Introduction of Flame and Gas detection systems

Today, choosing the right gas and flame detection system has become a key factor in projects.

In this article, we will review the different types of F&G systems and the advantages and disadvantages of each, and we will provide ideas for choosing the best system for each project.

What is the gas and flame measurement system?

A flame and gas (F&G) detection system is a very comprehensive and effective SIS. Detects any danger including fire or leakage of flammable or toxic gases and takes action to minimize the risk and prevent it from turning into an explosion.
An F&G detection system continuously monitors all covered areas and provides the operator with information about the detection and protection systems. Warns personnel about any dangerous situation and takes action depending on the level of danger identified.

What should we pay attention to when choosing a flame and gas detection system?

In order to design a suitable fire and gas detection system, a risk analysis should be done and in addition to that, the facilities and conditions of the project should be examined. After that, with the help of the obtained reports, he determined the system requirements, which include the following:

Determine the type of detectors to be used.
Determine the speed and type of reaction required during diagnosis
Determining the number, area and type of covered areas
Determining how alarm devices work
Determine the information required for the operator
Attention to the rate of false alarms of the detection system
And…

Types of F&G systems:

Gas detection systems

Gas detection detectors are divided into two categories:

Flammable gase Gas detectors:

These detectors, which detect the volume percentage of flammable gas in the air in terms of LFL (Low Flammable Limit) and UFL (Upper Flammable Limit), are divided into the following three categories:

Catalytic Gas Detectors
Infrared gas detectors
Open Path Gas Detectors

Toxic gas detectors:

The task of these detectors is to detect the ppm concentration of toxic gas in terms of TLV (threshold limit value). which can be divided into two main categories:

• Gas detectors that pose an immediate risk to people’s health (such as H2S, CO, HF, HCl, Cl2)
• Gas detectors that pose a health risk due to long-term exposure (such as vinyl chloride, benzene, toluene, etc.)

• Fire detection systems:

  Another type of gas and flame detection system, fire detectors are generally divided into 3 types:

  Smoke detectors

  Smoke detectors can be provided in the following two types:

  Ionization
  Photoelectric
  Thermal detectors

  Thermal detectors record the increase in temperature caused by fire. These detectors include:

  Constant temperature detectors:

  These detectors are automatically activated when the ambient temperature reaches a predetermined temperature.

Rate of Rise detectors:

Rate of Rise detectors, which are another type of F&G system, evaluate the rate of temperature rise in addition to the current temperature. If the temperature rises faster than the preset value in a certain period, the alarm will be activated.

Rate Compensated Detectors:

Rate Compensated detectors are activated at a predetermined temperature regardless of the ambient temperature increase. The operation of Rate Compensated detectors is such that a mechanical comparison is made between the temperature in the outer chamber and the inner chamber, and the device is activated as a result of the result of this comparison. This has made these detectors less likely to make an error than others.

Flame detectors:

Flame detectors are usually used to protect high-risk areas such as oil platforms, fuel storage facilities, petrochemical plants, etc. Hot objects (engines/exhausts/heaters) can cause false alarms in these systems.

Different types of flame detectors are:

• UV detectors
• Single-channel IR detectors
• Combined UV and IR single-channel
• Dual-channel IR flame detectors
• Three-channel IR flame detectors
• CCTV flame detection

Given the above, a suitable flame and gas (F&G) detection system, with the principled integration of a variety of gas and flame detectors, provides a coherent and reliable solution and a multi-layered approach to safety against fire hazards.