Fire suppression system

A wall-mountable spray head unit comprising:

• a pivot base including a first path for a fire-suppressant material and a shaft, the shaft including a central channel and an outer surface, wherein the first path includes at least one radial channel between the central channel and the outer surface;
• and
• a spray head assembly mounted on the pivot base configured so as to be rotatable about an axis between a first position and a range of second positions, the spray head assembly including a second path for the fire-suppressant material, a nozzle, and a hole having an inner surface, wherein the second path includes a channel between the nozzle and the inner surface, wherein the second path is configured to rotate with the spray head assembly between the first position and the range of second positions relative to the first path;
• a seal arranged to divide a space between the outer surface of the shaft and the inner surface of the spray head assembly into wet and dry spaces;
• wherein the spray head assembly is arranged such that, in the first position, the channel opens into the dry space such that the first and second paths are not in fluid communication and, in the range of second positions, the channel opens into the wet space such that the first and second paths are in fluid communication.