Different Types of Fire Alarm Initiating Devices

A fire alarm system's fire alarm initiating device detects signs of fire and activates an alarm. In terms of visibility, they are the most visible components of the system.

The initiating devices are connected via two or four-way circuits to the alarm system's control panel and are constantly monitored by the control panel. In the event of an activation of an initiating device, the panel determines the activation and goes into an alarm state, sounding the alarm in the building and alerting the emergency service provider.

Some common fire alarm initiating devices include smoke detectors, sprinkler water flow switches, and manual pull stations.

Various types of fire alarm initiation devices
The initiating devices can be classified into two types: Automatic initiating devices and Manual initiating devices.

Automatic initiating devices:
An automatic initiator is one that is triggered automatically when a certain set of conditions is met. They include:

Smoke detectors
Fire sprinkler water flow switches
Heat detectors
Automatic initiating devices come in spot type and linear type.

A spot detector focuses only on the area where it has been installed, whereas a linear device covers a wide area of space but communicates with a single control unit. A standard ionization smoke detector is an example of a spot type, while a light-obscuration photoelectric smoke detector is an example of a linear type.

Spot types are less expensive, but their connections to fire alarm systems must be made separately, and more devices are needed to adequately cover an area. While linear types are more expensive, they only require one connection to the fire alarm system, and one unit covers a larger area.

Manual initiating devices:
During a fire emergency, a manual device must / can be manually activated. Manual pull stations are, of course, meant by this.

As soon as one of these devices is activated by their respective conditions (smoke, heat, water flow, or manual adjustment), the control panel detects the change and initiates the alarm, which triggers a visual and audible alarm to alert building occupants.

What does the fire alarm initiation devices do?
Most fire alarm systems feature multiple types of initiating devices, each with its own purpose and trigger requirements. It is necessary to install each initiating device separately and connect it to the circuitry of the fire alarm system.

Below is the brief explanations of how each type of initiating device works:

Smoke Detectors
The use of smoke detectors enables fire alarm systems to respond quickly before a fire has the opportunity to grow. It is because fires cause smoke early on in their development, long before water sprinklers or heat detectors activate.

There are two main types of smoke detectors: ionization and photoelectric.

Ionization smoke detectors measure airflow current using ionized air held within a sensing chamber. As smoke penetrates the chamber, it reduces the current. The detector activates when the current drops enough.

A photoelectric smoke detector detects smoke by using light in one of two ways.

A light-scattering method involves arranging a light source and sensor (both within the detector) such that the sensor cannot detect the light under normal conditions. When smoke enters the detector, it scatters or reflects light back into the detector. The sensor is activated when enough light hits it.

The second photoelectric method is light obscuration, in which the light source and detecting sensor are usually separate components. When a light beam is projected into the sensor, the sensor remains inactive as long as it receives the light. In the event that smoke from a fire obscures the light beam from the sensor, the detector will be activated.

Sprinkler Water Flow Switches
Sprinkler water flow switches monitor the flow of water through fire sprinkler pipes.

The water in the pipes of a sprinkler system typically sits stagnant when it isn't activated. When a fire sprinkler is activated by a fire-induced temperature, water flows through its system and out of its open end. A sprinkler water flow switch detects this change in water activity and alerts the fire alarm control panel that the sprinkler system has been activated.

Heat Detectors
The oldest and most reliable automatic fire detection system is the heat detector, although they are often slow to respond to fires. The most common types are fixed temperature detectors and rate-of-rise detectors.

Fixed-rate heat detectors activate when the room temperature reaches a specific, predetermined level. In the event of a fire, it can take a long time before the temperature reaches this predetermined level, so the initiating device may not respond for some time after a fire has started.

In contrast, a rate-of-rise heat detector activates when the temperature around it rises 15 degrees or more in a minute. As a result of this rapid increase in temperature, the air inside the detector's chamber expands, pressing a metal diaphragm against contacts that trigger the detector's activation.

Manual Pull Stations
The manual pull station can be used to activate a fire alarm in an emergency, as shown in many films.

There are two types of pull stations: single-action and dual-action. Single-action stations require only one physical action: pulling a lever. A dual-action station, on the other hand, requires two actions, such as breaking a glass cabinet containing the lever or lifting a covering.

Choosing the right fire alarm initiation devices
Having a company like Quickshipfire who has made it their business to know the ins and outs of these systems and devices is essential to effectively protecting your property and those who live or work there.

Don't let the safety of your family be compromised - contact Quickshipfire today for information on best fire alarm parts. As one of the top fire alarm equipment suppliers in the USA, Quickshipfire provides high-quality fire alarm systems. We will assist you in selecting fire alarm components, fire alarm batteries, or replacement fire alarm parts that will provide the best protection for your people