vol 7, issue 10

Better inspections at height

22 October 2012
By Anne Harris
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A ROAV flying around a flare

As ROAVs allow images to be taken from a safe distance, flares can remain operational throughout inspection

Looking down from a tall chimney stack

Tall buildings, like this chimney stack, are awkward to inspect without the use of an ROAV

Malcolm Connolly flying the ROAV

The use of GPS makes the ROAV fail-safe

Inspections at height are part of the modern regulatory framework, but with a little forward-thinking they could provide much more useful results.

In today's economic climate, it is crucial for manufacturing plants to run smoothly and with as little disruption as possible. With regular inspections imperative in maintaining the health and safety of workers, this can be difficult.

There is, however, another way of doing things that goes far beyond traditional inspection techniques. By using remotely operated aerial vehicles (ROAVs) tall and hard-to-reach structures can be accessed safely and without disruption.

Until now, the primary use for these miniature flying vehicles has been visual inspection of assets using HD video and HD still cameras, where the highly detailed images are ideal for understanding maintenance and repair issues.

The ROAV technique leaves plants fully operational during the inspection. There is no disruption to output, which creates a major commercial as a well as a health and safety advantage, as an asset can be inspected live. "Not only do plants not need to be shut down to carry out the inspection, an ROAV inspection also allows for pre-ordering of defective components, or, alternatively, a deferral of a scheduled shutdown to a time which is more operationally convenient," says Malcolm Connolly, managing director and co-founder of Cyberhawk Innovations.

"It's worth remembering that many parts and components simply cannot be bought off the shelf and have to be specially manufactured. It is another factor that can add to delays when a plant is inspected by manual methods, with the time-consuming gathering together of staff and equipment that accompanies such inspections.

He adds"By contrast, inspection by ROAV is much quicker and allows more time for manufacture to take place, again removing a risk to commercial operations."

Time management

There are three key drivers for using ROAV technology for asset inspection: cost, safety and time. ROAV technology comes into its own in terms of inspecting live assets, but, says Chris Fleming, operations director at Cyberhawk Innovations, "it's quick too - an ROAV inspection can provide detailed engineering analysis in a matter of hours and highlight the extent of repair work, if any, that needs to be carried out.

"This means additional improved operational efficiency in that work can be planned and parts ordered in advance."

By contrast, inspections using rope access and scaffolding can take days, or even weeks, to carry out and involve plant shutdown - huge disincentives for plant operators.

Unlike ROAV inspection, there is a big investment of time and resources in rope access inspections - and all before an engineer gets to see the extent of the work that needs to be carried out. It may, of course, be the case that no work needs to be carried out, which can be even worse given the money, time and effort required to reach that conclusion.

Additionally, specialist equipment such as large cranes may have to be hired, again creating more delay and expense. Finally, specialist parts may require manufacture and aren't always immediately available.

At the height of safety

In terms of safety, falls from heights are still the biggest cause of industrial fatalities. ROAVs help to reduce this risk. Cyberhawk recently completed a thermal inspection of steel chimney ducting at a large UK refinery. Suspecting refractory damage within the ducting, the customer wanted to confirm the extent of the problem before ordering component parts and planning a shutdown to enable work to be carried out. Over a few hours, the ROAV captured thermal and visual images of the ducting from all angles, with engineers quickly identifying problem areas. The additional information removed uncertainty and risk from the project timeline. The refinery also avoided the extra cost of having to expedite shipping of critical replacement parts.

"This safer, faster and more cost-effective technology represents a major advance in the live inspection process, enabling critical decision-making to an extent that, quite simply, hasn't been possible up to now," Connolly adds. "A key benefit of this technique is that more regular inspection allows for faster identification of minor defects before they go on to become major hazards."

The ROAV technology has transformed the landscape of the inspection market in recent years. Demand is growing rapidly as more and more companies see the benefitsfrom inspections for maintenance purposes to emergency inspections; for visual and thermal inspections; from the on and offshore petroleum industry to petrochemicals and the electricity industry.

Keeping it live

Oil & Gas is a major sector because of the many live and inaccessible assets that require inspection and the high cost of shutting down these types of assets.

"Thermal imaging capability is important here; for example for steam leaks on insulted pipework, refractory breakdown on chimney ducting or for understanding the effectiveness of the radiation shield on the flare deck on offshore platforms," Fleming adds. "ROAVs, coupled with engineering expertise, represent the quickest and most effective route to gathering and interpreting this data."

Another major sector is the electricity supply industry, with its chimneys and transmission towers. The ability to inspect an asset while it is live is key to success. ROAV inspections remove disruptions to supply and to customers. This is a major selling point and is revolutionising maintenance.

According to commercial manager Phil Buchan, awareness of the possibilities of ROAV technology is the major factor in more companies not using the technology. "It is often the case that word spreads within organisations as engineers talk to other engineers, or see for themselves as part of a site visit," he explains.

"For example, Cyberhawk got one contract as it was carrying out an inspection on the petrochemical plant at Grangemouth for Ineos. A visiting engineer from the Ineos site in Cologne saw the ROAV in action and commissioned flare and stack work for Germany.

"There is a huge international market too," he continues. "ROAV inspection work is being undertaken in countries as far apart as Oman and Norway for everything from LNG plants to petrochemical works."

Two major inspection contracts were completed in Oman for a liquefied natural gas (LNG) plant and a chemical plant. For the LNG plant in particular, there was no interruption to the 34 million cubic metres of natural gas per day that is shipped to markets in Japan and Korea, where the client has long-term contracts.

Emergency situations

Besides planned maintenance, there is another important side to ROAV inspections: their use in emergency situations. Rope and manual inspections in these circumstances are, of course, completely out of the question due to the hazardous environment. Once again, ROAVs come into their own.

"In emergencies, time is at a premiumfacts have to be established quickly and have'to be 100 per cent reliable as serious and potentially far-reaching decisions are made by plant operators," Connolly says. "On arrival at an incident, the ROAVs, equipped with HD video, still cameras and thermal imaging equipment, can quickly be in place to inspect tall and inaccessible structures.

"Within minutes, detailed images and expert analysis are available to allow plant operators to make critical commercial decisions as to whether plants can be kept running safely or not. The ROAVs can also be equipped with infrared cameras if customer requirements are for monitoring temperature changes."

Connolly adds"In such emergency situations, there are not only major safety and commercial considerations, but also major reputational considerations too. It is absolutely vital to have the very best technical information on which to base and be able to justify decisions. We live in age where an asset going wrong has the potential to wipe millions off a company's balance sheet overnight and plunge the whole organisation into a media storm."

Critical testing

New legislation such as the Control of Major Accident Hazards (COMAH) and the Civil Contingencies Act have brought into sharp focus the need for companies to demonstrate that they can provide a measurable response to an incident at their facility using standardised best practices.

The ROAV used by Cyberhawk is small and lightweight. Being multi-bladed it can be positioned with great accuracy to capture the best images. State-of-the-art GPS positioning technology means that the image'can be accurately repeated if necessary, which has excellent advantages for long-term condition monitoring. Being battery-powered, the ROAV is quiet in operation and eliminates the need to have liquid fuel on site.

The ROAVs are operated by engineers, plant inspectors and technicians who can respond rapidly to provide live footage from the company's mobile monitoring station to provide highly detailed technical reports, images and analysis in various formats. The ROAV and camera are controlled from a console within the specially equipped mobile unit so that the pilot can guide the ROAV to specific areas of the structure.

As with any nascent technology it is evolving rapidly. On the horizon are a different range of payloads, with ever-changing camera and sensor technology. The technology will become even more crucial in determining asset conditions in the oil and gas sector as assets get older and require ever more detailed inspections and repairs.

Cameras and sensors will continue to get smaller, and smaller payloads will allow for even more functionality as ROAVs will be able to gather a wider range of data.

Inspecting the future

Emerging markets create new opportunities. With the growth of renewables, offshore windpower is a target market for ROAV technology. Out at sea there are particular challenges to the structural integrity of turbines due to the extreme weather, waves and saltwater that require a robust inspection regime. The environment offshore makes it difficult to access offshore turbines for inspection and so an ROAV solution may be very beneficial.

With the introduction of ROAVs, inspections may never be the same again.

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Details: The ROAV process

The two-man inspection is comprised of a pilot (CAA accredited) and an inspection engineer. The pilot remains in control of the ROAV at all times and there's a failsafe in case the connection with the ROAV is broken, in which case the vehicle will return to its last position. Everything is GPS driven so it's all repeatable; the vehicle can return to an exact GPS location time after time for verification purposes. The vehicle can reach the top of 100m flare stacks in less than one minute.

The inspection engineer's role is to look at the live images and guide the pilot to areas of interest and monitor progress. The vehicle can home-in on areas of interest, allowing anomalies to be identified and recorded alongside smaller defects. Thermal images are used to identify potential problems such as gas leaks and burn back.

The ROAV is equipped with cameras, hi-res photo, HD video and thermal. Video and photos are inspected in detail following the flight in a specialist mobile viewing and analysis unit and discussed immediately with onsite engineers. A full inspection report with recommendations follows - typically within seven days

The vehicle itself is small at 1m long, light at only 2kg, and multi-bladed for stability. It has in-built redundancy so that no one part can cause failure - with other parts taking over.

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