Fire Detector: Types, Design, Installation Standards and Maintenance
Timely detection of a fire is the basis of safety for any facility. This task is performed by fire detectors — devices that respond to smoke, heat, flame or gas. How quickly the system alerts people and initiates automatic fire suppression depends on their type, location and serviceability. In this article we will examine what types of fire detectors are manufactured by the industry, how they work, where and in what quantity they are installed, and how to check their operability. Individual models, for example for detecting open flames, can be found in the catalogue fire detector.
1. General Classification and Operating Principles
A fire detector is a technical device that generates a fire signal when the monitored parameter reaches a threshold value. All detectors are divided into automatic and manual. Automatic ones actuate without human intervention, responding to physical signs of combustion: smoke, temperature rise, flame radiation. Manual ones are activated by a person who has discovered a fire.
According to the method of signal formation, threshold, addressable and addressable‑analogue detectors are distinguished. A threshold detector outputs a “Fire” signal when a set level is exceeded. An addressable detector transmits to the control panel not only an alarm but also its unique number, as well as the current value of the monitored parameter. An addressable‑analogue detector transmits continuous data on smoke density or temperature, and the control panel makes the fire decision. Such an architecture reduces the number of false alarms.
2. Smoke Fire Detectors
Smoke detectors respond to the appearance of smoke particles in the air. This is the most widespread group, since most fires begin with smouldering and smoke formation. According to the operating principle, smoke detectors are divided into optical‑electronic and ionisation types, but the latter have been practically supplanted by the former due to environmental restrictions.
2.1. Point Optical‑Electronic Detectors
A point optical‑electronic detector contains a smoke chamber in which a light‑emitting diode and a photodetector are located. In the normal state, the beam of the LED does not reach the photodetector. When smoke appears, the particles scatter the radiation, and the photodetector registers the reflected light. The sensitivity of a smoke optical‑electronic detector is standardised by GOST 53325‑2012 and usually lies within the range of 0.05–0.2 dB/m.
The most popular types of point detectors are: IP 212‑34A, IP 212‑45, IP 212‑141, IP 212‑64. For example, the smoke optical‑electronic IP 212‑34A is a threshold detector with loop power. The IP 212‑64 is an addressable‑analogue optical‑electronic detector that transmits the smoke density value as a percentage. The addressable smoke DIP‑34A‑04 is used in “Rubezh” systems and provides individual addressing. Threshold models are often marked DIP (smoke fire detector), and addressable ones — DIP‑34A with additional suffixes.
2.2. Linear Smoke Detectors
A linear smoke detector consists of a transmitter and a receiver, or a single unit with a reflector. An infrared light beam passes through the protected zone. When smoke appears, the intensity of the received signal falls and an alarm is generated. Linear detectors cover large areas — up to several hundred square metres. They are used in atriums, warehouses, production halls, and sports halls.
Typical models: linear IPDL, linear addressable S2000‑IPDL, linear single‑ended IPDL‑52M. The S2000‑IPDL is an addressable detector operating under the control of the “S2000‑KDL” controller. The single‑ended linear version uses a reflector, which simplifies installation — there is no need to run a cable to the receiver on the opposite wall.
2.3. Aspirating Detectors
Aspirating smoke detectors draw air from the protected room through a network of pipes with holes and analyse it in a highly sensitive laser chamber. They are capable of detecting smoke at a very early stage. They are used in clean rooms, museums, data centres, where not only the detection speed but also concealed installation is important.
2.4. Autonomous Smoke Detectors
An autonomous smoke detector is a device containing a smoke chamber, a power source and an audible alarm in one housing. When smoke appears, it emits a loud signal, alerting people in the room. It does not require connection to an alarm loop. It is actively used in the residential sector: apartments, dachas, dormitories. Most often these are point optical‑electronic devices. A well‑known model is the autonomous IP 212‑142, which operates from a “Krona” battery. Also common is the IP 212 autonomous smoke detector powered by lithium batteries with a lifetime of up to 10 years.
3. Heat Fire Detectors
Heat detectors respond to an excess of temperature or the rate of its rise. They are divided into maximum, differential and maximum‑differential types. A maximum heat detector actuates when a threshold temperature is reached, for example, +70 °C. A differential detector — at a rapid temperature rise exceeding a set gradient. A maximum‑differential one combines both principles, which increases reliability.
The response temperature of a heat detector is set by a class according to GOST: class A1 (54–65 °C), A2 (54–70 °C), B (69–85 °C), and so on. Heat detectors are used where smoke detectors give false alarms: kitchens, saunas, boiler rooms, welding stations. Well‑known models: heat IP 101, heat IP 103, maximum‑differential addressable heat IP 101‑1A, addressable heat S2000‑IP‑03. The explosion‑proof heat version is intended for zones of class B‑I, B‑IIa.
A separate group is formed by linear heat detectors — thermal cables. A linear thermal cable is a sensor cable that responds to heating along its entire length. It is used in tunnels, cable collectors, tank farms.
4. Flame Detectors
Flame detectors register infrared or ultraviolet radiation from an open flame. They respond to the pulsations of radiation characteristic of combustion, which distinguishes them from constant light sources. IR sensors are sensitive to radiation in the 4.3 µm range, corresponding to the peak of carbon dioxide emission during combustion. UV sensors register the short‑wave part of the spectrum, invisible to the human eye.
IR‑UV detectors combine both channels to increase noise immunity. An addressable flame detector is connected to an addressable loop and transmits the exact coordinates of the source. For example, IP 330‑1 “Gerda” is an addressable flame detector operating as part of the “Rubezh” system. Its characteristics and description are available at the link fire detector.
5. Gas and Combined Detectors
Gas detectors register the appearance of carbon monoxide CO or carbon dioxide CO₂ released during combustion. They are effective for early detection of smouldering fires. A combined smoke‑heat detector combines smoke and heat sensing in one housing, which allows adaptation to different fire scenarios. For example, a combined smoke detector with a heat channel will actuate both during slow smouldering and during fast flaming combustion without smoke.
6. Manual Fire Detectors
A manual detector is intended for a person to give a fire signal. It is a manual call point, placed on the walls of escape routes. The height of manual detectors from the floor is standardised at 1.5 m. They can be electro‑contact, with button latching, and addressable. The addressable manual IPR 513‑3AM is connected to a two‑wire communication line and transmits an address code. A radio‑channel manual IPR makes it possible to do without wires, which is convenient for installation in historical buildings. An explosion‑proof manual detector is used at oil and gas facilities.
Popular models: IPR 513‑10, manual IP 535, manual addressable with a short‑circuit isolator. The sign of a manual fire detector is a red square with a white hand pictogram. Requirements for the sign are contained in GOST R 12.4.026.
7. Installation Standards and Distances
The number and placement of fire detectors are regulated by SP 484.1311500.2020. Main standards:
- in each protected room there must be at least two smoke or heat detectors, unless otherwise specified;
- distance between point smoke detectors — up to 9 m, from detector to wall — up to 4.5 m;
- distance between point heat detectors — up to 5 m, to wall — 2.5 m;
- monitoring zone of one point detector for smoke — up to 85 m², for heat — up to 25 m² with a ceiling height of up to 3.5 m;
- area protected by one linear detector reaches 1000 m² at an installation height of up to 10 m;
- manual detectors are placed at a height of 1.5 m from the floor, at a distance of up to 50 m from each other inside the building and up to 150 m outside;
- in suspended ceilings, detectors protecting the ceiling void are installed if combustible cables are laid there;
- when installing addressable detectors, it is recommended to use short‑circuit isolators that prevent the loss of the entire loop in the event of a single fault.
8. Installation, Connection and Testing
Installation of fire detectors is carried out in accordance with the project layout. Point sensors are fixed on the ceiling, and in rooms with beams, smoke stagnation zones are taken into account. Smoke optical‑electronic detectors are mounted with the smoke chamber oriented downwards. The installation height of heat detectors, as a rule, does not exceed 9 metres. The connection scheme to the alarm loop depends on the type: threshold ones are connected in series with an end‑of‑line resistor, addressable — in parallel to a two‑wire line.
Testing a smoke detector is performed with a test aerosol or a special test canister. Heaters are used for heat detectors. Performance testing is carried out at least once a year, as well as after each false alarm. During testing, the system is switched to test mode. Maintenance includes cleaning the smoke chamber of dust, replacing batteries in autonomous models, and visually checking the indicator. The indicator on the housing flashes green in standby mode and switches to continuous illumination or a red flash in alarm.
9. Table of Detector Characteristics
| Model | Type | Principle | Supply voltage, V | Current consumption, mA | Monitoring area, m² | Features |
| IP 212-34A | Smoke threshold | Optical-electronic | 9–30 | 0.05 | 85 | Widespread, in loop |
| IP 212-64 | Smoke addressable-analogue | Optical-electronic | 8–30 | 0.3 | 85 | Rubezh protocol, DIP-34A |
| IP 212-141 | Smoke addressable | Optical-electronic | 8–30 | 0.15 | 85 | With base, SC isolator option |
| Autonomous IP 212-142 | Smoke autonomous | Optical-electronic | 9 (battery) | — | 20–85 | Built-in audible alarm |
| IP 212-45 | Smoke optical-electronic | Point | 12–28 | 0.1 | 85 | Threshold, DIP |
| IP 212-34A-04 (DIP-34A-04) | Smoke addressable | Optical-electronic | 8–28 | 0.15 | 85 | Addressable DIP for Rubezh |
| S2000-IP-03 | Heat addressable | Maximum-diff. | 8–30 | 0.3 | 25 | S2000, class A2 |
| IP 101-1A | Heat addressable | Maximum-diff. | 8–30 | 0.3 | 25 | Addressable heat |
| IP 101 | Heat maximum | Threshold | 9–30 | 0.03 | 25 | Threshold heat, reliable |
| IP 103 | Heat maximum | Threshold | 9–30 | 0.03 | 25 | Class A2 |
| IP 330-1 (flame) | Addressable flame | IR | 8–30 | 0.5 | — | Addressable, Rubezh |
| IPR 513-10 | Manual electro-contact | — | — | — | — | Button latching, with key |
| IPR 513-3AM | Manual addressable | — | 8–30 | 0.2 | — | With SC isolator |
| S2000-IPDL | Smoke linear addressable | Optical-electronic | 8–30 | 1 | up to 1000 | Addressable, up to 100 m |
| IPDL-52M | Smoke linear single-ended | Optical-electronic | 12–28 | 5 | up to 500 | Single-ended, reflector |
10. Key Selection Parameters
When choosing a specific type of detector, the following are taken into account:
- Type of protected room. Smoke detectors are installed in living rooms, heat detectors in kitchens and saunas, flame detectors in workshops with an open fire.
- Environmental conditions. For outdoors, versions with IP67 are suitable, for explosive zones — explosion‑proof.
- System architecture. Threshold ones are cheaper, but addressable ones allow more precise source location.
- Availability of power. Radio‑channel detectors operate from batteries and communicate via radio protocol, convenient for facilities without wiring.
11. Typical Layout Schemes
When arranging detectors, the envelope method is used: the room is divided into equal squares, in the corners of which the sensors are placed. The distance between smoke detectors must not exceed 9 metres, and from a detector to a wall — 4.5 metres. In corridors less than 3 metres wide, detectors are placed along the centreline with a spacing of up to 15 metres. In rooms with suspended ceilings, the ceiling void is additionally protected if combustible materials pass there. Detectors are suspended on a wire so that smoke does not accumulate above them.
12. Conclusion
Fire detectors are a key line of early fire detection. The spectrum of devices is huge: from a simple autonomous smoke optical‑electronic detector for an apartment to linear addressable systems in hangars and explosion‑proof sensors at chemical plants. Compliance with installation standards, periodic testing and competent design of monitoring zones make it possible to protect human lives and property. For detailed acquaintance with models, for example flame detectors, please refer to specialised sources: fire detector.
