Nozzle plugs for a deluge fire protection system

A nozzle plug for a deluge fire protection system having multiple nozzles connected with a pipe network, each nozzle having a nozzle chamber and a nozzle orifice allowing water from the pipe network to pass through the nozzle and a deflector to disperse the water flowing from the nozzle orifice, the nozzle plug comprising:

• a sealing section configured to fit within the nozzle chamber and/or nozzle orifice and form a seal of the nozzle orifice;
• a deformable section connected with the sealing section and configured to:
• retain the sealing section within the nozzle chamber and/or nozzle orifice to maintain the seal of the nozzle orifice up to a predetermined pressure level above atmospheric pressure within the pipe network;
• and
• deform when a current pressure within the pipe network exceeds the predetermined pressure level to allow the current pressure within the pipe network to displace the sealing section from the nozzle chamber and/or nozzle orifice and release the seal of the nozzle orifice to allow the water within the pipe network to pass through the nozzle orifice;
• wherein the deformable section is configurable to calibrate a deformation point corresponding to the predetermined pressure level;
• and
• wherein the deformable section comprises one of:
• a wall having a first thickness, wherein the sealing section is provided with a second thickness and wherein the first thickness is less than the second thickness, or
• a deformable stem connected with the sealing section at a first end of the deformable stem and having a second end extending to and engaging a portion of the deflector extending toward the nozzle orifice and wherein the deformable stem comprises a resiliently deformable material.