SAFETY DURING GAS SAFETY DURING GAS CUTTING & WELDINGCUTTING & WELDING

SAFETY IN GAS SAFETY IN GAS CUTTING OPERATIONCUTTING OPERATION

SAFETY DURING GAS CUTTING WORKSSAFETY DURING GAS CUTTING WORKS

• Colour code of the Cylinder

Oxygen - Black

Acetylene – Maroon

Nitrogen – Light Blue

STORAGE OF GAS CYLINDERSSTORAGE OF GAS CYLINDERS

Keep minimum distance of 20 feet between fuel and oxygen cylinders

FUEL GAS CYLINDERS (DA CYLINDERS) SHOULD BE STORED SEPERATELY FROM OTHER GAS CYLINDERS

FUEL GAS EMPTY CYLINDERS SHOULD BE STORED SEPERATELY

STORE CYLINDERS IN COOL, DRY AND WELL VENTILATED PLACE AWAY FROM HEAT

NO OTHER MATERIALS SHOULD BE STORED IN CYLINDER STORAGE AREA

AFTER DAY’S WORK, REMOVE CYLINDER TO SAFE STORAGE PLACE

FULL

FUEL GAS OXYGEN

EMPTY

FUEL GAS OXYGEN

STORAGE OF GAS CYLINDERSSTORAGE OF GAS CYLINDERS

STORAGE OF GAS CYLINDERSSTORAGE OF GAS CYLINDERS

HANDLING OF GAS CYLINDERS

KEEP CYLINDERS AWAY FROM THE SPARK OF THE FLAME

KEEP ACETYLENE CYLINDERS UPRIGHT

DONOT USE CYLINDERS AS ROLLERS OR WORK SUPPORTS

DONOT USE MAGNETS TO MOVE GAS CYLINDERS

USE STD KEYS FOR OPENING THE VALVES

DONOT LUBRICATE VALVES

DO NOT SWEETEN FOUL ATMOSPHERE WITH OXYGEN

CHAIN ACETYLENE CYLINDERS UPRIGHT

CLOSE VALVES OF EMPTY CYLINDERS

USE TROLLEY FOR CYLINDERS SHIFTING

HAZARDS DURING GAS CUTTING

• BACKFIRE

• FLASH BACKFIRE & EXPLOSION

HAZARDS DURING GAS CUTTING

BACKFIRE:

•DURING GAS CUTTING, THE DUST & DIRT COMING FROM

THE CYLINDERS BLOCK THE HOLES OF THE NOZZLE

GRADUALLY.

•OXYGEN, WHICH IS STORED AT HIGHER PRESSURE,

STARTS FLOWING TO ACETYLENE CYLINDER AND FORMS

INFLAMMABLE GAS MIXTURE.

•THIS COULD LEAD TO EXPLOSION WHEN THE TORCH IS

REIGNITED.

FLASH BACK:

•THIS HAPENS WHEN FLAME VELOCITY EXCEEDS THE GAS

MIXTURE VELOCITY.

•THIS COULD OCCUR WHEN THE PRESSURE INSIDE THE

CYLINDERS IS CONSIDERABLY LESS.

HAZARDS DURING GAS CUTTING

INDICATIONS

• HISSING NOISE• HEAVY BLACK SMOKE• SPARK COMING OUT OF NOZZLE / TIP• TORCH HANDLE GETTING HOT

BACK FIRE / FLASH BACK

• FLAME HELD TOO CLOSE TO WORK• SLAG BLOCKING TIP• HOT METAL FALLING ON AND BURNING THROUGH HOSE• FAULTY EQUIPMENT• WRONG GAS SEQUENCE DURING START- UP• INSUFFICIENT PURGING TO CLEAN HOSE BEFORE USE.• GAS HOSES DAMAGED BY PREVIOUS FLASHBACK.

BACK FIRE / FLASH BACK CAUSES

FLASH BACK ARRESTORS ARE ESSENSIAL. THEY ARE NOT SUBSTITUTE FOR SAFE WORK PRACTICES

USE OF FLASH BACK ARRESTORS

GENERAL INFORMATION

NON COMBUSTIBLE

GAS CYL VALVES R H THREADS

COMBUSTIBLE

GAS CYL VALVES L H THREADS

SNIFT VALVE BEFORE CONNECTING THE REGULATOR

DONOT OPEN CYL. VALVE TOO MUCH. ONE TURNING OPENING IS ENOUGH

USE APPROPRIATE REGULATOR AND BLOW PIPE.

SINGLE STAGE REGULATOR

TWO STAGE REGULATOR

GAS CUTTING HOSE

AVOID DAMAGE TO HOSES AGAINST SHARP EDGES ETC.

HOSE CONNECTIONS

DONOT ALLOW TRAFFIC TO PASS OVER A HOSE.

FOR OXYGEN

THREADED RIGHT HAND PLAIN FACETS

FOR ACETYLENE

THREADED LEFT HAND NOTCHED FACETS

USE ONLY PRESSURE

TYPE RUBBER

CANVAS HOSE

1. PRESSURE:

OXYGEN - 1200 psi

ACETYLENE - 200 psi

2. EXPLOSIVE RANGE:

UPPER LOWER

ACETYLENE - 2.5% 82%

LPG - 2.2% 9.5%

OTHER IMPORTANT POINTS………

OTHER IMPORTANT POINTS……

3. KEEP THE ACETYLENE CYLINDER ALWAYS

VERTICAL/UPRIGHT. IF NOT,THE LIQUID

ACETYLENE KEPT DISSOLVED INSIDE THE

CYLINDER COULD LEAK THROUGH THREADS OF

THE VALVE FITTING. THE VOLUME OF THE LIQUID

ACETYLENE, WHICH HAS COME OUT, GETS

MULTIPLIED ENORMOUSLY AND FORMS A HUGE

VOLUME OF FLAMMABLE GAS MIXTURE IN THE

ATMOSPHERE.

OTHER IMPORTANT POINTS……

4. KEEP THE CYLINDERS ALWAYS PROVIDED WITH

VALVE PROTECTION CAP.

5. USE RAMP FOR UNLOADING CYLINDERS FROM TRUCK

6. USE TROLLEYS FOR MOVING CYLINDERS FROM ONE

PLACE TO THE OTHER AND KEEP THEM CHAINED.

7. ROUGH HANDLING OF THE CYLINDER COULD

DAMAGE THE VALVE. HIGH VELOCITY GAS JET

COMING THROUGH DAMAGED VALVE WOULD MAKE THE

CYLINDER FLY LIKE A MISSILE.

8. WHEN CYLIDERS ARE REQUIRED TO BE TAKEN TO

HEIGHT, DO NOT LIFT THEM WRAPPING SLINGS

AROUND THE CYLINDERS. INSTEAD, KEEP THEM

INSIDE SUITABLY DESIGNED CAGE/CRADDLE AND LIFT

BY USING CRANE.

9. NEVER LUBRICATE THE REGULATOR SET OF OXYGEN

CYLINDERS WITH OILS/GREASE. OIL /GREASE GETS

OXIDISED. HEAT PRODUCED DURING OXIDIZATION

COULD IGNITE OIL /GREASE.

OTHER IMPORTANT POINTS……

10. KEEP STORE ROOM OF THE GAS CYLINDERS WEL-

VENTILATED AND DO NOT KEEP ANY HEAT SOURCES

LIKE OPEN FLAME, ELECTRIC OVENS ETC.

11. NEVER LUBRICATE THE REGULATOR SET OF OXYGEN

CYLINDERS WITH OILS/GREASE. OIL /GREASE GETS

OXIDISED. HEAT PRODUCED DURING OXIDIZATION

COULD IGNITE OIL /GREASE.

OTHER IMPORTANT POINTS……

12. WHILE DOING GAS CUTTING IN CONFINED SPACE,

ENSURE NO LEAKAGE IN THE SET. KEEP ALL THE

VALVE CLOSED WHEN THE SET IS NOT USED. WHEN

THE WORK IS OVER IMMEDIATELY TAKE OUT THE

SET.

13. USE 24V HAND LAMP AND PNEUAMATICALLY

OPERATED HAND TOOLS WHILE DOING GAS CUTTING

INSIDE CONFINED SPACE.

OTHER IMPORTANT POINTS……

14. BEFORE IGNITING THE TORCH ENSURE THE HOSES

ARE PURGED/FLUSHED TO LET OUT THE FLAMMABLE

GAS MIXTURE, IF ANY.

15. KEEP KEYS ON THE CYLINDER ITSELF TO CLOSE THE

VALVE IN CASE OF EMERGENCY

16. USE FLASH BACK ARRESTER

OTHER IMPORTANT POINTS……

17. WHEN ACETYLENE CYLINDER IS ON FIRE

• CLOSE THE CYLINDER VALVE. • WHEN IT IS NOT POSSIBLE USE WATER JET OR DCP/CO2 EXTINGUISHERS• INFORM NEARBY FIRE STATION WHEN IT IS UNCONTOLLABLE

OTHER IMPORTANT POINTS……

SAFETY IN WELDING SAFETY IN WELDING OPERATIONOPERATION

ELECTRIC ARC WELDING

THREE IMPORTANT CONNECTION FOR A WELDING CIRCUITS

WELDING LEAD:

CARRYING WELDING CURRENT FROM SOURCE OF SUPPLY TO THE ELECTRODE HOLDER

WELDING RETURN:

CARRYING RETURN CURRENT BETWEEN THE WORK AND SOURCE OF SUPPLY

WELDING EARTH:

CONNECTION BETWEEN WELDING CIRCUIT AND EARTH

PERSONAL PROTECTIVE PERSONAL PROTECTIVE EQUIPMENT FOR WELDINGEQUIPMENT FOR WELDING

WELDING HELMETS

PPE FOR WELDING OPERATION

LIGHT FILTERS

•REDUCE INTENSITY OF LIGHT FROM THE WELDING ARC AND

ABSORB ULTRA VIOLATE AND INFRA RED REDIATION.

• THEY ARE GRADED IN ACCORDANCE WITH VISUAL DENSITY.

WELDINGCURRENT

UP TO 100 amps

100-300

300-400

over 400

Inert gas welding

SHADE NO.

8, 9

10, 11

12, 13

14, 15

14, 15, 16, IS 5893-1971

LIGHT FILTERS

MOBILE WELDING SCREEN

REACTION OF BODY TO

ELECTRIC SHOCK (100 VOLTS)

WILL CAUSE DEATH

MAY CAUSE MUSCULAR CONTRACTION

MAY CAUSE SOME SENSATION

100 MA OR 0.100 AMP

200 MA OR 0.200 AMP

15 MA OR 0.015 AMP

20 MA OR 0.020 AMP

1 MA OR 0.001 AMP

8 MA OR 0.008 AMP

SEVERITY OF SHOCK NOT DEPENDS ON VOLTAGE ALONE BUT…..DEPENDS ON

1 QUANTITY OF CURRENT FLOWING THROUGH THE BODY

PATH OF CURRENT FLOWING THROUGH THE BODY

LENGTH OF TIME BODY IS IN CURRENT

2

3

WELDING AND FIRE SAFETY WELDING AND FIRE SAFETY

FLAMMABLE AND COMBUSTIBLE MATERIAL FLAMMABLE AND COMBUSTIBLE MATERIAL MAY BE IGNITED BY MAY BE IGNITED BY

SPARKS

HOT METAL

CONDUCTED HEAT

FLAME

ELECTRIC ARC

STRAY CURRENT

GAS WELDING TORCH

BACK FIRE IN GAS WELDING EQUIPMENT

TO PREVENT WELDING FIRES

• REMOVE FLAMMABLE AND COMBUSTIBLE MATERIAL TO A

SAFE DISTANCE

• SUITABLE FIRE EXTINGUISHER SHOULD BE READILIY

AVAILABLE

• ISSUE PERMIT-TO-WORK WHEN SPECIAL PRECAUTIONS ARE

TO BE TAKEN

TO PREVENT WELDING FIRES

• DO NOT LEAVE ELECTRIC CIRCUIT ON OR BLOW TORCHES

BURNING WHEN WELDER HAS TO BE AWAY

• AFTER THE WORK IS THROUGH DO NOT LEAVE BEHIND ANY

MATERIAL SMOULDERING

TO PREVENT WELDING FIRES

• PROVIDE SCREENS OR PARTITIONS TO PREVENT WELDING

SPARKS SPREADING AROUND

• COVER COMBUSTIBLE MATERIALS WHICH CAN NOT BE REMOVED, WITH NON-COMBUSTUBLE COVERINGS

THANK Q