Every home should have smoke detectors and local home building regulations will suggest the locations and types but the selection can get a bit confusing.
In this How To we will look at some of your options however the information you read here should not be used on its own to make your final selection. You MUST use other sources of information when making your final choice about which devices are best for your specific application. Here we will explain how some of these devices work and the methods of install and we will touch on their ability to give you egress time to get out of your home but our research is based on Manufacture information and Government and Nonprofit Testing Center results and literature. We want to be completely up front with our readers that any information you find here is not enough to make a decision on which device is best for you or how you should install them. We care about our visitors and we want you to make informed choices.
Types of Smoke and Fire Detectors
There are three basic units that you might find in the average home and although there are variations they make up the majority of installs in the United States.
The first is a Carbon Monoxide Detector. This device tests for the presence of Carbon Monoxide in the are that may be present due to a fire or may be present from other sources such as a leaking furnace vent pipe or chemicals and gasses in the home. They are not on their own a good choice for early notification of an active fire in your home but they are important to warn you about a variety of associated problems and situations that can be life threatening. I strongly suggest that if you have a fireplace, wood burning stove, kerosene, propane or other fuel burning heater or if you have natural gas or propane in your home for cooking or heating that you install carbon monoxide detectors. These devices can be independent battery operated units or they can be tied into your wired smoke alarm circuit. They also come as a dual sensor unit where a smoke detector and carbon monoxide detector is in the same unit. That makes it easier for you to maintain but it may also mean replacement of the unit if either side of the equipment fails.
The second is a Fire Detector which is normally referred to as an ionization smoke detector. From this point on we may use either term for an ionization smoke detector because they work primarily best with fast burning fires and not as well for smoldering fires. These units use a small amount of radioactive material to sense smoke and gasses in the air.
The third is a Photoelectric Smoke Detector which is primarily used for smoke detection due to fires in your home. These units use a photoelectric cell to sense smoke in the air.
Finally you have dual or multi sensor units that can be a combination of many of these technologies. You may have a photoelectric unit paired with a ionization unit or you might have a photoelectric unit paired with a carbon monoxide unit or possibly all three technologies in the same unit.
Specialty items can provide more protection such as heat detectors that will sense the temperature in the room.
Use and Placement of Smoke Detectors
Local Fire and Building Code Regulations will determine what the minimal acceptable level of monitoring is in residential and commercial buildings but for most of us we will normally be better off if we exceed those standards.
Smoke Detectors are suggested to be installed in each bedroom, At the top of stairs leading to your second or higher floors. At the bottom of stairs in your basemen or first floor and in rooms that contain your heater.
It is also suggested that the detectors be interconnected so that you are immediately alerted at all detectors when any of them alarm.
Connecting your system may be performed by an electrician when your home is built or later if needed. Electrical wire will provide power to the detectors and also send a signal throughout the system when any detector alarms.
Battery backup will provide both power to the individual unit and also send signal to the other alarms if the power goes out.
Fully battery operated detectors are also available and new units may include a lithium battery that will last for many years.
Interconnection is also available in Battery Powered units through wireless communication.
Pressing the test button on any interconnected unit should sound all other units.
Smoke Detector Replacement is Required every few Years
Units will need to be replaced every few years. Normally 5 to 7 years is the life of any unit but some may be warranted up to 10 years. You will need to check with the manufacture on how often your devices need to be replaced. THIS MEANS THE ENTIRE UNIT NOT JUST THE BATTERIES.
If you have a battery operated or battery backup device that uses replaceable batteries they will need to be monitored on a regular basis. Normally manufacturers suggest a weekly test which requires pushing the test button on any of your units and verifying that the other units are operating. You should probably rotate which unit you test from and any units not connected should be tested individually at the same time.
Some smoke detectors also come with emergency lights that can help you get out of the home. This is not a bad option especially for basements and stairs.
Which is better Photoelectric or Ionization Smoke Detectors?
Ok this is where you really need to do your own research but I will give you some information that will get you started.
There are a number of businesses, testing organizations and government test centers that review smoke detectors and related devices and report their findings to the public. Some of the information is difficult to read but if you can do your taxes you can get through it and understand what they are saying.
Early on in this how to I described Photoelectric devices as smoke detectors and ionization devices as fire detectors and this is the reason. Photoelectric devices are better at detecting smoke from smoldering fires while Ionization devices are better at detecting fast burning fires.
Now you are thinking to yourself how are you suppose to know which fire will occur in your home and that is the hard part.
For best benefit you might want to go with a dual or multi sensor device that has both ionization and photoelectric sensors.
However if you are picking one type over the other then Photoelectric seems to react much faster to both smoldering fires and fast burning fires with this one notice. Although photoelectric is slower for fast burning fires it is not that much slower when compared with how much slower ionization detectors are when detecting smoldering fires.
Test results from the NIST.gov website can be viewed from this link
NIST Technical Note 1455-1
February 2008 Revision
Performance of Home Smoke Alarms
Analysis of the Response of Several Available
Technologies in Residential Fire Settings
INFORMATION FROM THIS DOCUMENT SAYS
For smoldering fires, the photoelectric alarms provide shorter alarm times compared to other technologies.
In all but one smoldering test, photoelectric alarms provided the first alarm.
For the cooking oil tests, an ionization alarm responded first in the manufactured home while the photoelectric aspirated alarm responded first in the two-story home test.
Dual Ion/Photo alarms in the bedroom in one test responded earlier than other alarms and moved the average alarm time downward.
The time differences in their tables are pretty dramatic and should be viewed by anyone researching these devices.
As was stated from the beginning no single source is good enough to depend on when selecting these devices. YOU MUST read all the literature you can from reliable sources and then make an informed decision on which type of sensors you want to purchase.
With that in mind you have many other choices to make such as wired verses wireless devices that are interconnected. Wiring in a home fire could be compromised and wireless connections would work better. On the other hand wired connections do supply power so a bad batter in your device may also not sound an alarm.
Placement is enormously important and each bedroom and the area outside bedrooms must have a device along with devices on each floor of the home. Other placement considerations include heating units, garages and kitchens but a device in each room is always considered best as it will give you more time to react.
Having detectors is not enough. You must have a plan to get out and to call your fire department. Sleeping with your cellphone in arms reach and having an emergency rope ladder for your second story is important. Also making sure everyone in your home knows where you will meet when you are out will limit the chance that anyone is left behind.
Research well and plan well.