Emerson U1F, U2F, U4F-UV, UVC120 User Manual

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Emerson U1F, U2F, U4F-UV, UVC120 User Manual

MODEL: U1F, U2F & U4F-UV and UVC120

ULTRAVIOLET FIRE DETECTION SYSTEM

1, 2 and 4 Channel Field Mount Controller

with the UVC120 Detector

Part Number: MAN-0016-00 Rev. 2

Copyright © 2002 Net Safety Monitoring Inc.

Printed in Canada

This manual is provided for inform ational purposes only. Although the inform ation contained in this m anual is believed to be accurate, it could include technical inaccuracies or typographical errors. Changes are, therefore, periodically made to the inform ation within this docum ent and incorporated without notice into subsequent revisions of the manual. Net Safety Monitoring Inc. assum es no responsibility for any errors that m ay be contained within this manual.

This manual is a guide for the use of a 1, 2 and 4 Channel Field Mount Controller and the data and procedures contained within this docum ent have been verified and are believed to be adequate for the intended use of the controller. If the controller or procedures are used for purposes other than as described in the manual without receiving prior confirm ation of validity or suitability, Net Safety Monitoring Inc. does not guarantee the results and assumes no obligation or liability.

No part of this manual may be copied, dissem inated or distributed without the express written consent of Net Safety Monitoring Inc.

Net Safety Monitoring Inc. products, are carefully designed and manufactured from high quality com ponents and can be expected to provide many years of trouble free service. Each product is thoroughly tested, inspected and calibrated prior to shipm ent. Failures can occur which are beyond the control of the manufacturer. Failures can be m inim ized by adhering to the operating and m aintenance instructions herein. W here the absolute greatest of reliability is required, redundancy should be designed into the system .

Net Safety Monitoring Inc., warrants its sensors and detectors against defective parts and

workm anship for a period of 24 m onths from date of purchase and other electronic assemblies for 36 months from date of purchase.

No other warranties or liability, expressed or implied, will be honoured by Net Safety Monitoring Inc.

Contact Net Safety Monitoring Inc. or an authorized distributor for details.

Table of Contents

 

Unit I GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

CONTROLLER SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

Figure 1 - Controller Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2

DETECTOR SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2

Figure 2b - Swivel Mount Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

Figure 2a - Detector Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

BASIC OPERATION - CONTROLLER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4

CONTROLLER FACEPLATE DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4

Figure 3 - Controller Face-Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4

OUTPUTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

Table 1 - Selectable Output Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

Figure 4 - Jumper Selection for Isolated or Non-Isolated Current Outputs . . . . . . . . . . .

5

PROGRAMMING OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6

EXTERNAL RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6

AUTOMATIC DIAGNOSTICS AND FAULT IDENTIFICATION . . . . . . . . . . . . . . . . . . . .

6

VOTING LOGIC (not applicable to U1F) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

DETECTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

Unit II UV FIRE DETECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

SYSTEM APPLICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 DETECTOR SENSITIVITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 SPECTRAL SENSITIVITY RANGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Figure 5 - Various Spectral Distributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

CONE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

VISION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Figure 6 - Detector Cone of Vision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

SYSTEM SENSITIVITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Unit III SYSTEM INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10

INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10

GENERAL W IRING REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10

CONTROLLER W IRING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10

Figure 7a - W iring for U1F-UV with Non-Isolated Current Output . . . . . . . . . . . . . . . . .

12

Figure 7b - W iring for U1F-UV with Isolated Current Output . . . . . . . . . . . . . . . . . . . . .

13

Figure 8a - W iring for U2F-UV with Non-Isolated Output . . . . . . . . . . . . . . . . . . . . . . . .

14

Figure 8b - W iring Diagram for U2F-UV with Isolated Current Output . . . . . . . . . . . . . .

15

Figure 9a - W iring for U4F-UV with Non-Isolated Current Output . . . . . . . . . . . . . . . . .

16

Figure 9b - W iring for U4F-UV with Isolated Current Output . . . . . . . . . . . . . . . . . . . . .

17

POSITION AND DENSITY OF DETECTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18

MOUNTING THE DETECTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18

Figure 10 - Detector with Swivel Mount Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18

DIP SW ITCH SETTINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18

Figure 11b - Dip Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

19

Figure 11a - Dip Switch Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

19

CHANNEL SELECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

19

CONTROLLER SENSITIVITY ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

19

FIRE AREA VOTING SEQUENCE (not applicable to U1F) . . . . . . . . . . . . . . . . . . . . . .

20

RELAY OUTPUTS LATCHING/NON-LATCHING . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

20

RELAY OUTPUTS ENERGIZED/DE-ENERGIZED . . . . . . . . . . . . . . . . . . . . . . . . . . . .

20

TIME DELAY FOR AREA ALARMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

21

RELAY SETTINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

21

Figure 11c - Relay Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

21

Figure 11d - Relay Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

21

Unit IV SYSTEM OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

STARTUP PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 CHECKOUT PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 MANUAL vi CHECK/COUNT TEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 MANUAL CHECK PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 ALTERNATE TEST PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

NORMAL OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 FIRE RESPONSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Table 2 - Current Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

AUTOMATIC DIAGNOSTICS AND FAULT IDENTIFICATION . . . . . . . . . . . . . . . . . . . 25

Table 3 - Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

MAIN MENU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 BYPASS MODE (bPS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 SPECIAL FUNCTION MENU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 FORCED CURRENT OUTPUT MODE (FoP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 CURRENT CALIBRATION MODE (CuC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 ADDRESS SET MODE (Adr Set) (Do not use) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Unit V MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

ROUTINE MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 DEVICE REPAIR AND RETURN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Appendix A Net Safety Monitoring Inc. Electrostatic Sensitive Device Handling Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Appendix B Procedure For Activating Reed Switches . . . . . . . . . . . . . . . . 33

Appendix C Record Of Dip Switch Settings . . . . . . . . . . . . . . . . . . . . . . . . . 34

Appendix D Common Ultra-Violet Absorbing Gases . . . . . . . . . . . . . . . . . . 35

Appendix E Wire Resistance In Ohms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Unit I GENERAL INFORMATION

DESCRIPTION

The UVC120 Flam e Detectors combined with the U1F, U2F or U4F-UV Fire Controller provide fast, reliable flam e detection in a wide variety of applications. The microprocessor based controllers sim ultaneously monitor up to four ultraviolet (UV) detectors to provide maxim um operating flexibility at minim um expense. The Autom atic Visual Integrity (vi) feature provides a continuous check of optical surfaces, sensitivity and electronic circuitry of the detector/controller system . Autom atic fault identification monitors system operation and provides a digital display of system status using a numerical code. Controller response includes actuation of relays for direct control of field response devices and a full array of faceplate indicators. Other features include individual channel and area identification, "voting" capability and manual vi testing.

FEATURES

<Non-Intrusive testing activated by magnets

<Instantaneous response to ultraviolet radiation

<Autom atic and manual Visual Integrity (vi) testing

<Adjustable sensitivity and tim e delay

<All autom atic test functions perform ed with the system on line

<Autom atic fault identification

<Individual channel identification with voting options

<Latching Area LEDs identify the area responding to fire

<Microprocessor-based controller is easily field-program m able.

<Two digital displays, one bar graph display and high intensity LEDs indicate system status inform ation

<Relay outputs are field adjustable as latching or non-latching

<Alarm relays are program m able for norm ally energized or de-energized operation

<Individual detector output (count rate) can be visually monitored on the digital display

<Two 4-20mA current outputs (U2F and U4F). One 4-20mA output on U1F

<Conduit seals recomm ended to prevent moisture dam age but not required

CONTROLLER SPECIFICATIONS

<Operating Voltage:

24 Volts DC nominal. 18 to 32Vdc.

<Power Consumption (controller only):

2.4 watts nom inal, 4.4 watts maxim um .

100 mA nom inal, 180 mA maxim um at 24 Volts DC.

Maxim um startup current is 1.5 Am peres for 10 m illiseconds. Power supplies with fold back current lim iting are not recom m ended.

<Maximum Ripple:

Ripple should not exceed 5 Volts peak-to-peak. The sum of DC plus ripple must be $18 Vdc and #32 Vdc

<Temperature Range:

Operating:

-40ºC to +85ºC

(-40ºF to +185ºF)

Storage:

-55ºC to +150ºC

(-65ºF to +302ºF)

- 1 -

<Relay Contacts:

Norm ally open/norm ally closed contacts rated for 5 Am peres at 30 Volts DC/ 250 Volts AC

<Current Outputs:

4-20mA DC into a m axim um external loop resistance of 600 Ohm s at 18-32 Volts DC

<Dimensions:

Refer to Figure 1

<Shipping Weight (approximate):

2 lbs (0.9 kilogram s)

<Certification:

CSA, NRTL/C, NEMA 4X certified for hazardous locations Class 1, Division 1, Groups B, C and D

IEC approval (Class 1, Zone 1 Groups IIB+H2 T5)

<System Sensitivity:

Sensitivity for the standard controller is field adjustable over a range of 8 through 120 counts per second (cps) in increm ents of 8 cps. The maxim um response distance is achieved at an 8 cps sensitivity setting. For applications involving high background radiation potential, the system can be de-sensitized by increasing the count rate required to actuate alarm s. The 120 cps setting is the lowest sensitivity.

<Response Time:

Response to a saturating (high intensity) UV source is typically 10 m illiseconds for the instant alarm outputs and 0.5 seconds for the area alarm outputs when sensitivity is set for 8 cps and tim e delay is set for 0.5 seconds (m inim um settings).

Figure 1 - Controller Dimensions

DETECTOR SPECIFICATIONS

<Operating Voltage:

290Vdc ± 3Vdc (provided for controller)

- 2 -

<Power Consumption (each detector): 0.29 W atts nominal, 0.5 W atts maxim um 1 mA nominal, 1.7 mA m axim um

<Temperature Range:

Operating:

-40ºC to +125ºC

(-40ºF to +257ºF)

Storage:

-55ºC to +150ºC

(-65ºF to +302ºF)

<Dimensions:

Refer to Figures 2a and 2b

<Detector Enclosure Materials:

Available in anodized copper-free alum inum or optional stainless steel

<Shipping Weight (approximate):

2 lbs (0.9 kilogram s)

<Certification:

CSA, NRTL/C, NEMA 4X certified for hazardous locations Class 1, Division 1, Groups B, C and D

IEC approval (Class 1, Zone 1 Groups IIB+H2 T5)

<Spectral Sensitivity Range:

The detector responds to UV radiation over the range of 185 to 260 nanometres (1850 to 2600 angstrom s)

<Cone of Vision:

The Detector has a nom inal 120 degree cone of vision

Figure 2a - Detector Dimensions

Figure 2b - Swivel Mount

Dim ensions

- 3 -

BASIC OPERATION - CONTROLLER

CONTROLLER FACEPLATE DESCRIPTION

The controller faceplate provides LEDs and two digital displays for identifying status conditions, a bar graph display for indicating an alarm condition and MENU/SET and SELECT/RESET pushbutton switches (See appendix for instructions on activation) for testing and resetting the system. Refer to Figure 3.

Figure 3 - Controller Face-Plate

<Digital Displays - The left side of the digital display is normally off. If a fire alarm or visual integrity fault is detected, it indicates the channel number of the alarm or fault. The digital displays indicate system status including system error codes, visual integrity (vi) faults, system faults or fire alarms. The right side of the display shows ‘nor’ in normal operating mode. If more than one channel is in an alarm or fault condition the digital displays will cycle through these channels. Since at least one side of the display is always lit they also function as a power indicator.

<Bar Graph Display - Normally off. Flashing when fire detected in any area.

<Instant LED - (no time delay) Flashes when any detector signal exceeds the fire sensitivity setting.

<Area 1 & 2 LEDs - (Area 1 only for U1F) If the selected “voting” criteria of the area and the preset time delay has elapsed the corresponding LED starts flashing.

<Fault LED - flashes upon detection of an overall system fault or vi fault.

<Channel LEDs - (1, 2 or 4 depending on model) flash to indicate detector in alarm and remain illuminated until reset after an alarm condition has returned to normal.

<MENU/SET Reed Switch - is used to enter the main menu, to toggle through menu selections and in conjunction with the SELECT/RESET Reed Switch to enter the special functions menu.

<SELECT/RESET Reed Switch - is used for a basic system reset, menu selection and with the MENU/SET Reed Switch to enter the special functions menu. This switch is also used during the manual vi test.

-4 -

OUTPUTS

Relay Outputs:

The Instant, Area and Fault relays have SPDT contacts rated 5 Amps at 30 Volts DC or 250 Volts AC.

The Instant and Area alarm relays are programmable for either normally energized or normally de-energized operation and for latching or non-latching (programmable as a group not individually). The fault relay is only normally energized. The relays can be configured with jumpers for normally open or normally closed contacts.

RECOMMENDATION

The fault relay output should not be used to activate an automatic shutdown procedure. The fault output indicates a potential problem with the controller, not an alarm condition.

Refer to Table 1 for a summary of the relay programming options.

 

Selectable Normally

Selectable Normally

Selectable

OUTPUT

Open/Closed

Energized/De-Energized

Latching/Non-Latching

AREA1

Y

Y

Y

INSTANT

Y

Y

Y

FAULT

Y

N2

N3

Table 1 - Selectable Output Options

1

2

3

Area alarms are programmed together, not individually. Fault relay is normally energized.

Fault relay is non-latching.

Current Outputs:

4-20 mA DC current outputs transmit system information to other devices. The current outputs can be wired for isolated or non-isolated operation by changing the jumpers as shown in Figure 4. Refer to Unit IV, System Operation for a description of the current output signal levels.

- 5 -

Figure 4 - Jumper Selection for Isolated or Non-Isolated Current Outputs

PROGRAMMING OPTIONS

DIP switches located on the circuit board are used to “program” various options including:

<channel selection,

<system sensitivity,

<fire area voting logic,

<time delay for fire area alarms,

<relay latching/non-latching selection, and

<relay energized/de-energized selection.

NOTE

Power to the controller must be cycled to make dip switch changes take effect.

EXTERNAL RESET

A normally open, momentary closure switch connected between the external reset terminal and the negative power terminal provides remote reset.

AUTOMATIC DIAGNOSTICS AND FAULT IDENTIFICATION

The microprocessor-based controller features self-testing circuitry that continuously checks for problems that could prevent proper system response. W hen power is applied, the microprocessor automatically tests memory. In the Normal Operating Mode it continuously monitors the system to ensure proper functioning. A "watchdog" timer is maintained to ensure that the program is running correctly.

The main loop of the operating program continuously cycles through the Automatic Visual Integrity test, checking each detector and its wiring. The microprocessor can be interrupted by

- 6 -

(Automatic Diagnostics and Fault Identification Cont)

any one of several status changes such as a fault or a "fire" signal from one of the detection areas to take appropriate action.

If a system or vi fault is detected the Fault LED flashes, digital displays and current outputs identify the nature of the fault and the fault relay is de-energized.

VOTING LOGIC (not applicable to U1F)

The controller can be DIP switch configured for either one or two monitoring areas. For a one area configuration, all channels are considered as being in Area 1 and both Area alarm relays will be activated together.

The dip switches can be set so that only one channel need be in alarm to activate the area alarm or any two channels must ‘vote’ (see a fire at the same time) to activate the area alarm. The instant alarm will be activated when any channel sees UV radiation exceeding the preset sensitivity setting, no matter what voting option is being used.

For a two area configuration, channel one (one and two for U4F) make up Area 1 and channel three (three and four for U4F) make up Area 2. W ith the U4F each Area alarm may be programmed with different voting criteria (ie. Area 1 may be set so that either channel one OR channel two may activate the area alarm, and Area 2 may be set so that both channels three AND four must see the fire at the same time to activate the Area alarm).

DETECTOR

The detector responds to UV radiation over the range of 185 to 260 nanometers. It is not sensitive to direct or reflected sunlight nor to normal artificial lighting.

The detector is housed in an explosion-proof enclosure that is designed to meet most national and international standards. It is available in anodized aluminum or optional stainless steel.

The detector is typically mounted with a swivel mounting assembly which is recommended. Other mounting arrangements are possible.

Unit II UV FIRE DETECTION

SYSTEM APPLICATION

The detector responds instantly to ultraviolet radiation emitted by a flame. It is designed for use in hazardous locations and is suitable for use in outdoor applications.

Typical applications for UV detection systems are:

<around highly combustible materials

<if instantaneous response to flame is needed

<where automated fire protection is required

<to protect large capital investments

Petroleum Products Handling

<petroleum loading terminals

<offshore platforms

<pipeline stations

<tank farms

- 7 -

<refineries

<engine rooms

Gaseous Fuel Handling

<butane and propane loading and storage

<pipeline compressor stations

<gas gathering facilities

<LNG loading, transfer and storage

<hydrogen

<gas turbines

Other Processes

<paint spray booths

<chemical and petrochemical production

<powder coating booths

Automated fire protection systems also have applications in any manufacturing or research facility where the potential of fire may be low to moderate but the losses due to a fire would be high.

DETECTOR SENSITIVITY

SPECTRAL SENSITIVITY RANGE

The UV fire detector responds to radiation wavelengths of 185 to 260 nanometres (1850 to 2600 angstroms). Figure 5 illustrates the range of sensitivity and compares this range to other forms of radiation. Note that UV radiation reaching the earth from the sun does not extend into the sensitivity range of the detector. Nor does radiation from normal artificial lighting, such as fluorescent, mercury vapor and incandescent lamps.

Figure 5 - Various Spectral Distributions

NOTE

Some mercury vapor lamps can operate for extended periods with cracked or damaged envelopes and will then emit UV radiation in the range of the detector. Remove defective mercury vapor lamps from service.

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