SAFETY DURING GAS CUTTING & WELDING

1. SAFETY DURING GAS CUTTING & WELDING

2. SAFETY IN GAS CUTTING OPERATION

3. SAFETY DURING GAS CUTTING WORKS • Colour code of the Cylinder • Oxygen - Black • Acetylene – Maroon • Nitrogen – Light Blue

4. STORAGE OF GAS CYLINDERS Keep minimum distance of 20 feet between fuel and oxygen cylinders

5. STORE CYLINDERS IN COOL, DRY AND WELL VENTILATED PLACE AWAY FROM HEAT FUEL GAS CYLINDERS (DA CYLINDERS) SHOULD BE STORED SEPERATELY FROM OTHER GAS CYLINDERS NO OTHER MATERIALS SHOULD BE STORED IN CYLINDER STORAGE AREA FULL EMPTY FUEL GAS OXYGEN FUEL GAS OXYGEN AFTER DAY’S WORK, REMOVE CYLINDER TO SAFE STORAGE PLACE FUEL GAS EMPTY CYLINDERS SHOULD BE STORED SEPERATELY STORAGE OF GAS CYLINDERS

6. STORAGE OF GAS CYLINDERS

7. KEEP CYLINDERS AWAY FROM THE SPARK OF THE FLAME DO NOT SWEETEN FOUL ATMOSPHERE WITH OXYGEN KEEP ACETYLENE CYLINDERS UPRIGHT DONOT LUBRICATE VALVES CHAIN ACETYLENE CYLINDERS UPRIGHT DONOT USE MAGNETS TO MOVE GAS CYLINDERS CLOSE VALVES OF EMPTY CYLINDERS USE STD KEYS FOR OPENING THE VALVES DONOT USE CYLINDERS AS ROLLERS OR WORK SUPPORTS HANDLING OF GAS CYLINDERS USE TROLLEY FOR CYLINDERS SHIFTING

8. BACKFIRE • FLASH BACK FIRE & EXPLOSION HAZARDS DURING GAS CUTTING

9. 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.

10. HAZARDS DURING GAS CUTTING • FLASH BACK: • THIS HAPENS WHEN FLAME VELOCITY EXCEEDS THE GAS MIXTURE VELOCITY. • THIS COULD OCCUR WHEN THE PRESSURE INSIDE THE CYLINDERS IS CONSIDERABLY LESS.

11. BACK FIRE / FLASH BACK • INDICATIONS • HISSING NOISE • HEAVY BLACK SMOKE • SPARK COMING OUT OF NOZZLE / TIP • TORCH HANDLE GETTING HOT

12. BACK FIRE / FLASH BACK CAUSES • 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.

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

14. TWO STAGE REGULATOR SINGLE STAGE REGULATOR NON COMBUSTIBLE GAS CYL VALVES R H THREADS COMBUSTIBLE GAS CYL VALVES L H THREADS GENERAL INFORMATION SNIFT VALVE BEFORE CONNECTING THE REGULATOR USE APPROPRIATE REGULATOR AND BLOW PIPE. DONOT OPEN CYL. VALVE TOO MUCH. ONE TURNING OPENING IS ENOUGH

15. AVOID DAMAGE TO HOSES AGAINST SHARP EDGES ETC. USE ONLY PRESSURE TYPE RUBBER CANVAS HOSE DONOT ALLOW TRAFFIC TO PASS OVER A HOSE. HOSE CONNECTIONS FOR ACETYLENE THREADED LEFT HAND NOTCHED FACETS FOR OXYGEN THREADED RIGHT HAND PLAIN FACETS GAS CUTTING HOSE

16. OTHER IMPORTANT POINTS……… 1. PRESSURE: OXYGEN - 1200 psi ACETYLENE - 200 psi 2. EXPLOSIVE RANGE: UPPER LOWER ACETYLENE - 2.5% 82% LPG - 2.2% 9.5%

17. 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.

18. 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.

19. OTHER IMPORTANT POINTS…… 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.

20. 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.

21. 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.

22. 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

23. OTHER IMPORTANT POINTS…… • 17. WHEN ACETYLENE CYLINDER IS ON FIRE • CLOSE THE CYLINDER VALVE. • WHEN IT IS NOT POSSIBLEUSE WATER JET OR DCP/CO2 EXTINGUISHERS • INFORM NEARBY FIRE STATION WHEN IT IS UNCONTOLLABLE

24. SAFETY IN WELDING OPERATION

25. ELECTRIC ARC WELDING

26. 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

27. PERSONAL PROTECTIVE EQUIPMENT FOR WELDING

28. PPE FOR WELDING OPERATION WELDING HELMETS

29. 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.

31. LIGHT FILTERS 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

32. MOBILE WELDING SCREEN

33. WILL CAUSE DEATH 100 MA OR 0.100 AMP 200 MA OR 0.200 AMP MAY CAUSE MUSCULAR CONTRACTION 15 MA OR 0.015 AMP 20 MA OR 0.020 AMP MAY CAUSE SOME SENSATION 1 MA OR 0.001 AMP 8 MA OR 0.008 AMP REACTION OF BODY TO ELECTRIC SHOCK (100 VOLTS)

34. 1 QUANTITY OF CURRENT FLOWING THROUGH THE BODY 2 PATH OF CURRENT FLOWING THROUGH THE BODY 3 LENGTH OF TIME BODY IS IN CURRENT SEVERITY OF SHOCK NOT DEPENDS ON VOLTAGE ALONE BUT…..DEPENDS ON

35. WELDING AND FIRE SAFETY

36. FLAMMABLE AND COMBUSTIBLE MATERIAL MAY BE IGNITED BY • SPARKS • HOT METAL • CONDUCTED HEAT • FLAME • ELECTRIC ARC • STRAY CURRENT • GAS WELDING TORCH • BACK FIRE IN GAS WELDING EQUIPMENT

37. 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

38. 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

39. 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

40. THANK Q