No, there are lots of ways to warn people of fires, some of them automatic and some of them require human input.
Human input: Someone shouting "fire" while pounding on your door often indicates that someone thinks there may be a fire. Pulling a manual alarm activation can trigger the fire alarm. Hearing fire-engine sirens stopping in front of your building is sometimes worth exploring further. There are numerous other ways.
Automatic: In addition to smoke detectors, there are also heat detectors that can activate an alarm. They may be set at a fixed temperature or may react to a rapid "rate of rise" of heat in the surrounding air. There are also flame detectors, which detect an IR or UV (or both) flickering light. One other sensor for automatic fire alarms is the water-flow alarm (meaning a sprinkler head is running).
Fire alarms help warn us when there may be smoke or fire that can cause injuries or damage. If people are not warned, the fire can grow until it's too late to stop it.
Smoke alarms are designed to sense smoke, which indicates fire, earlier than you may detect it if you are sleeping or in another part of the house. When the smoke alarm goes off, you know there is danger and can leave in time to stay safe.
Some fire stations offer smoke alarms at little or no cost. Fire stations always have smoke alarms available, to make sure that there community is kept safe.
People are typically warned of a fire through fire alarms that sound loudly, alerting individuals to evacuate the building. In some cases, there may also be visual alarms or text alerts sent to mobile phones. It is important to have an evacuation plan in place and to familiarize oneself with the fire evacuation procedures in the specific location.
The company, BRK produces electronic safety devices. BRK produces smoke alarms, battery and electric smoke alarms, plug in alarms and fire extinguishers.
I think THere good to have just incase of a fire
Yes, the requirements for smoke alarms and fire doors are often separate, although there could be overlapping requirements that reduce the need for one if you have more of the other, in specific cases.
No, generally, smoke alarms lose sensitivity as they get older. Some fire codes require smoke alarms in one- and two-family dwellings to be replaced every ten years. Commercial smoke alarms must be tested and replaced when they can no longer be calibrated within the manufacturers' specifications.
You should have a photo-electric smoke alarm in your house because they react more quickly to smoldering fire byproducts than most ionizing type smoke alarms. Having ANY type of smoke alarm is better than none, provided it has the necessary batteries and maintenance to actually work during a fire.
Smoke alarms are available from your local fire brigade as well as many homeware suppliers. Testing the alarms and changing the batteries on a regular basis is essential for their proper function.
Operational
Most public areas and buildings have them installed as a legal requirement. Some houses and residential buildings also have fire alarms but mostly smoke alarms. (Two different things).