Rigging

By

Taha Farooq

RIGGING PROCEDURESRIGGING PROCEDURES

What rigging is ? Rigging equipment Rigging Techniques Load Chart , Rigging Cards and Calculations Cranes Work Permits Safety Precautions


Rigger: Duties & Responsibilities

Determining weight of load

Selection of proper ropes, slings

Procedures for blocking, binding, jacking and leveling of loads

Knowledge of tying down load for transportation

Repair and maintenance and proper storage of equipment


Rigging Terms :Total Rated Load:

The maximum permissible load to be lifted is defined as the total rated load.

It is dependant on the following factors

boom length

working radius

The larger the working radius the smaller the total rated load.


Rigging Terms :

Working Radius :

The horizontal distance from the center of the crane to the center of hook of that crane.

The maximum value is the maximum radii at which the crane is operable to lift a certain load.

Lifting Height:

The vertical distance between the ground and the hook


Boom Length :

Axial distance between the fulcrum pin of the boom bottom and the lower sheave pin at the bottom head

Elevation Angle / Boom Angle:

Angle between the boom centerline and the horizontal line.


Jib:

An extended arm of the crane , that is attached to the boom to increase the boom length.

Lufing Jib:

The jib that is operable to a certain degree of rotation is known as the lufing jib

e.g. In TADANO 120 T crane the jib is operable to 45

Fly Jib:

The jib operable only to a restricted direction is called the fly jib.


Rigging Equipment

Slings :

Chains

Wire Ropes

Non Metallic Ropes

Connectors :

Hooks

Shackles

Eye Bolts

Links / Rings


Chains :

They are made of various grades of steel and on which their lifting capacities depend.

For most common uses Alloy Steel grade 60 or mild steel with 0.5% carbon are used.

Alloy steel grade 80 chains are high tensile chains

Before making a lift, the chain should be checked for kinks, knots or twists. Chain slings must be load tested manually.

Chain Hoists:Chain Blocks

Come Along

Slings


Come-Alongs:

It is a slang word for one half to about six ton chain hoists having a lever action pulling arrangement. They have short, about 5 to 10 feet hoist travel only.

There are a numerous uses for Come-Alongs : To level the face of load

To guide heavy loads in into position while lifted by a bigger crane.

To provide 3rd and 4th leg to a two leg sling.

Come-Alongs can be used in any direction compared to chain blocks which can be best used vertically

Slings


Chain Blocks / Chain Hoists:

Designed with a spur gear transmission system comprising :

A hand chain . Hand wheel with friction clutch and a ratchet stop,chain sprocket, a load chain and a swivel hook at the top.

FORCE REQUIRED ON HAND CHAIN FOR PULLING MAX LOAD

Capacity in tons 1/2 1 2 3 5 10 20Pull on Hand Chains in Pounds 43 46 72 76 82.5 88 95

Slings


Wire Ropes:

A wire rope is composed of wire strands formed helically around a central axis. Six to Eight strand ropes are the most popular and the axial member is known as the core.

Strand :Strands are made of various combination of individual wires formed helically around the center.

There are four types of cores:

*Fiber or Sisal Core

*IWRC or steel core

*Strand Core

*Special Core

Slings


Selection of Wire Ropes :

The factors for selection of a wire rope are :

Flexibility

Load bearing capacity / Strength

Corrosion

Accessibility for Inspection

Calculation of Safe Working Load ( SWL )

SWL = Rope Dia x Rope Dia x 8

Example

1. 1/2 inch dia rope SWL = 1\2 x 1\2 x 8 = 2 T

2. 5/8 inch dia rope SWL = 5/8 x 5/8 x 8 = 3.125 T

Slings


Non-Metallic Ropes :

1- Natural Fibre Rope :

Manila Fibre Strength, Durability, Withstand Severe usage & Weather Resistant

Sisal Fibre Less demanding requirements, Low Cost

2- Synthetic Fibre Rope ;

Nylon Approx twice the strength of Manila, Good resistance to weathering & Abrasion Resist.

Terylene

Dacron

Polypropylene

Slings


Important Points :

Do not drag over the ground and over the sharp edges

In a straight pull a rope will give 100 % , tie a knot and rope is weaken to 50 %

Prevent rope from coming in contact with acid

Care to be taken in cleaning and drying of the rope

Safe Working Load (SWL)

Manila Rope:

Change Rope Dia in to 8th of an inch

Square the numerator and multiply by 20

Example :

1/2 inch dia = 4/8 inch SWL = 4 x 4 x 20 = 320 lbs

Slings


Slings

Knots :Stopper Knot : Keep rope end from slipping through hole

Figure of 8 : makes a bulge in the rope

Binding Knot : Ties object Snugly

Loop Knot : holds an object with security

Reef Knot : Easy to open and a tight grip.


ConnectorsHooks :These are formed by drop forging and heat treating carbon steel.

Hooks are categorized on suspension system used ;

Eye Type Chain slings

Clevis Type Ease to install / Remove

Swivel Type Free load rotation , no wire twist

Clevis-Swivel Come-Alongs

Snatch Block Crane, Multi Pass chain blocks


ConnectorsPrecautions :All hooks should have safety latches

More links or sling eyes tend to pull the hook or develop a crack in the middle.

There should be no side pulling or improper loading of the hook during rigging.

The throat should not be open more than 0.5 %.


Connectors

Shackles:There are two types of shackles

a) Chain ( D Type ) Shackle - For chains only

b) Anchor ( Bow Type ) Shackle - For all rope/wire e.t.c.

Shackles are sized by the dia of the steel in bow section rather than the pin size.

A bolt must not be used as replacement for a pin.

The pin of a shackle should go in the eye of a hook and the sling ends on the bow side.


ConnectorsLinks and Rings :The links are used on top of slings and at the lower end of the chain slings and wire ropes

Missing Link .

These are made in two parts and is snapped shut together to make an oval ring.

It is used to join two pieces of chain or attaching a chain or an eye of sling to a lifting link.

Average Safe Load For Forged Steel LinksDia in inch 5/16" 3/8" 1/2" 5/8" 3/4" 7/ 8" 1

Safe Loads ( lbs ) 2500 3800 6500 9300 14000 12000 15200


ConnectorsEye Bolts :They are extensively used for rigging work where drilled or threaded holes exist in machinery and equipment.

Common Causes of Failure:

It should be one piece drop forged and not a ring welded on a stud.

Consult chart for lifting capacities of an eye bolt

Check dia , TPI and thread matches of the eye bolt with the tapped hole.


Load Chart , Rigging Cards and Calculations

A data sheet through which rigging requirements are calculated is called as a Load Chart

A Rigging Card is filled, so that a proper check is ensured for lifting of weights.

They help us to assess whether any particular job is safely planned or not.

It is a guideline to a crane operator to work with.


Cranes:

The cranes being used at ENGRO are as Follows:

TADANO 120 T

BUCYRUS 40 T

TADANO 16 T

TADANO 10 T

HYDRA LIFT


Work Permits Required :As per procedures any job that is executed is followed by a work permit system.The permits governing any rigging activity are as follows

Cold Work Permit

Lifting Over Process Equipment

Vehicle Entry Permit


Safety Precautions :

During hoisting operation all personnel must stay clear of loads and no one should be beneath the boom.

Hoist and Rigging equipment, chain , cables and shackles must be checked to be in good condition before every individual job.

Slings , Ropes , Cables, and chain must be protected from sharpedges.

Chain blocks must be installed using wire ropes or shackles andnot fibrous ropes.

All rigging equipment e.g. chain blocks, crane hooks ; should have safety latches.

Use of tag line to be implemented.

No one should work under suspended load.


Hand Signals:

The standard hand signals are employed.

In case, when the crane operator cannot see the load being moved , the following is to be practised.

More than one signal man

2-way radios

Sound powered Megaphone

Safety Precautions :

Date post:	13-Sep-2015
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Rigging

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