8 Steps for Building Safer Fluid Systems
We understand that the oil and gas industry is inherently complex and only becoming more complicated. Today there are deeper wells, new drilling techniques, and more sub-sea equipment and controls, together with higher temperatures and pressures in more corrosive environments. There also are increased health, safety, and environmental concerns as well as more demanding standards, regulations, and other forms of liability.
Where seizing opportunity means assuming more risk, how can oil and gas operators minimize safety concerns for rig, refinery, and plant personnel?
When it comes to the reliable operation of fluid systems, there is a real answer: Safe working conditions start with careful design considerations. Before you replace parts or put a completely new system in place, brush up on these best practices:
1. Never intermix components from different manufacturers.Leak-tight seals that will withstand high pressure, vibration, vacuum, and temperature changes depend on exacting tolerances, meticulous quality control, and time-tested design principles. Though components from different suppliers may look alike, there is no assurance they are manufactured to the same rigorous standards, meaning they may not perform properly when used with other manufacturers’ components. System surveys have found that roughly 35 percent of intermixed fittings leak, which have a higher risk of catastrophic failure. Read related blog on Intermixing/Interchanging tube fittings. |
2. Choose your alloys carefully.
Material chemistry is a major consideration in most oil and gas environments, particularly on offshore platforms. Component compatibility, if not controlled properly, can result in serious issues, including Chloride Stress Corrosion Cracking (crack formation in pipework and tubing in a chloride-rich environment with costly, even disastrous results).
Numerous alloys have been used or have presented themselves as candidates for use in installations that require resistance to seawater corrosion. The most frequently used alloys have been the 300-series austenitic stainless steels, mainly 316 and in some cases 317. Alloys with at least 6% molybdenum, the so-called “6-moly” alloys, have performed well in offshore systems. Typical 6-moly alloys include 254SMO, AL6XN and 25-6Mo.
More recently, alloys with slightly more than 6% molybdenum have been introduced: 654SMO, AL6XN Plus, 27-7Mo and 31. The published properties of these alloys suggest that they would perform well in chloride environments. Meanwhile, nickel alloys such as 825, 625 and C-276 are more frequently used for their performance in sour gas applications. Read more about Material Selection.
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3. Minimize opportunities for mistakes.Consider how better labeling and safety-minded system design can reduce opportunities for mistakes to happen. For instance, be sure to place tags on your equipment to indicate what an operator is viewing. Try to color-code handles, tubing, and pipe to make it clear at a glance what types of fluids or gases are flowing through them, even in processes where hydrocarbons are not present. Also take care to orient components in a way that avoids accidental contact with moving objects or people passing by. Read more on labeling critical components this related blog. |
4. Only use ideal materials for the job.
It may be tempting to make a price-based decision, but where the stakes are highest it is rarely worth the risk, and you should only rely on products with a proven reputation. The market has become saturated with counterfeit and substandard inventory that can harm your operation. Only purchase through trusted partners and authorized channels.
Also important is knowing the difference between similar-sounding parts and being precise when deciding which to use. For instance, a safety valve (which opens fully at a set pressure) is not the same as a relief valve (which opens gradually as pressure increases). While the terms are sometimes used interchangeably, it does not mean the parts should be.
5. Remove complexity wherever you can.Reduce system complexity where possible to minimize potential complications, and never stop looking for opportunities to make improvements. Simplifying systems also helps down the line, as it will be easier to troubleshoot problems when there are not as many components to analyse. Consult an expert who can make recommendations for making fewer connections. Ultimately, this reduces the number of parts that could potentially fail. Read more about considering the design of your system in this related blog. |
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6. Always follow manufacturer instructions carefully.
Failure to follow documented assembly and disassembly procedures might seem like a minor mistake but it can lead to major consequences. Common errors include:- Undertightening fittings, creating opportunities for leaks and blowouts
- Overtightening fittings, limiting the potential number of remakes
- Not ensuring tubing rests firmly on the shoulder of the tube fitting body before tightening
- Not following proper protocols for tube insertion depth or not “bottoming out” the tube
- Failing to properly check tubes for ovality, defects or scratches that can compromise a seal
For installation best practices and the most comprehensive tube fitting guidelines you will find, refer to
Swagelok's Tube Fitter's Manual.
7. Factor for vibration and motion in your designs. When assembling a de-energized system (something you should always do, as working on a pressurized system is highly dangerous), it can be easy to forget about the effects of machine vibration. Be sure you have the proper supports in place to ensure tubing and fittings will not be unduly fatigued or dislodged during high-pressure usage. The constant strain placed on a system by vibration can also gradually wear away at connection points, so specifying proper materials from the start and allowing for a proper range of motion are important. In some circumstances, switching to hose can eliminate certain vibration concerns. Keep in mind, however, that hoses can wear quickly and will need to be replaced over time. Some elastomers also have a limited shelf life—know the age of the hose you will be installing. |
8. Account for material hardness when making tube systems.
It is important that component materials be compatible with each other and will have the appropriate hardness to stay connected. Metal tubing materials should be softer than fitting materials to allow the fitting to grip and collet the tube well.
When fluid systems perform flawlessly day after day, it is easy to forget the dangers even one improperly installed component can present. Keeping best practices in mind will keep your operation on guard. These steps sound simple but are often overlooked. There are many ways to design for safety, and with extra care, you can avoid unexpected issues.
Swagelok can help you build safer fluid systems - Swagelok Essentials Training courses provide critical skills for developing, building and maintaining safe and dependable fluid systems, providing a strong foundation of knowledge and the techniques behind fluid component systems.