I. Overview

The temperature‑sensing self‑activating fire suppression device (hereinafter referred to as the temperature‑sensing self‑activating fire suppression device) is an innovative invention in the fire protection industry. As a simple, low‑cost, and highly reliable standalone automatic fire suppression system, it requires no external power supply, no dedicated smoke or heat detectors, and no complex equipment or piping. Relying on its own stored pressure and a pressurized fire detection tube together with a set of fire detection cylinders, it can rapidly, accurately, and effectively detect and extinguish fire sources, integrating alarm and extinguishing functions to put out fires at their very earliest stage. This approach not only significantly reduces project costs and per‑incident extinguishing expenses but also ensures that personnel remain unharmed. By adopting this temperature‑sensing self‑activating fire suppression device, protection can be shifted from safeguarding large enclosed spaces to directly protecting valuable equipment housed in various smaller enclosed areas.

II. Technical Specifications

1. Operating principle of the temperature-sensitive self‑activating fire suppression system

A heat‑activated automatic fire‑extinguishing system consists of a pressurized vessel containing the extinguishing agent, a container valve, and fire‑detecting tubes and/or discharge pipes that release the extinguishing agent. The fire‑detecting tube is installed near or directly above the area where a fire is most likely to originate, with detection carried out via multiple sensing points (linear) along its length. When a fire occurs, the tube softens and ruptures at the point of highest temperature, releasing the extinguishing medium into the protected area either through the tube itself (in a direct‑action system) or via nozzles (in an indirect‑action system). Its… Among them, the fire‑detecting tube is a newly developed product in the high‑tech field, a cutting‑edge nonmetallic composite. It combines long‑term leak resistance, flexibility, and reliable temperature sensitivity; within a specified temperature range, it bursts to discharge extinguishing agents or transmit fire‑alarm signals.

2. Features of the Temperature-Activated Automatic Fire Suppression System

● Combines alarm and fire suppression in one, with rapid detection and response, swiftly extinguishing fires at their earliest stage and effectively minimizing economic losses caused by fires.

● This device requires no external power supply and is unaffected by vibration or impact, ensuring reliable operation. It also maintains its fire‑detection performance and avoids false alarms caused by oil, dust, or smoke.

● The fire‑detecting tube is a flexible component that is unaffected by installation orientation, allowing it to be inserted into various narrow, complex, and flammable spaces or equipment. This feature addresses the limitation of existing fire‑protection products, which are unable to extinguish such fire sources.

● Close proximity to the protected object ensures high firefighting efficiency at low cost.

● Non‑total flooding; during discharge, it will not harm personnel in the protected area.

●Ideal for equipment and facilities that require critical protection while operating unattended.

● Simple design, easy installation, minimal footprint, and no need for a separate cylinder room.

3. Scope of Application

● Microwave equipment rooms, decimeter‑wave equipment rooms, meter‑wave equipment rooms, transformer and distribution rooms, and uninterruptible power supply (UPS) rooms within radio and television transmission towers;

● The program-controlled switchroom, control room, and signaling transfer point room of the communication system;

● Control rooms, electronic equipment rooms, computer rooms, relay rooms, and switchgear and distribution rooms in power plants, as well as areas such as cable crossings, cable bundles, and intermediate joints;

● Power distribution and transformation cabinets, elevator control cabinets, and cable trays or cable ladders with trunking;

● Special or critical cabinet equipment housed in relatively sealed enclosures at other locations.

III. System Architecture

1. Direct-Acting Heat-Sensitive Automatic Fire Suppression System

● The fire‑detecting tube is connected to the extinguishing‑agent container via a container valve to detect the fire source. When exposed to heat, the tube ruptures; the resulting pressure drop in the tube triggers the container valve, which, through a conversion fitting at the valve outlet, directs the extinguishing agent to be discharged through the original rupture point of the fire‑detecting tube.

Direct‑type heat‑sensitive self‑activating fire extinguishing devices can be classified according to the type of stored extinguishing agent as follows:

Carbon Dioxide Direct-Acting Heat-Sensitive Automatic Fire Extinguishing System

Heptafluoropropane temperature‑sensitive self‑activating fire suppression system

Perfluorohexanone heat‑activated self‑starting fire suppression system

2. Indirect-type heat-sensing self‑activating fire suppression system

● The fire detection tube is connected to the extinguishing agent container via a container valve to detect the presence of a fire. When exposed to heat, the tube ruptures; the resulting pressure drop activates the container valve, which releases the extinguishing agent through a discharge line to the nozzle.

Indirect-type fire‑sensing, temperature‑activated automatic fire‑extinguishing device, according to the stored extinguishing agent.

Depending on the type, they can be classified as:

Carbon Dioxide Indirect-Acting Temperature-Sensing Automatic Fire Extinguishing System

Heptafluoropropane Indirect-Acting Heat-Sensitive Automatic Fire Suppression System

Perfluorohexanone Indirect‑Type Heat‑Activated Self‑Starting Fire Suppression System

Table 1: Technical Parameters of Temperature-Activated Automatic Fire Suppression Systems

7. The release tubes used in indirect‑type heat‑activated automatic fire‑extinguishing systems shall comply with the following requirements:

A. Carbon Dioxide Release Pipe

Material: The release tube shall be made of seamless copper alloy tubing with an outer diameter of Φ14 mm.

Working pressure: shall not be less than 10 MPa.

B. Heptafluoropropane (Perfluorohexanone) Release Pipe

Material: Non-metallic flexible hose with an outer diameter of Φ6 mm and an inner diameter of Φ4 mm, used for release tubes.

Working pressure: shall not be less than 1.8 MPa.

8. Carbon dioxide extinguishing agents, heptafluoropropane extinguishing agents, and perfluorohexanone extinguishing agents shall each comply with the provisions of the current national standards GB 4066 and GB 18614.

The fire detection tube shall be installed no more than 1 meter from the protected area; see the figure below for installation requirements.

The effective protection zones of each nozzle are shown in the figure below:

V. Installation and Commissioning

1. The installation of temperature‑sensitive automatic fire‑extinguishing systems shall be carried out by personnel and teams who have undergone specialized training.

2. Prior to the installation of temperature‑sensitive automatic fire‑extinguishing systems, the following technical documents shall be available:

● Construction drawings, design documents, and relevant technical documents;

● Inspection reports certifying compliance with mandatory or type‑approval requirements issued by a nationally designated inspection body;

● Certificate of product conformity and instructions for use and maintenance;

● The design unit shall provide the construction unit with a detailed description of the project and relevant precautions.

3. After installing the fire detection device, remove the terminal pressure gauge from the pressure gauge valve, then connect the dedicated inflation connector to the valve. It is essential to ensure that the high-pressure ball valve remains closed at this time. Use the dedicated inflation connector to pressurize the fire detection tube to 1.2 MPa, with nitrogen or compressed air as the test medium. The test gas must not be drawn from the extinguishing agent storage cylinder of the fire detection device, and drawing test gas directly from the storage cylinder is strictly prohibited.

● Make a mark at the position indicated by the pressure gauge pointer.

● Inspect the fire detection tube for leaks; the typical observation period is 10 minutes per meter.   Explore the fire.

● While observing the fire detection tube, also inspect the device for any abnormalities.

● If, during the installation of a heat‑activated automatic fire‑extinguishing device, the protected space or area has not yet been completed, it is advisable to wait until the project is finished before opening the ball valve of the device, thereby preventing unintended activation.

● If the extinguishing agent container valve of the system is equipped with a pressure switch, the pressure switch measures only the pressure inside the container when the ball valve is closed; therefore, the electrical circuit can be installed at this time. After the ball valve is opened, the pressure switch will monitor the pressure in the fire detection tube.

● When commissioning indirect‑type systems, it is recommended to slightly restrict the outlet of the extinguishing‑agent container valve to prevent unintended discharge. Do not fully close the valve outlet to avoid pressure buildup. If pressure builds up, the extinguishing agent may be discharged when the restriction is removed at the end of commissioning.

● Once it has been confirmed that the installation of the heat‑activated automatic fire‑extinguishing device is fully compliant and that there are no pressure leaks in the fire detection tube, the ball valve may be opened gradually (by turning it 45° counterclockwise). The ball valve should be opened slowly to allow the pressure in the fire detection tube and within the container to equalize progressively.

FAQ on Temperature‑Sensing Automatic Gas Fire Suppression Systems

Q: What types of facilities are suitable for temperature‑sensing, self‑activating gas fire suppression systems?

A: Suitable for use in confined, enclosed spaces such as distribution cabinets, energy storage cabins, small server rooms, and packaged substations, for extinguishing electrical fires.

Q: What is the extinguishing principle of a heat‑sensitive, self‑activating gaseous fire‑extinguishing system?

A: It detects fires by means of a temperature-sensing element; when the temperature reaches a preset threshold, it automatically releases the extinguishing agent, rapidly suppressing combustion and putting out the fire.

Q: What startup methods are available for the device?

A: Standard configuration includes a heat‑sensitive glass bulb for automatic activation; optional electric‑control interlock activation is available, and certain models support manual emergency activation.

Q: What are the installation requirements for this device?

A: Installed inside the protected space to ensure unobstructed discharge of the extinguishing agent, securely fastened, and with the protection distance maintained in accordance with applicable standards.

Q: Does the fire‑extinguishing agent cause significant damage to precision equipment?

A: Use a clean‑gas extinguishing agent that leaves no residue after fire suppression; compared with dry powder, it causes less contamination to precision electrical equipment.

Q: What aspects should be inspected during routine equipment maintenance?

A: Inspect the housing for any damage or deformation, ensure the temperature-sensing element is intact, verify the product’s expiration date, and check for signs of heat‑induced deformation.

Q: Can the device be used independently, without connecting to a fire alarm control panel?

A: It can operate independently, with automatic activation triggered by a temperature-sensing element; if linked to an alarm system is required, it can be connected to a fire alarm control panel.

Q: What should be done after the device has discharged?

A: After the fire has been extinguished, ensure thorough ventilation and confirm there is no risk of reignition. The entire system may only be reused after all chemical‑agent components have been replaced with new ones.

Q: Can a heat‑activated, self‑starting gas fire suppression system be installed directly outdoors?

A: Standard models are not suitable for outdoor use; for outdoor applications, a waterproof and corrosion-resistant enclosure should be selected, and adequate shading protection must be provided.

Q: How long is the device’s shelf life, and what should be done when it expires?

A: Follow the service life specified on the product’s nameplate; upon expiration, the chemical agent or the entire system must be replaced. Unauthorized disassembly and refilling are strictly prohibited.