26 Jun 2020

The following article was written by Allied Heat Transfer’s Director of Engineering, Simon England, and published in the June/July 2020 edition of Australasian Drilling magazine.

2020 06 26 11.49.29 copyWith drill rigs incorporating equipment operating at high pressure, temperature, or a combination of both, it pays to ensure they meet legislated requirements.

Pressure equipment is hazardous and should be operated, maintained, and inspected by competent personnel.

Common pieces are receivers and separators, but there are other components that may fall under these requirements.

Regulations are different throughout Australia and you should check your local requirements to ensure your compliance.

The level of hazard that pressure equipment presents is determined by following calculations in Australian Standard AS4343 Pressure Equipment – Hazard Levels. The standard provides methods to calculate a potential energy equivalent. It also provides a hazard level for the equipment ranging from A (most hazardous) through to E (least hazardous).

There are specific regulatory requirements based on the hazard level determined.

Generally, the requirements are that an item of pressure equipment with a hazard level of D or greater shall be covered by design registration where: a competent person has reviewed the design and verified it is compliant with a recognised pressure vessel standard, and a design registration obtained from the regulatory body.

Items with a hazard level of C or greater shall also be covered by a plant registration, where each item of plant shall be registered with the regulatory body.

In addition to the registration requirements, the equipment shall also be installed, commissioned, maintained and inspected in a formal manner typically by following the processes in other Australian Standards such as AS3892 – Pressure Equipment – Installation and AS3788 – Pressure Equipment – In-service inspection.

These requirements are based on the equipment contents, volume, and pressure, not necessarily specific to particular items of equipment over others.

At Allied Heat Transfer we have found over recent years that equipment usually considered not necessary to comply with these standards in fact does. For example: air compressors on rigs have oil coolers to maintain a suitable oil operating temperature.

These coolers are rated to the same pressure as the compressor which can be as much as 500 psi. The coolers also tend to be large in order to provide the amount of cooling required.

The combination of contents, volume and pressure in these coolers can and does increase the hazard level for some to bring them into categories requiring formal registration, documentation, and operating practices in line with the legislated pressure equipment requirements.

Equipment that is typically recognised as being pressure equipment, such as receivers and separators, is usually operated well within the legislated requirements.

Equipment that is not typically recognised, such as the compressor oil coolers, often is not.

At Allied Heat Transfer we have spent much time and effort ensuring that the equipment we design and manufacture, including compressor oil coolers, is compliant with the requirements. This required a combination of engineering design, type testing, and third-party verification.

An example of a cooler that falls within pressure vessel legislation but may not be realised as such is the compressor oil cooler fitted to most of our V-Packs.

To check whether equipment falls into one of the hazard levels with more arduous requirements, contact the manufacturer or supplier and ask them for a hazard level calculation for the equipment. This can then be verified with a pressure vessel inspector to confirm whether there are specific requirements to that particular item.

The information within this editorial is general in nature and you should contact your regulatory body to confirm what is correct and required for the jurisdiction you are working in.

Vertical Pack

Vertical pack, side by side cooling package.

Pressure vessel

Examples of coolers that may be classified as pressure vessels.

V Pack cooling package

V-Pack cooling package.

Burst Test

Example of cooler burst test at 125°C and 9,000 kPa.