Chapter 5 Rigging

1
Chapter 5Rigging

• Rigging Calculating Load Weights Slings
  Rope Webbing Round (Tubular) Slings Chain
  Rigging Component Inspection Rigging Equipment
  Storage Rigging Component Recordkeeping

2

• The shape of a load normally determines its
  center of gravity.

3

• A load lifted outside its center of gravity will
  shift to create excess side stress on one sling.

4

• A load may be unstable and subject to topping if
  lifting equipment is placed below the horizontal
  weight center of the load.

5

• Stock material weight tables list the weight of
  materials by ft, sq ft, or cu ft.

6

• Numbers may be rounded off to allow rapid
  material weight calculations.

7

• Main sling components include wire rope, fiber
  rope, chain, webbing, and round sling.

8

• Other sling components include rigging hardware
  attachments such as clips, hooks, eyebolts,
  shackles, sockets, wedge sockets, triangle choker
  fittings, and master links.

9

• Basic slings include vertical (single-leg),
  choker, U, basket, and bridle.

10

• Tension increases and load capacity decreases as
  sling legs widen and sling angles are reduced.

11

• Fiber rope is constructed by twisting fibers into
  yarn, yarn into strands, and strands into rope.
  Wire rope is constructed by twisting wires into
  strands around a wire core.

12

• The diameter of wire rope is determined by the
  largest possible outside dimension.

13

• Moisture, temperature, chemical activity, and
  bending reduce rope strength.

14

• Rope bending efficiency rating increases as the
  diameter of the pulley increases.

15

• The most common wire ropes used for basic rigging
  are filler wire, Warrington, Seale, and
  Warrington-Seale.

16

• The strength of rope used for safely lifting a
  load is determined by its breaking strength.

17

• Rated strength capacities of 6 ?19 wire rope are
  based on the rope diameter and sling.

18

• Seizing is the wrapping placed around all strands
  of a rope near the area where the rope is cut.

19

• Common wire rope terminations include thimbles
  and sockets.

20

• Clip connections must be arranged, spaced, and
  assembled properly to maintain the strength of
  the rope.

21

• Proper installation of a wedge socket has the
  live end of a rope in line with the socket.

22

• Synthetic fibers are generally stronger than
  natural fibers.

23

• Fiber rope is constructed by twisting fibers into
  yarn, yarn into strands, and strands into rope.

24

• Most rope hitching and knotting terminology was
  derived from nautical (sailing) terms.

25

• Whipping is tightly binding the end of a rope
  with twine before it is cut.

26

• A splice is the joining of two rope ends to form
  a permanent connection.

27

• Crowning is a reverse strand splice that is used
  when an enlarged rope end is desired or not
  objectionable.

28

• An eye loop is a rope splice containing a
  thimble.

29

• Half hitch and double hitch knots are not secure
  knots, but are the base formation of other knots.

30

• A slip knot is a knot that slips along the rope
  from which it is made.

31

• A bowline knot is a knot that forms a loop that
  is secure but is easy to release.

32

• A wagoneers hitch knot is a knot that creates a
  load-securing loop from the standing part of the
  rope.

33

• A timber hitch is a binding knot and hitch
  combination used to wrap and drag lengthy
  material.

34

• A clove hitch is a quickly-formed hitch used to
  secure a rope temporarily to an object.

35

• A cats-paw hitch is a quickly-formed eye for
  light-duty lifting.

36

• A cow hitch is a hitch used to secure a tag line
  to a load.

37

• A scaffold hitch is used to support planks or
  beams.

38

• A blackwall hitch is a hitch made for securing a
  rigging rope to a hosting hook.

39

• Webbing is a fabric of high-tenacity synthetic
  yarns woven into flat narrow straps.

40

• Basic sling types are classified as Type I
  through Type IV.

41

• Sling load capacities vary based on the sling
  angles.

42

• Choker hitch load capacity is based on the angle
  of choke as the sling body passes through the
  choke eye.

43

• The type of web sling selected and its use must
  be made with safety as the main consideration.

44

• Round slings are slings consisting of one or more
  continuous polyester fiber yarns wound together
  to make a core.

45

• Chain should be removed from service if the
  measurement of used chain exceeds 1 1/2
  elongation from that of new chain.

46

• Each chain, except for hoist apparatus chain, has
  a periodic embossing of a grade number or letter,
  indicating its capability.

47

• Working load limits for slings using Grade 80
  chain can be determined for a 90? vertical load
  or quad leg load up to 30? pull angle.

48

• A shackle is a U-shaped metal link with the ends
  drilled to receive a pin or bolt.

49

• A master link is a chain attachment with a ring
  considerably larger than that of the chain to
  allow for the intersection of a hook.

50

• A hook is a curved or bent implement for holding,
  pulling, or connecting another implement.

51

• Hoisting hooks used for rigging purposes include
  choker, grab, foundry, swivel, and sorting hooks.

52

• A hoisting hook is a steel alloy hook used for
  overhead lifting and is connected directly to the
  piece being lifted.

53

• Kinking, core protrusion, and bird caging may be
  encountered when inspecting a wire rope.

54

• Fiber rope inspection is made to remove a rope
  from service before the ropes condition poses a
  hazard with continued operation.

55

• Webbing should be inspected at least annually and
  round slings should be inspected monthly.

56

• Chain should be inspected annually.