Welding in Confined Spaces on Stainless Steel and Avoiding Hexavalent Chromium

Welding in confined spaces is likely to be a familiar, if unpleasant, task for most welders. It can sometimes seem like most welding work needs to be done in an unairconditioned, unventilated broom closet and done to an object that can only be reached through a foot-by-foot hole in the wall. It can often seem that welding in confined, awkward, and downright unpleasant places is the norm in welding.

When it comes to welding pipe and tube, the issue is even more acute as most piping and tubing assemblies are tucked into inaccessible places by design and crowd as many into as small a place as possible, seriously reducing accessibility and room to weld in.

However, the most dangerous aspect of welding in confined spaces isn’t the difficulty or discomfort in reaching the workpiece. Instead, it’s being exposed to hazardous conditions like excessive heat, industrial chemicals, or heavy metals in tightly confined spaces without adequate ventilation. The results can be anything from immediate death to serious long-term health issues that can take years to make themselves known.

The Hazards of Welding in Confined Spaces

The hazards of welding in confined spaces are diverse and sometimes unexpected. While some of the risks of welding in confined spaces (like becoming stuck due to a lack of room to maneuver or accidentally burning oneself on the workpiece for the same reason) are obvious, others aren’t so clear at first glance.

Despite wearing a welding mask, one of the most reported issues amongst welders in vessels and tanks is flash burn to the eyes. The culprit is the light from the arc being reflected by the tank’s interior surface, especially if the tank is built from a reflective metal like stainless steel. The secondary reflection of the light off the interior of the lens of the welder’s mask into the eye is sufficient to burn the eye. Broadly the risks of welding in confined spaces fall under the following categories:

• Confinement Hazards: These hazards come from having freedom of motion restricted. They include everything from being injured due to falls, from having freedom of movement restricted to being pinned and or crushed by equipment, tools, or materials in the space with the welder.
• Radiation Hazards: That light and heat are both forms of radiation and are often overlooked. Burns to the skin or eyes due to the light from the arc, or this light being reflected are a form of radiation hazard. This hazard becomes more intense in confined spaces due to the proximity of the welder to the hazard and the difficulty they may have in maneuvering themselves away from it.
• Fire and Explosions: Fire is always a risk when welding due to the heat involved. It is a considerable concern to welding in confined spaces due to what may be minimal options for the welder to escape if a fire does break out when welding. Explosions are another significant hazard in a confined space, and the lack of airflow can allow vapors of volatile chemicals to build up to levels where an explosion is a possibility. This is not solely confined to familiar volatile chemicals like gasoline, as certain energy-dense particles, like grain dust, can create an explosion hazard.
• Fume Hazards: Like explosion hazards, fume hazards are caused by fine particulate matter becoming concentrated in the atmosphere. However, fume hazards are inherent to the welding process itself. Being released by the materials being welded or the equipment being used for welding them. Argon and carbon dioxide are inert gases, but if allowed to build up in a confined space, they can suffocate a welder. The more significant issue is the metal fumes that can be released from metal as it is welded and can build up to dangerous concentrations with immediate and longer-term adverse effects.

For the most part, avoiding the worst hazards of welding in confined spaces is a matter of common sense. Confinement hazards can often be addressed by disassembly or removal of equipment that isn’t likely in use while welding is underway. For example, suppose it isn’t possible to remove parts of the confining structure. In that case, the careful placement of welding equipment and leads can help minimize the risks of the welder becoming unnecessarily encumbered or trapped.

Radiation hazards like burns due to light and heat can be avoided by providing proper personal protective equipment (PPE). A simple hood blocks light from the rear entering a welders mask. Proper cleaning of a confined space before welding and monitoring during welding can reduce the risk of fire and explosions.

The same isn’t necessarily true of the fume hazards from welding, as welding often generates danger in the first place. As a result, it can be hard to tell if fumes are building up to a dangerous level until after work has already begun. This is especially true of fume hazards that don’t have immediate adverse outcomes but can cause serious health issues later. The best-known and most widespread example of this is the risk posed by hexavalent chromium.

Why is Hexavalent Chromium an Issue?

Chromium is one of the most valuable metals around. It is the primary alloying element added to iron to produce stainless steel. In addition, chromium is what gives this metal the ability to resist corrosion. It is also found in a wide variety of paints and pigments where it has similar anti-corrosive properties.

On its own, chromium is nontoxic, and its ionized form, missing electrons of trivalent chromium—missing three electrons—is a nutrient essential to human metabolism. When it is missing six electrons from its outer shell, it becomes the potently carcinogenic hexavalent chromium.

While hexavalent chromium does occur in nature, the action of the arc on stainless steel produces significantly more hexavalent chromium than would ever be encountered in nature. Therefore, when welding in confined spaces, the amount of hexavalent chromium can quickly build up to dangerous levels.

Avoiding hexavalent chromium is made somewhat more difficult because the initial signs of exposure are a runny nose, sneezing, and coughing. Symptoms that aren’t much different from regular seasonal allergies. Only when repeated exposure starts resulting in overt symptoms like sores is it likely that welders or supervisors will become aware of the issue. At which point someone has experienced long-term exposure to a potent carcinogen. While there is a guarantee this will progress to something more serious, the only sure preventative is to avoid exposure in the first place. This is typically accomplished through ventilation systems or full respirator systems for a welder that keeps the levels of hexavalent chromium at safe levels or ensures the welder has filtered air to breathe.

Preventative systems like ventilation and respirators effectively reduce exposure to hexavalent chromium. However, when it comes to welding in confined spaces, these systems are bulky and can be challenging to fit into the area. In addition, mitigating fume hazards can enhance the welder’s risks of becoming entangled, pinned, or confined.

Additionally, welders are a famously cavalier group about personal safety. They will frequently discard PPE if they see it impeding their work or interfering with the quality of their work. Automation offers a potential solution to avoiding fume hazards and most of the welding hazards in confined spaces.

How Orbital Welding Improves Welder Safety and Comfort

When discussing any automation of an industrial process, it’s important to note that automation is rarely a process where a machine handles every aspect from end to end. Instead, the machine often handles some of the more challenging parts while a human performs the initial setup, monitors the process and intervenes if anything seems wrong. It is this sort of automation that orbital welding falls under.

In turn, orbital welding can alleviate many of the hazards of welding in a confined space by removing the welder from the hazardous area during the actual welding process. This can be enabled by combining orbital welding with ancillary systems like an arc welding monitoring system that enables welders to oversee and control welding of large diameter pipe that requires lengthy welding time from an area removed from the hazard area.
On its own, this does significantly reduce the risk of injury due to radiation hazards. Although if someone still casually brushes against metal after welding they can still get burned. It can also help to reduce the risk of all types of injuries from welding in confined spaces, provided common sense is used. Avoiding hexavalent chromium in welding is made much easier when the welder doesn’t have their face close to the point of release while it is actively being welded. It does not remove the need for welding ventilation or other safety systems. It makes them more effective by reducing the potential exposure time for the welder.

Related Resources on ESAB University

• AMI Orbital TIG Welding Equipment
• Orbital Welding: Technology, Applications & Industries
• AMI Orbital Welding Equipment Overview