APPC Systems
APPC Systems

The purpose of the Firenor active pressure pulse compensator (APPC) is to protect the firefighting systems from damage by preventing pressure surges in the firewater distribution piping due to a deluge system or other water consumption systems activation before water pumps have started. Should a high flow firewater using system start before the fire water pumps, it will drain water from the ring main, creating a vacuum in the upper portions of the piping. To prevent this dangerous situation, a pressure control valve will discharge low pressure air into the upper sections of the firewater ring main. The system then continues to dynamically control the pressure in the firewater ring main by increasing air flow to avoid vacuum. This ensures that the entire system is properly pressurized at all times and prevents pressure surges in the firewater ring main.


The standard Firenor APPC system has an air cylinder rack capacity more than long enough to cover the startup time of the average firewater pump. A booster pump can be installed to ensure sufficient air pressure at all times and to allow rapid refill after use. This standard system is controlled by a pressure controlling valve and includes additional valves and instrumentation necessary for proper operation, maintenance, and testing. All design parameters of the Firenor hydrophore system can be customized as needed in order to meet specific project requirements.


Every system can be customized, upon request, for compliance with applicable rules, regulations and project specific requirements as well as standard such as CE, FM, UL, ASME, DIN, DNV, BV, NMD, IMO, NFPA, Norsok. Full documentation for any tailor-made products are available and include all necessary certifications, third party verifications such as DNV/GL, BV, ABS, etc., and full scale test reports, if required.

  • Flexible Design
  • Quick response to inquiries and requests
  • Light Weight (Comparing to Hydrophone systems)

Every Firenor system is available in the following materials:

  • Galvanized carbon steel
  • Copper nickel
  • Super duplex
  • Titanium
  • Duplex
  • SS316
  • 6Mo
  • GRE

The engineering department produces documentation relevant to all phases of the project. Documentation normally includes the following:

  • Quality plan
  • ITP
  • Drawings
  • Data sheets
  • Indexes
  • Procedures
  • Calculations
  • Certificates
  • Reports
  • User manual
  • MRB