Handling asbestos on MCP-01
  from: Offshore Engineer
  Wednesday, April 09, 2008

Aberdeen contractor RBG has been working on deconstruction in the Total E&P UK-operated Frigg field where ongoing decommissioning work has had to embrace and comply with all asbestos related legislation.

Roger Esson, RBG operations manager for decommissioning and asbestos services, told February’s seventh Norwegian Petroleum Society (NPF) North Sea decommissioning conference in Bergen how asbestos removal was handled on the MCP-01 main compression platform.

RBG’s role, under subcontract to Aker Kvaerner, was to provide access scaffolding, welding, specialist high pressure cleaning and deployment of a hazardous waste management team, including removal of fluorescent light tubes, printed circuit boards and batteries.

As part of an asbestos removal programme, large sheet boards had to be removed from a wall approximately 50m long by 10m high.

Legislation

‘Any platforms constructed before 1999 are assumed to contain asbestos,’ Esson says. Asbestos was banned under UK legislation that year. ‘With most platforms – anything built before 2000 – you have to assume it has asbestos somewhere onboard, until proven otherwise.’

In older installations, checks need to be made for its presence before deconstruction can begin. Although asbestos licensing is not new, UK legislation was amended into The Control of Asbestos Regulations 2006, which took effect last November. Since the material was banned, other mineral and manmade fibres have been used to replace asbestos. To comply with the relevant legislation, RBG developed sealed working habitats with negative pressure – so that a constant flow of clean air was pumped in. Habitat sealing was smoke-tested and exhaust air passed through high efficiency filters to prevent asbestos dust passing outside.

Under the latest regulations, exposure to asbestos dust is restricted to 0.01fibres per cubic metre of air over four hours. To measure and achieve that standard, apart from the creation of air-sealed working habitats, contractors like RBG have used very sensitive air pumps and highefficiency filters.

Air quality is checked by testing air samples for the presence of asbestos fibres under the microscope, which is performed by a UK Accreditation Service scientist.

Keeping asbestos dust out of the air can be achieved primarily by keeping material damp, to stop asbestos dust getting airborne.

Other techniques to prevent it include ‘shadow vacuuming’ where a highpowered industrial vacuum cleaner is placed immediately adjacent to cutting tools which are generating dust.

And then the final barrier of protection from asbestos dust is RPE – Respiratory Protective Equipment.

Exposure

Even drilling a hole in a platform bulkhead could cause exposure to the dust.

And when it to comes to deconstructing platforms, ‘as built’ drawings cannot be relied upon to provide an accurate guide to its location, says Esson. Pre-job surveying and sampling, often involving destructive inspection, is done to quantify the volume of material and to identify any work required prior to tender.

Habitats were constructed and sealed with plastic sheeting on MCP-01, where work is due to restart February 2008. ‘The job is not completed,’ reports Esson. ‘There is still a lot of work there.’

However, he adds that asbestos removal has gone really well there so far ‘because a survey was done up front before deconstruction – work has to be planned, which takes away all the issues’.

A type 3 survey, also known as an intrusive survey, was carried out on MCP-01 and material core samples were taken where appropriate to test for asbestos. Under UK regulations, the Health & Safety Executive must be given at least 14 days notice before work starts, giving them the chance to comment on asbestos removal plans, and to audit them on site.

RBG recently gained accreditation as a licensed asbestos removal contractor through the UK’s Health & Safety Executive, extending accreditation from one to three years, which Esson sees as a big endorsement of company efforts to ensure compliance with the latest regulations concerning asbestos.

Legacy

Asbestos was used extensively as a construction material in the UK from the 1950s through to the mid-1980s. Today there is a legacy of millions of tonnes of the material, and the effects of this are now being felt by industry.

Offshore it is commonly found in gaskets – ‘probably its most common use’, says Esson. ‘It goes in brake linings on cranes and winches, into durasteel panels to provide fire protection and production vessels could be lagged with it. It is also found in accommodation bulkheads.’ In short, it can be found anywhere that fire or heat protection was important, although it can also be found in items like floor tiles and electrical components.

Although airborne asbestos dust has been identified as a cause of lung cancer, in an undisturbed state, it doesn’t present a health hazard. ‘It is perfectly safe until someone does something to disturb the fibres, where there is the potential to inhale the dust,’ Esson explains.

Looking at the regulatory regime governing asbestos, Esson says the UK has gone further than most other EU countries with stringent controls, and he notes the UK regulations have even been used in other European markets and beyond including Kazakhstan where RBG has also worked on asbestos removal.

Corrosion

Turning to other technical issues for decommissioning contractors, Esson believes platform corrosion will be significant as heavy lift contractors have to grapple with the safety of lifting large structures which could be 25 years old or more. ‘There are various studies going on to make sure the structures are safe to lift off,’ notes Esson.

In the late 1990s, RBG carried out vessel and tank cleaning work on the Maureen platform, followed more recently by cleaning and engineering done as the fabric maintenance contractor on BP’s North West Hutton platform.

‘That was the beginning of our involvement [in decommissioning],’ says Esson. The decommissioning industry is still in its infancy, he believes. ‘There is a lot of theory relating to equipment that has not been tested.’ Various single lift decommissioning concepts which have been under development in the last few years have yet to be proven, he says, whereas reverse construction techniques – provided by the likes of Heerema and Saipem – are tried and tested.

Aside from the heavy lifters, Esson believes specialist contractors with patented technologies appropriate to the work will likely do well as the decommissioning market develops.

Related challenges for the industry are the issues of ensuring availability of sufficient skilled personnel for future major decommissioning and upgrade projects planned for next year, and knowledge transfer will be issues for the industry too, he says. Anticipating this, Esson’s company has already invested in a dedicated training and competency centre in Aberdeen. OE

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