Structural Welding: Shop and Field Work on Steel Frames

Structural welders join the steel that holds up buildings, stadiums, bridges and towers. Some work indoors in a fabrication shop. Others work outside on a rising frame, often high above the ground. Either way, the welds carry real loads, so they are made to a code and checked by inspectors.

What You Will Be Able to Do

• Describe shop and field structural welding.
• Explain why the work is done to a code.
• Name the hazards that can hurt you on day one.
• Explain the fall protection trigger heights that apply.
• Know what you need before you start.

Shop and Field Work

In the shop, fitters lay out the parts, and welders follow prints and weld symbols. Parts get turned and positioned, so most welding is in comfortable positions.

In the field, ironworkers lift and bolt the steel into place. Some ironworkers specialize as welders. Field welders make connections such as moment connections, column splices and metal decking welds, often from a lift, a float or a beam.

Working to a Code

AWS D1.1, the Structural Welding Code - Steel, sets the rules for most structural steel work. It covers how procedures are written, how welders are tested and what inspectors accept. Your job will have a written Welding Procedure Specification (WPS) that sets out how each joint must be made, and you must stay inside it.

Most shops and sites will test you before you weld on the job. Common tests are 3G and 4G plate tests with E7018 or flux-cored wire. An inspector can check your settings, your rods and your finished welds. That is normal, and it is a sign of a good shop.

What Will Hurt You on Day One

Falls

Falls are the biggest danger for field welders. In the US, general construction fall protection starts at 6 feet under OSHA 1926 Subpart M. Steel erection has its own rules under Subpart R, with a general trigger of 15 feet, and connectors have separate rules for work over two stories or 30 feet. Many sites and employers are stricter, such as 100 percent tie-off at 6 feet. Find out what yours requires before your first shift, and inspect your harness and lanyard every day.

Warning: Welding sparks and hot slag can burn through a lanyard or a rope. Keep your fall protection away from the arc, or use gear rated for hot work.

Falling Objects

Rods, stubs, tools and slag drop onto people below. Tie off your tools, use a stub bucket, and keep the area under you barricaded. Wear a hard hat, and look up before you walk.

Crane Loads

Never stand under a suspended load. Steel swings, and a load can shift without warning. Learn the signals on your site. Listen to the connector and the signal person.

Electric Shock

Steel frames are excellent conductors, and damp conditions are common on site. Keep gloves and clothing dry, inspect leads, and do not drape cables over your body. A lead dragged across sharp steel can wear through, and a shock at height can cause a fall.

Arc Flash and Fire

Other workers may be close, so use screens and warn them. Sparks fall a long way from height. A fire watch and hot work permit are normal, and combustibles below you need protection or clearing.

Fume

Flux-cored wire makes a lot of fume, and shop bays and box sections can trap it. Primer and galvanizing on steel add to it. Use the ventilation and respiratory protection the job requires.

Heavy Steel and Pinch Points

Beams and plates can roll or shift. Keep your hands out from between steel, and do not put your fingers in bolt holes to line up parts. Use a drift pin or a spud wrench.

Weather

Heat, cold, wind and ice all matter. Rain and wet steel stop welding work, and they also make steel slippery underfoot.

What You Will Need

• A current welder qualification, or a plan to take one
• Hard hat, safety glasses and boots
• Welding hood, leathers and gloves
• Harness and lanyard, if you work at height
• Stub bucket and tool lanyards
• Chipping hammer, wire brush and grinder
• Soapstone and a fillet gauge
• Any site training cards the job requires

Your First Week

In the shop, you may start by tacking, grinding and cleaning welds. In the field, you may help carry leads, set up machines and stage rods. Learn the WPS for your work, and learn where the rod oven is.

Your First Exercise

Pick a weld symbol from a shop drawing, and write it out in plain words: what weld, what size, which side and how long. Then find the joint on the real part, and check it with a fillet gauge. Ask a lead welder to check your reading. Doing this every day is a quick way to learn how the drawing connects to the steel.

Common Mistakes

• Using the wrong rods. A rod that looks close may not be on the WPS.
• Leaving rods out of the oven. E7018 picks up moisture, which can lead to cracks.
• Hooking up to anything handy. Your anchor must be rated for fall protection.
• Welding over a bad fit-up. Tell your lead. Do not bury the problem.

Check Your Understanding

You are welding on a beam 20 feet up, and your lanyard is lying across the joint. Why is that a problem?

Sparks and slag can burn through it. Move it clear of the arc, or use gear rated for hot work.

A new hire says that fall protection only starts at 15 feet because this is steel erection. What should you tell him?

Check the site rules first. Subpart R has a 15 foot trigger, but many employers and sites require protection at 6 feet.

A rod stub drops from your position. What should you have done?

Used a stub bucket, and kept the area below you barricaded. A small stub can injure someone below.

You find a beam splice where the gap is well outside what the WPS shows. What do you do?

Stop and tell your lead. Welding over a bad fit-up can leave a rejected weld.

Key Takeaways

• Structural welders work in shops and in the field, on steel that carries real loads.
• Most work follows AWS D1.1 and a written WPS.
• Falls are the top danger in the field, and trigger heights depend on the work and the site.
• Keep your lanyard away from sparks, and keep your tools tied off.
• Stay out from under loads, and keep your rods dry.