safe rigging practices.ppt

Safe Rigging Practices

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OVERVIEW • Rigging Selection • Fundamentals of rigging  – Basic Rules  – Rigging Devices/Attachments  – Sling angle  – Rope

• General use guidelines

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OVERVIEW • Rigging Selection • Fundamentals of rigging  – Basic Rules  – Rigging Devices/Attachments  – Sling angle  – Rope

• General use guidelines

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Rigging “The art of lifting heavy objects” The process of lifting and moving heavy loads with ropes, chains, and mechanical devices.

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TRAINED, QUALIFIED OPERATORS

SAFE LIFTING EFFECTIVE, EQUIPMENT MAINTENANCE

PROPER  EQUIPMENT DESIGN

THE SAFETY TRIANGLE

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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? 7

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)? 9

Rigging Basics • Weight of the object • Capacity of rigging device • Center of gravity

¼L

Fa

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.

Fh

Fb Fh

Center of gravity Total Weight = W

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Rigging Devices/Attachments • Shackles • Hooks • Wire Rope Clips • Wedge Sockets • Eyebolts • Spreader Beams • Turnbuckle • Slings

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

Shackle size is determined by the diameter of the bow or body.

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SHACKLES • 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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SHACKLES 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.

 Avoid eccentric loads

SHACKLES

Proper chocking of  shackles.

Bad

Good

SHACKLES 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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SHACKLES 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.

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 the saddle of the hook.

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Hooks 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.

Hooks 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 FREQUENT (PRE-US E) INSPECTlON 1. Before use, clips shall be visually inspected for damage, corrosion, wear, and cracks.

Clips should not be reused as they may not torque properly on the second application.

Installing Wire Rope Clips

Installed properly as to number, direction, spacing and torque.

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. D. Recheck torque after use.

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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  angular loading  – for angular lifts reduce working load • 45 degrees – degrees  – 30% of rated working load • 90 degrees – degrees  – 25% of rated working load

Angle of pull

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EYE BOLTS • Eye bolt - rigging

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SPREADER BEAM • Spreader beam - A belowthe-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. The spreader beam 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 along the beam. They do not! Spreaders only eliminate horizontal forces from affecting the load being hoisted. 27

Rigging Attachments • Spreader beam 1/2 L

1/2 L

Spreader Beam

¼L Fa 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.

Fb

Load

Center of gravity Total Weight = W

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SPREADER BEAM • Spreader beam 1/2 L

1/2 L

Spreader Beam

¼L Fa 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.

As shown, will the load be level during hoisting?

Fb

Load

Center of gravity Total Weight = W

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SPREADER BEAM • Spreader beam

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

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SPREADER BEAM • Spreader beam

¼L Fa Fh 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.

¼L

Fb Fh

Center of gravity Total Weight = W

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TURNBUCKLES • 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 1) Synthetic Web Slings

Wire Rope Components of Wire Rope 1.Core 2.Wire 3.Strand

Wire Rope 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

Right Lay

Crushing Because of loose winding on drum, rope was pulled in between underlying wraps and crushed out of  shape.

Birdcaging The sudden release of a load cause birdcaging .Here individual strands open away from each other, displacing the core.

Locking of strands Premature breakage of wires resulted from "locking" of strands, which was caused by insufficient lubrication.

 Abrasion Neglect of periodical inspection left this rope in service too long, resulting in considerable abrasion.

Kinking Kink or "dog leg“ was caused by improper  handling and/or installation. A kink causes excessive localized or spot abrasion.

Reverse bending Running this rope over one sheave and under another caused fatigue breaks in wires.

Pitting Too much exposure combined with surface wear and loss of lubrication caused corrosion and pitting.

Wear  Too long in service. Repeated winding and overwinding of this rope on a drum while it was under heavy stress caused the unusually severe wear.

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…

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

Horizontal Force • When a sling angle is 30 0 the total force is twice that of the load • Sling Angles of  450 are not recommended

Wire Rope Slings

single-rope legs

Wire Rope Slings

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

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 capacity.

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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 53

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% 0 - 29 = 49% °

°

°

°

°

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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:

Sling with 500# vertical hitch capacity

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Rigging Basics – Sling Angle  As angle decreases - tension on each leg increases - increasing the strain on each leg

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Sling with 500# vertical hitch capacity

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Rigging Basics – Sling Angle  A different look, with the same load and sling, changing the angle has a similar dramatic effect

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Rigging Basics – Sling Angle  A different look, with the same load and sling, changing the angle has a similar dramatic effect

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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

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Rigging Basics

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General Use Guidelines • Pre-use and periodic inspection is required on all sling and rigging components

OSHA 1926.251, 1910.184

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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

OSHA  –  before use (1910.184(d) 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

OSHA  –  before use (1910.184(d) ASME  –  daily w/o records

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

* Sling I.D., per ASME B30.9, shall be maintained to be legible for the

life of the sling

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General Use Guidelines • Rigging equipment shall not be loaded beyond its recommended working load limit (WLL)

OSHA 1926.251

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General Use Guidelines • When not in use, rigging shall be removed from work area and properly stored

OSHA 1926.251

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General Use Guidelines • During lifting, personnel shall be alert for possible snagging

 ASME B30.9

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General Use Guidelines • Slings should be long enough so that rated load is adequate

 ASME B30.9

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

 ASME B30.9

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General Use Guidelines

• Shock loading should be avoided

 ASME B30.9

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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)

 ASME B30.9

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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

 ASME B30.9

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General Use Guidelines • Slings shall not be shortened by knotting or twisting

 ASME B30.9

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General Use Guidelines • Slings should not be pulled from under a load when the load is resting on the sling

 ASME B30.9

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General Use Guidelines • Slings should not be dragged on the floor 

 ASME B30.9

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General Use Guidelines • Sharp corners in contact with the sling should be padded

 ASME B30.9

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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” signal is given.

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General Use Guidelines • Do not place body, fingers, etc. between the sling and load or  hook

 ASME B30.9

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General Use Guidelines • Personnel shall not ride the sling (or load)

 ASME B30.9

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General Use Guidelines • Personnel should stand clear of  suspended load.

 ASME B30.9

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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) 83

Barricades •

During rigging and lifting activities, areas in a construction zone must be barricaded or blocked off from the public as well as construction workers to maximize safety precautions.

•

The route the rigger takes to move an object through the air  must be clear to eliminate the danger of the object dropping onto someone below.

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