Fluid handling facilities depend on gas distribution system design to safely and efficiently deliver gases from a high-pressure source to various points of use at the required pressure and flow rate. The gases involved are under pressure and can be toxic, corrosive, or flammable, so safe and efficient operation requires careful design decisions. Proper gas distribution system design can prevent leaks, downtime, and safety hazards—protecting operators and keeping your system running efficiently.
Gas distribution systems typically have four subsystems: the source inlet, gas panel, changeover, and point-of-use. Here, we’ll look at each of these subsystems and go over some general design recommendations to maximize safety and efficiency.
Gas distribution systems may involve hazardous gases. To prevent harm to operators, equipment, and the environment, the gas distribution system design must account for these potential hazards and mitigate the risks as much as possible.
Here are a few things to keep in mind for any gas distribution system design:
Oxygen systems can be a significant fire hazard. Materials that may be safe in atmospheric oxygen levels can ignite in an oxygen-enriched environment.
The “fire triangle” above shows the three elements needed to ignite a fire: oxygen, fuel, and heat. Usually, fires in the atmosphere can be prevented by removing or limiting those elements, but oxygen and fuel inevitably exist in an oxygen handling system. Careful gas distribution system design decisions can minimize the risk of fires by eliminating sources of heat or ignition energy. Some ways to do this include:
The source inlet connection is the first stage of a gas distribution system, which connects the high-pressure gas source (one or multiple gas cylinders or bottles) to the rest of the system. For a single-cylinder, the source inlet may simply be a hose with a cylinder connector. When there are multiple cylinders or bottles, the source inlet can be a more complex system of hoses and valves that deliver the gas to the primary gas pressure control or automatic changeover system.
Like the rest of the gas distribution system design, the source inlet is based on the application. Some options include:
The gas panel is the primary gas pressure control. It must reduce gas pressure while maintaining the required system flow. It accomplishes this with either a one- or two-stage pressure regulator arrangement. The exact gas panel design specifications depend on the gas being handled and individual process requirements.
The pressure regulator is the heart of the gas distribution system, so it’s critical to select the right one. The regulator should operate along the flattest part of the flow curve.
The example above illustrates the three parts of a flow curve:
To prevent failures, the pressure regulator should have a filter upstream to remove solid particles and protect the regulator. The size and material of the filter element and its housing depend on the gas composition, solids content, pressure, flow, and other system characteristics.
An automatic changeover system seamlessly switches from one gas source to another when it reaches a set changeover pressure. It provides primary pressure control without ever interrupting the gas supply, letting the system operate continuously at a constant pressure. Eliminating manual changeovers also saves time and eliminates human error.
Changeovers can be semi- or fully automated. There are also additional safety options available for hazardous gas or oxygen systems.
Point-of-use systems are usually the least complex part of gas distribution system design. They provide the last stage of pressure control before the gas is used. A point-of-use station typically contains a pressure regulator, pressure gauge, and isolation valve to let operators precisely adjust the pressure for the application needs.
A point-of-use system should provide standard, consistent operation and be convenient and safe for the operator. Compact design and custom mounting options can help maximize space and make the system as easy and safe to use as possible.
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Whether you’re installing a new gas distribution system or upgrading an existing one, Swagelok can help. Our Field Engineers can evaluate existing systems, recommend the best components, subsystem design, and gas panel layout for new systems, and develop equipment management programs based on your facility’s needs. We provide standardized, modular systems and options, customized to your operation.
To find out more about how Swagelok Northern California can help with your gas distribution system design needs, contact our team today by calling 510-933-6200.
About Malik Durojaiye | Field Engineer, Assembly Services
Malik Durojaiye began his Swagelok career in 2019 as a Custom Solutions Engineer in our Assembly Services group. Prior to Swagelok, Malik developed as a design engineer as well as a manufacturing engineer for 6 years serving Kentucky and California with Altec Industries; a leading provider of products and services to the electric utility, telecommunications, tree care, lights and signs, and contractor markets.