Cutting & Welding

Burning, cutting and welding operations (referred to as hot work) are commonly associated with renovation and construction activities. Potential health, safety, and property hazards result from the fumes, gases, sparks, hot metal and radiant energy produced during hot work. Hot work equipment, which may produce high voltages or utilize compressed gases, also requires special awareness and training on the part of the worker to be used safely. Arc welders are trained to take appropriate precautions to prevent the skin and eye burns that can occur as a result of exposure to the UV emitted during arc welding. However, it is also important to ensure that persons in the vicinity of the welding operations are prevented from entering areas where arc welding is occurring and are warned not to stare at the arc. The hazards associated with hot work can be reduced through the implementation of effective control programs.

Preparing Hot Work Areas

Areas where hot work is done should be properly designated and prepared. Combustible and flammable materials within the work area should be protected against fire hazards and the operation should not pose a hazard to others in nearby areas. To help achieve this, the following controls should be used:

  • Cutting and welding operations are performed only by authorized, properly trained individuals;
  • If possible, hot work must be performed in a properly designed shop area equipped with all necessary controls and adequate ventilation;
  • Move combustible materials at least 35 feet from the work site. If this is not possible, protect combustible materials with metal guards or by flameproof curtains or covers (other than ordinary tarpaulins);
  • Cover floor and wall openings within 35 feet of the work site to prevent hot sparks from entering walls or falling beneath floors or to a lower level;
  • Fire resistant curtains and/or tinted shields must be used to prevent fire, employee burns, and ultra-violet light exposure.

The following sections provide further guidance when conducting cutting and welding on the Princeton University Campus.

Hot Work Procedures

A local fire code permit, which may be obtained from the local fire official, is required for all cutting and welding operations conducted in the Municipality of Princeton.

While Princeton University does not currently require hot work permits to conduct hot work on campus, the Office of Environmental Health and Safety (EHS) in conjunction with the Office of the Fire Marshal require that the following considerations be given prior to beginning any hot work on campus.

Hot Work Checklist

  • Have alarm systems been disabled prior to beginning work by calling Facilities Customer Service at 258-8000?
  • Has equipment been inspected and found to be serviceable prior to use?
  • Are sprinklers in service, where provided?
  • Have flammable liquids been removed from work area?
  • Have combustible or hazardous materials been relocated at least 35 feet from the operation? Have combustible materials that cannot be removed been covered with fire-resistive tarpaulins?
  • Have floor and wall openings within 35 feet of the operation been tightly covered?
  • Have screens or shields been erected to protect pedestrians from the welder’s arc?
  • Has the atmosphere been tested for presence of flammable gases or vapors?
  • Do all workers have personal protective equipment (PPE) appropriate for their tasks?
  • Are ample fire extinguishers available?
  • Has a fire watch been provided during work, breaks, and for at least 30 minutes after work is complete?
  • Have alarm systems been reactivated after work is complete by calling Facilities Customer Service at 258-8000?

University Fire Marshal

The University Fire Marshal is part of the Department of Public Safety. This position is concerned with issues related to fire and life safety, and acts as liaison with local fire officials.  The University has established a Fire Alarm Shutdown Procedure in order to avoid nuisance alarms due to construction activities. Additional steps are required if alarms are to be disabled in occupied buildings. The process and submittal form is found on the Facilities Customer Service Center web site.

Welding and Cutting Personal Protective Equipment

  • Eye, face, hand/arm, head and body protection (leather gloves, leather apron, gauntlets, safety glasses with side shields, welders helmet or welders goggles) are required that are appropriate to the potential hazards encountered during welding, cutting, brazing, soldering, grinding or other spark producing operations.
  • The intense light associated with welding operations can cause serious and sometimes permanent eye damage if operators do not wear proper eye protection. The intensity of light or radiant energy produced by welding, cutting or brazing operations varies according to a number of factors including the task producing the light, the electrode size and the arc current. The following table shows the minimum protective shades for a variety of welding, cutting and brazing operations for construction activities:
Welding Operation Shade Number
Shielded metal-arc welding 1/16-, 3/32-, 1/8-, 5/32-
inch diameter electrodes
10
Gas-shielded arc welding (nonferrous) 1/16-, 3/32-,
1/8-, 5/32- inch diameter electrodes
11
Gas-shielded arc welding (ferrous) 1/16-, 3/32-, 1/8-,
5/32-inch diameter electrodes
12
Shielded metal-arc welding 3/16-, 7/32-, 1/4- inch
diameter electrodes
12
5/16-, 3/8-inch diameter electrodes 14
Atomic hydrogen welding 10-14
Carbon-arc welding 14
Soldering 2
Torch brazing 3 or 4
Light cutting, up to 1 inch 3 or 4
Medium cutting, 1 to 6 inches 4 or 5
Heavy cutting, more than 6 inches 5 or 6
Gas welding (light), up to 1/8 inch 4 or 5
Gas welding (medium), 1/8- to 1/2-inch 5 or 6
Gas welding (heavy), more than 1/2-inch 6 or 8

Handling and Use of Gas Cylinders and Welding Equipment

Handling and Use of Gas Cylinders and Equipment

  • When moving and storing cylinders, make sure the cylinder valves are closed, caps are on, and the space is dry. If acetylene is being used, properly ventilate. Tilt and roll on bottom edges. Avoid dropping. Cylinders must be secured in a vertical position.
  • Remove regulators unless secured on a cylinder cart and have a 10 pound ABC rated fire extinguisher on cart. Remove regulators from oxygen/acetylene cutting assemblies/rigs unless properly secured on a cylinder cart. Note: Regulators are to be removed from the cylinders after use unless it can be determined that the cutting assembly/rig will be in use within the following twenty-four (24) hours.
  • When hoisting cylinders, use pallet, cradle, or sling board. Do not use choker sling or magnet.
  • When cutting or welding, protect cylinders from sparks, hot slag or flame by separating them, or use fire-resistant shields or blankets
  • Use friction lighters (not matches, cigarettes, etc.) to light torches.
  • When work is finished or cylinders are empty, make sure cylinder valves are closed and the caps are on the cylinders
  • Store regulators, hoses, etc. in a clean, dry, well ventilated space.
  • Oxygen and acetylene cylinders must be separated by a fire wall or a minimum of 20 feet when in storage.
  • Flashback safety valves must be used on all hoses and lines at the gauges and manifolds.

Handling and Use Welding Equipment

  • Only standard electric arc welding equipment such as generators, motor generator units, transformers, etc., conforming to the requirements of the National Electrical Manufacturer's Association or the Underwriters Laboratory, Inc., or both, should be used.
  • All electric welding machines must be properly grounded, and all electrical cables inspected prior to use for damage, excess fraying and loose connections.
  • Where it is necessary to couple several lengths of cable for use as a welding lead circuit, insulated connectors should be used on both the ground and positive lead. There must be no splices or connections within 10’ of the electrode holder (stinger).
  • Wherever practicable, shield anyone in work area from the direct rays of the arc. Barricade hot material with a fire blanket or other non-combustible tarp.
  • Regulators and gauges must only be repaired by qualified suppliers.
  • Inspect the work area and look for potential hazards. Move combustibles within 35 feet of the work area away from the work area. If combustibles can't be moved, cover them with a non-combustible tarp. Make sure equipment is in good working order.
  • Make sure a fire extinguisher is nearby. Post a fire watch if conditions warrant. Make sure a multi-rated dry chemical fire extinguisher is nearby. If aluminum, magnesium or other combustible metals are being welded, a Class D – Metals fire extinguisher needs to be directly available.
  • Perform atmospheric testing if the potential exists for flammable gases or vapors in the work area. Also be aware of combustible dust (sawdust, aluminum chips etc.). Provide ventilation if needed. Perform periodic gas tests if needed. Perform atmospheric flammable/combustible gas test if needed
  • Cover manholes, pits, sewers, doors, windows, wall cavities, floor openings and any other openings where it would be possible for a spark to fall and create a fire.
  • Shield nearby workers from flash burn. Communicate fire, burn and flash burn hazards to them.
  • Make sure you don't negatively affect other operations and equipment nearby.
  • Make sure you know the location of the nearest phone and fire alarm pull station.

For additional information on the proper handling and use of compressed gas cylinders visit the Compressed Gas Cylinder web page.

Compressed Gas Cylinder Safety (Cutting and Welding)

Visit the Compressed Gas Cylinder web page to learn more about the safe handling, storage, and operating procedures while using compressed gas cylinders during welding operations at Princeton.