ZM70 (4.2) denotes a heptafluoropropane automatic fire suppression system with a nominal operating pressure of 4.2 MPa at 20°C and a storage capacity of 70 L per extinguishing agent container.

I. Functional Diagram and Operational Principle of the Gas Fire Suppression System

 

 

 

II. Schematic Diagram of the Fire Suppression System Structure

1. Combined Multi-Zone Distribution System

1. Fire-extinguishing agent storage cylinder frame; 2. Fire-extinguishing agent storage cylinder; 3. Manifold; 4. Liquid‑flow check valve; 5. High‑pressure hose; 6. Cylinder head valve;

7. Starting pipeline; 8. Safety valve; 9. Airflow check valve; 10. Selection valve; 11. Pressure transmitter; 12. Start-up valve;

13. Starting cylinder; 14. Cylinder rack; 15. Automatic fire alarm and gas‑extinguishing control panel; 16. Control wiring; 17. Manual start control box;

18. Deflation light; 19. Audio‑visual alarm; 20. Nozzle; 21. Fire detector; 22. Extinguishing agent delivery pipeline; 23. Low‑pressure safety relief valve;

 

2. Unit-Independent System

1. Fire-extinguishing agent storage cylinder frame; 2. Fire-extinguishing agent storage cylinder; 3. Manifold; 4. Liquid‑flow check valve; 5. Cylinder head valve; 6. Safety valve; 7. High‑pressure hose;

8. Start-up piping; 9. Pressure transducer; 10. Start-up valve; 11. Low-pressure safety relief valve; 12. Start-up cylinder; 13. Automatic fire alarm and gas extinguishing control panel;

14. Control circuit; 15. Manual start control box; 16. Air‑release indicator light; 17. Audible and visual alarm; 18. Fire‑extinguishing agent delivery pipeline; 19. Nozzle; 20. Fire detector

 

III. Technical Parameters of the ZM(4.2) and ZM(2.5) Systems

System extinguishing method: total flooding; maximum protection area per zone: 800 m²; maximum protection volume per zone: 3,600 m³.
System nominal working pressure (at 20°C): 2.5 MPa for the first stage and 4.2 MPa for the second stage.
Maximum operating pressure of the system: 4.2 MPa for the first stage and 6.7 MPa for the second stage.
Minimum operating pressure of the system: 2.0 MPa for Stage I and 3.6 MPa for Stage II;
Maximum filling density of the extinguishing agent: Class I, ≤1120 kg/m³; Class II welded steel cylinders, ≤950 kg/m³; Class II seamless steel cylinders, ≤1120 kg/m³. Starting cylinder filling pressure (at 20°C): 6.0 MPa.
Nozzle design working pressure: Stage 1 ≥ 0.6 MPa; Stage 2 ≥ 0.7 MPa;
Protection radius R of a single sprinkler: sprinkler installation height

 

IV. System Model Specifications and Marking Examples

1. System Model and Specifications

 

2. Labeling Example

Example 1 label: ZM70 (4.2)
It is designated as a heptafluoropropane automatic fire suppression system, with a nominal operating pressure of 4.2 MPa at 20°C and a storage capacity of 70 L per extinguishing agent container.

V. Operating Principle of the Fire Suppression System

1. Automatic Control When the control mode selector on the automatic fire alarm and gas‑extinguishing controller is set to “Automatic,” the extinguishing system operates in automatic mode. If a fire occurs in the protected area, the fire detectors transmit a fire signal, prompting the alarm‑and‑extinguishing controller to activate audible and visual alarms and simultaneously issue interlock commands to shut down associated equipment. After a preset delay, the system issues an extinguishing command, opening the initiating valve to release the initiating gas. This initiating gas travels through the initiating piping to open the corresponding selection valves and container valves (cylinder head valves), thereby releasing the extinguishing agent and effecting fire suppression.

2. Electrical Manual Control When the control mode selector on the automatic fire alarm and gas extinguishing controller is set to “Manual,” the extinguishing system operates in manual control mode. When a fire occurs in the protected area,

The fire suppression system can be activated by pressing the start button on the manual control box or controller, initiating the discharge of extinguishing agent according to the prescribed procedure to carry out fire suppression. In automatic mode, electrical manual control remains available.

3. Mechanical Emergency Manual Operation When a fire occurs in the protected area and the control panel fails to issue a fire‑extinguishing command, personnel should be notified to evacuate the site, linked equipment should be shut down, and then the manual safety clip on the actuation valve of the corresponding initiating cylinder assembly should be removed. By pressing the handle, the actuation valve can be opened, releasing the initiating gas, which in turn opens the selection valve and the container valve (cylinder head valve), allowing the extinguishing agent to be discharged and the fire to be extinguished. If, at this time, the solenoid valve requires maintenance or the initiating gas pressure in the initiating cylinder is insufficient to operate, first open the handle of the selection valve for the corresponding fire‑suppression zone by lifting the pressure arm to fully open the selection valve. Then, manually operate the hand lever on the container valve (cylinder head valve) for that zone to open it, release the extinguishing agent, and carry out fire suppression.

4. When a fire alarm is triggered If an abnormal condition is detected during the delay period and it is determined that no fire suppression is required, pressing the emergency stop button on the manual control box or on the automatic fire alarm gas‑extinguishing controller will prevent the controller from issuing a fire‑suppression command.

 

VI. Inspection and Maintenance

1. This device is a new type of highly efficient fire‑extinguishing system with a high degree of automation and stringent sealing requirements. Therefore, a corresponding maintenance and servicing regime must be established, with designated personnel responsible for regular maintenance and inspections to ensure optimal operational performance.

2. Inspection and maintenance personnel must be thoroughly familiar with the equipment’s performance parameters, operating procedures, and the structural principles of all valves, as well as the disassembly and assembly techniques. When necessary, they may come to the factory for study and training.

3. During operation, inspect the initiating cylinder at least once per month. If the nitrogen pressure indicated on the cylinder’s gauge falls below 90% of its rated value, or if the gauge pointer drops into the red zone, the cylinder shall be recharged. Maintain detailed records of each inspection for future reference.

4. Routine maintenance of the equipment should be performed diligently. At least once a month, inspect the heptafluoropropane cylinder valve (cylinder head valve) and its pressure gauge; the gauge pointer must remain within the green zone, and records should be kept for future reference. If the gauge pointer drops into the red zone, the system should be immediately sent to the maintenance department for inspection and recharging. Every six months, verify the extinguishing agent weight; if the net weight has decreased by 5%, identify and eliminate the source of any leakage, then proceed with recharging.

5. Each year, all valves in this unit shall be inspected and maintained; they may continue to be used only if no abnormalities are detected.

6. Annually inspect the support condition of storage cylinders and verify that pipe hangers, brackets, or clamps are securely fastened.

7. Every three years, the pipelines and nozzles shall be purged once using compressed air (or nitrogen); the purging may be carried out in sections.

8. Every five years, the hose shall undergo a hydrostatic pressure test at 10 MPa and an air‑tightness test at 6.7 MPa; it may continue to be used only if it passes these tests. If any signs of aging are detected, the hose must be replaced before further use.

9. Conduct an air tightness test on the piping system every five years, with the test pressure in accordance with the design requirements.

10. Every five years, the pipeline network valves and initiating cylinder assemblies shall be disassembled, cleaned, reassembled, and retested.

11. Every eight years, inspect the storage cylinders for corrosion and mechanical damage, and conduct a hydrostatic pressure test at 10 MPa; only cylinders that pass the test may continue to be used.

12. Every eight years, during the inspection of storage cylinders, conduct hydrostatic pressure strength tests and leak‑tightness tests on the relevant valves.

13. After this fire‑extinguishing device has been activated, the following components shall be returned to their original positions and verified to be functioning properly before it may be put back into service.

(1) Reset the automatic fire alarm and gas fire suppression controller (see the electrical operating manual for details);

(2) Check whether the pressure transmitter piston has returned to its original position.

(3) Replace the diaphragm of the actuator valve with a new one to restore its original operating condition.

(4) Recharge the initiating cylinder with initiating gas to a filling pressure of 6 MPa.

(5) Lower the pressed arm of the selected relief valve to move the valve disc shaft downward, then press down on the valve disc shaft to return it to its original position.

(6) Check whether the check valve has reset.

(7) Restore the container valve (bottle‑head valve) to its original operating condition;

(8) Recharge the fire extinguishing agent in accordance with the design requirements;

(9) All hose and starter line connections must be properly installed to ensure a tight seal.

14. During maintenance and inspection, the user organization may notify the manufacturer by letter or telegraph to seek assistance in resolving any issues.

15. Detailed records must be kept for maintenance, inspections, repairs, and tests.

 

VII. Precautions

1. The installation location of this device shall meet the following requirements:

(1) Ambient temperature: 0 to +50°C, with dry and well-ventilated conditions;

(2) The air shall not contain explosive, conductive dust, or corrosive substances that could damage components; otherwise, appropriate protective measures shall be taken.

(3) The cylinder storage area shall be located in a space that is easily accessible to personnel, convenient for entry and exit, and unlikely to pose a fire hazard.

(4) The cylinder bank frame must be securely fastened with anchor bolts.
2. In accordance with the national standard “Code for Construction and Acceptance of Gas Fire‑Extinguishing Systems,” the installation, operation, and use of this fire‑extinguishing system shall be entrusted to personnel who have undergone specialized training.
3. Personnel installing, commissioning, and operating this fire suppression system shall be familiar with its basic structure, operating principles, performance characteristics, and sequence of operations, as well as the structure and operational status of each valve.
4. When installing the low-pressure safety relief valve, ensure that the arrow on the component is oriented perpendicular to the horizontal (ground) plane and that the valve is mounted near the initiating cylinder assembly to prevent slow leakage from triggering the fire suppression system.
5. During installation and prior to commissioning, the actuating valve must not be connected to the initiating piping under any circumstances.
6. The safety device at the end of the container valve (cylinder head valve) stem is designed to prevent the stem from turning and inadvertently opening the container valve (cylinder head valve) during transportation and installation; it must remain in place until the equipment has been transported, installed, and commissioned.

Moreover, it must be removed when the system is in the service‑ready state; otherwise, the container valve (cylinder head valve) will remain closed.
7. Before the fire suppression system is activated, all personnel must evacuate the premises during the delay period. Upon completion of fire suppression, the ventilation fan must be started first to exhaust the fumes; only after this can personnel re-enter the area.
8. Cylinder storage should be kept away from heat sources. During transportation, handle with care to prevent impacts, horizontal placement, and inversion.
9. When replacing the diaphragm and safety disc, only factory‑supplied components that match the original in material type, shape, size, and thickness—and have passed testing—may be installed in the valve. Do not substitute with untested diaphragms without authorization.
10. During disassembly and assembly, avoid damaging the surface to prevent compromising the appearance.
11. Unauthorized personnel should not tamper with or move any components of this fire suppression system to prevent accidents.