1.2.1. Ounce
1.1.2.1.2.2. Pound
1.1.2.1.2.3. kilopound (Kip)
1.1.2.1.2.4. Ton
1.1.2.1.3. Must know the common abbreviation for the following Imperial units.
1.1.2.1.3.1. Ounce
1.1.2.1.3.2. Pound
1.1.2.1.3.3. Kilopound (Kip)
1.1.2.1.3.4. Ton
1.1.2.1.4. Must be able to convert the following SI Units from one to any other unit.
1.1.2.1.4.1. Gram
1.1.2.1.4.2. Kilogram
1.1.2.1.4.3. Newton
1.1.2.1.4.4. Kilonewton
1.1.2.1.4.5. Metric Ton (Tonne)
1.1.2.1.5. Must know the common abbreviation for the following SI units.
1.1.2.1.5.1. Gram
1.1.2.1.5.2. Kilogram
1.1.2.1.5.3. Newton
1.1.2.1.5.4. Kilonewton
1.1.2.1.5.5. Metric– Ton (Tonne)
1.1.2.2. Newton’s Laws
1.1.2.2.1. Basic Physical Laws
1.1.2.2.1.1. Understand for every action there is a equal and opposite reaction
1.1.2.2.1.2. Understand that weight is a force caused by gravity
1.1.2.2.1.3. Understand that a force is required to stop or start an object.
1.1.3. Statics (the study of stationary rigid bodies)
1.1.3.1. Basic Laws of Stationary Objects
1.1.3.1.1. Understand that a force always acts in a specific direction
1.1.3.1.2. Be able to calculate forces on a support structure in 2 dimensions when
given a specified loading condition and geometry. This should include:
1.1.3.1.2.1. Total force (magnitude and direction) on each sling leg.
1.1.3.1.2.2. Horizontal component forces (magnitude)
1.1.3.1.2.3. vertical component forces (magnitude)
1.1.3.1.3. Be able to calculate forces on a support structure in 3 dimensions when
given a specific loading condition and geometry. This should include:
1.1.3.1.3.1. Total force (magnitude and direction) on each sling leg.
1.1.3.1.3.2. Vertical component forces (magnitude)
1.1.3.1.3.3. Total horizontal forces in each leg (magnitude and direction)
1.1.3.1.3.4. Horizontal component forces in X axis
1.1.3.1.3.5. Horizontal component forces in Y axis
1.1.3.1.4. Understand that the sum of all forces acting on a stationary object equals
zero.
1.1.3.2. Mechanical Advantage
1.1.3.2.1. Be able to describe how a gear system produces a mechanical advantage
or disadvantage.
1.1.3.3. Understand that a reaction is the force that acts to resist loads imposed on a
structure.
1.1.4. Dynamics (the study of moving objects)
1.1.4.1. Basic Laws of Moving Objects
1.1.4.1.1. Understand that a dynamic load is due to the acceleration or deceleration of
an object
1.1.4.1.2. Understand that the greater the acceleration or deceleration, the greater the
force acting on the system supporting the object
1.1.4.1.3. Friction
1.1.4.1.3.1. Understand that friction always decreases the efficiency of a system
1.2. Materials Science
1.2.1. Strength and Properties of Materials
1.2.1.1. Basic Material Properties
1.2.1.1.1. Understand that - trusses have a greater load capacity at panel points than
in between panel points
1.2.1.1.2. Understand that the strength of a structural member is dependent on:
1.2.1.1.2.1. The shape, size, material, support conditions, bracing, and length
1.2.1.1.2.2. Understand properties of cordage: Understand that the strength of
cordage is dependent of the fiber material, rope construction (ie, 3-strand twist,
double braid, parallel core, etc.) and rope diameter
1.2.1.1.2.3. Understand that the distance a fiber rope will stretch is dependent on fiber
material, rope construction, diameter, length and applied load.
1.2.1.1.2.4. Understand that the ability to absorb shock load is dependent on the fiber
material, rope construction, rope length, and rope diameter.
1.2.1.1.2.5. Must be able to rank the following fiber types from least elongation to most
elongation. (cotton, manila, polyester, polypropylene, nylon)
1.2.1.1.3. Understand the following properties of wire rope:
1.2.1.1.3.1. D:d ratio
1.2.1.1.3.1.1. Definition
1.2.1.1.3.1.2. effects on efficiency
1.2.1.1.3.1.3. how acceptable ratios are affected by wire rope construction
1.2.1.1.3.2. End terminations
1.2.1.1.3.2.1. How they affect sling efficiency
1.2.1.1.3.3. Know there is a minimum sling body length (minimum length must be
greater than/equal to 10 times wire diameter).
2. Entertainment Rigging Systems
2.1. General Rigging Principles
2.1.1. Definitions relating to load capacity
2.1.1.1. Must be able to define Breaking Strength.
2.1.1.2. Must be able to define as Working Load Limit.
2.1.1.3. Must be able to define Design Factor.
2.1.1.4. Must be able to define Efficiency as it relates to knots, slings and other rigging
materials.
2.1.1.5. Must be able to understand the primary reasons for the use of Design Factors
2.1.1.5.1. Degradation of material
2.1.1.5.2. Unknown or difficult to define forces (dynamic load, shock load, wind load)
2.1.1.5.3. Loads cannot be accurately calculated on a beam or truss with more than
two support points.
2.1.1.5.4. Errors in calculation or estimation.
2.1.1.5.5. Operational errors.
2.1.1.5.6. Incomplete knowledge of the system.
2.1.1.6. Working knowledge of load capacity terms, Design Factors (Safety Factors)
2.1.1.6.1.1. Design Factor = (Breaking Strength)(Efficiency) / Maximum Applied Force
2.1.1.6.1.2. Ultimate Strength (Rigging Strength)
2.1.1.6.1.3. Design Load (Allowable Load)
2.1.1.6.1.4. Design Factor
2.1.1.6.1.5. (Efficiency)
2.1.1.6.1.6. Maximum Applied Force
2.1.1.6.2. Must know the Ultimate Strength of the following wire ropes.
2.1.1.6.2.1. 0.125” — 7X19 Galvanized Aircraft Cable
2.1.1.6.2.2. 0.25” — 7X19 Galvanized Aircraft Cable
2.1.1.6.2.3. 0.375” — 7X19 Galvanized Aircraft Cable
2.1.1.6.2.4. 0.5” — 7 X 19 XIP IWRC Bright
2.1.1.6.3. Must know that the minimum Design Factor allowed for general purpose
wire rope slings in Federal OSHA is 5:1.
2.1.1.6.4. Must know that Federal OSHA requires higher Design Factors for
suspension of work platforms such as catwalks etc., than for general-purpose slings.
2.1.1.6.5. Must understand that an appropriate design factor greater than 5 must be
applied for systems supporting people.
2.1.1.6.5.1. 8:1 DF required for permanent cable suspended catwalks
2.1.1.6.5.2. 6:1 DF required for cable suspended work platforms
2.1.1.6.6. Must be able to approximate the efficiency of a sling due to the following
factors.
2.1.1.6.6.1. Use of U-bolt & Double Saddle type wire rope clips to form eyes.
2.1.1.6.6.2. Mechanical splices used to form eyes
2.1.1.6.6.3. Copper or plated copper hand swaged oval sleeves (100% efficiency)
2.1.1.6.6.4. Be able to identify examples of best case and worst case uses of a choker
hitch.
2.1.1.6.6.5. Be able to identify examples of best case and worst case uses of a basket
hitch.
2.1.1.6.7. Must know the Working Load Limit of common U.S. made brands of carbon
steel screw-pin anchor shackles of the following sizes.
2.1.1.6.7.1. 1/2"
2.1.1.6.7.2. 5/8”
2.1.1.6.7.3. 3/4"
2.1.1.6.8. Must know the Design Factor used by common U.S. made brands of carbon
steel screw-pin anchor shackles under 1” nominal size is 6:.
2.1.1.6.9. Must know that the minimum Design Factor allowed for the use of synthetic
slings in Federal OSHA is 5:1.
2.1.1.6.10. Must know the Working Load Limit of the following types of polyester
roundslings.
2.1.1.6.10.1. “30” series or violet (approximately 2.5 kips)
2.1.1.6.10.2. “60 series or green (approximately 5 kips)
2.1.1.6.11. Must know that the minimum Design Factor allowed for the use of Grade “8”
or “80” or “Alloy” chain in Federal OSHA is 4:1.
2.1.1.6.12. Must know the Design Load of the following sizes and types of chain.
2.1.1.6.12.1.
2.1.1.6.12.2. ¼” Grade 30 proof coil chain (1,300 lbs.)
2.1.1.6.12.3. ½” Deck chain (11,250 lbs.)
2.1.1.6.12.4. S.T.A.C. chain (12,000 lbs.)
2.1.1.6.13. Must understand that the maximum force applied cannot exceed the
Working Load Limit.
2.1.1.6.14. Must know the Design Factor for the following in common use in arena
rigging:
2.1.1.6.14.1. Wire rope slings = Minimum of 5 to 1
2.1.1.6.14.2. Running rigging on stages for counterweight or motorized drum hoist
rigging = 8 to 1
2.1.1.6.14.3.
2.1.1.6.14.4. Base mounted drum hoists = 7 to 1
2.1.1.6.14.5. Personnel lifts = 7 — 10 to 1
2.1.1.6.14.6. Fiber ropes = 5 — 12 to 1
2.1.1.6.14.7. Synthetic slings = 5 to 1
2.1.1.6.14.8. Chain = 4 to 1
2.1.1.6.14.9. Rigging Supporting Personnel = Minimum of 6 to 1
2.1.1.6.14.10. Misc. hardware (shackles, hooks, and rings) 5-6 to 1
2.1.1.6.14.11.
2.1.2. Forces in Rigging Systems
2.1.2.1. Must be able to define Load Weight. (Italics for weight)
2.1.2.2. Must be able to define Static Load.
2.1.2.3. Must be able to define Dynamic Load.
2.1.2.4. Must be able to define Shock Load.
2.1.2.5. Must be able to describe the difference between Static & Dynamic Load.
2.1.2.6. Know that force consists of two components:
2.1.2.6.1. Direction
2.1.2.6.2. Magnitude
2.1.2.7. Know the components that make up dynamic load:
2.1.2.7.1. Static load
2.1.2.7.2. Initial speed
2.1.2.7.3. Ending speed
2.1.2.7.4. Time between the two speeds
2.1.2.8. Be able to estimate dynamic load caused by starting or stopping:
2.1.2.8.1.1. 16 f.p.m. hoist (approx. = 20% load increase)
2.1.2.8.1.2. 64 f.p.m. hoist (approx. = 200% load increase)
Note: There is no published data
2.1.2.9. In any two legged bridle, be able to determine if a bridle leg sling is overloaded if
a vertical sling of the same size below the bridle is 100% loaded.
2.1.2.10. Know at what point the horizontal component force exceeds the vertical
component force in a bridle leg or other inclined support cable.
2.1.2.11. Understand that a rule of thumb for keeping bridle leg tension below sling
working load limits is that the S:H ratio in two legged bridles should be 3:1 or less.
2.1.2.12. Understand that a rule of thumb for keeping bridle leg tensions below sling
working load limits is that; the angle between the legs should not exceed 90 degrees.
2.1.2.13. Know that the 3:1 S:H and the 90 degree rules of thumb can be used for
determining proper basket hitch leg lengths. .
2.1.3. Equipment Specification
2.1.3.1. Must be able to select the proper size of equipment for a given load (using the
manufacturer’s specification sheet and the appropriate design factor)
2.1.3.1.1. Wire rope
2.1.3.1.2. Fiber rope
2.1.3.1.3. Web slings
2.1.3.1.4. Grade 8 chain
2.1.3.1.5. Shackles
2.1.3.1.6. Turnbuckles
2.1.3.1.7. Hooks
2.1.3.1.8. Eyebolts
2.1.3.1.9. Rings
2.2. Rigging Systems
2.2.1. Chain hoist
2.2.1.1. Capacity
2.2.1.1.1. Must know that rated capacity must not be exceeded.
2.2.1.1.2. Must know that ANSI B30.16 does not require overload protective devices
2.2.1.1.3. Must know that ANSI B30.16 requires the brake to hold 125% of the rated
capacity of the hoist.
2.2.1.1.4. Must know that adding loads to hoist suspended loads can cause dangerous
conditions as the brake may hold a load that overloads the hoist, but when the hoist
is operated the overload protection may cause the load to slip.
2.2.1.2. Speed
2.2.1.2.1. Must know that higher speed hoists create a higher dynamic force when
starting and stopping than do slower hoists
2.2.1.2.2. Must know that the dynamic force cannot be calculated but that a 16 f.p.m.
hoist can easily create a dynamic load 25% greater than the static load
2.2.1.2.3. Must be familiar with Chain Hoist Design Factors
2.2.1.2.3.1. There is a 5:1 or greater design factor on the material strength of all load
bearing parts.
2.2.1.2.3.2. Additional info relating to clutch performance (varies from slipping at 1.25
to 1; 1.8 to 1) (This is not part of the design factor section)
3. Formulas and equations / Specific Principles
3.1. Load Calculation
3.1.1. Be able to calculate the center of gravity of a multiple load system, in two and three
dimensions, given the location and weights of the individual loads.
3.1.2. Know that if the following factors exist the design load can be the “highest load seen
during normal operation” .
3.1.2.1. Factors that allow the use of the “highest load seen during normal operation”:
3.1.2.1.1. Loading has been determined by a competent person.
3.1.2.1.2. Loading is short term
3.1.2.1.3. The loads are very well defined.
3.1.2.1.4. The rigging is accomplished by competent riggers.
3.1.2.1.5. The hoists are operated and observed by competent riggers.
3.1.3. Know that if the above listed factors do not exist, design load must account for
mistakes in operation.
3.1.4. Rainwater should be prevented from accumulating on roof structures.
3.1.5. Be able to estimate the weight of a puddle of specific dimensions.
3.1.6. Understand the following effects of wind on an outdoor structure:
3.1.6.1. Wind pressure increases with height.
3.1.6.2. wind pressure will cause a stress increase in the structure.
3.1.6.3. wind pressure increase is a function of wind speed squared.
3.1.6.4. For a wind speed of 40 mph, wind pressure is approximately equal to a force of
10 psf on the projected vertical area of the structure.
3.1.7. Be able to calculate the total weight of a system, given the weight per unit of all
components and a diagram depicting the system.
3.1.8. Be able to calculate the loads on the supports of a two-dimensional, two-point
object at various angles of tilt (given the center of gravity, weight, overall dimensions and
location of the pick-up points).
3.1.9. The total allowable load on a beam or truss can be represented as a percentage of
various load cases. As long as the sum of the stresses imposed by all of the load cases
does not exceed the allowable stress (total of all load cases must be less than 100%),
the capacity of the beam or component has not been exceeded.
3.1.10. Know that dynamometers or load cells are needed to accurately determine loading
in a straight truss with more than two support points or a 3-D structure with more than 3
support points.
3.2. Calculation of Reactions Acting on Support Structure
3.2.1. Be able to calculate the resultant force acting on a supporting structure where
several loads of different weights and at different angles are acting at the same point.
Be able to determine the horizontal and vertical components.
3.2.2. Determine that show loads do not exceed allowable loads as determined by a
structural engineer (when available).
3.3. Force Calculation
3.3.1. Know how to calculate shock loads, given load weight, free fall distance, and
deceleration distance.
3.4. Beam Formulas
3.4.1. Understand how to calculate forces on the supports of a simple span beam/truss.
3.4.2. Know that loads rolling along a truss or track can create forces on the supports of
twice the forces caused by the same load not moving.
3.4.3. Know that you can determine the total forces, stresses and resultants for a multiple
load beam by calculating each of the loads and resultants separately and summing the
results (this is the principle of superposition).
3.4.4. Be able to estimate load distribution on a beam with a uniform load and multiple
equally spaced supports. Understand that the mathematically derived loads differs from
the estimate.
3.4.4.1. Basic concept for estimation of the forces on equally spaced multiple supports,
when the loads are uniformly distributed: Interior loads are approximately equal, end
loads are approximately ½ of interior loads.
3.4.4.2. Know that there are more exact methods of calculating the reactions for a multispan
beam.
3.4.4.3. For a multi span beam, the line tension varies and cannot be easily determined by
standard calculation methods.
3.4.5. Know how to estimate the reactions acting on the supports for a beam with more
than two unequally spaced supports for:
3.4.5.1. Uniform loading
3.4.5.2. Several concentrated point loads
3.4.5.3. A combination of uniform and concentrated loads.
3.5. Load Increase Factors
3.5.1. Understand that a variety of factors can cause a load increase on a rigging system.
3.5.1.1. Types of factors that can increase forces and stresses.
3.5.1.1.1. Wind loads (on outdoor rigging systems)
3.5.1.1.2. Dynamic loads.
3.5.1.1.3. Cables off angle from vertical
3.5.1.1.4. Other Items.
3.5.2. Be able to estimate load increase factors for dynamic loads.
3.5.3. Be able to calculate load increase factors for cable off angle from vertical.
3.5.4. Understand the effects of hoist operation on the reactions at the supports of a multipoint
truss and/or grid.
3.5.5. Be able to estimate the possible forces imposed on each support of a truss
supported by three equally spaced points and the loads on the truss are uniformly
distributed, due to irregular hoist operation. (the forces can vary between 0% and 100%
of the total load.)
3.6. Specific Principles
3.6.1. Know that a lifting system is as strong as the weakest link in the system.
4. Fall Protection
4.1. Know the three accepted types of Fall Protection
4.1.1. Guardrails
4.1.2. Safety nets
4.1.3. Personal fall arrest systems (PFAS)
4.2. The rigger must have an understanding of the design requirements of a PFAS
4.3. A worker on a surface with an unprotected side or edge which is 6’ or more above a
lower surface must be protected from falling.
4.4. Design requirements of most PFAS
4.4.1. Must limit Free Fall Distance to 6’
4.4.2. Must limit Maximum Arrest Force to 1800 Lbs. (8 kN)
4.4.3. Must limit Deceleration Distance to 42”
4.4.4. For vertical systems the Ultimate strength of all components must be 5,000 Lbs.
(22.2 kN), or 2:1 Design Factor if designed by a qualified person
4.4.5. Most PFAS are designed for workers between the weight of 130 and 310 lbs.
4.4.6. Energy Absorbers that meet the requirements of ANSI Z359.1-1992 are designed to
limit the Maximum Arrest Force to 900 Lbs. (4 kN)
4.4.7. Connect to approved anchor points/points capable of supporting 5000 Lbs or
designed by a qualified person.
4.4.8. Horizontal systems must be designed by and installed under the supervision of a
qualified person and maintain a design factor of 2:1.
4.5. Basic regulations pertaining to the use of PFAS.
4.5.1. Fall protection is required when a worker is exposed to a potential fall greater than
6’.
4.5.2. Employer must train all personnel that use PFAS prior to use and maintain records
of training.
4.5.3. All PFAS must be inspected daily prior to use.
4.5.4. Employer must have a rescue plan in place prior to anyone using PFAS. This
rescue plan must provide for prompt rescue.
4.5.5. All PFAS including horizontal systems should have documentation available
explaining capacity and limitations of the PFAS.
4.5.6. Employer must have a written site-specific hazard assessment, identified as a
hazard assessment and signed
4.5.7. Employer must have a written site-specific fall protection plan
4.5.8. Employer must have a rescue plan in place which provides for a prompt rescue,
prior to anyone using the PFAS.
4.5.9. Any equipment needed for Injured Worker Rescue shall be ready and available for
prompt use whenever workers are using FPAS
4.5.10. Workers must be trained in the site-specific FPP and IWRP
4.5.11. Employees must be tested to determine their understanding of the site-specific FPP
and IWRP
4.5.12. Records of the most recent testing shall be maintained
4.5.13. Employees who demonstrate a lack of understanding of the plans shall be retrained
Retraining should occur if:
4.5.13.1. Equipment has changed,
4.5.13.2. Environment has changes,
4.5.13.3. Employee demonstrates a lack of understanding of system
4.5.14. Employers shall periodically inspect the Fall Protection equipment and its use. (by a
competent person) Records of the inspections and corrective actions taken shall be
maintained.
4.6. Regulation locations regarding Fall Protection & PFAS
4.6.1. Federal OSHA 1910.66 Appendix C
4.6.2. Federal OSHA 1926 Subpart M
4.6.3. Rigger must know that industry standards are located in the following:
4.6.4. ANSI A10.14-1991 (Currently withdrawn, in process of revision)
4.6.5. ANSI Z359.1-1992
4.6.6. The employer must train all workers using PFAS prior to the use of the equipment
and must maintain records of training.
4.6.7. All PFAS must be inspected daily prior to use.
4.6.7.1. In addition, the employer on a periodic basis must do a thorough inspection.
4.6.8. Any PFAS including horizontal lifeline systems must have written documentation
available which specifies the capacity and limitations of the system.
4.6.9. All Connecting hardware must be individually proof tested to 3,600 lbs.
5. Principles relating to the use of equipment, facilities & techniques
5.1. General Principles
5.1.1. Load Ratings
5.1.1.1. Know that all rigging equipment should be load rated and approved for lifting
whenever commercially available.
5.1.1.2. Know and understand design factors as they apply to rigging equipment.
5.1.1.3. Know that the correct design factor must be used when calculating the working
load limit for any rigging equipment.
5.1.1.4. Know the following terminology relating to load ratings:
5.1.1.4.1. Manufacturer approves the item for lifting in industrial applications
5.1.1.4.2. Load rated
5.1.1.4.3. Drop forged
5.1.1.4.4. Proof tested
5.1.1.5. Load ratings for rigging equipment can be determined from a manufacturers
ratings or from approved association literature.
5.1.2. Facility Allowable Loads
5.1.2.1. Rigger should know a structures allowable capacity before hanging a load.
5.2. Dynamic loads and shock loads
5.2.1. Know that the starting and stopping of any type of hoisting method will increase the
forces on the rigging.
5.2.2. Know that the only way to determine the actual load increase is by measuring it.
5.2.3. Know that dynamic loading occurs when loads accelerate, decelerate, start or stop.
5.2.4. Know that the likely range of load increase from a block and fall is less than 10%.
5.2.5. Know that the likely range of load increase from chain hoists operating at 16 feet
per minute is from 10% to 35%.
5.2.6. Know that a shock load caused by just a few inches of free fall can create forces on
a rigging system from 5 to 20 times over the static weight.
5.2.7. Know that if a primarily support fails, the secondary support (safety cable or similar
item) will be shock loaded.
5.2.8. The longer the fall distance, the higher the shock load.
5.2.9. Shorter slings will create higher shock loads than longer slings.
5.2.10. The more elastic the support system is, the lower the shock load will be
.
5.3. Center of Gravity
5.3.1. The center of gravity of an object will always be vertically below the support point of
the beam.
5.3.2. The center of gravity for a rigged object will always be below the bridle junction.
5.3.3. When an object is suspended by a single point with a single direct connection to the
object, the object will rotate so that the center or gravity is directly below the direct
connection.
5.3.4. When an object is suspended by a single point with a bridle to the object, the object
will rotate so that the center or gravity is directly below the bridle junction.
5.4. Deadhangs
5.4.1. A deadhang is direct connection from the supporting structure to the load. This is
typically a straight connection (as opposed to a bridle).
5.4.2. When using angled deadhangs or inclined hanging points, rigger must know that the
load is likely to move horizontally when lifted off of the floor. Such conditions must be
controlled or prevented.
5.4.3. If a truss is rigged with two angled deadhangs at different angles, it will tend to tilt as
it rises.
5.4.4. If an object is rigged with 3 or more angled deadhangs at different angles, the
tension in the supporting lines relative to each other will change as it rises.
5.4.5. If a truss is hung with 2 angles deadhangs, and there is an option to angle the
deadhangs either in or out at equal angles, angling the deadhangs out makes the truss
more stable both horizontally and vertically. Also the position of the truss will be more
accurate in plan.
5.4.6. Angled deadhangs can cause a rigged object to move horizontally as it rises.
5.4.7. Moving the connection of an angled deadhang to a truss will adjust its horizontal
position.
5.4.8. Objects hung with angled deadhangs can shift horizontally at they rise if:
5.4.8.1. The beams supporting the object are at different heights.
5.4.8.2. The center of gravity of the object changes.
5.4.8.3. The vertical component forces on the deadhangs are different.
5.4.9. Be able to determine the force in an inclined support cable if the horizontal and
vertical distances are known and the vertical load is known.
5.5. Breastlines
5.5.1. There are two general types of breastlines; breastlines connected to the object,
breastlines connected to the rigging supporting the object (generally, the wire rope
sling).
5.5.2. Breastlines permit adjusting the horizontal position of an object after it has been
raised.
5.5.3. Raising or lowering an object with breastlines attached to the object and secured to
the building will cause horizontal movement of the object.
5.5.4. Pulling an object horizontally with a breastline connected to the object will cause the
object to move vertically.
5.5.5. For a breastline attached to the object, pulling the breastline can affect the tilt,
support loading and deflection of an object hung with angled deadhangs or from beams
at different heights.
5.5.5.1. For an object rigged with 2 non-parallel angled deadhangs, pulling a breastline
connected to the object will cause the object to tilt.
5.5.5.2. For an object rigged with deadhangs supported by different height beams, ,
pulling a breastline connected to the object will cause the object to tilt.
5.5.5.3. For an object hung with 3 or more deadhangs at different angles, a breastline on
the object may change the tension in the supporting lines.
5.5.5.4. For an object hung with 3 or more angled deadhangs if the support beams are at
different heights, a breastline on the object may change the tension in the supporting
lines.
5.5.6. Lowering an object with breastlines attached can create a dangerous condition
including excessive horizontal movement and significant changes in the loads acting on
the breastline and/or the supporting lines.
5.5.7. When a breasline is attaché to the cable above the object instead of to the object
itself, it si possible to rig it so there is not horizontal movement as the object rises or
lowers, or so there is less interation between horizontal and vertical movement than with
the breastline on the object
.
5.6. Bridles
5.6.1. A bridle is an assembly of slings from two or more locations on the support structure
connecting to a bridle junction (typically at a lower elevation).
5.6.2. Use of bridles allows for accurate horizontal placement of an object (a load).
5.6.3. A load suspended directly below a bridle junction can be raised or lowered vertically
with minimal horizontal movement.
5.6.4. H-Bridles:
5.6.4.1. When raising or lowering, the forces in the bridle remain constant.
5.6.4.2. A change in load on one side of the bridle can cause a large horizontal and
vertical movement of the load on the other side.
5.6.5. Motor Bridle:
5.6.5.1. The bridle junction on a motor bridle is adjustable both horizontally and vertically.
5.6.5.2. The forces continuously change in the bridle legs when the hoists are operated.
5.6.5.3. There can be increased horizontal forces on the beams and the object due to
dynamic loads caused by horizontal movement when operating the motors connected
to the bridle junction.
5.6.5.4. Motor bridles have a tendancy to cause the rigged object to swing when starting
or stopping the motors attached to the bridle junction.
5.6.6. When moving a hung object horizontally, such as with a breastline, the suspended
geometry may change. This can cause unequal forces in the tension legs supporting the
load.
5.6.7. Now that tape measures can be used to figure out the leg length, basket hitch
length and the drop of bridles, using standard cable lengths.
5.6.8. Forces in a “flat” bridle can be very high. They can be many times more than the
load weight hanging from the junction.
5.6.9. When bridles have a narrow included angle between the legs, a small change in the
leg length can cause a large change in the horizontal position of the bridle junction.
5.6.10. Must know to consider headroom when calculating the minimum bridle junction
height.
5.6.11. Be able to calculate the forces on the legs of bridles of a variety of different
configurations. This includes, but may not be limited to:
5.6.11.1. A simple bridle
5.6.11.2. A simple bridle with the load pulled off vertical.
5.6.11.3. A bridle with one leg below the junction, with the load acting vertically on the
junction.
5.6.11.4. A bridle with one leg below the junction, with the load pulled off vertical below the
junction.
5.6.12. Be able to calculate the forces in bridle legs and a stinger for these conditions:
5.6.12.1. Both bridle legs up.
5.6.12.2. One leg up and one leg down.
5.6.12.3. When the stinger is vertical and also off vertical.
5.6.13. Know how to accurately arrive at bridle leg lengths. There are several methods for
doing this:
5.6.13.1. Measure the beam and point dimensions on site.
5.6.13.2. Scale the venue measurements from building or show drawings (by using a plan
view and bridle junction heights)
5.6.14. When an object is supported by a bridle whose legs are connected to the object, the
greater the vertical height from the bridle junction to the center or gravity, the more
resistant the object is to rotation.
5.6.15. When an object is supported by 3 or more points and the center of gravity is within a
polygon described by the support points, the object will not rotate.
5.7. Block and Fall
5.7.1. Must know the mechanical advantage of the following block systems:
5.7.1.1. Single block
5.7.1.2. Single upper, single lower
5.7.1.3. Double upper, single lower
5.7.1.4. Double upper, double lower
5.7.2. Must be able to determine the force on the upper block suspension given the load
weight for the following, assuming the haul line is tied to something besides the load
weight:
5.7.2.1. Single block
5.7.2.2. Single upper, single lower
5.7.2.3. Double upper, single lower
5.7.2.4. Double upper, double lower
5.7.3. Understand that line tension is constant in a line and pulley system when the object
is not moving.
5.7.4. Understand that, when an object is moving, accumulated friction causes a
difference in the tension on different parts of rope for an object supported by a line and
pulley system.
5.8. Shackles
5.8.1. Principles
5.8.1.1. To develop 100% efficiency, load shackles in line with the long axis of the shackle
5.8.1.2. Side loading shackles reduces efficiency to 50% for screw pin anchor shackles
and nut & bolt style anchor shackles.
5.8.1.3. The width of the fitting or fittings in the shackle shall be less than the inside length
of the pin.
5.8.1.4. Make sure shackle pins cannot rotate and unscrew
5.8.1.5. When possible, put a shackle pin on a thimble
5.8.1.6. Screw the shackle pins all the way in
5.8.1.7. When possible, use oversized shackles so the shackles cannot rotate and get
loaded sideways
5.8.2. Working Load Limits (Commonly accepted [published] working load limit for most
North American manufacturers)
5.8.2.1. 0.5” : 2 tons (for an English ton equal to 2,000 lbs.)
5.8.2.2. 0.625”: 3.25 tons
5.8.2.3. 0.75”: 4.75 tons
5.9. Wire Rope
5.9.1. Loading
5.9.1.1. Cyclical Loading
5.9.1.1.1. Repeated cyclical loading results in progressive weakening of the rope.
5.9.1.1.2. Cyclical loading, if continued for enough cycles, will break a rope.
5.9.2. Running Rigging
5.9.2.1. To achieve a normal service life, running rigging using 6x19 IWRC should have a
sheave:rope D:d ratio of 30:1 or more.
5.9.2.2. Fleet angle for sheave and drum assemblies:
5.9.2.2.1. For smooth wire rope drums: +/- 1.5 degrees.
5.9.2.2.2. For grooved wire rope drums: +/- 2.0 degrees.
5.9.2.2.3. Maximum under any circumstances: +/- 5.0 degrees.
5.9.3. Terminations
5.9.3.1. Efficiency of wire rope terminations
5.9.3.1.1. Manually swaged eyes with copper swages (Nicopress): 100%.
5.9.3.1.2. Mechanically spliced eyes: 95%.
5.9.3.1.3. Wire rope clips for rope 1” diameter or less: 80%.
5.9.4. Principles
5.9.4.1. Put only one fitting in a cable eye (thimble)
5.9.4.2. Don’t bend a cable swage
5.9.4.3. Don’t bend the cable close to the swage (within 1 lay length)
5.9.4.4. The strength of wire rope (6x19) with a D/d ratio of 1:1 = 50%.
5.9.4.5. The strength of wire rope (6x19) with a D/d ratio of 30:1 = 90%.
5.9.4.6. The service life of wire rope with small D/d ratios is dramatically reduced from
wire rope in service with standard D/d ratios.
5.9.5. Breaking Strengths
5.9.5.1. 1/8” 7x19 Galvanized aircraft cable: 2,000 lbs.
5.9.5.2. ¼” 7x19 Galvanized aircraft cable: 7,000 lbs.
5.9.5.3. 3/8” 7x19 Galvanized aircraft cable: 14,400 lbs.
5.9.5.4. ½” 7x19 Galvanized aircraft cable: 22,800 lbs.
5.9.5.5. ½” 6x19 IWRC Bright XIP: 26,600 lbs.
5.9.5.6. ½” 6x19 IWRC Bright XXIP: 29,200 lbs
.
5.10. Fiber Rope
5.10.1. Loading
5.10.1.1. Sustained Loading
5.10.1.1.1. Polypropylene, polyester and nylon fiber ropes can support a load less than
25% of breaking strength indefinitely.
5.10.1.1.2. Natural fiber (manila) rope can break at a load significantly lower than its
catalog breaking strength if loaded for a long time.
5.10.1.2. Cyclical loading
5.10.1.2.1. Repeated cyclical loading will result in progressive weakening of the rope.
5.10.1.2.2. If cyclical loading is continued for enough cycles, the rope will break.
5.10.2. Knots
5.10.3. Terminations
5.10.3.1. Efficiency of common knots.
5.10.3.1.1. Bowline: 50%.
5.10.3.1.2. Clove hitch around a 4” diameter pipe: 75%.
5.10.3.1.3. Round turn with half hitches around a 4” diameter pipe: 75%.
5.10.4. Breaking Strengths (1/2” utility grade – 3 strand)
5.10.4.1. Manila: 2,650 lbs.
5.10.4.2. Polypropylene: 4,400 lbs.
5.10.4.3. Nylon: 6,000 to 7,000 lbs.
5.10.4.4. Dacron: 6,000 to 7,000 lbs.
5.10.5. The strength of fiber rope in a sliding conditions (such as around a belaying pin)
with a D/d ratio of 1:1 = 30% to 40%.
5.11. Rings, Hooks & Eyebolts
5.11.1. Principles
5.11.1.1. Put only one fitting on a hook
5.11.1.2. OSHA requires that all hooks have latches.
5.11.1.3. Do not rely on the retaining ability of sheet metal latches
.
5.12. Roundslings
5.12.1. Principles
5.12.1.1. Make sure roundslings don’t get cut, heated, or crushed.
5.13. Aluminum Truss (temporary truss including ground support systems that are not part
of permanent building structure such as arena roof systems)
5.13.1. Principles
5.13.1.1. Connecting a load to a truss
5.13.1.1.1. Keep welds in compression
5.13.1.1.2. Rig concentrated loads at the panel points.
5.13.1.1.3. Support the truss at the panel points.
5.13.1.1.4. Do not use wire rope to wrap chords.
5.13.1.2. Loading
5.13.1.2.1. Be able to calculate the loads and resulting forces acting on a truss
supported by two points for:
5.13.1.2.1.1. Uniform loading
5.13.1.2.1.2. Concentrated point loads (one or several)
5.13.1.2.1.3. A combination of uniformly distributed load and one or more concentrated
loads.
5.13.2. Allowable Loading
5.13.2.1. A rigger should always know whether the load on a show truss is within its
allowable capacity.
5.13.2.2. The capacity of a show truss must be determined from the manufacturers
literature.
5.13.2.3. Trusses with no published manufacturer’s load rating should not be used.
5.14. Hitches
5.14.1. A direct hitch is typically a direct connection to a point such as an eyebolt.
Typically, this type of connection is 100% efficient.
5.14.2. A basket hitch is a sling wrapped around a beam with both ends of the sling
connected together. (insert a chart or table with basket hitch capacity/efficiency when the
legs of the slings are acting at a variety of different angles)
5.14.2.1. A normal basket hitch is between 100% and 200% efficient.
5.14.2.2. A normal basket hitch has an included angle between the two sling legs of 90
degrees or less.
5.14.2.3. Know that a basket hitch can be less than 100% efficient (when the included
angle is greater than 120 degrees).
5.14.3. The maximum efficiency of a wire rope or polyester round sling choker hitch around
a large round tube is 80%.
5.14.4. The minimum load capacity of a choker hitch around a large round tube is 34%.
5.14.5. Pads should be used between slings and all sharp edges or corners. This is to
increase the D/d ratio. Padding also protects the sling from sharp corners. Also note,
OSHA CFR 1910.184 I (7) requires sling padding.
5.14.6. Hitches must be rigged so they cannot slide along beams
5.14.7. When possible, hitches should be rigged so that the pull is in line with the center of
the beam to prevent torsion on the beam.
5.15. Facilities
5.15.1. Loads imposed on building structures or temporary ground supported structures.
5.15.1.1. Rigger should attempt to find out the load capacity of the structure or component
of the structure being rigged to.
5.15.1.2. Rigger should know to consult a structural engineer in order to determine the
capacity of a structure.
5.16. Testing
5.16.1. A proof test ensures that an item will support its design load.
5.16.2. When proof tests are done, items are usually proof tested to 2 to 2.5 times their
rated working load.
6. Risk
6.1. General Risk
6.1.1. Know the risks inherent in overhead lifting. Know the possible consequence of
accidents.
6.1.2. When an accident occurs know that all parties involved may be found to have some
level of liability. This includes but may not be limited to the rigger, employer, show
management, show owner, producer, promoter, equipment owner, equipment
manufacturer, venue manager and venue owner.
6.1.3. Know that most accidents are the result of a combination of minor errors and/or
omissions, any one of which would not cause the accident by itself.
6.1.4. Know that the best way to avoid accidents is to remove all errors and/or omissions,
no matter how minor.
6.1.5. If the inherent risk in a rigging operation requires increasing the design factor, then
the design factors of all components should be increased proportionally.
6.2. Misc.
6.2.1. Understand the effect on bridle junction position when adding the basket hitch
length to the bridle legs, both for junctions half-way between the beams and near one
side of the beam span.
6.2.2. Know how to read a dynamometer.
d. Lower loads
“It is impossible for the average student to get an A in this class!”
~ Disgruntled Student ~
"Tenacious attempts at greatness are more important
than the actual achievement thereof"
~ GGTT ~
"A man who works with his hands is a laborer; a man who works with
his hands and his brain is a craftsman; but a man who works with his
hands, his brain and his heart is an artist."
~Louis Nizer~