safe rigging practices.ppt

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Safe Rigging

Practices

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OVERVIEW

•• Rigging Selection

Rigging Selection

•• Fundamentals of rigging

Fundamentals of rigging

–

– Basic Rules

Basic Rules

–

– Rigging

Rigging

Devices/Attachments

–

– Sling angle

Sling angle

–

– Rope

Rope

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OVERVIEW

•• Rigging Selection

Rigging Selection

•• Fundamentals of rigging

Fundamentals of rigging

–

– Basic Rules

Basic Rules

–

– Rigging

Rigging

Devices/Attachments

–

– Sling angle

Sling angle

–

– Rope

Rope

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Rigging

The process of lifting

and moving heavy loads

with ropes, chains, and

mechanical devices.

“The art of lifting heavy objects”

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SAFE

LIFTING

THE SAFETY TRIANGLE

EFFECTIVE,

EQUIPMENT

MAINTENANCE

TRAINED,

QUALIFIED

OPERATORS

PROPER

EQUIPMENT

DESIGN

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Rigging Selection

• The rigging capacity and the material to

be lifted must match. Using too small

capacity rigging or components is just

asking for an accident to happen.

1. Who is responsible

(competent/qualified) for the rigging?

a.

Communications Established?

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Rigging Selection

• 2. Is the Equipment in Acceptable

Condition?

a.

Appropriate Type?

b.

Proper Identification?

C. Properly Inspected?

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Rigging Selection

1. Are the Working Load Limits

Adequate?

a. What is the weight of the load?

b. Where is the center of gravity?

c. What is the sling angle?

d. Will there be side loading?

e. Capacity of the gear?

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Rigging Selection

4. Will the Load be Under Control?

a.

Tag Line available?

b.

Is there any possibility of fouling?

c.

Clear of Personnel?

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Rigging Selection

1. Are there any Unusual Loading or

Environmental Conditions?

a. Wind?

b. Temperature?

c. Surfaces?(Ice, Suction, Water)

d. Unstable Object(s)?

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Rigging Basics

• Weight of the object

• Capacity of rigging device

• Center of gravity

The center of gravity is the

point at which a load will

balance - and that point must

be directly below the hook or

principal lifting point.

Center of gravity ¼ L Fa Fb Total Weight = W Fh Fh

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Rigging Devices/Attachments

• Shackles

• Hooks

• Wire Rope Clips

• Wedge Sockets

• Eyebolts

• Spreader Beams

• Turnbuckle

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SHACKLES

• Anchor Shackles

Has a rounded eye which makes it suitable for attaching one or more lifting devices, such as hooks or slings.

• Chain Shackles

Has a straight eye

designed for connecting to a single lifting device

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• Shackles

– synthetic web slings

connected to shackles

of sufficient size to not

cause bunching or

pinching of the sling

Use wide shackles to prevent pinching or bunching

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Avoid eccentric loads

Do not pull shackle at an angle - the legs may open up or cause distortion at maximum loads.

Pack the pin with washers to centralize the shackle.

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Proper chocking of shackles.

Bad Good

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1. Never replace the shackle pin with a

Bolt

2. Shackles shall not be used if the pin

cannot be completely seated. The pin

need be only hand tight for lifting. Use

only shackles with screw pin.

Round pin with cotter should not be used

3. Screw pin shackles shall not be used if

the pin can roll under load and unscrew

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FREQUENT (PRE-USE) INSPECTION

1) Check pin to see if it seats

completely.

2) Check to see that pin threads easily

by and into and out of the shackle.

3) The pin shall show no signs of

deformation.

4) Check for excessive thread exposure

when pin is seated completely.

5) Check for opening of shackle throat.

6) Check for excessive wear, cracks,

and corrosion.

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Hooks

1.The safe working load (SWL) for a rigging hook shall be equal to or exceed the rated load of the chain wire rope, or other suspension member to which it is attached . The designed SWL applies only when the load is applied in

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1. It is a good practice to use a shackle when two or more sling eyes are used on a hook . This allows the load to be centralized on the hook for full capacity. Never tip load a hook 1. The load hook should be the weakest

member of the lifting equipment, so it will bend if overloaded before any other piece of equipment fails.

1. Hook tips should point out and away from the load, to assure when slack is taken up, the hook will not tip load

Hands, fingers, and body shall be kept away from between the hook and load.

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FREQUENT (PRE-USE) INSPECTION

1. Look for distortions such as bending, or twisting exceeding 10 degrees from the plane of the unbent hook.

2. Check for an increase in throat opening exceeding 15% of original throat opening. 3. Check for wear in the saddle area of the hook. Wear exceeding 10% of the original dimension is sufficient enough to take the hook out of service.

4. Check for cracks, severe nicks, and gouges. Transverse cracks are more critical to a hook's performance than longitudinal cracks.

5. Check the hook attachment and securing means for defects.

6. Rigging hooks shall be inspected as a part of the slings to which they are attached.

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Wire Rope Clips

•The most common use of wire rope clips on cranes is at wedge and socket-end fittings.

•The clip does not provide strength to the wedge and socket connection.

•It is there to prevent the wedge from accidentally being released.

Clips should not be reused as they may not torque properly on the second application. CLIPS FREQUENT (PRE-US E) INSPECTlON

1. Before use, clips shall be visually inspected for damage, corrosion, wear, and cracks.

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Installing Wire Rope Clips

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Operation Practices

1. Assure clips are orientated correctly 2. When using single grip clips, be sure to put the saddle on the live end of the

rope.

3.Be sure to torque clips to proper specification.

4. Check torque after use and re torque after use if necessary.

5. Follow the proper procedure when installing clips

A. Apply first clip one base width from dad end of wire rope. Tighten nuts evenly to recommended torque.

B. Apply second clip nearest the loop. Turn evenly but do not tighten.

C. Apply all other clips spaced equally in between the first two. Apply tension

and tighten all nuts to recommended torque.

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EYE BOLTS

• Eye bolts

– use only forged eye bolts rated for lifting

– never use if damaged, bent, elongated

– never use regular eye bolts for angular lifts

– always seat shoulder against the load

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•• Eye bolts

Eye bolts

–

– always shim eye bolts to seat shoulder in-line for

always shim eye bolts to seat shoulder in-line for

angular loading

–

– for angular lifts reduce working load

for angular lifts reduce working load

•• 45 degrees45 degrees – – 30% of rated working load30% of rated working load •• 90 degrees90 degrees – – 25% of rated working load25% of rated working load

Angle of pull Angle of pull

EYE BOLTS

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•• Eye bolt - rigging

Eye bolt - rigging

EYE BOLTS

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•• Spreader

Spreader beam - A

beam - A below-

below-the-hook lifting device that

the-hook lifting device that

utilizes two or more hooks

(attaching devices) located

along a beam and the

spreader beam attaches to

the hoist by means of a

bail.

bail. The

The spreader

spreader beam

beam is

is

used to handle long or wide

load and serves to "spread"

the load over more than one

lifting point. Often used in

conjunction with slings.

Note: a common misconception of spreader beams is that they equalize the loading Note: a common misconception of spreader beams is that they equalize the loading along the

along the beam. beam. They do They do not! not! Spreaders only Spreaders only eliminate eliminate horizontal forces horizontal forces from affectingfrom affecting the load being hoisted.

the load being hoisted.

SPREADER BEAM

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Rigging Attachments

•• Spreader beam

Spreader beam

Spreader Beam Spreader Beam Center of gravity Center of gravity ¼ L ¼ L 1/2 L 1/2 L Fa Fa Fb Fb With the CG off center of

With the CG off center of the hook as shown, the vertical the hook as shown, the vertical force at Fa will be 75% of the force at Fa will be 75% of the load weight and the vertical force load weight and the vertical force at Fb will be 25% of the total at Fb will be 25% of the total load weight.

load weight.

No horizontal forces will be No horizontal forces will be exerted on the load. exerted on the load.

Total Weight = W Total Weight = W 1/2 L 1/2 L Load Load

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• Spreader beam

Spreader Beam Center of gravity ¼ L 1/2 L Fa Fb With the CG off center of

the hook as shown, the vertical force at Fa will be 75% of the load weight and the vertical force at Fb will be 25% of the total load weight.

No horizontal forces will be exerted on the load.

Total Weight = W

1/2 L

Load As shown, will the

load be level during hoisting?

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• Spreader beam

The load will tilt until the center of gravity aligns with the hook.

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• Spreader beam

Center of gravity ¼ L ¼ L Fa Fb Without the use of a spreader

beam, the vertical forces remain the same, however, the sling load is a function of the sling angle and the sling load will be higher than the sling between the spreader and the load.

There will, in this case, be horizontal forces exerted upon the load, dependent upon the sling angle.

Total Weight = W

Fh Fh

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• Turnbuckles

– Turnbuckles can be used to adjust sling

length.

– Be sure to use only load rated components

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Types of Slings

1) Wire Rope Slings

1) Chain Slings

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Wire Rope

Components of Wire Rope

1.Core

2.Wire

3.Strand

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There are

three types of cores

:

Fiber

- synthetic or sisal, which is the

weakest,

Strand

- the core is a wire strand, just

like the other strands of the rope.

Independent Wire Rope (IWRC)

-this is

a separate wire rope. It is the strongest

of the three types. The core provides

7-1/2% strength of the wire rope. This

is the core used in the wire rope slings

provided on site.

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Left Lay

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Crushing

Because of loose winding on drum,

rope was pulled in between

underlying wraps and crushed out of

shape.

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Birdcaging

The sudden release of a load cause

birdcaging .Here individual strands

open away from each other,

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Locking of strands

Premature breakage of wires resulted

from "locking" of strands, which was

caused by insufficient lubrication.

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Abrasion

Neglect of periodical inspection left this

rope in service too long, resulting in

(43)

Kinking

Kink or "dog leg“ was caused by improper

handling and/or installation. A kink causes

excessive localized or spot abrasion.

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Reverse bending

Running this rope over one sheave and

under another caused fatigue breaks in

wires.

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Pitting

Too much exposure combined with

surface wear and loss of lubrication

caused corrosion and pitting.

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Wear

Too long in service. Repeated winding and

overwinding of this rope on a drum while it

was under heavy stress caused the

(47)

Wire Rope

Wire Rope Sling Identification

Rated Load (rated capacity) •Load test date

•Manufacturer’s name

•Periodic inspection due date

•Broken wires (10 in one lay or 5 in one strand) •Severe corrosion

•Localized wear

•Reduction in outer wire •Damaged end fittings •Distortion, kinking, etc…

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Before Lifting any load check

for hazards

• The sling must not be

attached to the load at a

point lower than the

loads center of gravity

– Exception to this rule

when lifting loads on

pallets or skids

– Then apex of sling

must be above the

center of gravity

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Horizontal Force

• When a sling

angle is 30

0

_the

total force is

twice that of the

load

• Sling Angles of

45

0

_{are not}

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Wire Rope Slings

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Wire Rope Slings

sling with single-rope legs, Torpedo loop-locks and choker hook

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Rigging Basics - Hitches

Vertical – having the load suspended vertically on

a single part or leg of the sling.

Characteristics:

• Load capacity is 100 % that of a single part

• Taglines should be used if the load tends to rotate as rotation can damage the sling.

• Use on items with lifting eye bolts or shackles or when a second sling is used in a spreader bar application

• Do NOT use when lifting loose or lengthy material, anything difficult to balance

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Rigging Basics - Hitches

Basket - loading with the sling passed under the load and

both ends on the hook, master link, or lifting device.

Characteristics:

• Effectively doubles the capacity of a single vertical sling

• Stress on each leg tends to be equalized • Use on straight lifts when the load is

shaped so that the sling (or slings) will not slide over the surface.

• Do NOT use on loads that are difficult to balance and could tilt or slip out of the sling(s).

• When terminating to a common point (like a hook), sling angle can reduce sling

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Rigging Basics - Hitches

Choker – loading with the sling passed through one

eye or choker hook and suspended by the other end.

Characteristics:

• Choker hitch is easy to attach & forms a noose that tightens as the load is lifted

• Rated capacity is 75% of the single part*. • Use to turn a load (if possible use a double

choker hitch) or when handling bundles of bars or pipes

• Do NOT use on loads difficult to balance or which may slip out the choke

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Rigging Basics - Hitches

Choke angle – the angle formed between the

load line and the noose

Angel of Choke

Rated Capacity Factor* 120 - 180° = 100%

90 - 119° = 87%

60 - 89° = 74%

30 - 59° = 62%

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Rigging Basics - Hitches

• Do not confuse choke

angle with angle of

inclination of the load

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Rigging Basics - Hitches

• Choker hitches are not suited to long loose

bundles

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Rigging Basics - Hitches

• Double Wrap Basket Hitch

– adjustment of slings is required while taking

up slack to avoid overloading one side of the

sling (this applies to all basket hitches)

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Rigging Basics – Sling Angle

Sling angle has a dramatic effect on the actual

load on the sling. Take a sling that has a 1000

pound vertical lifting capacity in a basket hitch:

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Copyright Pro Crane Services 59

Rigging Basics – Sling Angle

As angle decreases - tension on each leg

increases - increasing the strain on each leg

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Rigging Basics – Sling Angle

A different look, with the same load and sling,

changing the angle has a similar dramatic

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Rigging Basics – Sling Angle

A different look, with the same load and sling,

changing the angle has a similar dramatic

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Rigging Basics – Sling Angle

• The sling angle factor

equals H divided by L,

the inverse, L/H, can

also be used to

calculate sling load

L/H is useful to calculate sling load when the vertical force is known. L/H for common angles is approximately: 60º - 1.2; 45º - 1.4; 30º - 2

(64)

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General Use Guidelines

• Pre-use and periodic

inspection is required

on all sling and

rigging components

(66)

65 Periodic inspection frequency/records Periodic inspection performed by ? Frequent inspection frequency/records Label* Chain slings OSHA 1910.184(e)(3)_–at least annually with records ASME: normal_–annually; severe service_–monthly to quarterly with records

OSHA_–competent person

ASME - competent person

OSHA_–before use (1910.184(d) w/o records ASME: normal_–monthly; severe service_–daily to weekly w/o records

OSHA_–size, grade, rated cap., & reach

ASME: mfgr., grade, size, no. of legs, reach, rated load for hitches

Wire rope slings

OSHA_–none

ASME_–based on service, at least annually with records

OSHA_–no periodic ASME_–competent person

OSHA_–before use (1910.184(d)

ASME_–daily w/o records

OSHA_–none

ASME_–mfgr., size, rated load for type of hitch & angle

Synthetic web slings

OSHA_–none

ASME_–recommended at least annually based on service, records recommended

OSHA_–no periodic ASME - competent person

ASME - daily w/o records

OSHA_–rating @ each type of hitch, type of material ASME_–mfgr., mfgr. Stock no., rated load for each type of hitch, material type & construction

Metal mesh slings

OSHA_–none

ASME - based on service, at least annually; records recommended

OSHA_–no periodic ASME - competent person

ASME_–daily w/o records

OSHA_–rated @ vertical and choker hitch loading ASME_–mfgr., rated load for hitch & angle, width and gauge

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General Use Guidelines

• Rigging equipment

shall not be loaded

beyond its

working load limit

(WLL)

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General Use Guidelines

• When not in use,

rigging shall be

removed from work

area and properly

stored

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General Use Guidelines

• During lifting, personnel shall

be alert for possible snagging

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General Use Guidelines

• Slings should be long

enough so that rated

load is adequate

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General Use Guidelines

• Multiple leg slings

shall be selected so

as not to introduce

into the leg, a load

greater than permitted

ASME B30.9

Note: select multiple leg slings based on two legs supporting the entire weight of the load and the other leg(s) balancing the load.

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General Use Guidelines

• Shock loading should

be avoided

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General Use Guidelines

• The load shall be

applied to the center

of the hook (unless

the hook is designed

for point loading)

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General Use Guidelines

• When used in a

choker hitch, prevent

the load on any

portion of the sling

from exceeding the

rated load

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General Use Guidelines

• Slings shall not be

shortened by knotting

or twisting

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General Use Guidelines

• Slings should not be

pulled from under a

load when the load is

resting on the sling

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General Use Guidelines

• Slings should not be

dragged on the floor

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General Use Guidelines

• Sharp corners in contact

with the sling should be

padded

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General Use Guidelines

The following slide is not for the faint of heart. If you are are bothered by accident scenes, do not look at the screen until the “All Clear”

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General Use Guidelines

• Do not place body,

fingers, etc. between

the sling and load or

hook

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General Use Guidelines

• Personnel shall not

ride the sling (or load)

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General Use Guidelines

• Personnel should stand clear of

suspended load.

(83)

General Use Guidelines

• And not “Be” the

suspended load!!

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No Homemade Slings

WARNING

No wire rope sling shall be fabricated using wire rope clips!!

Preferred sling construction is to use a Flemish eye splice with a mechanical sleeve (turn back construction is not recommendable)