Fire & Gas

Heat Detector Testing Procedure

Heat Detector Testing Procedure 1

What are Heat Detectors?

  • A heat detector is a fire alarm device intended to acknowledge when the convicted thermal energy of a flame increases the temperature of a heat-sensitive element within the heat detector.
  • Heat detectors are designed to activate when they sense elevated temperatures, signaling a potential fire. 
  • On the occurrence of a potential fire, the heat detector element activates an audible alarm signal to alert everyone within earshot of the device.
  • Heat detectors are commonly used in industrial and commercial settings and are often employed in areas where the normal operation of the facility may produce dust, smoke, or fumes, leading to false alarms if smoke detectors were used.

What are the types of heat detectors?

However, various Heat Detectors operate      in a different way but provide the same outcome.

Heat Detectors are classified as 

  1. Electro-Pneumatic Heat Detectors
  • Electro-pneumatic heat detectors are a type of heat detector that operates on the principle of heat-induced expansion of gases or air. 
  • Electro-pneumatic heat detectors rely on the expansion of air or gas within a sensing chamber due to the increase in temperature. 
  • This expansion is proportional to the temperature rise and is used to activate a switch or trigger an alarm when a certain temperature threshold is reached.     .
  • An electric circuit is completed for the movement of the diaphragm which activates the alarm.
  1. Rate of Rise (ROR) Heat Detectors
  • These detectors work by using two heat-sensitive thermocouples. 
  • Here one thermocouple will monitor the transfer of heat by convection or radiation mode, while the other thermocouple measures the background temperature of the room. 
  • An alarm signal gets triggered sounds when there is inequality between these thermocouple outputs informing flaring up of fire
  • Basically, these Heat detectors are an essential part of fire safety and maintenance. 
  • Testing heat detectors is a critical aspect of fire safety, and it should be conducted in a responsible and organized manner to ensure the safety of building occupants.
  • Always follow the manufacturer’s guidelines and any specific procedures or recommendations provided by your local fire safety authority.
  1. Fixed Temperature Heat Detectors
  •  Fixed temperature detectors are set to activate when the temperature reaches a predetermined threshold. 
  • Once the temperature exceeds this threshold, the detector triggers an alarm. They are suitable for areas with consistent high-temperature conditions.
  1. Combination Heat Detectors
  • Some detectors combine rate-of-rise and fixed temperature features to provide enhanced fire detection capabilities. 
  • These detectors trigger an alarm if either a rapid temperature increase or a fixed high temperature is detected.
  1. Linear Heat Detectors: 
  • Linear heat detectors consist of a cable or wire that is sensitive to heat along its length. 
  • When the cable is exposed to elevated temperatures, it triggers an alarm. They are often used in specialized applications, such as protecting conveyor belts or storage facilities.

Steps for Testing Procedure of Heat Detector

Preparation for testing Procedure

  1. Ensure that the testing procedure adheres to safety protocols and regulations.
  2. Inform all sections about testing of heat detectors and get approval from respective departments.
  3. Force the respective logics or interlocks such as activation of fire suppression systems.
  4. Review the manufacturer’s guidelines and documentation for the specific heat detector being tested.
  5. Gather the necessary tools and equipment, including a heat source, test equipment, and appropriate safety gear.

Start of Testing Procedure

  1. Visually inspect the heat detector and its surroundings for any signs of damage, dirt, or obstructions that might affect its performance.
  2. Check the LED status of the Heat Detector, and ensure that the lamp of the Heat Detector is blinking RED.
Heat Detector Testing Procedure 2
  1. Check the voltage of the Heat Detector by using an addressable base of a Digital type detector the voltage must be +30VDC. 
  2. Now the Heat      Detector is said to be healthy and is ready to test.
  3. Clean the Heat detector dust by using a smooth cotton cloth, cotton waste, or a blower.
  4. Use the solo heat-detector      gun to apply the heat to the Heat Detector for about 10 seconds.
  5. Use a controlled heat source or heat gun designed for heat detector testing. These sources typically provide a known and controlled temperature increase.
  6. After 10 seconds the LED      status of the Heat detector shifts from blinking RED to Stable RED.
  7. An alarm signal gets activated along with the hooter on the fire alarm panel.
  8. Press the Acknowledge Key located on the Fire Alarm Panel to silence the hooter. 
Heat Detector Testing Procedure 3
  1. Isolate the Heat Detector from the heat-detecting test gun after the appearance of the alarm signal.
  2. Record the alarm tag and descriptions from the HMI or workstation in such a way that alarm details must match the tag number and installed location of the Heat Detector.
  3. Ensure the activation status of the Heat detector from the respective graphics page and everyone must have the ability to visualize the LED color of the respective Heat detector on that graphics page.
  4. Reset the alarm signal of the Heat detector from the Fire Alarm Panel.
  5. The status of the LED lamp changes      from steady RED to blinking Red.
  6. Ensure that the Heat Detector is now operating accurately under normal operating conditions.
  7. Observe the heat detector’s response to the test heat source. Check for the following:
  • Response time: Record how quickly the heat detector recognizes the rising temperature.
  • Alarm indication: Ensure the detector triggers an alarm or activates other predetermined actions when a temperature increase is detected.
  • False alarms: Confirm that the heat detector does not produce false alarms in response to minor temperature fluctuations.
  1. Document the results of the test, including response time, alarm indications, and any false alarms.Note the date, time, and details of the test.
  2. Conduct the same testing procedure for the rest of the available Heat Detectors.
  3. Normalize the forced interlocks or logics.
  4. Close the work permit.

General procedure for testing heat detectors

Before testing heat detectors, consult the manufacturer’s guidelines and local fire safety regulations, and ensure you have the necessary safety equipment and permits.

  1. Schedule Testing: 

Plan the testing during a time when it won’t cause disruptions and when the building is least occupied. 

You may need to notify relevant authorities or the building’s occupants in advance.

  1. Safety Precautions: 

Ensure you have the appropriate safety equipment, such as fire extinguishers, and make sure you’re working with at least one other person for safety. 

Have access to the building’s fire alarm control panel and notify monitoring services or personnel responsible for safety.

  1. Locate Detectors: 

Identify the heat detectors in your building. 

Typically, heat detectors are located in areas where smoke detectors are not suitable due to dust, smoke, or high humidity, such as kitchens, garages, or utility rooms.

  1. Check for Obstructions: 

Ensure that there are no obstructions around the heat detectors that might prevent them from sensing heat effectively.

  1. Testing Equipment: 

You can use a heat source to test these heat detectors. 

Some heat detectors may have a built-in testing mechanism. 

If not, source should be designed for heat detector testing and provide a controlled and known temperature increase. Common test heat sources include heat guns or heat test equipment.               

  1. Notify Monitoring Services: 

If your building has a central monitoring system for fire alarms, contact them to inform them that      you’re conducting a test to prevent false alarms.

  1. Isolate the Zone: 

If your fire alarm system is zoned, isolate the zone with the heat detectors you’re testing to avoid setting off the entire building’s fire alarm system.

  1. Test Heat Detector: 

Gently apply heat to the heat detector by aiming the heat source at it. 

Do this gradually and avoid overheating. 

Keep a safe distance while testing, and be prepared for the detector to activate.

  1. Observe Activation: 

Observe the heat detector for activation. 

It should activate once the temperature reaches its predetermined trigger point. 

This activation might trigger the fire alarm system.

  1. Reset and Verify: 

After testing, reset the heat detector (if necessary) and reset the fire alarm system. 

Verify that the system is functioning correctly.

  1. Document Testing: 

Keep a log of the testing, including the date, time, location of detectors tested, and the name of the person conducting the test. 

This documentation is important for compliance and future reference.

  1. Maintenance: 

If any heat detectors fail the test, they should be promptly replaced or repaired by a qualified technician. 

Regular maintenance is crucial for the proper functioning of your fire detection system.

Frequently asked Questions

How do you test an alarm heat detector?

An alarm heat detector can be tested by applying a gentle heat source such as a hair dryer with 6-8 inches away from the detector

This causes the alarm      heat detector to work on its rate-of-rise within 8 to 12 seconds.

What is the working principle of Heat Detectors?

When radiation passes inside a heat detector, ionization of gas atoms occurs to isolate atoms into positive ions and electrons.

Where the Heat detector can be installed?

Installation of Heat detector is essential to safeguard living areas.

Location of Heat detector is at the center of your room’s ceiling.

Heat detector can be fixed on a wall 50cm below the ceiling height.

What is Heat detector spacing?

Spacing of Heat detector is an essential ahead of time,

Locate the heat alarm very close to the center of the room to ensure coverage of the entire vicinity.

Select a location at least 10 cm  away from a wall or corner.

Do we need batteries for heat detectors?

Yes, In stand-alone systems or non-critical areas where a dedicated electrical power supply is not available, heat detectors may be equipped with batteries as a backup power source. These batteries provide power to the heat detector in the event of a power outage or in locations where hardwiring is not feasible. Battery-powered heat detectors are commonly used in residential settings, smaller commercial buildings, and non-critical areas where continuous electrical power supply may not be practical. The choice of power source for heat detectors depends on the specific application, building requirements, and safety regulations.

Where do we require heat detectors?

Heat detector is required in every kitchen area, & in the living      room in case of domestic or residential buildings.

What are the three types of heat detectors?

Heat detectors are classified into three categories: 

  1. Electro-Pneumatic Heat Detectors
  2. Rate of Rise (ROR) Heat Detectors
  3. Fixed temperature Heat Detectors.
  4. Combination of Rate of Rise (ROR) Heat Detectors, & Fixed temperature Heat Detectors.

What are the advantages and disadvantages of heat detectors?

Advantages of heat detectors

Reliable in environments

Disadvantages of heat detectors

Unable to detect smoke without flames

Sundareswaran Iyalunaidu

With over 24 years of dedicated experience, I am a seasoned professional specializing in the commissioning, maintenance, and installation of Electrical, Instrumentation and Control systems. My expertise extends across a spectrum of industries, including Power stations, Oil and Gas, Aluminium, Utilities, Steel and Continuous process industries. Tweet me @sundareshinfohe

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