Detectors
Monitoring your safety anytime anywhere.Some of them are as follows:
- Heat Detectors
- Smoke Detectors
- Early Warning Smoke Detection
- Linear Heat Detectors
- Video Image Detectors
- Gas Detectors
- Conventional Detectors
Heat Detectors
A spot type heat detector monitors temperature at a given point. These detectors vary with respect to the mechanisms used to detect heat. The two most common types of spot type heat detectors are:
Fixed-Temperature Heat Detectors – designed to initiate an alarm when its heat sensitive material or element is heated to a specific temperature. The air temperature at the time of alarm is considerably higher as it takes time for the surrounding air to raise the temperature of the element to its set point. The operating range of these detectors start at 100F. There are two types of fixed-temperature heat detectors:
- Restorable – returns to its ready state without any interaction from an outside source, once it has cooled below its set point.
- Non-Restorable – requires replacement of its element after actuation.
Rate-of-Rise Heat Detectors – operate on a rate-of-temperature change per unit of time basis. This type of heat detector contains a chamber with a calibrated vent. When the air in the chamber expands faster than it can escape from the vent, the increase in pressure causes the electrical contacts to close sending a signal to the fire alarm control unit. If the air in the chamber rises slowly and can escape from the vent, the electrical contacts do not close and there is no alarm.
Other types of spot detectors are:
- Rate-compensated heat detector
- Combination heat detector
- Pneumatic heat detector
Line type heat detectors are used in applications where it is not practical to use spot type detectors, such as on long industrial conveyors or cable trays. These detectors use heat-sensitive materials which affect the current flow through the electrical conductors.
Smoke Detectors
How do they work?
Ionization Smoke Detectors – Ionization smoke detectors electrically charge the air between two electrodes and measure the difference between the flow of ionized particles in the normal state and the flow of ionized particles in the presence of smoke particles. Smoke particles attach themselves to ionized particles, reducing their travel time to the electrodes. An ionization detector goes into alarm if the travel time of the particles lags by a predetermined amount of time.
Photoelectric Smoke Detectors – The two types of photoelectric smoke detectors are light-scattering and light-obscuration. The light-scattering detector involves the projection of a light source within a smoke detection chamber. The presence of smoke particles within the chamber deflects light to a light sensor. The light sensor will transmit a detection signal to the fire alarm control unit if the deflected light increases to a predetermined level. The light-obscuration principle is slightly different from the light-scattering process. In the light-obscuration detector, light is projected directly onto a light sensor, and smoke reduces the amount of light that strikes the sensor. When light transmission to the light sensor decreases to a predetermined level, the detector sends a signal to the fire alarm control unit.
Projected-beam Smoke Detector – A projected-beam smoke detector consists of two components, a sender and a receiver. It operates on the smoke obscuration principle. The sender sends a beam of light to the light-responsive receiver, completing an electrical circuit. When smoke interrupts the beam projected from the sender to the receiver, the receiver notices the loss or lessening of signal transmission, and notifies the fire alarm control panel unit of an alarm condition.
Duct Smoke Detector – A duct smoke detector is specifically listed for determining hazardous smoke levels in heating, ventilating, and air-conditioning (HVAC) ducts. Duct detectors are mounted within a duct, or mounted outside of a duct with air-sampling tubes projecting into the duct. These units are listed as either photoelectric or ionization duct detectors, with specific listing up to a maximum velocity of air movement within a duct.
Early Warning Smoke Detection
Why install an Early Warning Detection System?
- Low cost of ownership
- Reliable
- Highly sensitive without nuisance alarms
- Can tolerate harsh environment including low temperatures
In addition these units are suitable for various applications such as:
- Clean rooms
- Data & Telecom rooms
- Nuclear facilities
- Cold storage rooms
- Switch gear rooms and many more.
Linear Heat Detection
How does Linear Heat Detection work?
The outer jacket of the cable is specifically chosen for the environment and conditions where it will be installed. The Polymer or Mylar sheathing breaks down or becomes soft at specific temperatures allowing the inner conductors to contact each other or short, which causes an alarm condition on the initiating circuit. Lastly, the wire is typically comprised of a combination of metals, such as steel, copper, tin, etc., which gives the wire extremely low resistance. The wire is twisted in order to give it strength and to provide shielding from EMI and RFI, which can cause unwanted interference affecting supervision of the integrity of the wire.
Additional features include:
- Compatibility with any new or existing conventional as well as addressable fire alarm panels
- Distance locating (with additional module)
- Easy installation and maintenance
- Minimal false alarms
Gas Detectors
In addition, these detectors can be used to detect oxygen depletion or in firefighting. A typical gas detector is calibrated for the specific gas and detects a range of that gas concentration. If that level exceeds its preset range, an alarm is activated. These units can be installed in an alarm system or they can be stand-alone.
Stand-alone units activate a flashing light and horn to notify the operator of the condition, providing an opportunity for evacuation. The units can also be connected to a control system to automatically shut down the process.
Video Image Detection
Video image detection has the ability to provide early warning fire detection independent of airflow or environmental conditions. Video detection can detect smoke particles that are invisible to the human eye regardless of lighting conditions and provide advanced early detection that can dramatically reduce the loss of life and property.
Some typical applications where Video Image Detection can be used include:
- Warehouse/Distribution Centers
- Energy
- Marine
- Manufacturing
- Education
- Aircraft Hangars
- Transportation
- Museums
Conventional detector
Like addressable systems, conventional systems can be wired Class A or Class B. For Class B wiring, an end-of-line device resistor is required for wiring supervision.
As an independent company our strength is our flexibility. We have forged strong links with many manufacturers and don’t buy our equipment from only one source so we can recommend the best product for the job in hand at a competitive price.
Our experts are only interested in giving you the fire detection system you need, at the best possible price. Once you’ve made your choice, our team of experts can install all the necessary systems and make sure it’s working perfectly.
