Tunnel N-Pipe 3 MS

TUNPROTEC® Model 3 MS N-pipes is a system of small dimension stainless steel pipe prepared for direct installation of low pressure watermist nozzles into the pipes in pre-fabricated installation threads. The design saves cost on fittings as well as reduces the risk of getting impurities into the pipe when installing the system. The design does also ensure correct installation spacings. The N-pipes are supplied in 6 meter length pipes and in different dimensions with blank ends prepared for press fittings. The N-pipes does come with different thread configurations for different applications.ontroller

Min. working pressure

10 Bar

Max working pressure

16 Bar

Droplet size

DV90 = 300 um

Design area


Kv Metric

2.0 and 3.2

Flow rate at min pressure

27 l/min/meter pipe

Nominal density






TUNPROTEC® Model N-pipe Type 3MS system has been designed with a modular approach in mind, which lowers the time required when designing and installing the system and makes it easier to incorporate into both new and existing tunnels. The Model 3MS nozzle pipes are supplied in 6-meter-long segments and feature 18 threaded holes in three different orientations, which allows for quick installation of the Model BM-1-20 and Model BM-1-32 low pressure water mist nozzles immediately prior to installation. The threaded hole pattern repeats for every meter of the nozzle pipe to ensure the correct spacing. When installed the Model 3MS nozzle pipe will have a Model BM-1-20 nozzle in the downward position and Model BM-1-32 nozzles in the side position, angled 70 degrees from the downward facing Model BM-1-20 nozzle.



TUNPROTEC Model N-pipe Type 3MS have been successfully tested in full scale tunnel test fires in accordance with UpTun WP2 D-251 guidelines for fires with a potential heat release rate of 250 MW and verified by a ISO 17025 fire lab and the water mist nozzles have been component tested in accordance with FM 5560 and the IMO MSC.1/Circ. 1165 component test program.