The nationwide rental company is installing the TRAM system, produced by Standfast Corporation. TRAM – Travel Restraint Access Module – enables users to walk on top of the crane boom with no risk of falling. The user has a double lanyard that clips onto a moveable handlebar at waist height. The handle is fixed at foot level to a rail along the length of the boom. By tying off at waist level rather than foot level, TRAM users have no distance to fall in the event of a slip or trip, and still have total freedom to do their work.
The handle, or arm, rotates 180° to aid manoeuvrability and to allow the arm to fold down for storage when not in use.
As the user climbs up the side of the crane, he or she clips the lanyard onto the arm. Squeezing the hand brake releases an air-powered spring that pushes the arm gently but firmly to vertical, helping the user climb up and over onto the top of the boom. Similar assistance is given in descent.
A deadman’s brake prevents the arm moving along the rail unless the hand brake is squeezed.
NZ Crane managing director Deane Manley said that for too long crane workers had been taking too many risks when pinning jibs onto booms. “It has been standard industry practice for years to climb on top of booms without adequate fall protection, but this has just got to stop,” he said. “It is clearly hazardous but no one seemed to know of a better way before. At four metres above the ground, a fall from that height is enough to kill someone. When we found out about TRAM it was clear that ignorance was no longer an excuse.”
Most of NZ Crane Group’s cranes are Grove brands. The first two machines to be fitted with TRAM were a GMK 5170 and a GMK 4100. These installations were completed last month and the company has ordered a further 10 TRAM units to be fitted to its other cranes before December when summer starts.
For the first installations, TRAM Australia Pacific, Standfast’s agent in the region, worked closely with long-standing Grove distributor Tidd Ross Todd (TRT) and NZ Crane to produce a methodology for fixing the rail to the booms. The precise method for fixing the rail to the boom can be different for each crane type, depending on such diverse features as the location of rope retainers and angle of tilt of the cab.
Previous TRAM installations have seen the rail welded or banded on the boom. TRT engineering director Robert Carden proposed a chemical bonding solution instead, where the brackets that hold the rail are bonded to the boom by pressure injecting an epoxy resin into the joint.
Carden said: “We have used this method for the past six years to bond the fibreglass insert into our steel booms for live-line aerial platforms. We have also used it to bond the trailing boom trailer mast mounts under the boom of a GMK 4100 and GMK 5130-1.”
TRAM Australia Pacific director Martin Jones designed a bracket that forms to the contour of the boom and laps over each side of the boom at the top, to resist shear forces. “Grove have been very helpful in supplying me with drawings of their boom profiles,” he said. “This allowed me to manufacture brackets more easily knowing that they fit perfectly.”
The bonding process has been designed and tested to AS/NZS 1891.4: 2009 Industrial Fall Arrest Systems and Devices – Selection Use and Maintenance, and certified to equivalent international standards. The TRAM unit itself is also independently certified as meeting all relevant international standards.
While welding and strapping have both worked perfectly well on other installations, Jones believes that bonding has the benefit of looking very neat. The requirement for overnight curing adds to the installation time and there was an additional cost to the first two units simply because they were the first, but costs are expected to reduce rapidly.
With the methodology in place, tested and proven, Manley says that NZ Crane and TRT will do the remainder of the installations themselves.
The two Groves with TRAMs already fitted are now back at work on the North Island grid update project, a NZ$230m (£120m) project to build a new 400kV power transmission line from Whakamaru to Auckland. NZ Crane’s customer is BBUG, a joint venture of Balfour Beatty and United Group (BBUG). For Deane Manley, the benefits of TRAM go beyond being able to sleep at night knowing that his workers are more likely to get home alive. There are also commercial rewards. It helps to position the company as likely supplier of choice for any customer like BBUG that takes safety seriously. And it has been a key component of a safety programme that has secured a 20% discount on insurance premiums for the country’s mandatory Accident Compensation Corporation (ACC) scheme. “It’s a no brainer,” said Manley. “The only reason why you wouldn’t fit TRAM is because you are too miserable.”