Kiewit Building Group Newsletter 7/29/14 Volume 2 Week 31

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Welding joins two pieces of metal by the use of heat, pressure, or both.

Arc Welding

Shielded Metal Arc Welding (SMAW)

Carbon Arc Welding (CAW)

Submerged Arc Welding (SAW)

Oxy-acetylene

And Many More …more than 80 in all

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THINK! Safety Begins with ME

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Electric & Gas Welding

Safety Check:

Ensure electrical cord, electrode holder and cables are free from defects

No cable splices within 10 feet of electrode holder

Ensure welding unit is properly grounded - This helps to avoid over heating

All defective equipment shall be repaired or replaced before using

Remove all jewelry – rings, watches, bracelets, etc…

Ensure PPE e.g.. welding hood, gloves, leather boots or safety shoes, apron are available, utilized and in good condition

Ensure fire extinguisher is charged and available

Ensure adequate ventilation and lighting is in place

Set Voltage Regulator to Manufacture’s specifications

Avoid electrical shock DON’T wrap cables around any body part

Ensure fittings are tight

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EVERY welding operation, no matter how small, will have a complete JHA.

The JHA will go over the steps of the operation, what the hazards are for that step, then how that hazard is going to be reduced or eliminated.

Your crew input is important, we may miss hazards you recognize.

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Health Hazards:

Gases, fumes, and smoke

Welding “Smoke” is a mixture of very fine particles called fumes and gases

Welding “Smoke” contains fumes and gases including… Chromium, nickel, arsenic, asbestos, manganese, silica, beryllium, cadmium, nitrogen

oxides, phosgene, acrolein, fluorine compounds, carbon monoxide, cobalt, copper, lead, ozone, selenium, and zinc

Generally, gases and fumes come from…

Base material & filler material

Coatings & paints

Shielding gases & chemical reactions

Process & consumables used

Contaminants in the air

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Electrical Hazards: Even though welding generally uses low voltage, there is still a danger of

electric shock Wet work areas, cramped work spaces Falls, fractures and other accidents can result from electrical exposure Even small shock can cause brain damage Death can occur from large shocks (electrocution)

Electrical Do’s and Don'ts: Always use dry gloves Always wear rubber soled shoes

Always use insulating layers Protect yourself from surfaces that conduct electricity When working on electrically powered machinery, make sure the frame is

grounded Keep insulation on all welding equipment and components dry and in good

condition Don’t change electrodes with bare hands, wet gloves or while standing on wet

or ungrounded surfaces

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General Requirements

Focuses on using Acetylene Safely

Flammable

Unstable

Cannot be adjusted above 15 psi

Safe Work Practices

Blow out cylinder valve

Turn on cylinder valve first and then adjust the regulator pressure screw

Never stand in front or behind a regulator when opening the cylinder valve

Open cylinder valve slowly

Purge oxygen and acetylene passages

Light the acetylene

Never use oil or grease

Do not use oxygen as a substitute for air

Keep your work area clean

The pressure adjusting screw: Turning clockwise allows the gas to flow. Turning counterclockwise reduces or stops the gas flow.

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Away from heat sources (such as radiators) Well-protected, ventilated, dry location at least 20 ft from combustibles Assigned storage spaces, protected from damage & tampering When empty: closed valves When not in use: hand-tight valve protection caps

Distance: 20 ft from fuel-gas cylinders or combustibles, or Barrier: 5 ft high noncombustible partition with half-hour fire-resistance rating

Protect oxygen cylinders from fire hazards such as acetylene

Operation must emphasize the absence of oily or greasy substances. Follow these rules of operation:

Cylinders, cylinder valves, couplings, regulators, hose, and apparatus shall be kept free from oily or greasy substances.

Oxygen cylinders or apparatus shall not be handled with oily hands or gloves.

A jet of oxygen must never be permitted to strike an oily surface, greasy clothes, or enter a fuel oil or other storage tank.

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Intense heat and sparks can cause fires or explosions if in the vicinity of combustible or flammable materials

Welding and cutting should only be performed in areas free of combustible materials such as trash, wood, paper, textiles, plastics, chemicals, and flammable dusts, liquids and gases

Never weld or cut on containers that have held a flammable or combustible material unless the container is thoroughly cleaned or filled with an inert gas

A fire watch should be performed during the welding operation, prior to leaving a work area, and for at least 30 minutes after the operation is completed

Fire extinguishers should be nearby, of proper size, type and number for the hazards involved

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After a specific hazard(s) has been identified…you can implement appropriate control method(s)

Engineering Controls:

Substitute less hazardous materials for hazardous materials

Use cadmium-free silver solders

Use asbestos- free electrodes, gloves, and hot pads

Use ventilation to move away or dilute hazards

Use work area barriers to protect others working in the same general area

Welding booths should be painted with dull finishes so they don’t reflect UV light

Acoustic and arc flash shields should be used to reduce noise and radiation exposure

Noisy machinery can be totally enclosed

Modify the process or follow Kiewit safe work practices so that hazards are eliminated or reduced to the minimum

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Personal Protective Equipment (PPE):

When engineering administrative controls have not effectively eliminated or substantially reduced the hazards, PPE is your last line of defense.

PPE must be used in conjunction with engineering controls and safe work practices.

Use of one does not eliminate the need for the other

Fire-resistant gloves

Aprons

Safety shoes

Hearing protection – ear plugs

Helmet

Ultraviolet radiation filter plate (arc welding)

Goggles with filter lenses

Filter corresponding shade numbers:

SMAW – 1/16 - 5/32 = #10

Gas SAW - 1/16 - 5/32 = #11 (nonferrous)

Gas SAW – 1/16 – 5/32 = #12 (ferrous)

SMAW – 3/16 – 1/4 = #12

5/16 & 3/8 electrodes = #14

Carbon Arc Welding CAW = #14

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