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Asset Life Extension (ALE) | How Can T&D Help?

Posted on 30 June 2023


Asset Life Extension

Many offshore assets are now reaching the end of their anticipated life expectancy. Ageing processes can affect the integrity of your assets and increase the risk of failure if not maintained correctly – which in turn can affect operational performance.

Today, ageing asset infrastructure requires expensive maintenance, repair and asset life extension programs which in turn requires compliant, efficient and cost-effective maintenance products to enable safe infrastructure repairs.

⚠️“Ageing is not about how old your equipment is; it’s about what you know about its condition, and how that’s changing over time” ⚠️

Floating Production Storage and Offloading (FPSO) units are a popular choice in today’s rejuvenated offshore industry, offering lower CAPEX, more flexibility and cheaper abandonment costs in comparison to fixed platforms. Repair work on idle or ageing FPSOs enables owners and operators to extend an asset’s lifespan as offshore oil and gas demand increases.

Several FPSO-related process safety incidents in recent years have led to calls for improved safety and action in order to prevent environmental disasters and fatalities.

Ensuring assets can operate effectively and efficiently while safeguarding life and the environment requires carefully planned and executed repairs and maintenance, particularly when dealing with ageing equipment. Plan in advance for the implementation of any future life extension programs to avoid unwanted downtime.

FPSO ship

How Can T&D Assist?

Part of asset life extension involves the inspection and maintenance of ageing equipment.

During 2022, Thorne & Derrick were employed by a major energy company to assist in the upgrade and change out of ageing and obsolete hazardous area electrical equipment on an FPSO which was being brought back into operation after many years sitting idle. The vessel had originally been built in 2000 and was due to be upgraded and put back into operation.

Contractors began inspection of hazardous area equipment and soon found failure rates far exceeded the predicted 3%. Equipment was found to be damaged beyond repair, spares were no longer available and equipment no longer complied with relevant IECEX standards.


During inspections carried out by on board contractors, it became apparent that much of the ex electrical equipment needed to be replaced to avoid future obsolescence and compliance issues. After carrying out 10,000 inspections with a predicted failure rate of 3% the true failure rate was closer to 50%!

The FPSO had been in use for more than 30 years and the aim of the owner was to prevent the vessel from being decommissioned and extend the asset life cycle to 5 years by carrying out an extensive replacement program of the ex equipment. Given the age of the FPSO it was no surprise to find that all the equipment was originally built to American UL Class/Division standards.

The integrity of the ex electrical equipment needed to be inspected to make sure it was still in working order and compliant with all the standards that FPSO had set out to achieve.

Equipment Integrity 

The inspection checked the integrity of the equipment highlighting and raising the following questions:

  • Is the equipment safe?
  • Any signs of wear and tear?
  • Is it still fit for purpose?
  • Does it still work or has the integrity been compromised?
  • Is it still compliant?
  • Can it be futureproofed?
  • Should it be replaced?
  • How quickly can it be replaced?

Any equipment that failed the inspection had to be upgraded and replaced as quickly as possible to ensure the FPSO met all safety and compliance standards. It was also a race against time as the client was working to strict deadlines and needed the vessel back in to operation as quickly as possible.

Conforming with IECEx standards meant the FPSO could enter international waters in the future and still be compliant. As previously mentioned this created issues such as obsolescence as certain equipment was no longer available and did not meet current IECEX standards.

Thorne & Derrick were able to look at the current equipment and provide the client with suitable alternatives thanks to over 35 years experience in succession planning. We were able to assist the client with the replacement of obsolete, non-conformant and legacy product.

We were further able to assist and make recommendations for equipment upgrades, putting forward solutions which were suitable for the application, complaint and readily available.


We have a robust reputation for supporting our customers with the replacement and upgrade of end-of-life hazardous area equipment to deliver significant operational safety and process improvements to their project or plant. Design services and heat loss calculations are part of Thorne & Derrick’s extensive remit.

The client’s main priority was time, Thorne & Derrick were able to source multiple IECEx certified equipment on the shortest lead times offering the fastest shipping possible, consolidating the clients supply chain.

The equipment that was deemed to be unsafe, non-compliant and that had failed the hazardous area inspection included heat tracing, lighting, cable glands, plugs and sockets, junction boxes and conduit to name a few.

Equipment Inspection FPSO

What is Obsolescence?

Structures, systems or components passing out of usefulness as a result of changes in knowledge, standards, technology or needs. Typically characterised by absence of necessary spares and technical support in the supply chain.

How Do You Inspect EX Equipment?

Every piece of Ex equipment has a detailed maintenance schedule set out by the manufacturer of the product. Hazardous area inspections are split into two categories. Types of inspections and Grades of inspections.

There are 2 types of Hazardous Area Inspections:

  1. Initial Hazardous Area Inspections
    Initial inspections are required to ensure that the selected type of protection is appropriate for the hazardous area installation and apply to new installations
  2. Periodic Hazardous Area Inspections
    Periodic inspections should be carried out as part of an inspection regime or routine and apply to existing installations. The purpose of the periodic inspection is to monitor the effects of deterioration or change. The intervals between periodic inspections should not exceed three years

There are three grades of Hazardous Area Inspections:

  1. Visual Hazardous Area Inspections
    Visual hazardous area inspections identify without the use of access equipment or tools, those defects, such as missing bolts, which will be apparent to the eye
  2. Close Hazardous Area Inspections
    Close hazardous area inspections encompass those aspects covered by a visual inspection, and in addition, identifies those defects, such as loose bolts, which will be apparent only by the use of access equipment, for example, steps (where necessary) and tools. Close inspections do not normally require the enclosure to be opened, or the equipment to be de-energized
  3. Detailed Hazardous Area Inspections
    Detailed hazardous area inspections will encompass those aspects covered by a close inspection and, in addition, identify those defects, such as loose terminations, which will only be apparent by opening the enclosure and/or using where necessary, tools and test equipment. These inspections may require the enclosure to be opened, equipment to be de-energized and dismantling of cable glands where applicable, as per the BSEN60079-17/14 Electrical Installations Inspection & Maintenance Standards

Thorne & Derrick have a wealth of experience and competency in supporting clients implementing Asset Life Extension Programs understanding that harsh industrial or hazardous environments demand reliable and correctly certified equipment. We understand that safety is paramount when checking any ageing equipment for damage. Changes in the risk profile of an asset will occur as the equipment gets older.

Thorne & Derrick are approved vendors to assets owned and operated by some of the largest international Oil & Gas companies including BP, Shell, Apache and Total. Expediting goods worldwide for almost 20 years; we are experts in the administration, logistics with an extensive knowledge of export documentation and customer-service levels required to support projects wherever you are and whatever your requirements.

Stock + Staff + Delivery + Support

We stock and supply an extensive range of Hazardous Area (ATEX, IECEx UKEx) and Industrial Equipment to provide safe Lighting, Heating & Power Distribution in Zone 1/2 (Flammable Gas) and Zone 21/22 (Combustible Dust) areas from market leading manufacturer’s helping to consolidate your supply chain.

All of our Sales Engineers hold CompEx Certificates (Hazardous Awareness Course EX F) and undertake continuous learning and advanced Explosion Protection training with our supply chain to ensure their knowledge of the latest standards is regularly updated.



Asset Life Extension

Below we will look at each piece of ex equipment that was installed as part of the project in more detail and how Thorne & Derrick used their expertise to source and supply suitable replacements.

Heat Tracing

The majority of the trace heating cables that were installed on this project had become obsolete. Thorne & Derrick were able to identify that the cable was providing frost protection thanks to a heat loss calculation and a suitable alternative was swiftly sourced.

Thorne & Derrick challenge the existing heat tracing philosophy culminating in a marked reduction of requirements for trace heating and insulation on ageing offshore assets. We can help to prevent corrosion under insulation issues which in turn reduces the number of Ex inspections the asset requires saving money in the long run.

Our Team of Trained Technical Sales Engineers were available to advise and support with all the trace heating enquiries for this project. As a team we can design and supply of complex multi-kilometre, major-project systems to custom heat trace cable kits for the Winterisation of your offshore facility.

With access to all the market leading trace heating manufacturers we can help you schedule your shutdowns identifying key areas for concern and planning to completion. Working with our supply chain we can deliver the latest product innovations to replace obsolete trace heating systems on high temperature installations.

We can provide heat loss calculations and a design service to keep your plant and personnel operational all year round.

Typical needs for heat tracing on FPSO’s are deck lines for oil and chemical products. Thorne & Derrick can design trace heating systems for frost protection and temperature maintenance of:

  • Loading and unloading lines
  • Gas/vapour-return lines
  • Strip and cleaning lines
  • Fuel oil lines
  • Storage tanks and vessels
  • Deck and tank cleaning lines
  • Fire protection lines
  • Engine room fuel and drip lines

Lighting & Emergency Lighting

The types of lighting fixtures for offshore platforms can be divided into: fluorescent lamps, high pressure sodium lamps, metal halide lamps, emergency exit lamps, aircraft deck boundary lamps, windsock lamps, etc.

During offshore inspections, it has been noted that emergency lighting often fails when called upon. A failure rate of 40%+ of fittings is not unusual with typical failures relating to battery supplies. This inspection was no exception. The lighting no longer switched on or off as the lamps were no longer functioning. This again created an obsolescence issue as the lamps that fit the lighting were no longer on the market – the only viable solution was to switch to LED lighting.

Emergency light fittings had to be upgraded to ensure all escape routes were well lit, visible and safe for all workers.  Such a high failure rate calls into question the operability of the system; failures could lead to personnel panicking and being unable to escape to a place of safety during an emergency, or being unable to attend to emergency tasks.

Many of the ballasts and batteries had been damaged and due to being installed in the 1990’s spare parts were also no longer available. Some of the lights were full of water so the IP rating couldn’t be maintained and therefore failed the hazardous area inspection. A saline environment (exposure to seawater spray and salt water-saturated air) presents a higher risk of corrosion so any lighting installed in an offshore location needs to withstand these aggressive conditions. Once evaporated, salt water can also leave a thin salty film on the luminaire which may interfere with the performance by reducing light intensity.

Originally the client wanted to replace the lighting with a similar fitting but this wasn’t possible. Thorne & Derrick suggested that the old fluorescent lighting should be upgraded to LED lighting as fluorescent bulbs are being phased out of use. The design service provided ensured Thorne & Derrick could offer a suitable alternative with the same footprint. The client simply had to undo the gland and cable to fit the new LED light fitting.

Other factors that can cause damage include prolonged exposure to the sun and UV rays as they can degrade GRP and cause the enclosure to become brittle over time, compromising the integrity of its IP rating. This causes maintenance issues and degrades the structural integrity of the luminaire’s enclosure. For offshore applications designated as a hazardous area, this could also provide a critical safety risk.

Hazardous Area Lighting Design

💡 Using the latest software, we can provide a FREE LIGHTING DESIGN SERVICE for the specification and supply of ATEX & IECEx light fittings to provide safe and reliable lighting in hazardous areas and industrial locations 💡

Junction Boxes

Many of the junction boxes on the FPSO had corroded creating a risk of electrical shock. Again salt water had penetrated the boxes so the IP rating was compromised. Once the boxes had been opened to be emptied of water they were no longer suitable for use in explosive atmospheres and needed to be replaced.

The rugged design of these junction boxes provided by Thorne & Derrick offered a high degree of safety for offshore applications where the boxes could be subject to adverse chemical, mechanical or climatic operating conditions.

Thorne & Derrick provided a variety of enclosure sizes and custom configurations with different terminal and cable gland types to suit the offshore environment. Junction boxes and terminal boxes can be manufactured from glass fibre reinforced polyester (GRP), aluminium or a high quality stainless steel. The client opted for stainless steel to ensure the safe power distribution and termination of cables in hazardous areas and potentially explosive atmospheres.

Cable Glands

During the inspection it became apparent that many of the cable glands were cracked and had been mechanically damaged. There were clear signs of fire damage that compromised the integrity of the glands. Cable glands are designed with safety in mind, so they come with an IP rating. Once this is compromised the gland needs to be replaced. Corrosion was also present due to the saline environment and the originally installed brass glands were no longer fit for purpose.

Cable glands perform a number of essential roles in cable management. Ideally the cable gland should be made of the same material as the equipment and the cable armour it is connected to. The glands needed to be able contain electrical sparks of flames as well as repelling outside contaminants such as dust, dirt and fluids found in these kind of environments. In addition to this, their job is to stop cables becoming twisted or pulled to ensure a secure connection and continual performance.

Thorne & Derrick recommended switching to stainless steel or nickel plated brass glands that were easy to install, can easily be inspected and can withstand the demands of harsh conditions.

Plugs & Sockets

The client requested a specific brand of plug and socket when the current fittings failed the inspection. Thorne & Derrick offered a wide range of 32 Amp and 63 Amp sockets that were on short lead times and could be expedited quickly.

With sealing to IP66/67, the plugs and sockets supplied provided a watertight and dust-tight connection, whilst the robust construction ensures an extended operational lifetime despite the heavy-duty operating environment and high levels of salt-water and spray. They also provided electrical energy reliability and power connectivity to harsh and hazardous locations with high safety standards for secure performance in aggressive and explosive atmospheres.

FPSO Asset Life Extension


Similarly all conduit failed the inspection and needed to be replaced with an IECEx certified equivalent. Thorne & Derrick sourced stainless steel flexible conduit systems that protect power, control, signal, instrumentation and communication ship wiring applications.

The stainless steel liquid tight conduit is designed to perform in extremes of weather, and to be resistant to adverse elements such as humidity, oil, acid, mud and salt water, as are prevalent in most marine and offshore operational environments.


Cable ageing is dependent upon the type of cable (e.g. whether or not it is armoured), the type of insulation (e.g. some types of insulation degrade more rapidly when exposed to sunlight), the potential for mechanical or thermal damage, and humidity.

Well-specified cabling can survive for twenty years or more outdoors and for thirty years or more indoors. One reference source suggests 60 years as the accepted economic life for cables. This benchmark value is of course dependent on many factors, such as environmental factors and physical damage. Appropriate reviews should be carried out periodically.

Cable damage is common offshore due to the extreme mechanical conditions caused by vibration, shock and movement on oil and gas platforms. Overtime, EPR type rubber cable sheaths are degraded and complete cable change-out can be cost prohibitive or actually impossible.

Thorne & Derrick have the solution to ensure your assets stay operational. 3M LVI cable joints provide an excellent cable repair or full cable joint to damaged offshore cables preventing possible downtime caused by cable failure due to salt sea atmospheres reacting with cable braiding and conductors and causing a short circuit.

 See Products Supplied on Asset Life Extension Project



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