SAFETY IN CRANE

OPERATIONS

CRANES

MOBILE CRANE

TOWER CRANE

GANTRY CRANE

OVERHEAD TRAVERSE

CRANE

CRANE WITH HEAVY LIFT

ATTACHMENT

CRAWLER MAUNTED

WHEEL MOUNTED

FORK LIFTS

SEMI GANTRY CRANE

CANTILEVER GANTRY CRANE

TYPES OF CRANETYPES OF CRANE

CRAWLER MOUNTED LATTICE BOOM CRANES - NOMENCLATURE

CALCULATING THE SIDE CLEARENCE AND HEAD ROOM

CALCULATING THE SIDE CLEARENCE AND HEAD ROOM

r

R

A

D C

O B

DCOB

ACAB

DC OB X ACAB

SAFE USAGE OF CRANESAFE USAGE OF CRANE

VARIOUS LOAD TO BE CONSIDERED:

1. VERTICAL FORCES DUE TO LOAD / WEIGHT OF CRANE

2. HORIZONTAL INERTIA

3. SLEWING FORCES

4. WIND FORCES

5. SIESMIC FORCES

STABILITY OF THE STABILITY OF THE CRANE CRANE CRANE ACT AS A LEVER

C.W.

wFULCRUM

THE FULCRUM IS NOT A POINT CONTACT. AREA OF CRAWLERS ACTS LIKE THIS

CRANE ACT AS A LEVER

STABILITY OF THE STABILITY OF THE CRANE CRANE

FOUR PARAMETERS ARE IMPORTANT1. OPERATING RADIUS

2. HEIGHT

3. BOOM LENGTH

4. WEIGHT OF THE LIFT

FOUR PARAMETERS ARE IMPORTANT

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TIPPING DUE TO IMPROPER GROUND CONDITION

TIPPING DUE TO OVERLOADING

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SAFETY CONSIDERATIONS OF CRANESSTABILITY OF CRANE AGAINST TOPPLING:

STABILITY CONSIDERATION IS THE MAIN CONCEPT CONTROLLING LOAD RATING IN A CRANE. HENCE THE ELEMENTS WHICH CONTRIBUTE TO ACT AGAINST STABILITY SHOULD BE KNOWN :

IT IS GENERAL PRACTICE, THAT BASED ON STABILITY THE CRANE RATING ARE SET AS A PERCENTAGE OF TIPPING LOAD AND IN CASE OF ‘TATA CRANE’ ALL RATINGS INDICATE, 75% OF TIPPING LOADS

SAFETY CONSIDERATIONS OF CRANESTHE TIPPING STAGE ONCE REACHED, THE CRANE

MAY START TILTING.

WHEN THE CRANE STARTS TILTING, OPERATOR

IS IN A VERY DIFFICULT POSITION TO CONTROL

THE PROBABLE ACCIDENT BECAUSE THE TILTING

MOVEMENT IS FAIRLY RAPID.

THIS FOLLOWS THE LOAD GETTING OUT OF

RADIUS, MORE AND MORE AND ULTIMATELY

LEADING TO THE ACCIDENT.

OPTIONS OF THE OPERATOR

1. TO DROP THE LOAD WHICH POSES SERIOUS THREAT. THE OPERATOR SHOULD POSTPONE THIS OPTION UNTIL IT APPEARS THAT OVER-TURNING OF THE CRANE IS INEVITABLE

2. BOOMING IN (HOISTING THE BOOM) QUICKLY CAN RECOVER STABILITY BUT THIS REQUIRES VERY FAST ACTION FROM THE OPERATOR.

CRANE BOOM FAILURE

•BOOM SUSPENSION IS REQUIRED WHEN LENGTH OF THE BOOM IS MORE THAN 70 FT.

•WITH MAXIMUM BOOM LENGTH AND GANTRY IN FOLDING POSITION - CRANE SHOULD NOT TRAVEL.

•WITH GANTRY LOW (FOLDING POSITION) NO LOAD SHOULD BE LIFTED

FROZEN LOAD HANDLING

THE LOAD WHICH IS FROZEN ON THE GROUND SHOULD BE LOOSENED UP BY OTHER MEANS NOT BY USING CRANE POWER.

IN THE TOP MOST PART BUCKLING TENDENCY IS OBSERVED

BOOM SHOULD NOT BE LOADED BY OTHER LOAD OTHER THAN DESIGNATED LOAD

FROZEN LOAD HANDLING

CONSEQUENCES OF FROZEN LOAD HANDLING

BOOM OVER CAB ACCIDENT

BOOM BACK STOP DOES NOT STOP BOOM FROM GOING BACKWARDS, BUT IT HELPS TO :

1. PREVENT THE OPERATOR’S CABIN FROM BEING DAMAGED - WORKING AS A WEDGE

2. WHILE TRAVELLING WITH LOAD ON UNEVEN SURFACE IT PROVIDES CUSHIONING

BOOM OVER CAB ACCIDENT

REASONS:

1. IMPROPER ADJUSTMENT OF CLUTCH.

2. OPERATOR’S FAILURE TO DISENGAGE THE CLUTCH.

OPERATOR CAN SEE THE BOOM BACK STOP AND ASSESS THE CONDITION TO TAKE ACTION

BOOM BACKSTOP

“BOOM - OVER - CAB” ACCIDENT

PREVENTION OF “BOOM - OVER - CAB” ACCIDENT1. MANY PEOPLE MISTAKENLY FEEL THAT BOOM BACKSTOP PROVIDED ON A CRANE WILL PREVENT BOOM-OVER-CAB OCCURRENCE.

THIS WOULD HAVE BEEN POSSIBLE ONLY IF THE BOOM IS PULLED TOWARDS THE CAB WITH FAIRLY LOW LEVEL PULLS AND A DEVICE PROVIDED IN THE BOOM HOIST CLUTCH, TO SLIP WHEN ENCOUNTERED LOAD RESISTANCE, BEYOND CERTAIN SAFE AMOUNT OF PULLS, WITH SIMULTANIOUS ALERT SIGNAL TO OPERATOR FOR CORRECTIVE CONTROL ACTION.

HENCE ‘TATA’ CRANES ARE FURNUSHED WITH BOOM HOIST KICK-OUT IN ADDITION TO BOOM BACK STOPS. THE BOOM HOIST CUT-OUT STOPS THE LIFTING MOTION WHEN THE BOOM REACHES CERTAIN PREDECIDED ANGLE. A FUNCTIONAL DEVICE OF THIS TYPE WOULD PREVENT OVER LIFTING OCCURRENCE. THE CRANE OPERATOR SHOULD ENSURE THAT THE BOOM HOIST KICK-OUT DEVICE IS IN OPERATIVE CONDITION ON DAILY BASIS.

PREVENTION OF “BOOM - OVER - CAB” ACCIDENT

HOWEVER THE POSSIBILITY OF BOOM-OVER-CAB ACCIDENT IS STILL NOT COMPLETELY RULED OUT AND REMAINING FACTORS WHICH COULD CAUSE SUCH AN ACCIDENT IS DEPENDENT ON OPERATOR’S JUDGEMENT. THE CONDITION CAUSING SUCH AN ACCIDENT ARE AS UNDER:

1. DROPPING OF A HEAVY LOAD SUDDENLY OR ACCIDENTLY WITH BOOM AT NEAR VERTICAL ANGLE OR SUDDEN FAILURE OF HOIST ROPE.

2. WHEN TRAVELLING ON ROUGH TRAVEL PATHS CAUSING EXCESSIVE BOUNCE

BOOM KICK OUT- FOR TATA CRANE

HOW IT FUNCTIONS:

WHEN THE HYDRAULIC KICK OUT SWITCH IS DEPRESSED DUE TO BOOM OVER-HOISTING, THE OIL UNDER PRESSURE FROM THE COMPENSATOR, IS RETURNED BACK TO ZERO PRESSURE OF THE RESERVOIR LINE, THEREBY DISENGAGING THE BOOM HOIST CLUTCH.

THE PURPOSE OF BOOM BACKSTOPS IS THEREFORE LIMITED TO FOLLOWING1. TO GIVE VISUAL INDICATION TO CRANE OPERATOR THAT HE IS REACHING UNSAFE ANGLE.

2. IN CASE OF BOOM-OVER-CAB ACCIDENT OCCURING, THE DAMAGE TO MACHINE IS LIMITED TO BENDING OF BOOM WHICH WOULD ARCH OVER THE DECK MACHINERY, AVOIDING A DIRECT HIT ON THE MACHINE.

3. TO ABSORB MINOR BOUNCING ON THE BOOM, RAISED CLOSE TO MAXIMUM ANGLE WHEN THE CRANE IS MOVING WITH LOAD.

SAFETY RULES FOR CRANE OPERATORS

1. NEVER PICK UP A LOAD BEYOND THE RATED LOAD CAPACITY AT THE GIVEN ANGLE AND THE LENGTH OF THE BOOM

2. NEVER MOVE THE LOAD OR THE CRANE UNLESS CLEARED BY THE SIGNALER ON THE JOB. THIS IS EXTREMELY IMPORTANT WHEN THE LOAD IS HANDLED BY MORE THAN ONE CRANE.

3. WHEN THERE ARE SEVERAL PERSONS ON THE JOB OBEY SIGNAL FROM ONLY THE PERSON ASSIGNED AS THE SPOTTER (SIGNALLER). OBEY ON EMERGENCY STOP SIGNAL GIVEN BY ANY ONE.

4. WHEN RAISING, LOWERING OR SLEWING THE LOAD, PLEASE ENSURE THAT IT WOULD SAFELY CLEAR ADJACENT STOCK PILES OR MACHINERY.

5. NEVER LEAVE THE CRANE, WITH LOAD SUSPENDED.

SAFETY RULES FOR CRANE OPERATORS

SAFETY RULES FOR THE HOOK ON HELPER

1. BEFORE BEGINNING EACH SHIFT, CHECK SLINGS, CHAIN, HOOKS ETC.

2. WHEN CRANE IS TRAVELLING, WALK AHEAD OF THE LOAD. NEVER PERMIT ANYBODY UNDER THE LOAD.