Amit Bhan discusses the API standard for compressed air systems in the oil and gas industry

Industry standards play a vital role in the development of equipment used in the oil and gas sector. 

Adhering to American Petroleum Institute (API) standards for compressed air systems can realise improved operational efficiencies for engineering, procurement and construction (EPC) clients.

The API is a leading authority on establishing and maintaining standards to help the oil and natural gas industry to safely, efficiently and responsibly supply energy to billions of people worldwide. These standards serve to improve the safety of industry operations, assure quality, help keep costs down, reduce waste and minimise any confusion around recommended best practice.

There are a range of API standards governing compressed air installations that are adhered to by many oil and gas projects around the globe. These standards include 618 for reciprocating compressors, 619 for rotary compressors, 681 for liquid ring compressors and 672 for centrifugal compressors.

Industrial air compressors play a major role in the oil and gas sector, with everything from pneumatic drilling equipment to pipeline transportation utilising compressed air systems. For large-scale EPC projects, then, understanding what these rigorous standards entail and the requirements compressors need to meet to comply with them, is key.

What Are the Requirements?

Used in oil, chemical and gas industry services for handling process air or gas with either lubricated or non-lubricated cylinders, API 618 sets out the minimum design requirements for reciprocating compressors of low to moderate speeds (typically between 300 and 750 rpm). A key section of the standard (7.9) focuses on the design to control pulsation and vibration for systems and is used throughout the oil and gas industry. API 618 also covers lubrication systems, controls, instrumentation, intercoolers, aftercoolers, pulsation suppression devices, and other auxiliary equipment.

Intended for compressors in special-purpose applications, API 619 describes the requirements for dry and oil-flooded, helical-lobe rotary compressors used for vacuum or pressure (or both) in the oil, petrochemical and natural gas industries.

While API 681 covers the minimum requirements for liquid ring vacuum pump and compressor systems. This includes vacuum pump, compressor design and system design. The design of the system is critical to the successful operation of the liquid ring vacuum pump or compressor and close attention must be paid not only to the design of the ring liquid system but also to how it is integrated into the client’s process.

Finally, API 672 covers the minimum requirements for constant speed, packaged, general purpose and integrally geared centrifugal air compressors. This standard is not applicable to machines that develop a pressure rise of less than 0.35 bar (5.0 psi) above atmospheric pressure, which are classed as fans or blowers.

Those working to API standards are able to offer EPC clients in the oil and gas sector key assurances with equipment built to API specifications and operated according to API recommended practices. Some compressed air suppliers – such as Ingersoll Rand – can customise packages to meet API demands. In the case of some EPC contracts, these standards are legislative and regulatory requirements because they are viewed as critical for helping to safeguard the health and safety of those using a facility. Other key benefits of adhering to API standards include:

Improved Efficiency

Compressed air systems that are designed to API standards will be optimised for performance and managing any potential issues that might arise, so these can be resolved quickly. Many industrial installations will require a customised compressed air solution to meet the specific needs of a site. Any standardisation efforts ensure equipment interchangeability, meaning EPC contractors can meet the technical specifications of the end customer for a greater number of projects.

Operational Safety

Guaranteeing the health and safety of site operatives should be a number one priority and adhering to API standards demonstrates that the correct steps have been taken to safeguard employees. Specifying compressed air equipment that has been designed and built to API specifications and best practice can mitigate any risks to the operator, or at least reduce these to an acceptable level. Industry standards written to meet the industry’s needs also provide a clear structure for operating processes, resulting in better working methods and risk reduction.

Environmental Safety

Today, eliminating potential damage to any ecosystem by reducing waste and possible hazards is a priority for organisations operating in the oil and gas industry. Specifying equipment that meets API standards helps ensure any opportunities to lessen the environmental impact of operations or limit risks to ecosystems will have been taken.

Downtime Costs Cut

Equipment that meets API standards can provide added assurance that all possible measures have been taken to ensure safer operations with little to no downtime. Any equipment inefficiencies will result in production losses and impact potential revenue and profit. Also, should problems arise with a compressed air system, then there will be additional costs to remedy these.

Production Reliability

To help ensure a compressed air installation continues to deliver against expected projections for its service lifetime, equipment that adheres to API standards should perform as expected throughout the duration of its working life. As such, clients can protect their capital investments with products that meet API standards.

Many API standards will be included in contractual agreements to guide the specification and control the quality of compressed air systems, and so it is critical that suppliers have the experience and expertise to meet these demands.

API standards cover every aspect of compressor technology. From general system considerations, such as its design, the materials used, casings, rotating elements, dynamics, bearings and bearing housings, shaft and seals, and integral gearing. Factors such as a site’s altitude, ambient temperature and the weather and humidity of the region can all influence the best compressor for the job. For example, when it comes to the design of a compressor for an oil and gas installation, there are many factors that can be customised to help meet API requirements. This might include special separators for wet gases, or stainless-steel components and piping to overcome the effects of demanding operating environments.

A compressed air system, particularly those specified on EPC projects in the oil and gas sector, is a huge investment. By understanding the value of participating in API industry standardisation efforts, not only does the industry as a whole benefit but EPC clients receive tangible benefits too.