national

Iknow battery backup hardwired but you have photoelectric & ionazation..i have heard there was a big thing on TV about the ionazation ones not working good or until the fire was up to them does anyone know anything about this..i hate having decisions but which of the 2 would you put in your personal house?

Electric_Light

The dual sensor type. They exist.

frenchsparky

Most smoke alarm manufacters do have dual sensors type but only catch is mounting loaction just follow the manufacter spec very carefully it will just work fine as standard run of mill smoke alarms is.

get at least 2 or 3 with battery back up with interconnecting system.

Merci, Marc

national

if this is kinda standard run of the mill what would be a better choice to upgrade to now as to not have to buy twice..again this is my personal house..what do you have in all of yours?

L. B. Condulet

Ionization smoke detectors are most common and they will detect the byproducts of fire the fastest. They use a small amount of Americium (pronounced am-er-iss-e-um) to ionize air in a small chamber, then a small electrical current flows through the ionized air, when foreign particles are present in the chamber, the particles cause the current flow to drop below a preset level and the detector goes into alarm.

Some ionization detectors draw air from various areas using tubes many meters in length, the air is drawn into a "cloud chamber" and analyzed. These employ a computer and can discriminate between various "signatures" and tell you exactly what is burning. These are used in areas where smoke detection is desirable but certain types of other particles may be present. These smoke detectors cost over $30,000 and are a tough sell for the average home owner.

Photoelectric detectors take longer to respond but are less prone to false alarms. There are "spot type" photo detectors and "beam type". The beam type fire an invisible beam across an open space (up to 300 feet) and the intensity is measured by a receiving device. These are "obfuscation" type in that they go into alarm when the beam is obscured by particulate matter.

But obviously you are interested in a "spot type" detector device. These devices come in 2 versions, obfuscation type and "light scatter" type. The obfuscation functions in the same manner as the beam except the beam in confined within the detector housing. The light scatter photoelectric detector has a beam, but the receiver is offset from the beam. When particles of smoke are present in the beam, light is reflected off the particles and the receiver detects the light and goes into alarm.

In homes, the ionization type is recommended. Should false alarms become a problem, switch to a photoelectric detector, should false alarms continue to be a problem, switch to a heat detector.

There are 4 different types of heat detectors but primarily fall into 2 categories: fixed temperature and rate of rise.

Hope this helps.

Mark Twenhafel

Nice summary, thanks.

Mark Twenhafel

[wrong thread]