EuroWire July 2021

Technology News

Better understanding of fire-resistant cables improves building safety

Wrexham Mineral Cables (WMC), a UK manufacturer of fire-resistant mineral insulated cables, says that now is the time to focus and understand the pivotal role such cables play in building safety, before more lives are put at risk. WMC’s call to action comes after a recent fire in a London high-rise residential building. The company says that this latest high-profile incident is a timely reminder that it is vital for building designers and specifiers to be able to identify and install appropriate cables that can survive, not just resist, real-life fire scenarios.

The preheating process also needs to be precisely monitored and controlled. Lune CHF, based in Kalkar, Germany, manufactures contact-free temperature control gauges utilising the CHF method (convective heat flow). The Lune system works with all materials and surfaces (copper, aluminium, steel and other metals, as well as non-metals such as plastic, silicone, Teflon and ceramics). Currently, no fire-resistant cable under 20mm undergoes any type of direct impact testing. While there is a test for fire with water, the actual pressure in this test is over 60 times less pressure than would be expected from a standard household sprinkler, let alone a commercial application or even a fire hose. However, fire-resistant cables that are larger than 20mm undergo testing for direct impacts and “water jet” tests. WMC has been calling for all enhanced fire-resistant cables to undergo true fire scenario tests, along with the introduction of a higher classification of fire survival cable, for those that can continue to power critical circuits in the event of a fire and withstand the rigours of safety systems such as falling debris, collapsing walls, fire hoses or even activation of high- pressure sprinklers and smoke extraction. Steve Williams, commercial manager at WMC, commented, “There has been a real

drive across the construction industry to make everybody in the supply chain more accountable throughout the various stages of the building’s existence. Sadly, the events at London’s New Providence Wharf remind us that multi-occupancy buildings remain high risk, and we must do all we can to make them safe. “Fire survival cables are a vital component of building safety, yet we believe they remain an unidentified hazard. And because there is a lack of understanding about the important role they play in keeping buildings safe, all too often inferior cables are installed. The sad reality is these cables are not likely to be adequate in the event of a fire. This uncertainty can only be ascertained when all current fire-resistant cables, regardless of size or construction, are subjected to true fire scenario tests.” WrexhamMineral Cables www.wrexhammineralcables.com

▼ WMC wants all fire-resistant cables to be subjected to true fire scenario tests

Temperature control in the extrusion process

Extrusion is a common coating method in the cable and wire industry. Precise temperature control is key in such extrusion processes. The temperature of the extruder crosshead needs to be closely controlled. It is also important that the conductor or wire entering the extruder has the correct temperature for the particular jacket material. The conductor is usually heated by a pre- heater – either conductive or inductive.

The system is suitable for closed-loop control of wire-preheaters, ensuring that the wire or conductor temperature is correct when the material enters the extruder. The Lune measurement head can be positioned directly in front of the extruder or crosshead to ensure the best performance and to compensate for heat losses between preheater and extrusion.

Lune CHF GmbH www.lune-chf.com

Doublebacker belt exceeds expectations Within just six months, during its market launch in Spain and Portugal, the new Conducto® 3322 doublebacker belt from GKD was sold twelve times. It has been installed in four systems belonging to corrugated board manufacturers and is said to be exceeding their expectations. many of these customers have already recommended the Conducto 3322 within their global company networks.

thick, the Conducto 3322 has a thickness of just 5.7mm, and a weight of 3.95kg/m 2 . Despite the low weight, its robust design ensures even pressure for optimal contact between the corrugated board and the heating plates. This stability is due to a special thermosetting, which also avoids unwanted stretching. The high air permeability of the Conducto 3322 permits fast, full-surface moisture evaporation of the corrugated board, allowing the systems to be run at a higher speed. GKD – Gebr Kufferath AG www.gkd-group.com

Initially launched in the German market two years ago, the Conducto 3322 is used by corrugated board manufacturers in the heating and traction section as the top belt, and sometimes as the lower belt. Its construction from two-and-a-half- ply hybrid mesh combines an internal structure of polyester monofilaments and bronze wires in the running direction with a warp of staple fibre yarn. In addition, the edge is reinforced with aramid.

In addition to higher air permeability, cor- rugated board quality and productivity than was achieved with previous belts, customers claim that the GKD doublebacker belt also allows savings in drive energy. Customers took the advice of technicians and followed their recommendation to switch their doublebacker belt. GKD states that

While conventional belts are up to 8mm

26

www.read-eurowire.com

July 2021