POSCO Develops 'Internal Single Safety Belt Strap'... Ensuring Safety for High-Altitude Workers

Safe lanyard for fall accident prevention. Photo by POSCO

[Asia Economy Reporter Jeong Dong-hoon] POSCO is actively working to establish workplaces free of accidents by utilizing smart safety technology.

According to POSCO on the 1st, the "shear-resistant safety harness lanyard," developed for the first time in Korea by POSCO, is a safety device that prevents the shearing and breaking of safety ropes caused by sharp metal objects and friction during high-altitude work, thereby preventing serious accidents.

Generally, according to the "Ministry of Employment and Labor Safety Harness Performance Standards," the materials that determine the performance of safety harness lanyards are classified into two types: synthetic fiber and wire. In particular, the commonly used synthetic fiber material is vulnerable to shearing caused by friction with sharp objects, while wire has the disadvantage of being bulky and difficult to carry.

In fact, accidents where safety harness lanyards are cut by pipes or metal structure edges during high-altitude work, causing workers to fall, frequently occur at work sites. According to last year's industrial accident death statistics from the Ministry of Employment and Labor, out of 828 industrial accident fatalities, falls accounted for 351 cases, exceeding about 40%.

POSCO developed the "shear-resistant safety harness lanyard," which combines the advantages of existing synthetic fiber and wire materials, making it resistant to shearing while also easy to carry. This product can withstand up to 70 minutes without breaking when the lanyard rubs against surrounding structures after a first fall occurs, preventing a secondary fall and allowing for the rescue of the suspended worker during that time.

The shear-resistant safety harness lanyard developed by POSCO uses "Dyneema," a plastic material used in bulletproof vests and fishing lines, unlike conventional materials. Dyneema is an ultra-lightweight, ultra-high-strength fiber made of ultra-high molecular weight linear polyethylene. It is the strongest plastic currently available in terms of impact resistance and is more than 15 times stronger than steel of the same weight, while weighing about 70% of nylon.

Since July last year, POSCO has been working with "Estop," a safety protective gear manufacturer, to develop the product. The most important goal in developing the safety harness lanyard was to secure more than 40 minutes of golden time required for rescue when a worker is suspended in the air after a first fall, thereby preventing serious fall accidents.

In particular, POSCO installed a test device within the steelworks under conditions of 120 kg load, 90-degree lanyard bending angle, and pendulum motion converted to a shear object's left-right reciprocating motion speed of 60 mm/s, to analyze the shearing and breaking mechanisms caused by pendulum motion from falls and friction with sharp objects. After conducting multiple tests, it was confirmed that the combination of wire, an existing material, and the new material Dyneema had the longest shear resistance time. Based on these results, additional repeated tests were conducted by increasing the thickness of Dyneema and wire core strands, resulting in a lanyard that does not shear for more than the targeted 40 minutes.

Estop, a specialized safety protective gear developer, derived optimal conditions for securing shear resistance by mixing Dyneema material and wire rope, and produced commercial products based on the optimized conditions.

The "shear-resistant safety harness lanyard" was officially certified as protective gear in January this year and is being prioritized for application at in-house high-altitude work sites. POSCO plans to expand its application to group companies such as POSCO Engineering & Construction and partner companies.