Welding Cutting and Brazing by Progressive Business Publications

Copyright Progressive Business Publications

Welding, Cutting and Brazing


Safety Hazards of Welding

Fire and explosions

Compressed gases and cylinders

Confined spaces

Electrical hazards

Dangerous machinery

Trips and falls


Health Hazards of Welding

Welding fumes and smoke

Heat and sparks Visible light,

ultraviolet andinfrared radiation

Musculoskeletalinjuries

Noise


Fire Prevention: Basic Precautions

Asses the fire hazards If object to be welded or cut can’t be easily

moved, remove all fire hazards in vicinity If object and fire hazards can’t be moved, use

guards to confine heat, sparks and slag If these requirements can’t be met, then

welding shouldn’t be done Have fire extinguishers ready for instant use


Special Precautions: Fire Watch

Purpose: detect and extinguish smoldering fires Required for locations where more than a minor

fire might develop or:– Appreciable combustible materials closer than 35

feet to operation OR more than 35 feet away, but easily ignitable by sparks

– Wall of floor openings expose combustible materials within a 35-radius

– Combustible materials on other side of walls/ceilings Maintained for at least 1/2 hour after completion


Fire Prevention: Welding is Prohibited in Certain Areas

Areas not authorized by management

Buildings with impaired sprinkler systems

Areas with explosive atmospheres

Areas where explosive atmospheres may develop


Fire Prevention: Used containers

Make sure used drums barrels, tanks or other containers have been thoroughly cleaned

Disconnect pipes or connections tothe container


Personal Protection: Fall Protection

When working at heights– Use railings, safety belts,

lifelines or other safeguards– Protect workers below

from falling sparks or slag

Place welding cables and other equipment clear of passageways, ladders or stairways


Personal Protection: Eye Protection

Use helmets, shields and goggles during arc welding or cutting

Use goggles or other eye protection duringgas welding or oxygen cutting operations

Shield other from welding light with an individual booth or screen, if practical


Personal Protection: Eye Protection - Shading Requirments

Shielded metal arc welding 10

Gas shielded arc welding (non-ferrous)11

Gas-shielded arc welding (ferrous)12

Torch Brazing 3 or 4

Heavy cutting (6 inches & over) 5 or 6


Personal Protection: Clothing

Welding gloves, gauntlets and sleeves Flame resistant aprons High-cut safety boots and leggings Shirts: heavyweight, wool, sleeved, collars

buttoned, no pockets Pants: no cuffs and long enough to extend

over boots For overhead work: shoulder capes, skullcaps,

ear protection


Personal Protection: Ventilation

Ensure adequate ventilation prior to working

Use local exhaust ventilation where needed

Respirators worn:– When cancer-causing agents present – During certain confined space work

Materials requiring extra precautions: fluorine compounds, zinc, lead, beryllium, cadmium, mercury, cleaning compounds, stainless steel


Before Entering Confined Spaces

Acquire confined space permit Ensure adequate ventilation

– Test before entering for flammable/toxic gases or oxygen deficiency

– If flammable or toxic gases are present - ventilate– If ventilation is inadequate, use a respirator

Disconnect pipes, ducts and power lines Leave gas cylinders and welding machines

outside of the confined space


Confined Spaces

Attendant must observe the welder and be ready to execute a pre-planned emergency rescue plan

If arc welding is suspended for a period of time: – Remove electrodes from holders– Disconnect machines from power sources

If gas welding is suspended for a period of time: – Close the torch valves– Shut off the gas supply to the torch– Remove the torch and hose, if practical


Cylinder Storage

In a well-ventilated, dry, location >20 ft away from highly combustible materials such as oil

Away from sources of heat and ignition Away from high traffic areas and exits Stored in compatible groups

– Oxygen and Acetylene: separated by 20 feet or a 5-foot wall with 1/2-hour fire rating

In upright position with valve protection caps on and secured with straps or chains


Cylinder Handling

Never work with unidentified cylinders Refer to MSDS for specific hazards, special

handling instructions, emergency response and first aid information

Inspect cylinders for damage prior to work When transporting:

– Secure to wheeled hand cart with theregulator removed

– Never use valve caps to lift the unit– Don’t drop or bang


Cylinder Handling (cont’d)

Valve protection caps must always be in place when not in use - empties included

If cylinder must be left unattended, close cylinder valve and shut down system

Keep cylinder in an upright position atall times

Keep cylinders and valve caps free from oilor grease

Mark work areas when finished work


Placement of Cylinders During Use

Cylinders must be placed where sparks, hot slag or flames can’t reach them

If that’s not possible, use fire-resistant shields

Keep cylinders away from electrical circuits or objects used for grounding

Cylinders must be placed outside any confined space


To Begin Work

“Crack” the cylinder valve Ensure regulators are compatible, clean and

in good condition before attaching them Make sure hoses and connections are secure When opening the cylinder valve, stand to the

side and open s-l-o-w-l-y. Keep any vendor-supplied keys in place Keep the valve within easy reach


Purge Hoses Prior to Lighting

First, acetylene– Open acetylene

cylinder valve 3/4 turn– Open torch valve

1/4 turn– Adjust to working

pressure with regulator screw

– Close torch valve

Then, oxygen– Open oxygen cylinder

valve fully (slowly)– Open torch valve

1/4 turn– Adjust to working

pressure with regulator screw

– Close torch valve


Lighting and Shutting the Torch

To light torch:– Reopen acetylene

torch valve– Light with friction

lighter: • Never matches• Never cigarettes

– Open oxygen 1/4 turn and adjust flame

To shut off torch:– Close torch valves:

acetylene then oxygen– Close cylinder valves:

acetylene then oxygen– Open both torch valves

to release pressure– Shut off regulator

adjusting handle– Close torch valves


For Safe Use of Acetylene

Never used at pressure in excess of 30 psi absolute or 15 psi gage

Never open acetylene valve more than 1 1/2 turns.

Never use copper fittings or connections


Arc Welding and Cutting

Ensure the work area is dry Double-check the grounding Check connections to the machine

– Make sure work lead is firmly attached – Keep metal clamps free from debris

Never use cables with splices within 10 feet of the holder

Replace cables with damaged insulation or exposed bare connectors


Arc Welding and Cutting (cont’d)

Spread out cables Never coil cables around your body Never strike an arc on a gas cylinder Never change polarity switch during

operation If work must be stopped, disconnect power

source and remove electrodes Store holders where they can’t make

unwanted contact


Summary

Safety and health hazards = special precautions Fire prevention Personal Protection

– Fall safety– PPE– Confined spaces– Ventilation

Use of compressed gas cylinders Safe welding procedures