Laser- based smoke detectors Lzr-1 7251. Schneider Electric 2 - Division - Name – Date LZR-1...

Laser- based smoke detectors

Lzr-1

7251

Schneider Electric 2- Division - Name – Date

LZR-1 Detector Chamber

Laser Diode

• Laser produces a brighter, more concentrated beam of light

• More signal is achieved due to the more concentrated light

• Smaller particles can be detected due to the brighter light


Laser Detector Benefits

• Focussed beam

• improves settled dust performance

• improves airborne dust performance

Light Source(LED)

Smoke Sensor

(Photodiode)

Standard optical smoke detector princible


Applications suitable for LZR-1

• High value property, clean environments•Telecommunications switching rooms•Computer Rooms•Electrical equipment rooms•Museums, galleries etc..

• Avoid•cigarette smoke, dust, steam, exhaust fumes, textile fibres


• Low Airflow ( < 10 air changes per hour)•40m2 per detector (3.5m radius)

• High Airflow ( > 10 air changes per hour)•25m2 per detector (2.8m radius)

• Extra detectors may be placed•at inlets to air conditioning systems•areas of high air movement•inside cabinets•floor and ceiling voids

Detector spacing / coverage


Function of LZR-1 laser detector and a laser group in Esa1 system

PW4 analogue value of the new detector is between 100 … 500s.

The Basic Environment Level (B.E.L) in panel memory is updated every 5th minute.

Time constant is 21h when the value is rising (up to 65% of the new value) and 25min when it’s decreasing (65% of new value).

Fire- and pre-alarm levels can be set between B.E.L + 60 … 2000s.

Saturation value of panel’s memory is updated once during daytime between 10.00 … 16.00, and it can be between 2600 … 4000s.

Time constant for saturation is 16 days (65% of new value).

Fire level or pre-alarm level are in any case 100s under the saturation value, no matter what the configured value is.

Maintenance warning level is fixed to 1200s.


Configuration levels vs. analogue values

Level 1 = 60s over B.E.LLevel 2 = 280s --------“-------Level 3 = 490s --------“--------Level 4 = 710s --------“-------Level 5 = 920s --------“--------Level 6 = 1140s --------“------- (default value for pre alarm)Level 7 = 1350s --------“------- (default value for fire alarm)Level 8 = 1570s --------“-------Level 9 = 1780s --------“-------Level 10 = 2000s --------“-------


Signal processing

-Panel is filtering interferences from the signal of detectors, and will proportionate the signal between 0 and 1, so that B.E.L is 0 and alarm value is 1.

Example 1 Fire alarm set to level L1

360s Fire alarm level = B.E.L + 60s (level 1)

330s Measuring value 330s proportion value is 0.5

300s B.E.L 300s


Example 2 Fire alarm set to level L7

1350s Fire alarm level = B.E.L + 1350s (level 7)

330s Measuring value 330s Proportion value is 0.022

300s B.E.L 300s

Signal processing


Function of a laser group

•Laser detectors in the same fire zone will automatically form a laser group

•There is no need for configuration.

•Proportion values of all detectors in same laser group are squared and added together. •If the sum value is 1 or more, it will activate the alarm, which is shown from the address where the proportion value is highest.

•If the value of a single detector is 1 or more, it will activate the alarm.

•The function is the same with Fire-alarm and Pre-alarm


Grouping Algorithm

• Signal from detectors in close proximity is summed using a ‘mean square’ algorithm - 2= A 2 + B 2 + C 2

• Grouping of detectors gives a higher effective sensitivity with less risk of false alarms

• For best performance always use more than one detector in any area



Example 1: Three laser detectors in the same fire zone

Fire zone X Laser group

01.001 01.002 01.003

0.25 + 0.64 + 0.04 = 0.93 <1 No Alarm

Proportion value 0.5 0.8 0.2

Square rooting 0.5² 0.8² 0.2²



Example 2: Four laser detectors in the same fire zone

Fire zone X Laser group

01.007 01.012 01.053 01.094 Proportion value 0.5 0.8 0.2 0.3 Square rooting 0.5² 0.8² 0.2² 0.3²

0.25 + 0.64 + 0.04 + 0.09 = 1.02 >1 ALARM

-- Fire alarm is shown from this address.


Selection of Sensitivity

• High Sensitivity Pre-Alarm•Alarm sensitivity from 0.01% / ft to 1.0%/ft•Set Pre-alarm sensitivity just high enough to meet ‘hot-wire’ test•Monitor system for three months

• Use lower sensitivity alarm (> 1.63%/m)


Analyzing of LZR-1 signals

ZONE 0001 ADDR. 01.001 ENABLED

LASER SENSOR A2 S28 C204 M186 P 0 F 0

Analogue values of LZR-1 detector can be seen on access level three

There are six PW4 values at one window for one detector

A = Basic Enviroment Level (BEL), from which two least significant digits are removed.In this case A2 can be between 200s … 299s. S = Saturation value, from which the two least significant digits are removed.

In this case S28 can be between 2800s … 2899s.

C = Last value from detector without filtering.

M = Value after filtering (lowest of the last tree readings).

P = % of Pre alarm level.

F = % of Fire alarm level.


POWER ELECTRONIC CABINETS

DETAILS

ASPIRATING TUBE

AND DETECTORS

VESDA / AIR-SENSE

CENTRAL UNIT

Test: Aspirating system vs. ESA1+LZR-1


F IR E ZO N E 1 F IR E ZO N E 2

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s mo k e s o u r c e

= L ZR - 1 d e t e c t o r

= v e s d a a s p ir a t io n t u b e

Smoke test 1 Fire Zone 1

00:00 START

00:55 ESA1 FIRE

01:20 ESA1 2nd FIRE

01:25 ESA1 3rd FIRE

01:40 VESDA FIRE

01:45 ESA1 4th FIRE


00:00 START

00:45 VESDA WARNING

00:55 ESA1 FIRE

01:10 VESDA FIRE

01:15 ESA1 2nd FIRE

01:20 ESA 3rd FIRE

01:25 ESA 4th FIRE


00:00 START

00:50 VESDA WARNING

01:05 ESA1 FIRE

01:15 VESDA FIRE

01:15 ESA1 2nd FIRE

01:20 ESA1 3rd FIRE

01:25 ESA1 4th FIRE

Laser- based smoke detectors Lzr-1 7251. Schneider Electric 2 - Division - Name – Date LZR-1...

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Transcript of Laser- based smoke detectors Lzr-1 7251. Schneider Electric 2 - Division - Name – Date LZR-1...