Word is out that abseil access is a cost effective and speedy way of carrying out inspection and maintenance at height, and business is booming. Mike Walter reports.
For years specialist roped access contractors have been pushing to have abseiling recognised as a fully fledged, even preferred method of working at height. Their efforts are now starting to pay off, with many specialists reporting steadily increasing workloads. Abseil access is regularly used on an ever wider range of structures and natural landforms to inspect and maintain parts other techniques find it difficult to reach.
'The sector is booming, ' says director of abseil access specialist HRS Services, Ed Westgate. 'In the early days the rope access sector mainly served the geotechnical and oil industries. Now we are as likely to undertake bridge inspections or building maintenance.
'Difficult access is becoming more of an issue and abseil techniques can offer a safe and effective way of carrying out maintenance and inspection work, ' he adds.
In recent years, growth of the sector has been fuelled by consultants developing dedicated in house teams of abseil access specialists. Simon Lawrence manages Arup's rope access team and is the new vice chairman of the Industrial Rope Access Trade Association (IRATA).
'We have just been awarded a commission from British Waterways for inspection of around 60 bridges, and we believe that around 10% will be looked at more closely by rope access engineers, ' he says.
'Arup is working hard not just at winning work but at cementing relationships to deliver consistent service, ' he adds.
Consultant Scott Wilson set up an in house rope access unit four years ago when it became highway managing agent for Highway's Agency Area 14.
Scott Wilson structures manager Tom Dean notes: 'People in the industry recognise that rope access is a very safe and relatively cost effective means of getting to a cliff face, for instance. The technique lends itself well to inspection.
Engineers can also carry out testing while on the end of a rope and write up the reports later.'
Roped access has proved itself particularly versatile in the geotechnical field.
'Rope access work on cliff faces often involves working under overhangs, inside caves and above occupied residential and public access areas, ' says Golder Associates civil and geotechnical business manager Stewart Lightbody.
Vertical Technology has just completed installing 2,000 soil nails on rock faces between Shanklin and Sandown on the Isle of Wight using abseil access techniques, and Rock Solutions solved cliff stability problems in Devon using similar skills.
But 'the challenging nature of the work means there are fairly few contractors with the necessary experience', Lightbody adds. Competition for jobs is limited. 'Our hope is that in the near future, we will be able to offer clients an expanded select tender list resulting in greater competitiveness.'
Abseiling is catching on in other areas. 'Designers of new buildings increasingly look at rope access as a principal system of accessing the outside, ' reports IRATA chairman and technical director of rope access specialist Total Access, Graham Burnett. Architects and engineers are now designing with the needs of abseil access technicians in mind, he says.
'We recently installed a special anchor system on a new halls of residence in Portsmouth to allow technicians to clean and maintain the building, and many similar safe access systems are included in the design of new buildings in London's Docklands, ' says Vertical Technology director Chris Flewitt.
'Architects and designers increasingly ask for advice on where access points should be located to avoid the need for cradles. Cradles are more noticeable than a discreet eye bolt on the top of a building, and a lot of modern structures are of unusual shape, so cradles could cause damage or prevent a technician accessing all parts, ' he adds.
Work can range from inspecting damage to windows, checking for leakage and assessing the condition of sealant, to surveying bridges and castles for conservation agencies or erecting wind turbines, reports a spokesman for access firm Up & Under.
As abseiling becomes more mainstream, IRATA is placing heavy emphasis on training to ensure the high working standards that helped the key players gain a foothold.
Westgate says: 'We always ensure that a written risk assessment and method statement are prepared for every project before any work on site begins.
'This is not only necessary to maintain our ISO9001 accreditation but is also essential for staff safety.'
Safe and sound
CAN is nearing completion of a 10 week rock slope stabilisation contract on the A890 at Stromeferry for client the Highland Council. The works involve clearing vegetation and removing extensive areas of loose rock, followed by installation of rock bolts and rock retention netting, and construction of reinforced concrete support structures.
Roped access has enabled personnel, plant and materials to be positioned on 70m high faces over a 4km stretch of carriageway. This, combined with a flexible traffic management system and a series of temporary catch fences, has allowed work to continue without closing the A890 or the adjacent railway.
Rock and roll
A thorough programme of rockface inspection has been carried out within steep limestone valleys of the Peak District to ensure motorists can drive safely underneath. Rope access engineers from Scott Wilson inspected heavily weathered and vegetation damaged natural and engineered slopes, following a rapid visual assessment of the rockface using a new Rock Slope Hazard Index system (RoSHI). The system produces a numerical score indicating the level of risk a section of rock face could present, and indicates where further inspection should be carried out. Results showed that 11 of the 27 rock faces required detailed inspection within two years.
High and mighty
High cliffs above a railway line in Devon were stabilised using the skills of rope access engineers and a variety of rockfall prevention systems earlier this year.
The 85m high cliff face between Teignmouth and Dawlish is formed from relatively weak sedimentary deposits of red mudstones, breccias and weak sandstones.
Stability has been a long standing problem, and following a major landslip two years ago, Railtrack commissioned a package of remedial work to stabilise areas in greatest need of attention.
Specialist industrial roped access company Rock Solutions was called in to carry out remedial work at four different sites from this January. Over 550 cement grout bonded stainless steel anchors, varying in length from 2m to10m, were installed.
Because the rock was so weak, the anchors had to be installed into holes with a minimum diameter of 100mm to guarantee a competent bond.
Rope access engineers used modified drilling rigs on the cliff faces, which were manoeuvred using pneumatic and Tirfor winches.
Over 6,000m 2of steel cable reinforced mesh was installed to take care of surface spalling and to contain any further shallow slippages.
Rock Solutions director Phil Burke says: 'The work went ahead throughout one of the worst periods of winter weather in years and the cliffs are certainly among the highest faces worked on using roped access in the UK.'
Abseil access engineers are well on with a cliff stabilisation project above Brighton Marina in Sussex. Main contractor CJ Thorne has called in a team of specialists to install erosion control protection, rock bolts and rockfall protection mesh to the cliff face, which is designated as a Site of Special Scientific Interest.
This work forms the second phase of a 16 week contract which began towards the end of April. The first phase involved reprofiling the upper 7m of the cliffs to a gradient of 60infinity. Contracts manager Chris Webb said: 'We couldn't have tackled the contract without the use of rope access because properties at the toe of the cliff severely restricted access.'
Room at the top
Rope access specialist HRS Services has just completed local inspection and repair of concrete on the tallest free standing structure in the UK - the NTL Emley Moor Transmission Tower, near Huddersfield. Technicians positioned themselves under the tower's working platforms, allowing them first to inspect and then to carry out any necessary concrete and coating repairs.