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Safety in welding and Gas cutting

Safety in welding and Gas cutting





Objective



Safety in Welding


Arc welding


Risk involved


Electrocution


Precautions


Fire hazards


Burns


Precautionary measures


Health Hazards


Eye Damages


Risk involved


Precautions to be takes


Welding shield


Welding shield


Protective measures


Protective clothing


Welding fumes


Welding machine with "VED"


Welding machine with "VED"




Safety in Gas cutting


Acetylene cylinder


Oxygen  cylinder


Cylinder storage



Stacking Cylinder


Unloading from Truck


Lifting cylinder by crane


Use of cylinder trolley


torch cutting attachment


Nozzle mixing Techonology


Care & Maintenance of the Regulators


Regulators...


Hose


Right Opeartion


Right Opeartion


Hazards


Flash back & Back fire


Flash back arrestors


Reason for Flash back & Back fire


If flash back occurs...


Flash back prevention


Fire on cylinder


Explosion



PPE



General safety Tips

General safety Tips

Gas Cutting,


Gas Cutting,


Gas Cutting,


Thank you.







Welcome to Safety
in
Welding and Gas cutting 


Safety  in  Welding

Risk involved……



nElectrocution
nFire
nBurns
nHealth Hazards


Electrocution

nSecondary side voltages are max. 80 v
nHowever  factors such as 
nWet ground
nEasy closure of circuit
nMetal structures
  Makes it severe.


Precautions…..

  The voltage shock occurs when you touch an open cable and the job under welding at the Same time.  It means when your body becomes Conducting   path and the arc is not “on”.
    Wear dry gloves.
  Do not weld on wet metals under direct rain
  Ensure proper connection between cables, Holders, earth and machine clamps.
  Do not rest your body on work piece / job

Fire hazard



nInsert plates and reinforcement rod welding

nWelding near Liquid and solid fuels,   

Burns

nReaches 20000C.
nBarricade
nFire watchers
nMark it as “HOT


Precautionary Measures

nProper current rating
nTrained welders
nFire Curtains
nFire Resistance Tarpaulin
nAsbestos / GI sheets etc
nFire watchers
nFire Fighting techniques.   

Health Hazards

nEye damages
nSkin diseases
nBronchitis,Asthma,Pneumonia, Pneumoconiosis, decreased lung capacity and Silicosis.   

Eye Damages

Visible light, and ultraviolet and infrared radiation
Intense light can cause damage to retina
Infrared radiation may damage the cornea and result in cataracts
Invisible UV light can cause “arc eye” or “welders’ flash”

Risk involved

  WHEN SEEN WITH UN PROTECTED EYE-MAY CAUSE
   ARC EYE AND LENS OPACITY .   

  ARC EYE IS FREQUENTLY ENCOUNTERED PROBLEM
   MAINLY  DUE TO SHORT TIME DIRECT/INDIRECT
  EXPOSURE  ( UNINTENTIONAL ).
         EYE INJURIES FROM FLYING OBJECT IS ANOTHER
   PROBLEM  MAINLY  DURING  CHIP BACK  OR
   CLEANING / GRINDING.   


Precautions to be taken

Welding Shield

nAutomatic welding shield
nWelding shield fully covered – UV rays attacks side wise.

How about Helpers  ?

Welding Screens
  USE WELDING SCREEN TO  PROTECT  FACE  
  &  NECK   FROM  WELDING ARC.
  RECOMMENDED WELDING SCREEN -
  FIBRE REINFORCED PLASTIC  WELDING SCREEN   ALONG  WITH  FACE SHIELD.

Protective measures

  USE PROTECTIVE CLOTHING TO COVER            
          UNPROTECTED SKIN
  -   NECK  COTTON HOOD
  -   HANDS   CHROME LEATHER GLOVES
  -   FORE HANDS  CHROME LEATHER HAND GUARD
  -   LEGS   CHROME LEATHER LEG GUARD
  -   BODY   BOILER SUIT ( COTTON ), IF
  REQUIRED APRON ON FRONT

  ( CHROME LEATHER )

Protective clothing
Welding fumes

  COMPARABLE TO ATMOSPERIC DUST / AUTOMOBILE   SMOKE / TOBACCO SMOKE
  RESPIRABLE SIZE IS UP TO 10 Microns
  CUP MASKS TYPICALLY FILTER PARTICLES >0.5 Microns

Welding Machine with ‘VRD’

nThe Tp 2500 is a new generation welding Inverter
nExcellent Ignition and welding properties
nExtremely light weight (13.5 kg)
nA powder coated sheet steel housing is provided
n
nA Safety device known as ‘VRD’ (Voltage Reduction Device) for voltage reduction from 80V to 12V


Welding Machine with VRD

nELCB doesn't senses secondary voltage.
nNew device with Voltage Reduction Device.
nYields power saving,  




Safety 
in

Gas Cutting


Acetylene cylinder 



nMaroon in colour.
nAcetylene gas (C2H2) is dissolved in acetone (liquid) and stored at 250 psi, in a specially designed cylinder.
nAcetylene cylinders has a volume of 8.5 m3



Oxygen cylinder


nOxygen is a colourless, tasteless, and odourless gas and is slightly heavier than air.
nOxygen cylinder is black in colour.
nOxygen stored at 2200 psi
nOxygen cylinders has a volume of 6.9 m3
n


Cylinder storage

nWell ventilated room
nNo open flame in the store
n10 m distance from oxygen and acetylene cylinders
nNo materials that are prone spontaneous combustion
nShould not be stored in direct sunlight.




Stacking cylinders


Avoid over-stacking
Chock the stack


Unloading from Truck



¬Never drop
¬Use wooden Ramp and coir matters (50cm thick)
¬Keep the top of the cylinder up
¬ Roll the cylinder keeping it upright 


Lifting cylinders by crane


¬Use of cradle
¬4-leg bridle sling
¬D-shackle and lifting lug


Use of Cylinder trolley


¬Shifting cylinders at site
¬Avoid Rolling & Manual carrying
¬Use trolley



Torch cutting attachment


There must always be two o-rings on the cone end.  The absence or damage of either of these o-rings allows premixing and leaks of oxygen and fuel gases.  This can lead to flashback within the torch handle.



 Regulators…..


qWarning -Always keep the regulator free of oil, grease and other flammable substances
q Never use oil or grease on the regulator, cylinder or manifold connection
qDO NOT change the inlet connection on a regulator in an attempt to use the regulator for a different gas service
 Never stand in front or behind a  regulator when opening the cylinder valve


  Hose


qThe hoses are usually color coded
qOxygen (blue)   
qAcetylene(red)
qBe careful not to use other hoses, such as air lines, LP gas, etc.
qBe careful around sharp objects, they can be cut very easily
qThey are constructed of flame retardant materials, but will burn if there is a flashback or exposed to sustained heat
qHoses are graded
    Make sure you are using the right hose for the right gas


Right operation


¬Keep the cylinder upright and away from hot jobs.
¬Fix the DA and oxygen regulator to the respective cylinders    after ensuring free from dirt or grease.
¬Connect the cutting hoses to the regulators and cutogen with hose clamps.Blue or black hoses for oxygen and red for DA.
¬Open the cylinder and check for leakage by soap water test   at the joints. The same to be followed for the oxygen  cylinder. Close the  cylinders .


Right operation ……


¬Purge the oxygen line and then the DA line one after the other and close the valves.
¬Open the DA regulator, the torch valve and light the gas.
¬Then open the oxygen valves to the required pressure.
¬After cutting, start closing from oxygen and then DA.


HAZARDS



nFlash back
n
nBack fire
nGeneral fire
n
nExplosion


Flashback arrestors



q  Flashback arrestors are designed to prevent
     flashback from reaching upstream equipment.

q They offer added safety and often include reverse
     flow check valves in a single unit






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