Safety Parameters Considered During Pressure Vessel Design and Testing

September 9, 2019

According to engineering manuals, pressure vessels are exactingly fabricated containment units. Each tank-like fluid shell is designed by engineering professionals to safely contain overwhelming outward-acting fluid energies. The pressures rise above 100 kPa and keep on climbing. Then there are temperature fluctuations and chemical reactions, which add more punch to an already strained metal framework. Preventing the strain and volatile chemical reactions from violating a system-ingrained hazard threshold, scores of vessel safety parameters must be implemented.

Five-Way Safety Parameter Benchmarking

It all begins with a scientifically metallurgically analysed look into potential alloy families. The heat-treated metal must be malleable so that it can be rolled or cut. Weld compatible, the material requires an elasticity modulus that'll handle fluid expansion and contraction effects. Hard as steel, the sheet metal still has to be able to bulge and then subside when compressed fluids are stored. Fracture-resistant 3000 series stainless steel sheets are one thing, but pure tensile strength isn't any good without a quality-assured welding department to join all of the container elements. ASME P1-F3 weld compliance is an absolute minimum when working on pressure vessel projects. Two testing phases come next. There are NDT (Non-Destructive Tests) to conduct, then ASME specified load-bearing inspections as well. Somewhere among those tests and fabrication codes, inbuilt safety devices are installed, too.

Designing and Implementing Built-in Safety Devices

This safety parameter has earned a whole paragraph to itself. Remember, pressure thresholds and temperature extremes can cause pressure vessel steel plating to swell dangerously outward. Chemical reactions add insult to injury, which means unpredictable transient compressive effects can severely impact metallic elasticity thresholds. On top of these safety-compromising factors, the fluid in question could be volatile, could be explosive or combustible. A contained liquid might behave perfectly innocuously when stored, but it might just vaporize and become a respiratory threat when it leaks. To deal with these potentially hazardous scenarios and more, mechanical and instrument-based devices are mounted on pressure vessel fittings. The available devices include pressure gauges and fluid level indicators, plus several fire suppression solutions.

Last in a wide range of incorporated hazard-mitigation solutions, drainage vents and pressure tank depressurization mechanisms act as a final line of defence. If a fluid monitoring steam gauge goes into the red, the dynamic pressure relieving systems safely release the pressure. So, when installing a pressure containment unit, the above factors must always be considered. They're the primary safety parameters, the system hazards that come under the keen eye of a pressure designer. From here a bare minimum approach will conceive of a design that'll comply with all ISO and ASME standards. More likely, however, multiple redundancy systems will find their way into the final installation.

Contact Details

Fusion - Weld Engineering Pty Ltd
ABN 98 068 987619

1865 Frankston Flinders Road,
Hastings, VIC 3915

Ph: (03) 5909 8218

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