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Cresent - Making Work Safe

Why should companies perform a regular Control of Work review?

Why should companies perform a regular Control of Work review or audit? There are a number of reasons this is important for your business, read more...

Organisations have a legal duty to put in place suitable arrangements to manage health and safety. The Management of Health and Safety at Work regulations 1999 require all employers to put in place arrangements to control health and safety risks. Companies will have put in place a health and safety procedure or process, and depending on the size and nature of the business this often includes a separate Control of Work procedure or system.


There are various names which are used, often depending on the industry, but all broadly mean the same:

  • Control of Work (CoW)
  • Safe System of Work (SSOW)
  • Integrated Safe System of Work (ISSOW)
  • Permit to Work System (PTW)

Control of Work systems will include three primary elements: Hazard Identification and (Task) Risk Assessment (HIRA or HITRA), Permit to Work (PTW) and Lock Out Tag Out (LOTO).

The Health and Safety Executive (HSE), with input from Cresent, created two guidance documents to support companies looking to implement a Control of Work system; HSG250 Guidance on Permit to Work Systems and HSG253; The Safe Isolation of Plant and Equipment. These documents give companies the tools they need to fully understand PTW and Isolations and implement the effective controls and solutions.

The HSE recommend a Plan, Do, Check, Act cycle approach to health and safety management systems. So when and why should you check the whole process?


Companies with a Control of Work system in place should review the system or process at regular intervals. It’s important to perform an audit or review of the system for the following reasons:

  1. Legislation and industry standards change; a review of the current CoW system in place will identify gaps and where changes must be made to the process or system to ensure that it is current and compliant with these standards or legislation.
  2. Carrying out a review will check the validity of your Control of Work system and ensure that it is effective, while also identifying areas for improvement.
  3. Reviewing your current system or procedure will allow you to identify areas where your control measures are possibly no longer relevant or correct, allowing you to realign and set new standards for these measures.

4. There may have been changes to your organisational structure. An example of this is the Oil and Gas industry. Due to the downturn, there has been a change to shift patterns of offshore staff. Where previously they were likely working 2 weeks on 2 weeks off a regular shift has become 3 weeks on, 3 weeks off. Permit systems generally validate a permit for 2 weeks before it expires. This is an example where it makes sense to update your Control of Work system.

5. Are you learning from experience? Organisations will have a lessons learned process in place, but can you show that you are really learning from experience? An audit or review of your Control of Work system will identify whether or not companies have used their lessons learned and provide ways for organisations to really start to implement changes based on their findings.

It is too often the case that companies do not review their risk assessments, permits or isolations until after an incident has occurred.

Companies should aim be proactive and not reactive and a regular Control of Work review is one way of achieving this.


It is advisable that companies perform a review of their control of work system annually. Depending on the company risk profile or size you may not need to perform this review annually but it should never be left more than two years. Any longer and your company is at risk of being non-compliant as changes internally and externally to the organisation impact on the system you have in place.


Control of Work reviews should be completed by someone who is impartial and independent. For example, a contractor could have a site operator perform a review of their Control of Work system but there is a risk that the operator may not be completely impartial and provide a fair and honest review.

Although companies can undertake a review of their system at any time themselves, this certainly should not be the only review which its Control of Work systems undergoes. Again, the organisations themselves are unlikely to detach themselves from their own system and effectively identify areas where improvements are necessary to ensure that accidents do not occur.


Cresent can provide companies seeking a review of their Control of Work system or underlying procedures with an independent and professional assessment.

With more than 35 years’ experience, Cresent are experts in Control of Work. Our subject matter experts have over 100 years’ experience combined in the oil and gas industry: working with and training the workforce in Control of Work and Health and Safety. We even train the Health and Safety Inspectorate (HSE) in the UK each year!

We have worked on hazardous industry sites all around the globe: from deep sea to desert, marine vessels to upstream platforms and downstream refineries to nuclear sites.

Cresent can support companies looking to perform a review on their Control of Work system by performing a desk-top review of a selection of risk assessments, permits and isolations before providing an impartial report and any actions which need to be taken forward.  Alternatively we can visit your site and carry out an in-depth Control of Work audit involving interviews with staff/contractors, a review of your existing procedures and systems and an assessment of your CoW training records.

These are just examples of how Cresent can help. We understand that no two customers are the same and we work with you to find the right solution. Get in touch with us today to find out more about how Cresent can help you make work safe.

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