The process of welding gas or diesel tanks can be extremely dangerous. There is the possibility of igniting fuel vapors, and if the welder is using the welding process of MIG or TIG inside a fuel storage tank, they are in danger of suffocating from fumes if argon gas is used.
This not only poses a threat to the welder but to anyone who tries to rescue the welder from the interior of the fuel tank. We hope that the tips we’ve listed below will help keep you safe if you are required to perform any welds in a fuel tank.
Before beginning to work on the fuel tank you should first ensure that the battery has been disconnected and that the ignition is in the off position. By making sure that all of the power sources are off, you are reducing the chance that a spark might set off any fuel in the tank. Once you have done this you can then proceed to drain the fuel tank of fuel that may still be inside.
The next step would be to completely drain the fuel tank in an approved gas container designed for use with flammable liquids. It is highly recommended that the draining of gasoline tanks not be performed over or near inspection pits.
Once you have completely removed all of the gas from the tank you can now remove it from the vehicle. It is important that you use the proper ventilation equipment when working with gas tanks due to the high amount of fumes that may be present.
After you have safely removed the gas tank from the vehicle you should thoroughly rinse the tank several times with warm, soapy water. The water should be placed in an approved flammable container. Do not dispose of the water in the street or in drains — it can cause a very dangerous situation.
Your next step will be to evacuate the fuel fumes from the tank using an air hose for a minimum of one hour or until you can no longer detect any fuel fumes. You can conduct chemical tests to determine whether all of the fuel fumes have been thoroughly removed and whether the tank is safe to weld.
Why Welding a Fuel Tank is Dangerous
The main concern with welding a fuel tank lies in the risk of combustion or fire.
The vapors from the gas can easily ignite at any time while you are welding a tank that has housed any type of fuel at any point.
Whether you are working with a large, stand-alone fuel tank or a vehicle fuel tank – many of the concerns remain the same.
The constant flying sparks, while you are welding, is the primary concern for interaction with any residual fuel left in the tank.
Those sparks may seem small and harmless, but they stay surprisingly hot even as they fly through the air.
According to the American Welding Society Safety and Healthy Fact Sheet, flying sparks, molten metal, and spatter are the leading causes of fires and explosions in welding. From the work area, those little particles can travel up to 35 feet.
Not only can they travel a far distance, but they can also get lodged in different areas without you even knowing. For example, they easily get stuck in:
- Pipe holes
- Cracks or crevices
- Pipe holes
If a spark has lodged itself in any of these areas while gas is present, it can easily cause a fire. Any type of welding in an area that gas of any type is or was present is going to be a fire and safety hazard.
The other main concern over welding a fuel tank is the process being used for the welding itself.
If MIG (Metal Insert Gas) or TIG (Tungsten Insert Gas) are being used, there is even a risk of suffocation while inside the fuel tank if there is a presence of argon gas.
Both MIG and TIG commonly use argon gas or a mixture that includes argon as a shielding gas.
Mixtures of argon containing oxygen and carbon dioxide or helium are not considered dangerous to your health. However, they are considered asphyxiants.
Because of the added asphyxiation risk, welding inside of a larger fuel tank can be hazardous.
While there is still a threat posed for smaller, vehicle fuel tanks and any mixtures of argon gas, it is far more dangerous when working in larger tanks where airflow could be compromised.
Therefore, without proper ventilation, equipment, and precautions, if argon is present inside the fuel tank, it can cause suffocation.
Because argon and other gases used as shielding gas are scentless and cannot be seen, they are a danger that often time will go undetected if proper safety precautions are not put in place.
It is always recommended to have a gas detector that will be able to alert you of the presence of argon or other dangerous elements in the air that are undetectable by scent or sight.