Blog | Lloyds British

How to inspect pressure vessels

Written by Roohul-Qadeer Hamid | Mar 5, 2020 3:13:49 PM

The Pressure Systems Safety Regulations 2000 (PSSR) relates to pressure systems for use at work. Their aim is to prevent serious injury from the hazard of stored energy and scalding effect of steam as a result of the failure of a pressure system consisting of pressure vessels and/or pipework, along with associated protective devices.

The main reasons for pressure-related incidents occur due to a number of reasons:

  • Manufacturing defects
  • Poor installation
  • Poor maintenance of equipment
  • Inadequate repairs or modifications
  • Operator error, poor training/supervision
  • Unusual incidents e.g. damage through impact
  • In rare cases, bad design, particularly for imported non-notified equipment.

Each of these issues can be avoided with an efficient inspection and testing process in place, which helps in identifying any defects and ascertain the need and type of repairs required. Employers (or duty holders) have a responsibility to ensure that these examinations are done, otherwise they risk being non-compliant to PSSR, which in turn jeopardises health and safety in the workplace.

When does inspection/testing need to take place?

PSSR Regulation 8 requires that before pressure systems are used a Written Scheme of Examinations (WSE) must be in place. According to PSSR, the WSE may specify the need for an initial examination prior to the first use of the system. PSSR Regulation 6 requires that the installation doesn’t give rise to danger or impairs the operation of protective devices. Developing a WSE before the use of a system would ensure adherence to this regulation. PSSR also requires regular periodic inspections of pressure systems. The frequency may vary from 12 months to many years, depending upon the type of equipment and their condition.

The Safety Assessment Federation (SAFed) has made comprehensive recommendations for inspection frequencies. See their Guidance PSG01, which is freely downloadable from their website.

After a pressure vessel is manufactured and installed it may undergo alterations or repairs throughout its lifecycle. Whenever this happens, the pressure vessel needs to be examined again to ensure that it still meets all requirements.

 

 

Prepare for your PSSR inspection with a comprehensive checklist

This easy to follow checklist will ensure that you are ready to create a WSE with a competent person and remain fully compliant:

Why do you need to inspect/test pressure vessels?

  • To establish Safe Operating Limits (SOL) of a pressure system

According to PSSR, a user/owner of pressure systems is required to establish the SOL (maximum/minimum pressures and temperatures amongst others) of their systems. These are normally established through the information provided by the designer, manufacturer, assembler, or the modifier of the system. Initial inspection may consist of a review of such information if the user/owner requires the Competent Person to help in establishing the SOL. Moreover, in some instances e.g. after repairs and modifications, the process of establishing a SOL may involve testing and inspection of the system.

  • Safety

If, even a small part of, the pressure equipment fails, the results can be disastrous. Furthermore, failure of a vessel or large pipework can cause an explosion, which could be devastating. Any failure could be dangerous and potentially cause injury to people or damage property. Inspecting vessels as required by the WSE will reduce, or potentially eliminate, this risk.

  • Compliance

Because of their potential for serious damage, pressure vessels are one of the most regulated pieces of equipment. PSSR states that owners/users have a legal responsibility to ensure that those systems are properly maintained, correctly operated and regularly inspected. This will help businesses comply with legislation and ensure safety in the workplace.


What does inspection/testing involve?

First of all, as required by law (PSSR), you will have to get a WSE drawn up, or certified, by a ‘Competent Person’. This WSE lays down which equipment/components of a system will be examined, what will be the examination frequencies and what the inspection will consist of. This WSE may require that an inspection is completed before any pressure system can be used or hired out.

Each pressure system is unique, yet there are some general points, which should be taken into account while deciding which parts of the system need to be included in the WSE after establishing which systems qualify to be Pressure Systems in accordance with the Regulations:

  • Pressure vessels should be included (excluding vessels with small stored energy – link to blog?)
  • All devices protecting the system should be included, even if they are on a part of the system which is not included
  • Pipework, which is widely defined to include pipes, associated valves, pumps, compressors, hoses, bellows and other pressure-containing components, will only need to be included in the scheme if:
    • Its mechanical integrity is liable to be significantly reduced by corrosion, erosion, fatigue or any other factors; and
    • Failure resulting in the sudden release of stored energy would give rise to danger
      (For more quantitative description of pipework needed to be included in the WSE see SAFed Guidance PSG 05 from SAFed’s website)

The scheme must also include the safety measures required, preparation of the system for inspection and any other special measures. Please note the type and nature of inspection will vary for different pressure systems.

If the WSE has been written by an individual with the required technical expertise, but not a ‘Competent Person’ as defined by the Health & Safety Executive (HSE), it should subsequently be certified for the accuracy of its contents by a ‘Competent Person’.

The examinations should then be carried out by the ‘Competent Person’ in accordance with the WSE. The objectives of the examinations will be:

  • To detect real and potential defects in the pressure system
  • To judge the significance of the defects - if the system is still fit for purpose
  • To report the results of the examination, as well as to specify any remedial action and/or recommendations for repair
  • To comment on the suitability of the examination and any necessary changes to inspection methods/the WSE/safe operating limits.

After examination, it is required to keep a record of the last examination relating to the system, as well as any previous reports that contain information that could be useful in the future, such as if the system was safe to operate, or if any repairs have had to be made.

This historic record will help in the diagnosis process of any future failure and in preparing an effective repair plan. Moreover, background knowledge is important for the safety of personnel carrying out the repairs.

The user/owner should make sure that pressure vessels under their control are properly maintained prior to, and after, examination and that any issues throughout a system’s lifecycle are recorded immediately and reported to the ‘Competent Person’ or, if needed, to the relevant enforcing authorities.

Who can perform pressure equipment inspection/testing?

As stated, inspections must be carried out by a ‘Competent Person’ as defined by PSSR, which is a person with the necessary breadth and depth of knowledge, experience and independence to carry out the examinations. Companies are free to select a ‘Competent Person’ of their choice, however, they must choose wisely.

They must have adequate industry knowledge and expertise, but they must also be both independent and impartial. This ensures the inspection is fair and there is no conflict of interest.

Summary

For Engineering Managers, overseeing the inspections of pressure vessels can be frustrating. The whole process may look complex, time consuming and difficult to understand. For a simple guide on everything you need to know about making your business fully compliant with PSSR, please download ‘The No-Nonsense guide to your Engineering Inspections’.

This guide contains all the information you need to ensure your pressure systems are fully compliant with regulations. With this guide, you can gain an understanding of the entire inspection process, helping you choose a competent inspecting body and improve health and safety at your workplace.