Blog-12-Detectors

Detectors, why are they our first line of defense?

Detectors, why are they our first line of defense? Detection systems are the firstlayer of defensein case of fire. These are madeup of automatic sensors,control equipment and identification panels. It isexpected that this system will activatethealarm systems, smoke controlsystems andactiveprotection systemslikesprinklers. Therefore,weshouldtake special consideration when selecting and maintaining detectionequipment. In this blog we want to talk about the types of detection systemsofferedin the market.

As a detection strategy, manual or automatic systems can be implemented.The formercouldbe located in an open office floor where people will be alertand can give an earlier warning of the fire, compared to an automatic detectionsystem.However, the manual system should not be implemented on its own.It should be accompanied by an automatic system, and should only be a fasterdetection alternative. In addition, it is necessary to reflect on the contextwhere it is installed, for example,in a school, you could expect falseactivations, reducingconfidence in detection systems and therefore in alarms.

On the other hand, there are different automatic detection technologies that can be activated by detection of smoke, heat, gaseous products of combustion or radiation. Ionization and optical sensors are the most widely used due to their sensitivity and price. They base their detection on captured smoke, meaning that if a fire has a low smoke production or a clean burning is expected, another type of technology should be use. Heat detectors are typically not allowed on their own because they fail to detect slow-developing or early-stage fires.

In addition, the combustion product detectors are based on the registered measurement of CO and CO2. The context must be considered since a production plant, for example, has higher levels of CO and CO2 than normal. In a similar way, radiation detectors are based on recording infrared or ultraviolet waves. They can generate false alarms in high radiation sites such as a production plant. Finally, in order to avoid false alarms, there are multiple sensors, which detect more than one signal before being activated.

Similarly, different factors affect the selection of a detection system. Among the most important aspects are: the required detection speed, the type of expected fire and tolerance to false alarms. These factors stand out because it is what ultimately determines the speed of the alarm and therefore the evacuation. However, they are not the only variables to take into account, it must also be considered, the proposed evacuation strategy, the geometry of the building, other installed protection systems, the humidity of the environment, among others.

It is important to emphasize that the detection system must be connected with other protection systems so that it fully fulfills its function. Initially, it should be connected to the alarm system to give evacuation warning, but it could also be connected to ventilation systems, smoke curtains, fire station, pressurization systems, among others. All systems interconnection is directly related to commissioning. However, it is worth emphasizing this aspect in order to get the best system performance.

Finally, through a risk analysis, it is possible to perform a performance design, where the detection system could optimize what could potentially lead to a reduction in the capital cost. It should be clarified that this type of design would require a longer time, a more detailed analysis and should be developed by a competent professional.

At EHR S.A. we have with the experience and excellent trained professionals to advise you in the design and installation of fire protection systems.

For more information about our services and products, please contact us, we will gladly be part of your project.

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Editor.
Lorena Cifuentes.
Ingeniera Química
Departamento de Diseño EHR S.A.

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