SAFETY BASICS *WELDING

Purpose:

This procedure defines safe practices in welding. Supervisors should consider the length of the work period, ventilation conditions, work locations (e.g. enclosed space), materials (e.g. alloys), and specialized operations. Information on processes not covered by this safety standard or assistance in applying the recommended practices listed herein can be obtained from Safety or Industrial Hygiene.

Primary Users and Responsibilities

? Mechanical ? Process ? Industrial Hygiene ? Safety ? Contractors.

Safety and Environmental Precautions ? The principle that is common to all welding, burning, soldering, brazing, and similar metalizing operations is the heating of metals to cause their joining or separation. ? Many types of health and safety issues can arise, which can be grouped into the following general classes: ? Inhalation of fumes and gases ? Eye irritation from fumes and gases ? Burns / flash burns

Safety and Environmental Precautions (cont’d) ? High noise levels ? Electric shock ? Inadvertent ingestion of toxic substances * From both metalizing operations and residual material on equipment surfaces

References:

OSHA 29 CFR 1910.101 - Compressed Gases (General Requirements) ? OSHA 29 CFR 1910.252 - Welding Cutting and Brazing (General Requirements) ? OSHA 29 CFR 1910.253 - Oxygen-Fuel Gas Welding and Cutting ? OSHA 29 CFR 1910.254 - Arc Welding and Cutting ? OSHA 29 CFR 1926.350 - Gas Welding and Cutting ? OSHA 29 CFR 1926.351 - Arc Welding and Cutting ? OSHA 29 CFR 1926.353 - Ventilation and protection in welding, cutting, and heating ? OSHA 29 CFR 1910.133 - Eye and Face Protection ? OSHA 29 CFR 1910.1026 – Hexavalent Chromium ? AIHA - Welding Health and Safety, A Field Guide to OEHS Professionals (2002) Definitions

• Hot Work - operations capable of providing a source of ignition, such as riveting, welding, cutting, burning, and heating.
• Hot Work Permit - the Field Safety's written authorization to perform operations capable of providing a source of ignition (riveting, welding, cutting, burning, heating and grinding).
• Dilution Ventilation – the dilution of contaminated air with uncontaminated air to remove fume and gaseous contaminates by means of natural or mechanical (for example maintaining 2000 cubic feet per minute per welder in a confined space using Coppus blower attached to man way and/or air horns attached to flanges).
• Local Exhaust Ventilation – the capture and removal of contaminated air from a space by freely movable ducts placed as close to welding/burning task as possible (for example maintaining 100 feet per minute capture velocity in the zone of the welder using air movers such as air horns or squirrel cages with flex duct hose positioned no more than 12 inches from the weld).
• Enclosed Areas - areas that may have restricted air, such as field enclosures, area maintenance shops with out local exhaust ventilation systems, etc. As outlined in OSHA 1910.252 – any space with a volume less than 10,000 cubic feet per welder, or ceiling height less than 16 feet, or has barriers that obstruct cross ventilation – moving fumes horizontally away from welders breathing zone)
• Outdoors/Open Areas - large open areas with natural ventilation (field welding without enclosures)
• Confined Space - it is large enough and so configured that a worker can bodily enter the space and perform the assigned task, has limited access and egress, and is not designed for continuous human occupancy (1910.146). Examples include, but are not limited to the following: - Storage Tanks - Open Surface Tanks - Boilers - Furnaces - Manholes - Railroad Tank Cars - Silos - Storage Drums - Pits - Process Vessels - Storm Drains - Excavations - Truck Tanker Trailers - Hoppers - New or old piping.

Documentation and Records ? Job Safety Analysis ? Ventilation Records ? Safety Work Permits

Procedure Safety Work Permit Requirements

• Welding and/or burning operations shall not be conducted until the proper permits are issued, and all required gas tests completed.
• Welding or cutting equipment must be located in the permitted area (except during T/A) or a gas test must be completed at the machine location or grounding point.
• PPE required to protect welders from gases produced by welding process shall be identified and used at all times. Also proper PPE should be identified in a JSA, as required.
• Welding Hood/Helmet o Proper Filter Shade Protection
• Automatic Darkening Filters for UV o Protective Clothing (FRC)
• Pyrolon Tyvek (confined spaces)
• Welding Gloves appropriate for the task (e.g., standard welding gloves for stick rod welding, TIG gloves for TIG welding, etc.)
• Leather Boots

General Welding Safety

• Prior to Welding
• Inspect welding machine for obvious fuel or oil leaks and general condition (terminal covers, muffler condition and cooling fan guards). Use proper lifting techniques and care when moving a welding machine manually and chock wheels to prevent movement after placement if required.
• Welding cables should be clean, dry, free of damage (torn insulation, torn repair tape, or inadequate splices) and no bare or loose connections or connections supporting the weight of the cable.
• Use non-conducting cable supports or "S" hooks for long lengths of cable run over standing water and to prevent tripping hazards.
• All grounding contact points shall be clean metal surfaces.
• Special care should be taken around rotating equipment.
• Welding ground cables shall form a continuous electrical path between the work and ground. (Welding ground cables should be connected directly to the work piece whenever possible.)
• Ensure the proper gauge / length of welding lead and grounding cable is used for specific welding tasks and the amperage required for those tasks. o Area to be welded shall be cleaned (grinding, wire brushing, blasting).
• Coated surfaces are to be cleaned 4 inches on each sides of weld to minimize exposure to the heated coating.
• Depending on the lead concentration, some abatement tasks on galvanized or other lead coatings can only be conducted by authorized lead abatement contractors.
• Apply ground clamps as close to weld location as possible to minimize circulating current in the structure.
• Run ground and hot electrode lead bundled together and loosely twisted to reduce common mode noise. o Do not locate welding leads closer than 10’ from instrument cable trays

During Welding

• Keep cables and electrodes dry, do not change welding rods with wet hands or while standing in water.
• Never refuel the welding machine while it is in operation.
• No welding machine shall be left operating when not in use.
• Welding machines/Leads shall be grounded when operating.
• Welding operations in open shops lay down areas or areas with multiple welders in close proximity (i.e. a storage tank) should consider using welding curtains to shield other personnel from glare and sparks.
• Follow all ventilation and personal protective requirements for each job.

Gas Cutting, Welding and  Related Operation Safety

• Cylinders/Regulators o Cylinder valves and regulator fittings shall be clean, dry and free of hydrocarbons, oil and debris before use.
• Cylinders shall be stored properly (secured, drained and ventilated area, temperature below 125 degrees F, and away from corrosive, chemicals, liquids, bases, and vapors).

Ventilation

• General dilution ventilation and local exhaust ventilation are the best prevention against adverse health effects from welding and burning.
• Other personnel exposed to the same atmosphere as the welder are required to utilize the same personal and respiratory protection (conducting work inside the same enclosed space, personnel holding the local exhaust system, etc.)
• OSHA ventilation requirements (1910.252)
• Confined or enclosed spaces require either
• Mechanical dilution ventilation maintained at 2000 cubic feet per minute per welder (2000 CFM/welder), or
• Local exhaust ventilation maintained at 100 feet per minute capture velocity (100 fpm)

Dr. Juan Abdel Aziz

MD, HSEQ SPECIALIST