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Welding Safety

 

Welding Safety Practices:  Also see University of North Florida Hot Work Policy (section 1.5).  Radiation from welding flares and arcs can seriously injure eyes and burn skin.  Splashing metal and hot sparks can cause other burns.  The welding operation must meet the State Fire Marshal and NFPA 51B codes.  For further assistance call EH&S.

A.  Only qualified personnel should be authorized to perform welding operations.  

B. Employees should be provided with protective equipment that includes welding helmets, shields, aprons, gloves and gauntlets.  

C. Arc welders should ensure that fireproof screens are placed around the work area to prevent eye flash burns to personnel in the area.

D. Welders should wear eye protection when chipping scarf metal fragments.

E. Forced ventilation should be used in welding operations when natural ventilation is insufficient to prevent the accumulation of gases and fumes.  In confined areas, local exhaust ventilation will be required

F. Welding Fire Hazards:  Welding or cutting near flammable or explosive  materials requires close attention to the following safety requirements:

  1. A fire extinguisher must be available within 100'.  
  2. Welders working near combustible materials should be provided a watch person to stand by with suitable fire suppression equipment.  
  3. Flammable materials should be removed from the immediate area. 
    ***Wooden floors and other combustible surfaces should be protected.  When it is impractical to remove flammable materials from the area, they should be protected by a suitable fire resistant shield.  
  4. After welding operations have been completed, the area should be thoroughly inspected for smoldering material. 
  5. Welding is prohibited where flammable gases or liquids are present until their presence has been eliminated.  
  6. In confined spaces, welding itself may produce flammable and explosive gases.  Refer to the UNF Confined Space Entry Program. 
  7. When a fire hazard still exists after precautionary measures have been taken, the decision to weld or cut should be made by the supervisor.  A fireguard should stand by the welding operation.  
  8. Compressed gases: The precautions for the handling and storage of compressed gases are contained in Chapter 4.

G. Welding Containers:

Before welding or cutting any tank, cylinder or other container, personnel should make certain containers are free from any trace of explosive material.  The following procedures will minimize accidents: 

  1. Containers which contain or have contained flammable substances should be purged or made inert prior to the welding operation.  Refer to the UNF Confined Space Entry Program. 
  2. Containers should be vented during welding operation. Adequate venting is necessary to prevent containers from exploding or rupturing.  

H. Oxyacetylene Welding/Cutting: 

Careful handling of the gases and equipment used in oxyacetylene welding is essential. In addition, observe the following:

  1. Oil or grease should not be allowed to come in contact with welding equipment.  
  2. Acetylene should not be used at pressures exceeding 15 psi.  
  3. Leaking and creeping regulators should be removed from service. 
  4. Control valves should never be opened more than 1 1/2 turns; 1/2 turn is sufficient for most welding operations.  
  5. The special T-wrench used to open cylinders should be left in place during welding operations to permit quick shutdown in emergencies. 
  6. Control valves should be unobstructed and immediately accessible to the welder.  
  7. Control valves of cylinder not in use should be covered by protective caps.  
  8. Acetylene cylinders should be stored and used in an upright position to prevent loss of acetone.  This will also minimize external corrosion of the cylinder.  
  9. Welding-torch hoses should be protected from damage by contact with hot metal, open flames or other destructive agents.  
  10. Inspect hoses periodically for leaks. 
  11. Only standard ferrules or clamps should be used to secure hoses to cylinders and torches.  Makeshift tape or wine connections should not be used.  
  12. The oxygen hoses should always be green in color.  
  13. Hoses should be released of pressure at the end of each workday.  

I. Gas Welding Flame:  

The flame should always be kept within the welder's field of vision and not be allowed to contact any part of the welding equipment.  The following additional procedures should be observed: 

  1. The torch should be extinguished when not in use and its control valves turned off.  
  2. The torch should not be pointed at concrete surfaces because a miniature explosion could occur and result in flying concrete fragments.  
  3. If a flashback occurs, the operator should turn off  both torch valves. 
  4. If a hose burst or escaping gas ignites at the tank regulator, the control valves should be immediately turned off. 
  5. On manifold cylinder systems, each fuel-gas cylinder should be provided with a backflow check valve.  

J. Electric Arc Welding:  

Eye injury can occur while operating arc welders.  Be sure to use fire-resistant curtains or screens during the welding operation and post warning signs.  In addition: 

  1. Always deenergize electrical circuits before testing or checking.  
  2. Rotary and polarity switches should not be operated while the equipment is under an electrical load.  
  3. Motors, generators and other electrical welding equipment should be grounded.  
  4. Arc welding equipment should undergo careful inspection before each day's use.   5. Arc-generating equipment should be repaired by qualified electricians only.  

K. Cadmium Welding Hazards:

When cadmium plated or cadmium-bearing metals are being welded, local exhaust ventilation should be provided.  In addition: 

  1. The exhaust hood should be kept as close to the point of generation as possible and should never be more than 8" away.  
  2. If local ventilation cannot be supplied and welding is being done in small, confined spaces the operator should wear an approved air-line type respirator.  
  3. Welding should never be performed on a metal or alloy of unknown identity.  Cadmium-plated metals can easily be confused with other electroplated metals.  When there is any doubt about the composition of a metal to be welded, a sample should be submitted to a metallurgical or chemical laboratory for analysis. 
    1.  Oxides commonly generated in welding processes may originate from the material being welded, the surface coating or the electrodes of the arc equipment. Cadmium oxide is extremely poisonous, particularly in the vapor form. Heavy concentrations cause rawness in the throat, irritation of the mucous membranes and edema (fluid) in the lungs.  Death or permanent lung damage can result from prolonged breathing of cadmium oxide. Unless the welder is familiar with the differences between cadmium containing metals and others similar in appearance, exposure to toxic concentrations of cadmium oxide can occur when welding cadmium bearing or plated metals. 
    2.  Protective measures against harmful gases, fumes and dust should be taken by providing adequate ventilation and respiratory protective equipment. Refer to the UNF Respiratory Protection Program. 

UNIVERSITY OF NORTH FLORIDA HOT WORK POLICY

OBJECTIVE

 

To establish requirements for fire safety and the safe performance of all tasks involving welding, cutting, brazing and soldering.  

APPLICABILITY 

This policy applies to all maintenance activities on campus. The project manager will provide contractors working on University facilities a copy of this policy. 

MINIMUM REQUIREMENTS 

 

Fire hazards: 

If the object to be welded, cut, brazed or soldered cannot be readily moved, all movable fire hazards in the vicinity shall be taken to a safe place. 

Guards:  If the object cannot be moved and all fire hazards cannot be removed, then guards shall be used to confine the heat, sparks and slag and protect the immovable fire hazards. 

 

Combustible material: 

Whenever there are floor openings or cracks in the floor that cannot be closed, precautions shall be taken so that no readily combustible materials on the floor below will be exposed to sparks which may drop through the floor. The same precautions will be taken with regard to cracks or holes in walls, open doorways and open windows. 

 

Fire extinguishers:  

Suitable fire extinguishing equipment shall be available within 100' of the work area and inspected monthly.  

 

Fire watch:  

Fire watches shall be required whenever tasks are performed in locations where: Appreciable combustible material, in building construction or contents, are closer than 35' to the point of operation; Appreciable combustibles are more than 35' away but are easily ignited by sparks; Combustible materials are adjacent to the opposite side of metal partitions, walls, ceilings or roofs and are easily ignited by conduction or radiation (radiant heat). 

 

Prohibited areas: 

Welding, cutting, brazing and soldering shall not be permitted in the following situations: 

 In sprinklered buildings while such protection is impaired. 

 In the presence of explosive atmospheres (mixtures of flammable gases, vapors,  liquids or dust with the air). 

 Where adequate ventilation cannot be provided. 

 On piping or ducts that may permit sparks or fumes to be transferred to other areas of the facility. 

 

Soldering:

Soldering of metals affixed to combustible materials shall be performed using an electric iron rather than gas flame. 

 

Personal Protective Equipment: 

The individual performing the task shall wear the appropriate protective devices. All observers and individuals assisting in the performance of the job shall wear appropriate protective devices. 

 

Authorization:  Before cutting, welding, brazing or soldering is permitted, the area shall be inspected by the individual responsible for authorizing the operation. They shall designate precautions to be followed in granting authorization to proceed. They shall also ensure that the person performing the operation is properly trained and qualified. 

 

Special Exemption:  When a task cannot be conducted under the restrictions of this policy, EH&S should be contacted to assist in the development of alternate procedures. 

 

References:  Code of Federal Regulations 29, Part 1910 and National Fire Protection Association (NFPA) 51B.