A guide to cost effective Hazardous Area Test and Inspection
06 June 2018
Anyone responsible for statutory compliance in hazardous areas will have views on the best ways in which this should be done, but it can be a daunting prospect to try and understand the requirements. In this article, Graham Doggett of Z-Tech offers an insight into how an inspection schedule can be managed to comply with BS60079 legislation, while at the same time using an approach to minimise expenditure.
Before we go into too much detail on inspection schedules and the factors that should be considered, it is important to remember the initial inspection stage, without which the equipment should not be brought into service. I am often asked to advise on the best way to carry out periodic inspections of a hazardous area installation.The problem occurs when I ask to see the initial inspections, the equipment register or current inspection strategy.
More often than not, the records have been misplaced or archived somewhere with the rest of the project documentation. Sometimes an initial inspection was not carried out, and no verification dossier was produced for the installation.
There are essentially 10 steps to achieving a compliant hazardous area inspection schedule and it starts with the conception of the project:
1. The design
2. The installation
3. The hand over
4. Implementation of inspection strategy
5. First sample inspection
6. First periodic inspection
7. Review of inspection results,
8. Assessment of inspection strategy
9. Implementation of amended inspection strategy
10. Periodic inspection with a detailed sample
Subsequently, steps 7,8,9 and 10 need to be repeated for the life of the installation.
Now, let’s save some money in 6 of these steps:
1) The design
Often during the design stage all equipment is selected correctly, but in many cases a lack of thought is given to the first principle of managing a hazardous area – does the equipment need to be in the area or can it be located away from the hazardous area OR do we really need it?
An example might be small, remote pumping stations. These are unmanned 90% of the year with visits for basic maintenance of equipment and inspection only, and commonly these sites will still have lighting installed, where with properly documented access procedures, portable lighting would totally eliminate the need for fixed lighting. If this is taken into account at the design stage, then there is significant financial benefit not only from the reduced installation costs but also from the ongoing benefit of a reduced number of inspections.
2) The installation
In the installation and commissioning process, timing is crucial as these must be carried out before power is applied to circuits before live commissioning.
This initial inspection can be used by the project documentation team as an opportunity to identify missing documentation and the accuracy of the asset register that should be compiled as part of the verification dossier for the installation.
It is important at this point to remember that equipment will be maintained during the commissioning process and while the initial inspections have been completed, a close inspection of all equipment should be carried out to check that no external faults have been introduced to the installation. This will have an initial financial cost but hugely increase confidence in the compliance of the installation.
Some of the most common faults I have seen in inspections are items forgotten in the pressure of meeting final project deadlines. This commonly includes missing or loose enclosure bolts and covers, which cause issues with both the certification of the equipment and the safety of the installation.
If this additional verification of the installation is carried out, then it can pay back very quickly by reducing the number of failures picked up at the first sample or periodic inspection.
3) The handover
This is the stage where most missing documentation or inspection records can be traced back to. The process at this point should be no different for internal or externally delivery installations. At handover you should be provided with a verification dossier as per BS60079-14.
One of the most common mistakes made here is not incorporating this information into the document management system that is being operated within your organisation. This verification dossier is a live document and without maintenance of the information it is easy to introduce non-conformances. For example, updating the equipment register to reflect a change in ‘make and model’ of equipment, or updating the descriptive system documents to reflect changes to intrinsically safe systems.
The retrospective compilation of the verification dossier will cost substantially more and consume a potentially vast resource, especially in the case of hard to access equipment or IS systems where calculations must be redone.
4) Implementation of an inspection strategy
This can be one of the hardest things to settle on but it is key to ensuring compliance of the installation, so what should be considered?
* The environment
Is the equipment outside? Is there a high level of UV radiation? Are the substances in the process likely to cause an increased rate of corrosion?
* The Zone or EPL
You may wish to inspect equipment in Zone 1 more frequently than Zone 2.
* Type of plant
What is the perceived risk level of ignition, taking into account persons exposed, environmental pollution and financial implications. Guidance on this can be found in RG101, published by UKAS.
* Frequency and quality of maintenance
Does the equipment require regular calibration?
* Susceptibility to damage
If the item is in a high traffic area where it is likely to be impacted? Then you may want to inspect more frequently.
Once you have decided on the provisional periodic inspection interval, it is important to document the justifications and considerations, as this will be a key part of transferring responsibility should the responsible person change.
Alongside the definition of an inspection interval, you will also need to decide on a sample size. Good guidance on the calculation of sample sizing can be found in the Guidelines for managing inspection of Ex electrical equipment ignition risk in support of IEC 60079-17 published by the Energy Institute, and key performance indicators linked to the results of inspection should also be set.
5) The first sample inspection
This is going to be the inspection that confirms or indicates the need for a variation from your inspection interval that is implemented in your inspection strategy. At this point, BS60079-17 suggests that a sample inspection at a close grade is carried out. This should be after a time period that allows the plant’s operation and environmental conditions to take effect but not your full inspection interval, so if you have decided on a 24-month inspection interval a sample at 12 months should give a good indication of the suitability of the interval.
The results of this sample should be compared to the KPIs that you have set out in your inspection strategy ensuring that the time period is taken into account. If you have set out that a 20% failure rate is acceptable over 24 months, you would not expect to see more than 7-8% at the 12-month mark. Using this information and by analysing the type of faults, you should either confirm or modify your inspection interval to suit.
6) The first periodic inspection
This is going to be your first idea of the full condition of the plant. Following the guidance of BS60079-17, this should be a close inspection of all equipment with a sample as defined in your inspection strategy at detailed grade. As per you first sample inspection you should review this against the KPIs in your inspection strategy and assess whether a modification to the inspection period and sample size is required.
This process of inspection and review can then be carried out for the life of the plant, ensuring that any justification to the inspection strategy is documented and recorded.
Should you be fortunate enough to find that a justifiable increase of the inspection interval to three years has been achieved and are still finding low levels of failure and can justify a change to the inspection strategy, then you can look to move to a visual inspection of all non-ignition capable equipment and close inspection of ignition-capable equipment. It is vital to keep your detailed sample, as this will fulfil the requirement under BS60079-17 for equipment to be subjected to inspection of internal and external components throughout it its life cycle.
It is important to remember that when looking at inspection results, different areas of plant can be inspected at different intervals based on location of installation, likelihood of mechanical impact and frequency of maintenance. An example of this would be a junction box that is on a wall 20ft up will be less likely to become damaged than a low level transducer that is calibrated every 6 months, and therefore would require less frequent inspection from a risk-based point of view.
Any increase of the inspection interval after this point will need justification by a specific safety assessment carried out by an expert. This would involve looking into the environment, operation and manufacturers guidelines for maintenance of the asset.
To summarise there are a few key points that you will have noticed throughout:
*Don’t rush it. In a world where economics drive so much of the way we work and operate, it may be tempting to allow the pressure budgetary requirements to lean you towards prematurely increasing inspection intervals. But this will not demonstrate a risk based approach to inspection and ultimately not satisfy the questions raised in the event of an ignition.
* Document everything. If all modifications to plant are assessed and documented then you will have an accurate verification dossier that will allow you to make clearer decisions around your justifications and be able to demonstrate competence to an auditor.
*Plan to leave. Sounds like an odd one, but if you make your records clear so that anyone can step in and take over, your life will be easier.
*The better your inspection and maintenance records, the easier to justify an increase in inspection interval and therefore more financial benefit.
Finally, bring in the experts as it will make your life a lot easier and help to reduce your own personal risk if things go wrong - but do be a knowledgeable customer who knows the basic principles.
About the author
Graham Doggett is Operations Manager (ATEX) at Z-Tech Control Systems. He has been working as an Ex-qualified contract delivery manager for over 7 years, specialising in the Utility Sector. With an in depth knowledge of hazardous area management and inspection, Graham has a background in MEICA maintenance and commissioning.
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