Smoke Detector, Smoke Alarm or Fire Alarm or All Together, What Should I Fix ?

Should I Fix Fire Alarm or Smoke Alarm  or Both   I   Which should I fix Fire Alarm or Smoke Alarm  I  Which is better Fire Alarm or Smoke Alarm  I  Should I go with Fire Alarm or Smoke Alarm  I  Fire  Alarm or Smoke Detector or Both  I 

When we think of any alarm , a kind of warning or something which needs immediate attention , comes to our mind . The fire and smoke alarm are few of the alarm sounds which needs highest attention and they work as a first line of defence against fire in your facility. it is becomes beyond your control . As per a recent survey , the success rate of controlling the fire in its initial stage with minimal or marginal damage was 93% . They inform you in the very initial stage of fire so that you can either tackle the fire , call the fire department and evacuate the propertyin case you are not able to control it. Although the Smoke & Fire Alarms can save you from a fire hazard , it is better to have an idea of each of them in details so that we can use one or in combination as per the specific requirement of our place .

How smoke alarms and fire alarms are different?

As implies by the name , one tells you about smoke and other tells your about fire .. But as per the saying , there is no smoke without fire, so both are equally important. When we see, fire looks more devastating , but it is smoke inhalation during fire , which is more dangerous to human life than the fire burn .

To read more about difference between Smoke Alarms & Fire Alarms , Click Here . 

Smoke  Detectors

Smoke Detectors

Smoke detectors are strictly smoke-sensing devices only and are  not self-contained. Smoke detectors normally don’t have an inbuilt sounder and are interconnected together and then back to the main control panel. Once they detect smoke , they sends signal to the building’s Fire Alarm system to activate audible( Alarm) or sometime visual warning . They are sometime monitored remotely. Smoke detectors are normally used in hotels, hospitals and in other commercial and industrial buildings.

Put simply, a smoke detector senses smoke only and must be connected to a fire alarm system control panel. Smoke detectors are a detection device only – not an alarm.

To read more about type of smoke detectors  and how they work , click here . 



Smoke Alarm

Smoke Alarms:Smoke Alarms =Smoke Detector+Inbuilt Audio or Visual Alarm. 

Smoke alarm are self contained all –in-one device which detects the product of combustion( smoke) and also sounds audible and sometime visual alarm . Some Smoke Alarms can be interconnected however they are most likely found as a stand alone device.Smoke alarms are mostly used in residential buildings.

Most smoke alarms now have hush buttons, for use where false alarms can be a nuisance e.g. when cooking. The alarm lets you know it’s been silenced by “chirping” or by displaying a red light – while a real fire producing lots of smoke will set it off anyway. A smoke  detector don’t have hush button as it don’t have inbuilt alarm.

Put simply, a smoke alarm detects smoke and sounds an alarm.

There are three type of Smoke Detectors/Smoke Alarms :

1-Ionization Smoke Detector/Alarm –

These type of Smoke Alarms  are the least costly and very common . It is very sensitive to the small particle of smoke which is generated by fast flaming fire , i.e. in case of burning of paper  & wood . It works good on smaller amount of smoke produced by flaming fires . They are marginally less sensitive to slow burning and smoldering fires which give off larger quantities of smoke before flaming occurs. They can also be too over-sensitive near kitchens.

Working Principle-An ionization smoke alarm contains a small amount of radioactive material. The radiation passes through an ionization chamber which is an air-filled space between two electrodes and permits a small, constant current between the electrodes. Any smoke that enters the chamber absorbs the alpha particles, which reduces the ionization and interrupts this current, setting off the alarm.




2-Photoelectric( Or Optic ) Smoke  Alarm –

This type of smoke alarm usages a light beam and sensor to detect smoke. As smoke travels into a compartment on the detector, that smoke covers the light beam, causing the detector to sound. It is better for smoky fires (ex. a mattress or cloth fire).

Working Principle-Photoelectric smoke alarms operate using a light source, a light beam collimating system and a photoelectric sensor. When smoke enters the optical chamber and crosses the path of the light beam, some light is scattered by the smoke particles, directing it at the sensor and thus activating the alarm






3-Combination ( Ionization + Photoelectric) Type Smoke Alarm-

Here comes the combination smoke alarm with goodness of Photoelectric Smoke Alarm in detecting low smoke flame-ups and Photoelectric Smoke Alarms for slow burning densely smoky fires .

If you don’t want to think and research  more about which type of alarm you should buy , but do not want to compromise on the safety of your house , just buy the Combination Type Smoke Alarm and you can be sure to be informed in case of any type of fire .

To read more about type of smoke alarms and how they work , click here . 

Fire Alarms :

A Fire Alarm system is a comprehensive fire detection & alarm system which includes smoke detectors, heat detectors , CO Alarms etc . In brief , a fire alarm system can sense heat as well as do everything a smoke alarm can do .

A fire alarm system can sense heat as well as do everything a smoke detector can. Depending on the type of fire alarm you get and the money you’re willing to pay, a fire alarm can do much more than just signal that there’s a fire in the house.

It has a number of devices working together to detect and alarm by audio or visual methods in case of smoke, carbon-monoxide , heat and fire . The alarm may get activated by the feed given from the smoke detector, CO detector or hear alarm or can be manually switched on using manual activation at manual call points or pull stations.

To read more about Fire Alarm System & How it works  , Click Here . 

What all A fire Alarm System Do ?

As fire alarm is an automated system, apart from alarming the occupants by audio and visual means , fire alarm can also do the following work on its own:

  • Inform the Fire Department about the incident .
  • Shut down the air handling fans and the smoke dampers in the air ducts to prevent the spread of smoke and flame
  • Turn off electricity and gas in kitchens (shunt)
  • Capture the elevators
  • Turn off the electricity in computer rooms (Emergency Power Off or EPO)
  • Turn on a deluge sprinkler system to extinguish a fire
  • Activate a pre-action sprinkler system to allow it to extinguish fire
  • Unlock doors to allow exit
  • Lock doors to prevent entrance
  • Close smoke barriers or smoke curtains to prevent the spread of smoke or flame
  • Release door holders on fire doors to prevent the spread of smoke
  • Activate fire suppression systems .
  • Turn on the emergency escape light to show the escape route.

Part of a Fire Alarm System :

A Fire Alarm System commonly will have following components :

  • 1-Alarm Initiating Devices : Smoke Detectors , CO Detectors , Heat Detector .
  • 2-Alarm Notification Device : Bells , Chimes , Horns , Strobes , Horn-Strobes , Voice Evacuation System
  • 3-Fire Alarm Control Panel
  • 4-Back-up power supply
  • 5-Remote Control & Display Panels
  • 6-Sprinkler Systems

Heat Alarms

Heat Alarms

Heat alarms works on the principal of sensing surround temperature and the alarm is off if the temperature reaches a threshold level. It is recommended to use heat alarms in some part of the house like kitchen , garage etc where a smoke alarm may give repeated false-alarm .

Heat alarm will not react to the smoke and should never replaced for the smoke alarms . It should be used as a part of complete Fire Alarm System.

To read more about heat alarms and how they work , Click Here .


How many smoke / heat  alarm should I fit in my home?

It depends on particular circumstances of every home and as there is no harm in fixing one or two more as we believe more they are fitted, you have the higher level of protection. If you want to have maximum protection , fix alarm in every room ( leaving bathrooms ) . Make sure the you do the risk assessment of the full house and fix the  type of alarm recommended for that place . For the minimum number of alarm , you can fix one at each floor of your house , preferably the optical type and it will be enough to warn you in advance in case of smoke/fire.

A general rule of thumb and what most smoke alarm manufacturers’ instructions say, that smoke detectors should be installed every 30 feet in straight runs, such as a hallway or large rooms without obstructions in the ceiling. Most smoke detectors will cover approximately 900 square feet. For a commercial  facility it may be better to consult a Fire Safety Company or the Govt Fire Department as the rules in different state may be different for location and numbers .

The heat alarms covers a small area , hence even a big residential kitchen can have a few of heat alarms .

Where do I fit/screw  my smoke alarms?

Smoke alarms are fixed upside down at the ceiling by means of screws or double sided special sticky tape. It is recommended to fix it in the centre of the room. In case you are fixing it in some side , keep a minimum 1 Ft distance from a wall or light fitting . In case you are fixing only one alarm at one floor , make sure you are fixing alarm at a place from where it can be heard from any corner of the house –mainly when you are at sleep.

Note-Don’t install it in kitchen and bathroom as it it will get off frequently by smoke in kitchen and steam in bathroom . You can try heat detector or a combination of smoke alarm & heat detector in one which don’t gives false alarm.

Lets come to the question , which alarm should I fix ? 

In our view, if it is a commercial place , go with the comprehensive Fire Alarm System with the connections to the Fire Sprinklers .

If it is for a home , the generic rule is

  • For Kitchen & Garage –Heat Alarms .
  • Bedroom , Living Room & Drawing Room ( Hall ) –Ionization smoke alarm or combined optical smoke and heat alarm.
  • Passages and Staircase –Optical smoke alarm or combined optical smoke and heat alarm.

Where can I buy them?

We always recommend you to buy and get installed Fire Alarms & Smoke Alarms of a well known brand and get it installed from  reputed company which gives you proper location suggestion and after sales service on a short notice.