Maintaining Gas Distribution System Health
Facility gas distribution systems may handle reactive, toxic, corrosive, or high-purity gases and are meant to:
- Provide an access point to a gas supply system
- Reduce the source pressure to a lower constant
- Enable an uninterrupted supply of gases
Serious risks can result when a gas distribution system is not functioning properly. For example, the systems often handle contents at high pressures and temperatures. Any leaks can therefore cause burns or other injuries, even if the gas is inherently non-hazardous. In addition, overpressurization can damage sensitive equipment and lead to costly repairs and replacements.
There are also added costs to contend with when gas distribution systems leak. Minor leaks can go unnoticed for a long time, and result in significant losses annually.
How Subsystems Can Help
Operating a safe, efficient gas distribution system starts with a proper system design that can effectively reduce pressure from a supply source and deliver it at a stable pressure to a point of use with minimal interruption. While such systems can be fabricated on-site, it can be more economical to source key subsystems from suppliers, including the following:
Source Inlet: The inlet connects the high-pressure gas source to the gas distribution system and should include appropriate cylinder connections, hoses, tubing, filters, and vent, purge, and relief functions. Always verify that panels include a standard source inlet and use the correct cylinder connector. In addition, special application hoses may be used for some high-pressure and/or hazardous gases (including oxygen).
Primary Gas Pressure Control Panel: This panel performs the first pressure reduction and ensures the source gas is delivered at the correct flow rate to the next stage of the system. It may use either a single pressure regulator or a dual pressure regulator arrangement. Although, many bottles that use a two-stage arrangement may not require one, so you can save costs by eliminating one regulator.
Automatic Changeover Panel: This panel enables an uninterrupted supply of gas to critical points of use by automatically switching the system from one gas source to another. Doing so removes humans from the changeover event, saving direct labor costs and reducing risk. Within the panel, two pressure regulators with staggered set points allow the system to continue operating as the primary gas source is changed. Doing so helps to ensure as much gas can be used from each bottle as possible.
Point-of-Use: Providing the critical last stage of control, point-of-use subsystems typically include a pressure regulator, gauge, and isolation valve so operators can conveniently and accurately adjust pressure.
System Design and Assembly
Proper component selection, sound design and assembly, and ongoing maintenance are essential for long-term gas distribution system reliability.
Components
When selecting components, ensure they will be fully compatible with the system and its contents. Incompatibility is a common cause of unsafe and costly systems, so getting this step right can help systems operate as safely and efficiently as possible. For example, the materials of construction must be able to handle the type of gases flowing through the system in addition to the maximum anticipated operating temperatures and pressures.
Design
Thoughtful system design is also critical to delivering optimal system efficiency and safety. For example, be sure that any subsystems used have minimal threaded connections to reduce the number of potential leak points. They should also be designed for intuitive operation and maintenance. In addition, make careful, consistent choices for the entire system, considering tube routing, component selection, and more to create safer and more efficient systems.
Assembly and Installation
Undesired safety consequences can occur when errors are made during system assembly and installation. Be sure to adequately test systems to ensure the safety of operators and bystanders – not to mention the system’s longevity. Maintaining proper training for assemblers and installers will help to minimize leaks or improper component operation. Once installation is complete, make sure operators are properly trained to use and maintain the systems.
Maintenance
The design of a gas panel can significantly enhance operating and maintenance efficiencies. For example, a panel with primary components like regulators on the front, rather than in the rear, will be easier to access when performing filter changes or other maintenance tasks, saving time and maintenance costs.
Enhancing Systems
A third-party evaluation may help facilities identify opportunities for larger gas distribution system upgrades, inform the sizing and selection of components, and guide the design and assembly of an engineered system. Fluid system specialists can help facilities follow the guidelines shared above to develop new systems and enhance existing ones to be safer, more efficient, and more economical.
An original version of this article appeared on the Swagelok Reference Point blog here.
By Jeff DeWitt, Applications Engineer, Swagelok