Innovative fastening solution for fire protection in tunnels

Last year, the topic of fire safety in tunnels was a hot issue after the Department of Public Works conducted laboratory tests to determine the fire resistance of Dutch road tunnels. These showed that a number of tunnels had reduced fire resistance. To ensure that these tunnels once again comply with national tunnel legislation (Warvw and Ravw), it was necessary to take additional measures, such as installing heat-resistant cladding.

Text and image | HECO-Schrauben

The application of heat-resistant cladding is done by mounting fire-resistant boards on the wall surfaces of tunnels using mechanical fastening systems. These fastening systems must meet special requirements with regard to fire safety and corrosion. The screw anchor MULTI-MONTI-plus from the German fastening specialist HECO-Schrauben is approved for the installation of fire-resistant slabs in tunnels and offers a number of advantages over other mechanical fastening systems. The efficiency values of the MMS-plus screw-anchor are applicable to fire exposure according to fire resistance classes R30 to R120 in accordance with NEN EN 13501-2. This makes the MMS-plus suitable for the installation of fireproof boards, as well as for other elements such as information boards and lighting systems. The screw anchor is characterized by a shallow mounting depth, the possibility of mechanical machining without a torque wrench and an attachment with less lateral forces so that it can be mounted closer to edges.

The screw anchor is characterized by a low mounting depth, the possibility of mechanical machining without a torque wrench, and a fastener with less lateral forces so that it can be mounted closer to edges.

Mounting without dowels

The MMS-plus screw anchor has European certification (ETA-05/0011) for fixing fireproof boards in tunnels. The self-cutting thread of the screw anchor allows the anchor to be screwed into the drilled hole without dowels, ensuring fast and economical installation. No curing time is required as with chemical anchors, while the fastener can carry loads immediately. The low mounting depth of about 40 mm with a drilling depth of 45 mm prevents contact with the reinforcement of the concrete.

Reusable

A particular advantage of the MMS-plus screw anchor is that this fastener is fully dismountable and reusable. If necessary, the anchor can be unscrewed and then reused in the existing hole. Thus, this anchor allows for disassembly of panels for inspections of the underlying concrete or replacement of damaged panels, as is often the case after an accident. The screw anchor can be reused up to ten times in accordance with certification.

Depending on the required corrosion resistance class, the anchors are available in different materials, for example in stainless steel A5 1.4571 or for particularly aggressive conditions in highly corrosion-resistant steel 1.4529 (HCR).