Safe rigging at height

There are numerous occasions when it is necessary to climb over a mobile crane. Routine maintenance operations such as refuelling and filling the central lubrication reservoir are usually done at height. Just getting into the cab is not without risks.

In the main, crane manufacturers have tried to make this as safe as possible, with improved walkways and railings, to minimise the risk of falling. In the face of practicalities, however, compromises remain: better an inadequate ladder than an elaborate one that gets easily damaged and rendered useless, many would argue.

Where progress has been perhaps slower, and where the greater risks remain, is during the rigging process, both on telescopic boom cranes and more particularly on lattice boom cranes.

What is the incidence of people injuring themselves by falling off mobile cranes? We do not know exactly. No such authoritative statistics exist. However, there is more than enough strong anecdotal evidence to suggest safe working at height on cranes is a real issue.

“I’ve known two bad injuries in the past three years—a smashed jaw and a smashed elbow—just getting into the cab,” says Mick Hoyle, a heavy lifting and rigging consultant.

There are several international standards that crane manufacturers must observe relating to safe working at height. The European Union Machinery directive 2006/42/EC states (section 1.5.15): “Parts of the machinery where persons are liable to move about or stand must be designed and constructed in such a way as to prevent persons slipping, tripping or falling on or off these parts.

The EU standard EN 13000 Cranes: Mobile Cranes sets out greater detail about the provision and dimensions of walkways and handrails.

In the USA, the document produced by the Cranes & Derricks Advisory Committee (C-DAC), set up by the USA’s Occupational Safety & Health Administration (OSHA) to advise on new rules for hoisting operations, also has much to say on the subject and will place greater burden on manufacturers, according to committee member Doug Williams, president of Buckner Companies.

Despite consideration given to safe working at height in the standards, there are those who believe that it is simply not good enough for manufacturers simply to comply with legal requirements that date rapidly. Rather, they should seek continuous improvement and go beyond the standards to embrace best practice in the drive to reduce the industry’s injury toll.

This was the theme of a presentation given by Hoyle at the Cranes Asia conference in Singapore in December 2009. He says that while the manufacturers focussed on “the safety of the pick”, they made only “a small amount of effort to make access/egress safe”. He was also highly critical of the efficacy of fall prevention and fall protection measures offered for the assembly and rigging process.

“It is not enough to make a crane that lifts loads safely,” Hoyle says. “They have to be safe to build, to inspect and to maintain. We have to be able to put cranes together safely. Cranes are getting bigger and bigger. Someone’s got to put them together.”

Height safety has climbed to the top of the safety agenda in the UK since the introduction of the Work at Height Regulations in 2005. These state, in outline, that: working at height above 3m should be avoided wherever possible; where you have to work at height, you must take measures to prevent falling; and the consequences of any fall should be minimised.

The 3m rule is a slightly grey area, since a fall from just 1m has the potential for serious injury. In a presentation at the recent Middle East Cranes conference in Dubai, Ralf Ressel of Terex quoted statistics that say not only do falls from height cause 59% of fatalities in the construction industry, but 60% of serious injuries are caused by falls below head height.

The Work at Height Regulations have prompted construction clients both in the UK and on other sites around the world that embrace international best practice to question the operations of crane companies.

The UK’s largest crane operator, Ainscough Crane Hire, has certainly noticed a change in mood in recent years. “Our major clients give us hassle and ask us what we are doing to protect our workers,” says John Lowton, director in charge of safety and training at Ainscough.

Speaking about his current work for a major oil company, Hoyle says: “As a client, we are stopping our subcontractors from working if they do not have safe systems of working, with safe access and egress. But it is not the fault of the crane users. It is the manufacturers. They are the ones who should be looking at this. They should consider access.”

Unable to satisfy its strictest clients with even the most modern cranes on the market, Ainscough began putting pressure on manufacturers. There was also a £200,000 ($300,000) compensation claim from an employee who fell off the deck of a crane, demonstrating the financial benefits of fall prevention. Ainscough began specifying the provision of fixing points for harnesses around its telescopic boom cranes, a safety railing on the top for safer winch inspections and a foldable ladder at the back. Initially manufacturers were not hugely responsive. “It’s like pulling teeth sometimes,” Lowton says. “We ask for these things and they look like we have grown another head.”

Pressure came from other quarters too. In 2003, Canadian oil company Syncrude noted that its accident rates showed two fall injuries a year from wheeled or crawler mobile cranes and modified its specifications accordingly. Steps and handholds were introduced at the back of its Grove rough terrain cranes, between the counterweight and superstructure, to provide access and platforms for winch inspections. It fabricated improved steps to make it easier to clean the windows on its Liebherr all terrains. It changed the ladders it uses when working on booms, using ones with hooks at the top and Level Ladder attachments at the bottom. It attached light, portable, aluminium fall arrest anchor posts, extendable to provide a higher tie-off point when necessary.

Manufacturers have responded to such demands in recent years: improving access with non-slip walkways and platforms; introducing self-reeving systems and rigging winches; putting boom pins on the side rather than on top, reachable by ladder to avoid the need for going on top; boom pendants bars rather than rope, reducing the need to get onto the machine; remote controlled counterweight rigging devices; and swing away jibs deployable from ground level.

It is clear that manufacturers are paying more attention to height safety when designing their new cranes. Rüdiger Zollondz, Terex Cranes senior manager, product marketing offers the examples of the new AC350-6 and AC1000 where the need to go high for jib installations has in several cases been designed out, for example securing the pin. “Some steps no longer require someone to go up. We can’t totally eliminate it, but we are reducing it,” he says.

Certain risks still remain to be addressed. On lattice boom cranes, for example, working at height is still required for rigging the main boom extension and superlift, and for pinning the jib, and for working on the superstructure. For these, harnesses are looked to for protection, but there are limitations to relying on harnesses. Often they are worn more to satisfy safety officers than to protect the worker. A lanyard long enough to allow free movement to do the work may not arrest the fall before the ground is reached when working at 1m height. What was really needed was an anchor point at or above head height.

A potential answer has come from Australian company Standfast Corporation and its Total Restraint Access Module (TRAM), which uses overhead wires to tie on to, allowing the free movement along the boom with no possibility of falling. Standfast safety director Grant Tracy says: “TRAM is unique in that it offers a handhold that is also a mobile anchor point. The TRAM unit moves along an installed rail. The movement of the TRAM is controlled by a deadman’s brake. The handhold can also pivot and turn if required.

“A lanyard or pair of lanyards attach to the TRAM and to the operator’s harness. The TRAM is normally configured to prevent the operator from reaching a position where it is possible to fall. However, it allows the operator to perform all work tasks without restriction.”

TRAM was initially designed for tank trailers but was first used by the crane industry five years ago, on a 160t Terex telescopic crane owned by Boom Logistics, to meet the height safety requirements of mining company BHP Billiton. It has subsequently been adopted in Europe by Ainscough and Dutch rental company Royal Saan.

However, whereas Terex cooperated with Standfast with the installation of Boom Logistics’ TRAM, supplying a methodology for the necessary welding, when Ainscough wanted to fit the system to a Liebherr LTM 1500, Liebherr would not allow it to be welded to the boom. Instead, a system of strapping the TRAM to the boom was devised, without impacting on lifting capacity.

Terex has now adapted the TRAM system for its lattice booms and unveils it at Bauma this month on a 600t CC 2800-1. Terex has patented how it fixes the system to the boom, with two fabricated box sections that telescope out from inside the boom section. How it works, and the benefits it offers, were explained by Ressel at the Middle East Cranes conference.

Liebherr has also now introduced a fall prevention solution for lattice booms, with two wires running at foot level either side of the walkway. Clipping on to both wires on either side prevents a fall from the boom.

The difference in approach that these two solutions represent illustrates the complexities that manufacturers face when trying to harmonise the conflicting demands of maximum safety and maximum practicality. How to resolve such issues was debated at length by C-DAC, says Doug Williams. “On the superstructure of the crane itself, around the winches and engine, it is a very tough situation. I am very concerned about having anyone in those areas with a harness and lanyard on because if it gets caught on any turning part they could get pulled into the draw works. In those areas you have to make a determination on the greater hazard. So you have to rely on walkways with slip-resistant surfaces and handrails.

“In recent years manufacturers seem to have improved,” Williams adds. “It is still a tough situation between railings that work but are not a hindrance when you try to mobilise the cranes. I’d like to see more fold-down railings. If you have to install railings when you build the crane, they could probably have already done the work that they are putting up the railings for to protect them.”

Williams believes that the manufacturers can still make further progress in both eliminating the need for working at height, except on a ladder, and in fall prevention systems.

“I’d like to see on cranes where it is feasible a small catwalk with a fold-up cable rail to tie onto,” he says.

Naturally manufacturers and crane buyers have conflicting attitudes to whether all these new height safety features that are emerging should be standard items or optional extras. Mick Hoyle’s view is that it is unacceptable for them to be extras. “Would you buy a car that wasn’t fitted with safety belts?” he asks.

Lowton offers both praise and criticism: “The system Terex has done looks very good. I think that’s the best it is ever going to be. It is now a financial issue. They want a lot of money for these systems. Is health and safety an optional extra? We just can’t understand that.”

Rüdiger Zollondz says that the Terex TRAM system will soon be available on all Terex lattice boom cranes. “In a few years I think this will be more or less standard. We expect most customers will take this, but they will be able to buy the crane without it.”