Despite high awareness of the risks, the Health and Safety Executive’s figures reveal that the number of fatalities in workplaces is not falling. A significant proportion of these deaths is caused by falls. In 2014, 25 people were killed after falling from height, while the total rose in 2015 to 29 deaths. In 2014, falls from height were the second-largest cause of significant injury, with 567,000 days lost because of falls.
Good employers are always keen to minimise risks in the workplace. So for staff working at height – no matter whether at extreme height or a short distance from the ground – companies are using sophisticated safety systems.
One firm active in this field is MSA Safety in Devizes, Wiltshire, which has put its faith in the solid engineering of its products and is reaping the dividends in the market. Its team of 20 engineers, out of a total 240 staff on site, are trying hard to improve the safety of people working at height. It may not seem an obvious area for innovation, but the engineers of safety systems are using clever mechanical solutions and technology from sectors such as motorsport and electronics.
Controlling energy
The company, formerly known as Latchways until its acquisition by the larger US safety firm MSA last year, exports 65% of its products. Latchways produces personal fall-arrest equipment and designs and installs safety systems on buildings. Its engineers have worked on some of the most important structures in the world, from the London Eye to the Pentagon. This small firm punches above its weight.
“Anything you can fall off, we have a solution for,” says Andrew Pass, engineering manager for the Latchways product range. “We’ve not had a single fatality in 40 years of use. Contracts such as the Pentagon are testament to the engineering and the quality of the products we supply. We are masters in the control of energy. Fall protection is about controlling energy to the end person as well as the structure, to make sure it doesn’t fail.”
One of the developments that Latchways’ safety systems have had to adapt to is changes in the roofing industry, which now uses different and thinner materials and more unusual designs. Accordingly, constant-force posts, which workers latch on to when they are on buildings, are no longer the accepted solution. When alternative technology may work better, the firm works as closely as possible with the client to develop solutions in a consultancy capacity. “We always start with the risk hierarchy of fall protection – if possible, avoid the risk completely,” says Pass.
Engineers also test for misuse cases, such as when many people use a single device, and the use of incorrect lanyards. This necessitates a belt-and-braces approach to development and testing. For example, the constant-force post is tested to 300kg dropping 2.5m, simulating three people falling on one line without any energy-absorbing lanyards in place.
Falls don’t have to be from an extreme height to cause severe injury, and the company has tailored products for specific markets. The Wing Grip uses a vacuum to attach to aircraft wings so that maintenance can be carried out – essentially using the weight of the atmosphere to save people in the case of a fall. The single-point, quick-access system is portable, so it can be moved from aircraft to aircraft.
The company has also developed a barrier system, where the barrier attaches onto the wing using a vacuum. “We get some strange challenges,” says Pass. “We’ve had to develop a heavy-duty energy absorber for the North American market that can absorb 190kg – much higher than the standard version.”
Another example in a growing sector is offshore wind turbines. The environment is challenging – the safety system is mounted at the top of the ladder on the turbine’s tower, up to 25m high. Pass says: “The environment out there is amazingly harsh, and changes from windfarm to windfarm – the size of the tidal swells, different currents.”
MSA engineers are able to design the safety system and the ladders and constant force posts. The designs of turbines, and the harsh weather conditions, can vary considerably. The first difficulty is transferring the worker from the boat to the safety system. “It seems simple, but is the biggest challenge,” says Pass.
Most systems initially used rope, but that doesn’t last long in the marine environment and can cause an additional hazard. The solution is a guided tether line that controls the movement of the rope and doesn’t blow around, minimising risks. The firm has been involved with the development of standards across the industry, for ladders, posts and tether lines, and 80% of offshore turbines are now standardised, says Pass.
Energy absorber
One of the company’s newest pieces of technology is the radial energy absorber – a spring that locks up, which does not actually contain any springs. The locking action is created by a shaft with a tolerance ring between the shaft and the housing at precision tolerances, to 50µm. When it locks up, the shaft rotates around the housing and the tolerance ring rotates within, generating friction and heat to absorb the energy. The tolerance ring is pressed steel in a circle with small undulations in it, and each undulation acts as a spring force. Inspiration for the device came from the slipping action of the arm inside a computer hard disc drive. The technology and technique are also borrowed from the automotive industry.
The radial energy absorber is being deployed in the firm’s mini-Personal Fall Limiter and Personal Rescue Device, a wearable mechanism that solves the problem of how to get someone down after a fall, suspended on a harness.
Karl Jones, product development manager of the Latchways range, says: “We are trying to get away from using nuts and bolts. To make the radial energy absorber, we need only the minimum number of operations, and it has minimum parts.” The mechanism also makes products lighter and smaller, and removes the need for calibration during manufacturing. “It’s easier to manufacture and easier to make more,” he adds. The inside of the mechanism is produced by a company that makes parts for Formula One, but all the tooling has been developed in-house.
Pass says the company’s approach to innovation is to “look in the gaps” between markets. “We are looking at forseeable misues, developing a foolproof system, in recognition that not everyone reads all of the instructions.”
The engineers who design safety systems are also close to the end-use point. “We know the outcome of installing the wrong system. Stuck behind a desk, how do you develop a product that solves a problem? On site, you can understand problems better.”
IN FOCUS – RISING OUTOUT
Volumes at the MSA factory in Devizes are ramping up. It was making 5,000 mini-Personal Fall Limiters a year but so far in 2016 has made 15,000. Its daily output of the devices is now 300, and it expects to produce 30,000 this year. The firm’s efforts are bound to make working at height safer for many people around the world.