Maintenance on oil and gas rigs: In and out safely and swiftly
How the challenges of accessing items for maintenance on oil and gas rigs can be overcome using rope access, the history of rope access and its benefits and limitations are disclosed by EDDIE NICOL, director of Independent Maintenance Services.
The driving consideration behind the design of oil and gas platforms is to extract the hydrocarbon, crude oil or natural gas, quickly and cheaply. Unfortunately, this approach often leaves maintenance as a secondary design consideration. The structure and plant aboard most platforms are designed for the conditions they are likely to face – brutal winds, a harsh maritime environment and every other difficult environmental headache found in the middle of the ocean.
Onshore processing facilities are not dissimilar and, being subject to a major safety case under legislation, these facilities are also often in remote and possibly harsh environments. Further complicating matters is scale. Producing millions of litres of refined product requires big bits of kit.
OVERCOMING MAINTENANCE CHALLENGES
So, how are these facilities maintained safely? Common forms of access such as crane and scaffolding are regularly used, but these approaches have their limitations.
Imagine having to replace a section of pipework below the cellar deck of an oil platform in the Bass Strait, a notoriously cantankerous stretch of water. The pipe section is under the floor, some 50 feet above the water.
The traditional approach has been to erect suspended scaffold beneath the cellar deck, launched from a nearby stair landing. A team of scaffolders will take several days erecting and suspending the scaffold, ready for the maintenance fitters to access the site and replace the pipeline.
But, the weather is turning. Overnight, the sea state changes from manageable to absolutely dreadful, and the fitters arrive to find the scaffold they were to use is not there, a victim of enormous swell that has literally stripped 90 percent of the scaffold and sent it to the sea floor.
What next? Wait for more scaffold to be erected – an expensive and time-intensive process – or are there alternatives?
Industrial rope access is a safe, expeditious and cost-effective option for problems like those described in the above example. First thought to have been employed on platforms in the North Sea over 25 years ago, rope access was borne of a combination of oilfield workers noticing their recreational caving skills and methods, and those used in rigging and steeplejack industries, could be safely applied as a work positioning system in an industrial setting. The cornerstone of the methodology is 100 percent redundancy on all safety systems. Two ropes are always used, providing immediate back-up should one of the ropes become severed.
Returning to our example, but using rope access instead of scaffolding, and the problem is solved. Maintenance fitters trained in rope access methods would rig ropes to structural components of the platform and pass them through penetrations in the cellar deck floor, protecting the ropes as they pass through the floor from all sharp edges. Depending on the size of the pipe section to be replaced, a winch would also be rigged in similar manner.
Following the development of a rescue plan, cross-trained fitters would then ascend their ropes to the work site and commence the removal and replacement process. No delays waiting for scaffold, and single-source supply is achieved as the same people accessing the site perform the work.
FROM LITTLE THINGS…
From an inauspicious beginning in the North Sea, industrial rope access has spread rapidly across the globe, and in many offshore oilfields it is the preferred method of access over scaffolding for light industrial maintenance and construction work.
There are several reasons for this growing popularity, not the least of which is that the use of cross-trained personnel and single source supply means fewer people are required to perform the task, which is also completed in a shorter time-frame when access methods are included in the calculation.
Aside from the cost savings through a smaller headcount, this is very attractive for operating companies because the shorter project time-frame equates to a smaller window of exposure to occupational health and safety (OH&S) risks for personnel. Less exposure means fewer accidents, injuries and downtime, more production and lower overall cost.
Another driver of increasing use of rope access is short mobilisation time, as the time to erect scaffold is monstrous when compared to the rigging of rope access systems, including any additional rescue systems for rope access operators if these are not already incorporated into the primary systems.
Equipment requirements are also minimal by comparison to more traditional methods of access. Scaffolding is shipped by stillage, with overall stock weights held aboard many platforms weighing several tonnes. By comparison, an industrial rope access operator can carry all the kit required to access almost every part of a platform down to the waterline in a rucksack or heavy-duty tote weighing no more than 30 kilograms.
Yet industrial rope access is not without limitations, and the access method for each maintenance work scope aboard a platform should be considered on a case-by-case basis. Much of the rope access equipment is constructed of nylon-based polymers, which don’t hold up particularly well when they come in contact with equipment running at high temperatures.
In fact, the majority of the very few incidents that do occur with rope access are related to a root cause of unprotected equipment coming into contact with either heat sources or sharp/abrasive surfaces.
Weight can also be an issue for operators. While rope access equipment is particularly lightweight, tools operated from work positioning systems like rope access become unwieldy when the tool weight is above about eight kilograms. Beyond this weight, tooling is generally suspended on a separate system from the operator.
Separate equipment suspension systems are not difficult to manage, but they do complicate the task at hand. Most rope access teams try to avoid this situation through alternative task planning or recommending more traditional access methods like scaffold.
However, rope access is not limited in the area of application. Since inception, the use of rope access methodologies has spread across industries, from construction to building and structure maintenance through to inspection in the food industry and maintenance of coal-fired power station boilers.
Sea-going tankers often have biannual hull thickness measurements undertaken by rope access while underway between ports, and rope access has been extensively employed in the rigging of cameras for sporting events at the MCG. Imagination appears to be the main limitation to use.
In 2011, the UK Health and Safety Executive (HSE) explicitly called out rope access as an exemplar arrangement in a public report entitled ‘A commentary on routes to competence in the construction sector’.
Using the globally operating Industrial Rope Access Trade Association (IRATA) as an example, the HSE (at p.51) explicitly stated: “Perhaps one of the most demanding registration and certification schemes is that run by the IRATA. It… maintains exceptionally rigorous standards in all aspects of its work.”
Not all Australian firms operate to IRATA standards; however, acceptance is growing as more companies become aware of rope access and begin to insist on IRATA qualified operators on their sites. I agree with this IRATA push by clients.
Industry has come a long way from what we used to be allowed to do as steeplejacks in Scotland and this is not a bad thing. Fewer accidents and more productivity is what all clients want, and only using IRATA operators is the quickest way to deliver that kind of service.
And, since you cannot do everything off ropes, I recommend making sure that a firm’s crews are scaffold and rigging qualified as well. The right access method for the task has to be chosen – take shortcuts or try to force-fit a solution and things get pear-shaped pretty quickly. Not a good day out.