Industrial Gases by the Numbers

About this book

Almost every fabrication workshop runs on gases it never sees made. Oxygen and acetylene arrive in cylinders for cutting and heating; argon and carbon dioxide mixtures shield the arc in wire and tungsten welding; nitrogen purges pipework; propane fires a heating torch. The gases are delivered, connected and used, and the bills are paid, often without anyone asking where the gas came from, how much is really being used, how much is leaking away, or what would happen if a cylinder leaked in a small room.

This book is for workshop managers, fabricators, maintenance engineers and safety officers who buy, store, pipe and use industrial gases. It assumes basic chemistry, physics and algebra in SI units. It does not replace the gas supplier’s safety data sheets and instructions, the applicable standards, or the safety regulator’s codes of practice. It explains, with numbers, how each gas is made, what its properties mean in practice, how much a workshop uses and what it costs, and how the hazards arise.

Early manuals as a starting point

In the decade after 1905, oxy-acetylene welding spread from France across the world, and its suppliers and teachers wrote manuals for workshops that often had to make their own gas. The Vulcan Process Company’s Instructions on Welding and Cutting of Metals of 1914 began with calcium carbide, acetylene, oxygen and hydrogen before reaching the torch. Calvin F. Swingle’s Oxy-Acetylene Welding and Cutting of 1915 devoted long chapters to the operation and care of acetylene generating plants and to producing oxygen. The Davis-Bournonville company’s 1919 course of instruction for its welders taught combustion, oxygen manufacture, acetylene cylinders and generators, and the dangers of explosive mixtures.

Those workshops dealt directly with gas production, its chemistry, heat and hazards. Most of their methods have been replaced by gases delivered in cylinders and bulk tanks, but the chemistry and physics they taught still explain what is in the cylinder and why it behaves as it does. Each chapter takes one of their themes, checks it and applies it to a modern workshop.

The running case

This is an illustration. A regional fabrication and repair workshop uses oxygen and acetylene for cutting and heating, an argon and carbon dioxide mixture for wire welding, pure argon for tungsten arc welding, nitrogen for purging stainless steel pipe welds, and propane for a heating torch. Its gas bills have risen, it has had a near miss with a leaking cylinder, and its manager wants to review the whole gas system: what is used, what it costs, whether to move from cylinders to bulk supply, and whether storage, piping and controls are safe.

The workshop, its consumption, prices and incidents are invented for teaching. They are not KEVOS® work. Real gas systems are designed with the gas supplier and installed and maintained by competent people to the applicable standards.

How to use the book

Chapter 1 compares the workshop gases and their properties. Chapters 2 to 4 cover acetylene: making it from carbide, generators and why dissolved acetylene replaced them, and purity. Chapter 5 deals with oxygen production, Chapter 6 with hydrogen, and Chapter 7 with shielding and inert gases. Chapters 8 and 9 cover storage and supply, and piping and leaks, and Chapter 10 the hazards and the workshop’s gas plan. Every chapter ends with an exercise and its worked answer.

Limits and professional responsibility

This book is educational. Industrial gases can cause fires, explosions, asphyxiation, cold burns and injuries from pressurised cylinders. Their storage, handling, piping and use must follow the supplier’s safety data sheets and instructions, the applicable standards, such as AS 4332 for storage and handling of gases in cylinders and AS 4839 for portable and mobile oxy-fuel systems, and the work health and safety regulator’s requirements, including Safe Work Australia’s model codes of practice for welding processes and for confined spaces as adopted in each jurisdiction. The historical methods of making gas described here are history, not practice.

An original treatment

READOS covers the oxy-fuel process itself, including cylinder contents and withdrawal, regulators, hoses and flashback, in Oxy-Fuel by the Numbers, and this book links to it rather than repeating it. It concentrates on the gases: how they are made, purified, stored, distributed and controlled. The explanations, the workshop case, the calculations, figures and exercises are original KEVOS® writing. The historical manuals are public-domain works in the United States; their facts are summarised, checked and corrected in new words, and none of their text, tables or illustrations is reproduced.