Forming gas is a gas mixture people use in certain industrial processes when they need the properties of hydrogen gas without the explosion risk. People mix hydrogen with an inert gas like nitrogen, keeping concentrations below the level where they pose a significant explosives risk. As long as the volume of hydrogen in the mixture remains below 5.7% of the total, it should not spontaneously combust, and people can work with the gas in relative safety. People can produce this product with a chemical reaction or by blending the contents of gas cylinders.
One area where people use forming gas is in the preparation of photographic films and plates, particularly for operations where any contaminants could seriously compromise the resulting image. Astronomers, for example, need very high quality film and plates for their work, as the exposures are long and the details are often faint; people do not want to mistake a fleck of dust on the film for an object in the sky. Manufacturers fill chambers with forming gas to drive impurities out of the film and control the quality.
This product is also useful in metal soldering and annealing applications. Manufacturers with a need for this product can use it in a variety of settings and may produce it on site using their own equipment, or order it from a supplier. People learn to work with forming gas while handling metals to determine when it is appropriate to use and how to use it safely and effectively. People use a variety of other gas mixtures in metalworking as well.
When companies use metal heat treatments to develop metals with specific characteristics, forming gas is available for use in the furnace or kiln. People must carefully control the environment to keep it as safe as possible and to avoid contaminants in the metal, as a small error can result in structural weaknesses like bubbles or flecks of impurities. Personnel must also monitor the composition of the mixture to make sure it does not enter the danger zone.
Forming gas is not explosive, but it can still be dangerous. People working around gas mixtures need to be careful about inhalation and the risks of leaks from canisters, tubes, and regulators. If enough gas leaks out, it may displace the oxygen in the room and people could be unaware until it is too late. Some companies add odors to their gases so people working around them will be able to tell by smell when there's a problem.