As drilling operations explore ever greater depths and pressures, operating pressures for new valve assemblies are going beyond traditional limits. The service-duty requirements for new valve designs push the limits of material strengths, in what can be a highly-corrosive and challenging environment. Some testing requirements may reach 50,000 psi (3450 bar) working pressure or higher, with a 1.5 safety factor. Adding to these requirements are new American Petroleum Institute recommendations for testing components under API 598, RP591 and others.
The requirements for these complex assemblies are evolving and manufacturers are reaching the limits of current testing capabilities for components. This can include operations at extremes of temperature, pressure and flow. The safety issues associated with extreme testing simulation are not for the uninitiated. Uncontained events have the potential to be catastrophic, endangering equipment and personnel.
There are three basic types of test enclosures: Modular, Containment Pit and Portable.
Let's discuss some of the unique design challenges associated with each type. First, the most common type is a modular, steel frame design. These are called Modular Test Enclosures (MTE), because the basic design can be scaled based on size, pressure, and duty requirements.
A number of practical considerations must be determined before choosing the appropriate design. To properly evaluate the design requirements, consider:
- Maximum component size, including accessories and instrumentation
- Maximum component weight
- Fluids capability (i.e., hot oil)
- Maximum pressure
- Maximum temperature
- Corrosion environment
- Production volume
Modular Test Enclosures
Modular Test Enclosures (MTE) are designed for low- to medium-pressure applications that require personnel protection from uncontained release events. The testing enclosure will have a unique set of safety requirements, procedures and routine tests to maintain its safe operation—which would be true of any large safety system. MTEs will generally accommodate simple pressure testing up to about 20,000 psi (1380 bar), depending on the size and complexity. Manufacturers want a design that accommodates their maximum production rate, so that testing does not become a “bottleneck” in the process flow. Above 20,000 psi (1380 bar), other design features and redundancies may be needed.
Ultra-High Pressure Enclosures
Ultra-High Pressure Enclosures (UPE) are generally above 20,000 psi (1380 bar) working pressure. These may be above-ground structures or below-ground containment pits. The safety features for these systems require considerations for complete isolation and containment of the equipment, in the event of an uncontained release. These features may include a reinforced-concrete safety pit, as well as added protections for personnel and equipment isolation.
The designs are enhanced using hydraulically-actuated steel canopies to contain any possible vertical release. The side walls are designed with reinforced-concrete, and the surfaces are sealed. The design must accommodate possible fluid releases and include the capability for remedial cleanup.
Portable Test Enclosures
Another type, Portable Test Enclosures (PTE), are gaining interest due to their ability to be deployed into the field or into a smaller footprint-type working environment. They can be designed for small assemblies that can be manufactured and tested on-site, resulting in significant cost and schedule savings. Other capabilities such as torque and dyno measurements can be added to reduce test cell time and turnaround.
Beyond the testing issues are the considerations for the customer end user. Many test enclosures are designed with the customer in mind; for example, witness testing. Additional considerations for customer convenience may require remote viewing capability, data streaming and features that are not usually considered in a manufacturing environment. The end goal for a successful component test is more than assurance of the component or valve; it should demonstrate a safe operational capability under the most hazardous conditions, with the service provider able to confidently duplicate any field environment, prior to its release for service.
Given the increasing industry requirements for testing prior to service introduction, it is likely that many component manufacturers will require service-duty testing. Manufacturers find that providing this assurance to customers can prove beneficial for developing new designs and gaining market acceptance quickly. API 598, RP 591, ASME B16.34 and other industry standards are helping design teams to develop the best approach for engineered product solutions. Each solution can be a unique design based on needs and space requirements, even while the service-duty requirements may be similar. The next few years will be critical for the industry as it adapts to these changes and evolving engineering requirements.
- American Petroleum Institute (API), Standard 598, Valve Inspection and Testing, September 2009. (under revision)
- American Petroleum Institute (API), Recommended Practice 591; Process Valve Qualification Procedure, 2014.
- American Petroleum Institute (API), Specification 6D, Specification for Pipeline and Piping Valves; August 2014.
- American Society of Mechanical Engineers (ASME) B16.34, Valves - Flanged, Threaded and Welding End; 2013.
- Canadian Standards Association (CSA) Z662-15: Oil and Gas Pipeline Systems; 2015.
- International Standards Organization, BS EN ISO 4413: Hydraulic fluid power – General rules relating to systems; 2011.
- High Pressure Testing Bunker; Lee Pistell, EMC Services, 2012. https://www.youtube.com/watch?v=Ft5CKjOMmPE
- Securing Manually Operated Testing Bunker; Lee Pistel, EMC Services, 2014. https://www.youtube.com/watch?v=-qx9AZSs0g4
- R&D High Pressure Testing Blast Containment Pit Cover; Lee Pistel, EMC Services, 2014. https://www.youtube.com/watch?v=T7JfTQ3hClo