Posted by Andy Kidd on 27-Oct-2017 09:57:00

Why do you need a Written Scheme of Examination?


The Written Scheme of Examination (WSE) is a document that details safety devices and components associated with a pressure system; it defines the system in operation, the safety devices present, as well as the type and frequency of thorough examinations required. The document also lays out periods for any additional inspections required for each device or component. Under the Pressure Systems Safety Regulations 2000 (PSSR), users and owners of most pressure plant must have a WSE.

Written Schemes are also used in specialist applications for lifting equipment. However, this is not a standard approach and requires risk based justification.

If you don’t have a WSE, or it’s insufficient, your plant may be operating outside of statute. Legally this should be shut down. Alternatively, you face costly fines and even prosecution from the Health & Safety Executive or Local Authority.

Why do you need a WSE?

There are a number of reasons why you need to have a WSE for your plant and equipment. These include:

1. It's a legal requirement

For most equipment that falls under the PSSR, you must have a WSE in place. The WSE determines the equipment’s safety operating parameters and has to be reviewed to support the examination. Legally, a third-party inspector cannot complete the examination without a WSE being in place. Furthermore, the scheme must be available for review by each relevant Enforcement Authority (e.g.: the HSE or a Local Authority Environmental Health department). This is often the first document they ask you to produce should they visit your site. 

2. To ensure that your plant is safe

Under PSSR, all duty holders responsible for pressure systems need to demonstrate that they know the safe operating limits of their systems and that the system is safe under those conditions. The WSE and associated examination reports are the proof you have taken appropriate measures to ensure that your plant is safe and it is going to deliver what you need it to deliver in production.

3. UK compared to other countries

In some countries you don’t need to have a WSE. In others, there are variations from the UK about certain types of equipment. For example, there is a slight variation in the requirements for Written Schemes in the Republic of Ireland, compared to the UK.

Europe also has variations on different pieces of plant. It might be the case that while a certain item may fall under the pressure systems safety regulations in England (such as an air receiver), in places like Germany they won’t require a WSE as long as the product is built to a certain design criteria. This is where international providers of plant can often get unintentionally caught out.

4. Allows you to prolong the life of your plant

A WSE for a more complex system could allow you to vary the examination scope and periodicity following a risk based inspection review. The Written Scheme is designed to ensure the application of the pressure equipment is suitable for its situation and the system it has been incorporated within, or medium it conveys. The inspection periods should also be reflective of its age and use. 

Therefore, a WSE can support an elongation of a plant regime. So, for example, if you want to continue using some items of plant beyond when you’re expected to, the Written Scheme can be adjusted to help you achieve that, so that you get more usage and productivity out of your plant. This tends to be accomplished by putting in some additional supplementary tests, like Non-Destructive Testing, to ensure that the defects are identified in advance of failure. (To find out more about how you can extend engineering inspection periods, click here to read our blog.)

The WSE is also tied in with a risk-based inspection approach and you need a WSE as part of your RBI regime. Or it will need a form of Written Scheme.

The normal period for thorough examinations of pressure plants tends to follow industry standards. Whereas, if you do additional, less intrusive inspections and tests, supplementary to your main inspection service as part of your Written Scheme, you may be able to extend that period.

This is a significant benefit of having a WSE.

Click here to download 'Essential questions to ask your engineering inspection  supplier'

Can the plant manufacturer provide me with a WSE?

Manufacturers can only provide a WSE on very specific items of plant. This is because the Written Scheme needs to include how the equipment has been installed and how it’s connected to pipework. For example: compressors, as they are a self-contained unit, may actually come with a WSE, but a vessel that is going to be attached to pipework and safety valves can only have a Written Scheme issued when it’s been installed.

How often do I need to review my WSE?

The Written Scheme is normally issued once, when the machine is new and has been just installed. It can lasts the life of the pressure vessel, with amendments made, as/when required. At periods stated by the Written Scheme, a ‘Competent Person’ will need to examine the pressure items and issue a report in accordance with the Written Scheme.

The Scheme must be permanently in place and it must be reviewed while conducting a thorough examination. The WSE will state when the next inspection should be conducted and the specific elements it should cover.

Who can issue and review WSE?

A WSE needs to be written and reviewed by a ‘Competent Person’ that has the relevant experience, knowledge and certifications to ensure that the Scheme is complete and reaches the desired safety standards.

According to the HSE, to arrive at a properly informed decision, users and owners may need to seek advice of third-party advisors and consultants. But even when advising with an external expert, the legal responsibility for defining the scope of the Scheme still lies with the user or owner. This is why you need to be extremely careful when having a WSE completed. Ensure that you’re not taking any short cuts or compromising on quality for the sake of saving costs. A failure to do so could result in serious and detrimental consequences for your business.

Following the issuing of a WSE, you will need to have all inspections outlined in it completed by a ‘Competent Person’ and in accordance with the Scheme.

At British Engineering Services, we’re proud to be an approved Notified Body, with a Type A UKAS accreditation. This enables us to produce and certify WSEs in accordance with UK regulations. All of our WSEs are posted electronically and each one of our clients has 24/7 access to their own web-based portal, which means that your Written Scheme will be instantly available to you, at all times.

To find out more about the most important factors to consider when choosing a third-party company to issue and implement your Written Schemes of Examination, download our quick and easy to read guide ‘The essential questions to ask your engineering inspection supplier’.

New Call-to-action

Topics: Written Scheme of Examination

Andy Kidd

Written by Andy Kidd

Chief Engineer