Pressure tests can assess any potential weaknesses in a pipeline before it is put into use, but they can also result in serious injuries and death when confined energy is unintentionally released with the sudden pressurisation or depressurisation of these systems.
Technical executive Reece Riley explains that such incidents prompted EEMUA (Engineering Equipment and Materials Users Association) to release guidance following an IMechE pressure testing seminar in 2017. “At the seminar, which was organised in response to an increase in statistics relating to fatalities and serious injuries during pressure test operations, a full and open discussion was had with the pressure equipment industry, and there was a call for EEMUA to form a working group and put some guidance together on safer pressure testing that extended beyond in-service equipment to include the full lifecycle.”
EEMUA 168 ‘Guide to pressure testing of equipment’ provides guidance on how to carry out pressure testing safely and is applicable for all types of non-transportable industrial pressure equipment and systems, including pressure vessels and pipework. The document seeks to ensure that organisations are fully aware of the risks and can use qualified staff to develop safe systems of work.
However, Riley clarifies that this guidance allows companies to develop their own competencies. The material comes with separate selection charts for new and existing equipment that a user can follow to decide what type of test needs to be carried out on a particular piece of equipment.
ABOUT THE TESTS
According to Riley, a safe pressure test can help prevent safety incidents from occurring with appropriate exclusion zones and barriers. The test also involves coordination between a pressure test operator who serves as a level 1 worker, a supervisor at level 2 and an expert at level 3 who has been made aware of when the test is happening.
Each worker has a range of duties that relate to competency. The level 1 worker must adhere to local health and safety rules in the test facility, establish barriers and exclusion zones, review the equipment under the test, prepare and check joints and establish safe gauge positions. Meanwhile, the level 2 supervisor will draw up test procedures for the routine and maintain local records and outputs from the pressure test competence scheme, while the level 3 expert plans procedures for complex pressure testing and engages the expertise of specialists in corrosion.
Additionally, the guidance contains a ‘lessons learned’ appendix that allow companies to look at incidents and understand where the risks are to ensure they establish suitable barriers and exclusion zones. It also offers support for carrying out risk assessments, which should identify the equipment and hazard controls in the test and clarify the extent of the exclusion zones and control points.
To what extent does the guidance solve the problem? “It allows the companies to ensure that the staff are competent in what they are doing and ensure that the right levels are given to the appropriate people,” says Riley.
While EEMUA delivers the guidance to its members, Riley admits there needs to be more awareness of the document externally. “The best ways to raise awareness would be having interviews with the likes of your magazine and sharing it on LinkedIn. For every incident that pops up, if we could put this document next to it, hopefully the incidents will stop happening.”
However, the absence of a training course that provides certification to the different levels of competency does present a gap in the industry.
“We have managed to put together an e-learning module, which gives an awareness level stamp on pressure testing which is based off the document,” Riley concludes. “Although there may be a need for certified training schemes, we believe companies can potentially put together their own internal training until such training exists.”
The EEMUA e-learning module covers how to conduct safe pressure testing. It is mainly aimed at operatives, supervisors and leaders managing and carrying out pressure testing at manufacturers’ works, repair shops and industrial sites, but is also relevant to engineering managers and plant operations managers.
BEARING WITNESS
While EEMUA offers support for the tester, SAFed (Safety Assessment Federation) serves as an impartial body that verifies that pressure tests are being carried out correctly. Miles Gardner, pressure testing equipment consultant at SAFed member Zurich Consultancy Services, says: “If we turn up and the people doing the test are not following the requirements, we will say it is not safe and walk away, so the test can’t carry on.”
SAFed – whose members also include Allianz Engineering, HSB Engineering Insurance Services and Safety Check Engineering – started providing ‘Guidelines for Competent Persons involved in witnessing of Pressure Tests’ following an incident in 2018.
“In this incident, the competent person was injured by a hose that broke away from a pressure testing station, which led to a leg amputation,” Gardner continues. “That’s where the whole issue of pressure testing became a lot more focused in everybody’s mind.”
Specifically, the guidance focuses on establishing a competent person that serves as an assessor to verify the vessel or system in terms of whether the design of the system under the test is sound, can withstand pressure, that it does not leak and that it functions correctly. They will also interact with a test engineer, who is responsible for setting the test equipment up, filling the system (hydraulic) and vent, operating the test pump, monitoring test progress and depressurising the system and disassembling the test equipment.
“Within the interaction, there should be a briefing on the test to all parties concerned and a discussion on the physical safeguarding,” Gardner continues. “They also have to address whether the test equipment is the right equipment; the required test pressure; and whether the gauge is calibrated. It is really about passing on knowledge to make sure the pressure test is safe.”
The competent person and test engineer should conduct a visual inspection of the system in preparation for the test. This could include the access and egress of the system under test, including the location of the test pump and gauges, while also considering if it is feasible to install remote monitoring and control of the test pump. They should also look at how the test pump is safely turned on and how the pressure is regulated and monitored. Part of the inspection will include evaluating potential weak points.
To complete the test, the competent person must confirm that risks from the failure of the vessel system under the pressure test are minimised. They should be provided with a pressure test specification that includes details of the procedure for filling the system, along with documented methodology for filling a hydraulic system.
The initial proof and standard pressure tests should include a range of measures such as nominating a single person responsible for the test, maintaining and selecting test fittings and associated test equipment and securing all hoses. These tests should also include a briefing for all involved in or witnessing the test, a safe system of work for monitoring the test, test procedures, temporary screens where required and completing the monitoring during pressurisation and proof/standard test remotely.
Looking ahead, Gardner recognises the importance of continually providing up-to-date guidance: “The industry is changing so our job is to keep on top of that and issue guidance that is pertinent to these changes.”
While EEMUA and SAFeD are setting out to improve the safety of pressure tests from slightly different angles, the need to crack down on injuries and deaths remains as important as ever.
BOX: INCIDENTS
The SAFeD guidance includes an incident history section with some examples of incidents in which those witnessing and carrying out pressure tests have been injured or killed:
August 2005
Hydraulic fitter was killed when a pressure test fitting was ejected under force from a hydraulic cylinder under test.
May 2008
Worker was water testing a large process valve. A smaller vent valve forming part of the venting assembly ejected, striking the individual.
December 2013
A worker carrying out inspection of a boiler undergoing a pressure test received a leg injury following ejection of a component forming part of the test assembly.
January 2014
University experiment involving a pressure test behind a protective screen. Overpressure occurred, shattering the screen which injured a student.
May 2014
A worker was killed by hydraulic ejection following failure of grease nipple on a piling rig.
June 2015
A maintenance fitter was carrying out repairs to a hydraulic cylinder. While checking for leaks under pressure, a component failed, resulting in a fatality.
October 2016
A worker suffered serious burns while setting up an experimental hydrogen test rig, to test a prototype hydrogen storage vessel. The threads to a pipework connection stripped and the fitting ejected, causing ignition.
July 2017
While pressure testing a heat exchanger forming part of brewery process machinery, a coil ejected, injuring a member of staff who had been watching the activity.