Data Sheet for Product

Siemens
Smart Infrastructure - Building Products
–2–
usa.siemens.com/fire
Product Overview – (continued)
The encompassing result is an intelligent detector that provides enhanced detection capability to a wide range of products
of combustion – while offering unsurpassed rejection to nuisance-alarm sources, including: dust | steam | cooking
aerosols and other deceptive phenomena that could cause false alarms. It is known at Siemens as the “No-false-alarm
guarantee”.
Since Model FDOOT441 is a two-wire, addressable device, functioning as a multi-purpose detector – satisfying the revised
requirements of UL 268 7
th
edition using smoke-and-heat detection in a singular, aesthetically pleasing package.
Comparable to other multi-functional detectors, Model FDOOT441 also serves as a very cost-effective, viable detection
solution that saves on product
| installation | maintenance costs. The unit’s value is multiplied with built-in
ISOtechnology the True Class-X - NFPA 72 compliant SLC isolation feature supporting up to 252 isolation ready devices
per loop. When used in mixed mode a maximum of 30 non-isolated devices between isolation devices (wired in polarity-
insensitive mode). Each detector fits into one (1) wall-or-ceiling footprint, occupying one (1) address on the signal-line
circuit (SLC).
A patented forward-and-backward, light-scattering technology, capable of distinguishing both small and large products of
combustion, operates at the core of each Model FDOOT441 intelligent, addressable detector. Each Model FDOOT441
detector provides an eco-friendly solution to legacy ionization detectors - eliminating the need for a radioactive source,
along with inevitable HAZMAT-disposal requirements. The powerful ASAtechnology enables simultaneous detection of
smoldering and flaming fires
while rejecting nuisance sources in an ecological friendly manner while meeting RoHS -
compliant (Restriction of Hazardous Substances) detection alternative to legacy ionization detectors.
Two (2) thermal sensors make each Model FDOOT441 detector a robust, reliable detection device suitable for the most all
challenging applications. Additionally, Model FDOOT441 works as a heat detector, compliant with NFPA 72 and UL521.
Operation
Forward-and-Backward Light-Scattering Technology
The high-quality, optical-electronic measuring chamber for each Model FDOOT441 houses the following components:
 Two (2) optical transmitters
 Two (2) thermal sensors

One (1) optical receiver
The transmitters illuminate the smoke particles from different angles: one sensor creates forward scatter, and the other
sensor creates backward scatter. The scattered light subsequently reaches the receiver (photodiode) and generates a
measurable electric signal. The combination of a forward-and-backward scatter facilitates optimum detection, as well as
differentiates between light-and-dark particles / particle size.
This type of detection creates standardized, responsive behavior, therefore optimizing the differentiation between
wanted signals and deceptive phenomena. Additionally, the heat sensors make it possible to detect fires without smoke generation.
Additionally, this scenario generates the following advantages:
 Early detection of all fire types of fire ─ whether they generate light-or-dark smoke, or no smoke
 The fire detector can be operated at a lower sensitivity level, thus achieving a higher immunity against false
alarms that may otherwise be caused by cold aerosols (e.g. ─ by smoking, electrical welding, etc.).
In the case of an open fire, the smoke sensitivity is heightened by a temperature increase ─ which means that a
detection-reliability level that is comparable to a wide-spectrum smoke detector ─ can be achieved and
maintained.
Model FDOOT441-
Forward-and-Backward Light-Scattering Technology
4. Forward
scatterer
5. Labyrinth
1. Heat
sensors
2.
Receiver
3.
Backward
scatterer