Staying safe at height21 November 2017
Paola De Pascali talks with fall protection companies and crane manufacturers about new product developments that help reduce the risk of working at height.
The level of risk incurred by working at height has led to relevant regulation and standards around the world. Crane manufacturers and fall protection companies are constantly developing their products to address the regulations and reduce the risk.
“The working at height regulations set out a hierarchy of controls that should be followed when planning a task which involves working at height,” says Luke Harrison, lead trainer and technician at Checkmate, a British manufacturer of height safety equipment. “Avoid working at height if possible, but if you cannot avoid it, do it in a way that prevents anybody from falling. If you cannot prevent falls then make sure you minimise the distance and consequences of a fall.”
Checkmate’s products include permanently installed fall protection systems for tower crane ladders and jibs as well as a full range of personal fall protection equipment for tower crane erectors. Training, installation and implementation of the above is available from Checkmate’s specialist training division, HART (Height and Rescue Training).
Harrison says: “An area that is unfortunately overlooked quite often in our experience is evacuation and rescue on tower cranes. Duty holders look at how to follow the hierarchy of controls, but fail to think about what happens if somebody actually does fall or has a medical emergency at height on a crane.
“Due to the height and nature of tower cranes, the emergency services may only be able to offer limited assistance in an incident, so it again falls to the duty holder to be able to get a casualty to the ground or a safe area where the emergency services can provide appropriate care and transport to hospital.”
Checkmate can provide training and equipment for a site to have their own rescue team, or for particularly hazardous sites or tasks, it can provide specialist technical rescue teams of its own to be on standby.
A product recently launched by Checkmate is the MAX rescue device, a constant rate descender capable of lowering people at a set speed without the need for manually controlling it. The company says the use of this product reduces the risk of human error. It has the capability to rescue casualties in any situation on a tower crane, from a crane operator in their cab or the tower, to erectors on any part of the structure, even if they are out of reach of their colleagues.
Harrison says models are available for both automatic hands-free operation and multiple descent models with advanced rescue functionality, as well as power assisted option. The MAX is designed to be used attached to the anchor point in regular mode of operation, or in an inverted mode, attached to the user and casualty. The device is completely symmetrical, allowing full use of all functions regardless of the direction the MAX is running.
Science-based technology company 3M has developed a range of fall protection solutions for those who work on mobile and tower cranes. Stephen Morris, UK fall protection technical specialist at 3M, says: “When considering undertaking work at height on mobile cranes, due to the layout of these machines, the only practical method of fall protection may be the use of fall arrest equipment. This includes the presence of suitable anchor points, the limited fall clearance to the surface below, and the presence of sharp edges that could potentially cut through lanyards or lifelines.
“Using traditional fixed-length fall arrest lanyards, the fall clearance required to arrest a fall would include the total length of the lanyard, the deployment length of the shock absorber, and the body length of the person. Obviously, when working on mobile cranes, the fall clearances are restricted, so we need to look at effectively arresting a fall in a shorter distance.”
The 3M DBI Sala Nano-Lok Self-Retracting Lifeline (SRL) is a compact unit that is mounted directly to the rear of a compatible EN 361 standard harness and pays out and retracts, giving a “good degree of movement.” In the event of a fall, the unit locks the lifeline, limiting the fall clearance to a minimum.
“We also need to be aware of the presence of sharp edges, which could sever a lanyard or lifeline in a fall situation. Tests have shown that standard lanyard cable or webbing can fail over even a 5mm radius rounded edge in a fall arrest situation. Therefore, ordinary sharp edge rated lanyards and SRLs cannot guarantee protection against extreme sharp edge failure,” says Morris.
The Nano-Lok Edge Cable from 3M is an extreme zero radius edge rated SRL, it has been uprated to withstand falls over sharp edges with no rounding whatsoever.
The product meets CE EN: 2002 requirements and those of the VG11.60 rev 7 edge drop test, a German standard that goes over and above EU standards.
It has been designed to replace the wearer’s conventional fixed lanyard. It must be worn in conjunction with a fall arrest harness that is compatible with the lanyard system and meets EN 361:2002 standards.
The galvanised steel 5mm lifeline has a 141kg capacity, so it can accommodate wearers who carry heavy equipment. The system also includes an integrated back-packstyle energy absorber, which works with the connector to further limit fall forces.
3M offers standard and bespoke working at height courses, which can be delivered at its training centre near Manchester, UK, or at the customer’s facilities.
“One of the company’s popular courses is designed specifically to address tower crane rescue situations, which can arise when an operator or a fitter becomes incapacitated or unwell, or in the event of a fall from height onto fall arrest equipment,” Morris says. “Tower cranes present several issues, such as access via long vertical ladders, the jib and the counterbalance. Rescue from these areas can be particularly challenging because of the heights and the environments associated with tower cranes.”
3M’s one-day tower crane rescue course aims to give operators and maintenance workers the theoretical knowledge and the practical skills to enable them to undertake a simple rescue of a casualty at height using a constant rate descender rescue device. The course covers relevant health and safety legislation, and includes emergency procedures and company policies in the event of an emergency at height.
“The law also requires that people working at height are adequately trained. All training should be relevant to the tasks undertaken and the equipment used, and should include both knowledge and skills learning,” Morris says. Mobile cranes US manufacturer of access equipment and truck mounted cranes Altec has recently launched a cab for their truck mounted cranes with doors at the front and side. According to the manufacturer this 20° tilt cab not only improves the operator’s viewing spectrum but reduces the risk of a fall.
Dan Brock, Altec cranes market manager, says: “Altec’s patent pending dual entry cab provides convenient access to the controls at any position throughout the range of rotation. Altec’s front entry reduces slip, trip, fall hazard exposure when the crane is stowed.
“By contrast, a side entrance forces the operator to climb a vertical ladder to access the crane controls, which exposes the operator to slip, trip, fall hazards. A front entrance is a safe way to access the crane controls when the crane is in the stowed position, or when the crane is positioned 180° from the stowed position.”
Altec’s side entry offers convenient access and degress when the crane is positioned perpendicular to the carrier. A transparent thermoplastic polymer front and top surfaces maximize the viewing spectrum and reduce falling object hazard exposure.
Talking about other design changes that make access to the crane safer, Harrison says: “On Altec’s stand-up units, like the AC18- 70B and AC23-95B, the operator is afforded direct access to the bed, or from the bed back to the controls, via our dual walk-through control stations. These control stations make it safe to access the bed.”
Pat Collins, director of marketing Link-Belt Cranes, says the manufacturer’s design philosophy includes a major emphasis on reducing work at height exposure on new and existing models.
“Semi-bore weldments for attachment pin locations eliminate the need for driving pins in place and cam stops align for quick pinning. The use of a live mast on lattice crawlers versus a high gantry limits work at height so that a rigger does not have to unpin the gantry from an elevated position on the crane upper,” Collins says.
Link-Belt’s new approach to on-board fly erection and stowage for recent models focuses on minimising working at height and being a one-person operation. The on-board fly pivots on and off the storage brackets with a hydraulic cylinder. Power pins actuated by a cordless drill do the work when engaging and disengaging the fly lugs to the boom head, eliminating the need for hammering pins.
Collins says: “What really sets our system apart from the rest is the patent-pending Sure-Lock, which prevents the pivot pin and boom head power pins from disengaging at the same time, ensuring that the sequence is done correctly. Other conveniences are coloured-coded pins to further simplify the process and a wire rope keeper on top of the boom head that make reeving changes a one-handed operation.”
Regarding the upper access, Collins explains that upper guardrails can be found across the Link-Belt product line and serve as a significant barrier while working at height performing daily routine checks. “Link-Belt’s rough terrain flat carrier decks maintain six points of access with folding or integrated steps and handholds despite additional space needed for Tier IV upgrades (urea tank). Link-Belt’s pull-out “Cabwalk” provides for easy access and egress of the operator’s cab.”
In terms of maintenance, newer Link-Belt designs like remotely mounted filters are accessible from the ground. Lubrication points are as low as possible either by means of lowered grease banks or maximizing sealed bearing and self-lubricating bushings, eliminating the need altogether for any maintenance.
Terex Cranes has incorporated diverse design features, depending on equipment type and model, to reduce the need to work at height. On the recent smaller all-terrain models, the Demag AC 55-3 and AC 60-3, the boom can be luffed to 5° below horizontal. This allows the operator to reeve the hook from the ground, eliminating the need to work at height. Access to filler caps can be positioned to allow filling from ground level.
“To reduce the need for climbing, oil level monitoring for winches in highly elevated positions may be done by means of sensors for example CC3800 winch in SL mast,” says Frank Schröder, director product management all terrain cranes at Terex.
“Where work at height is inevitable, our cranes are equipped with anchor points for attaching personal protective equipment (PPE).”
Ingo Noeske, director product management crawler cranes adds: “We also offer our fall protection system. We initially introduced this system on the Superlift 3800, and in 2012 it won an ESTA award. This system is available on our crawler cranes and on the lattice boom extensions on the larger AC cranes.
“The fall protection system permanently mounts to the lattice boom sections. It consists of two poles at the end of each section, holding a cable above head level, when standing on the section.
Riggers can fasten the carabiners of their PPE to that cable, easily preventing them from hitting the ground in the event they fall. The system is foldable so it doesn’t add any bulk for transportation. It is also quick to assemble or disassemble. For other models and situations we offer the TRAM system which provides a moveable anchor point.”
Liebherr’s head of strategic marketing and communications Wolfgang Pfister takes the duty cycle crawler crane type HS 8130 HD as an example to highlight the safety features, which have been designed as standard for the new product series.
“The HS 8130 HD, with an operating weight of approximately 115t, sets new standards in terms of safety.
The duty cycle crawler crane can be transported with the railings, walkways and pedestals fully assembled on the upper carriage. This accelerates the mobilization of the crane on the jobsite. Further features that facilitate the mobilization are the self-assembly system for crawlers and counterweight as well as the telescopic jack-up system,” Pfister says.
As an option the machine can be assembled and disassembled with a remote control, for example the service engineer does not have to walk underneath the machine.
Even the assembly of the boom foot can be arranged via remote control. In addition the access ladder onto the roof of the machine is fully integrated into the machine’s design and does not need to be removed during the transport. These design features increase safety and speed of mobilisation.
Regarding the boom walkway fall protection, the lanyard connections of the fall arresting device are hitched to both sides of the catwalk onto runners sliding in rails. The lanyard adapts automatically to the movements and the size of the technician. For safe working on the catwalk, the Liebherr fall protection allows technicians to easily change directions and walk on the whole length of the main boom without the need to unhook the system and fix it again subsequently.
“Both hands are free for work at any time. To ensure optimum safety, the fall protection additionally has an automatic locking function. In case of a fall this locking function reacts immediately and prevents impact with the ground,” Pfister says.
In the last ten years, revisions of the European norm for tower cranes, EN14439, included a number of recommendations for improving safety of tower cranes.
Raimondi Cranes has adopted additional solutions to complete the norm requirements based on their internally-executed risk analyses.
“A simple example of this is the phase when we are disconnecting the jib from the counter jib or from the first jib section. It is possible, due to an imperfect balancing of the jib, that the jib moves suddenly when removing the pin or the bolts,” says Domenico Ciano, technical director at Raimondi cranes. “This sudden movement can unbalance the technician, thereby creating a potentially dangerous situation.
We have eliminated this risk by implementing a system that maintains the jib movement control and limits it, even if the jib is not correctly balanced.”
Ciano adds that Raimondi is about to launch the new MRT234 flat top crane, and they are testing a new luffing jib model. “For both projects, we focused on reducing the risks of working height, analyzing all of the installation and maintenance phases. We have designed specific solutions to help the technicians and the crane operator work in safe and productive environments. In terms of the MRT234 flat top crane, we have a new safe line and a new no-slip walkway along the full jib. All jib areas that exceed 2m in height are accessible using platform or rung ladders, and the technicians can work safely fixed to the hooks welded to the structure.
“The design of our counter jib allows for work in this area, enclosed and protected from the side falls perfectly. With this new crane, Raimondi introduced additional protection to avoid human contact with the counterweight area during normal or maintenance phases.”
Regarding Raimondi’s new luffing cranes, Ciano says: “We have also strategized how to reduce risk and stress related to installation and maintenance phases with new accessories like auxiliary winches for installation activity and big platforms for an easy maintenance.
All areas are protected with handrails and equipped with comfortable platforms.”
As one of the promoters of the EN-14439 norm, Jaso is implementing all of the recommendations of the sole tower crane safety norm existing.
“This is a dynamic process and currently our technical director is actively participating in the update of this norm which address mainly safety at access,” says Dick Huitema, export manager at Jaso. “Internal and external climbs are dangerous operations, which require safety measures. For a safe working environment, our jacking cage has a landing platform with a trolley in which the tower to be inserted, is secured to avoid tumbling backwards. Afterwards the trolley with the tower is pulled to the position and connected. If we compare this principle to the one typically adopted by some competitors, where an upper rail is used to hook on and drag in the extra tower, we believe that our system does offer much more safety and a smoother work process.”
Huitema says the technology of hook cameras, the use of digital LMI systems with zoning and anti-collision systems incorporated, black box and data log systems certainly have helped to raise the standards of safety and reduced working at height.
Fellow crane manufacturer Terex has altered the design in their new tower crane models taking the risks associated with this type of work into account. Matteo Bellotto, tower cranes engineering at Terex says: “Our latest tower crane models have jib sections with pre-equipped independent safety lines. The tower sections have pre-assembled inclined ladders and platforms with knee rails.
“We designed the walkways on the slewing section, the counter jib and the cabin platform to be wide and provide enough space for the operators and technicians to work safely. The jib basket allows a safe jib inspection and maintenance.”
Bellotto also highlights the ‘Alarm/inform’ button on the slewing platform, which can be used to inform the operator if someone is climbing through: “All movements have emergency stop switches in case the crane movements must be stopped immediately.”
Hans-Martin Frech, marketing manager at Liebherr tower cranes explains how the safety is ensured for the crane driver, fitters and every people involved in working at heights.
“Regarding the safety for the crane driver, the access to the crane cabin (EN 13586) is without any safety equipment because all pedestals are equipped with side protection; inclined ladders with back protection,” Frech says. “In the cabin you find a noise and heat protection safety glazing; ergonomic crane cab; the best view to the job site. To ensure safety to the fitters there is a safe access to the working positions in addition to safe footprints, lifelines on the jib and lift cage on the trolley jib.”
Gerd Tiedtke, product managers at Wolffkran says all jib sections are fitted with a rope along the upper chord of the jib onto which the assembler or technician can hook the safety harness of PPE.
The rope along the upper chord of the jib is used for hooking up the PPE. All jibs are equipped with a man basket for maintenance work on the jib.
In terms of safety features on the counter jib, Wolffkran is fitting all new cranes with special guardrails suitable for connecting PPE.
“These guardrails are considerably sturdier than regular guardrails and are located at the rear of the counter jib around the opening for the counterweight blocks, since this opening poses the danger of somebody falling through it during assembly or disassembly when the counterweight blocks are not in place,” says Tiedtke. “The new PPE-suitable guardrails are fitted with hooks onto which the technician and operator can hook the PPE. A sturdy platform of galvanized stretch metal across the entire width of the counter jib further increases safety of work performed on the counter jib, such as the assembly of the bracing rods, and allows for easy access to the hoisting winch.”
Wolffkran has launched the WOLFF 6020 clear, a 140mt flat-top tower crane, which will replace the WOLFF 6015 clear introduced in 2008. Like the WOLFF 6015 clear, it is designed for a pure two-fall operation.