Tunnel fire protection system

A deluge fire protection system for an area having a surface for vehicular transit, comprising:

• a main water supply pipe disposed a first distance from the surface;
• and
• a horizontal spray nozzle arrangement disposed a second distance from the surface, the second distance being less than the first distance;
• the horizontal spray nozzle arrangement including:
• a nozzle device having a deflector and a frame supporting the deflector, the frame having a body defining an inlet portion, an orifice and a nozzle axis extending from the inlet portion to the orifice, the inlet portion defining an internal diameter and a cross-sectional area defined by the internal diameter of the inlet portion;
• and
• a coupling arrangement between the main water supply and the nozzle device, the coupling arrangement defining at least a two-direction flow path between the main water supply and the nozzle device;
• the two-direction flow path having an effective length of at least eight times the internal diameter and a cross-sectional area along the coupling arrangement that is greater than the cross-sectional area defined by the internal diameter of the inlet portion;
• wherein the frame of the nozzle device includes a pair of frame arms disposed about the orifice to define a plane, the nozzle axis disposed in the plane, the deflector including a face plate portion centered and disposed orthogonal to the nozzle axis and a canopy portion having a leading edge, the face plate being axially disposed between the leading edge and the body, the leading edge being radially spaced from the nozzle axis and extending substantially parallel to the plane.