GasAlert. Introduction. WWarning. Table 1. GasAlert Models. Gas Monitored

Transcription

1 Introduction Table 1. GasAlert Models WWarning To ensure your personal safety, read Safety Information before you use the detector. The GasAlert gas detector ( the detector ) warns of hazardous gas at levels above a factory set alarm setpoint. This product is a gas detector, not a measurement device. The detector is a personal safety device. It is your responsibility to respond properly to the alarms. Table 1 lists the GasAlert models. This manual includes examples from each model. Model GasAlert (CO) GasAlert (H 2S) GasAlert (SO 2) GasAlert (Cl 2) GasAlert (NH 3) GasAlert (HCN) GasAlert (NO 2) GasAlert (O 2) Gas Monitored carbon monoxide (CO) ppm hydrogen sulfide (H 2S) ppm sulfur dioxide (SO 2) ppm chlorine (Cl 2) ppm ammonia (NH 3) ppm hydrogen cyanide (HCN) ppm nitrogen dioxide (NO 2) ppm oxygen (O 2) % by volume 1 Edited Sept 16, 2000 rev.1

2 Users Manual Contacting BW Technologies To contact BW Technologies, call: USA and Canada: BW America: Europe and U.K.: +44 (0) Anywhere in the world: Or visit us on the World Wide Web: ISO 9001 Safety Information - Read First Use the detector only as specified in this manual, otherwise the protection provided by the detector may be impaired. A Warning identifies conditions and actions that pose hazard(s) to the user; a Caution identifies conditions and actions that may damage the detector. International symbols used on the detector and in this manual are explained in Table 2. Read the Warnings and Cautions on the following pages before using the detector. =Note This instrument contains a lithium battery. Do not mix with the solid waste stream. Spent batteries should be disposed of by a qualified recycler or hazardous materials handler. 2

3 Safety Information - Read First WWarning To avoid possible personal injury: Substitution of components may impair Intrinsic Safety. Do not use the detector if it is damaged. Before you use the detector, inspect the case. Look for cracks or missing plastic. If the detector is damaged or something is missing, contact BW Technologies immediately. (See page 2.) Make sure the back is closed and fastened before you operate the detector. Use only a sensor specifically designed for your GasAlert model. (See the section, "Replacement Parts and Accessories.") Make sure the sensor screen is not blocked. Periodically test the sensor s response to gas by exposing the detector to a targeted gas concentration that exceeds the High Alarm setpoint. Manually verify that the audible and visual alarms are activated. Calibrate the detector before first-time use, and then at least once every 90 days. Do not turn off the detector during a work shift. Turning off the detector resets the TWA (time-weighted average) and maximum gas exposure values to 0. (See the section, Alarms. ) Use only the following batteries: Energizer CR2. (See the section, Replacing the Battery or Sensor. ) To reduce the risk of ignition of a flammable atmosphere, batteries must only be changed in an area known to be nonflammable. 3

4 Users Manual Caution To avoid possible damage to the detector: Do not expose the detector to electrical shock and/or severe continuous mechanical shock. Do not attempt to disassemble, adjust, or service the detector unless instructions for that procedure are contained in the manual and/or that part is listed as a replacement part. Use only BW Technologies replacement parts. Do not immerse the detector in liquids. The detector Warranty will be voided if customer personnel or third parties damage the detector during repair attempts. Non-BW Technologies repair/service attempts void this Warranty. The Oxygen GasAlert Detector is tested by Underwriters Laboratories Inc. up to an atmosphere of 21% Oxygen. Connect only to the Remote Vibrator Alarm (BW Part #: GA-VIB3) or the Earphone (BW Part #: D4-E2358) to the GasAlert Detector. Table 2. International Symbols Symbol P Classified to both U.S. and Canadian Safety standards by Underwriter s Laboratories, Inc. Conforms to European Union directives. Cenelec (DEMKO) EEx ia IIC 4

5 Getting Started Getting Started The items listed below are included with your detector. If the detector is damaged or something is missing, contact the place of purchase immediately. 3 V lithium CR2-series battery. GasAlert H 2S model: H 2S sensor; GasAlert CO model: CO sensor; GasAlert SO 2 model: SO 2 sensor; GasAlert Cl 2 model: Cl 2 sensor; GasAlert NH 3 model: NH 3 sensor; GasAlert HCN model: HCN sensor; GasAlert NO 2 model: NO 2 sensor; GasAlert O 2 model: O 2 sensor. To become familiar with the features and functions of the detector, study the following figures and tables: Figure 1 and Table 3 describe the detector s components. Figure 2 and Table 4 describes the detector s display elements. Table 5 describes the detector s pushbuttons. Test Cap and Hose. The detector comes with battery and sensor installed. To order replacement parts and accessories, see the section "Replacement Parts and Accessories." 5

6 Users Manual Table 3. GasAlert Detector 1 Item Function 2 A Visual alarm 3 B Display C D E Pushbuttons Audible alarm Sensor and sensor screen F Accessory Output Jack G Clip 7 Figure 1. GasAlert Detector 6

7 Getting Started Table 4. Display Elements Item A B C D E F G H I J K Function Numeric Value Battery Time-Weighted Average Alarm Set Alarm Setpoints High Alarm or Alarm Setpoint Low Alarm or Alarm Setpoint Alarm or Alarm Setpoint Sensor Is Automatically Zeroed Set Sensor Span Value Apply Gas Increment or Decrement Numeric Value Figure 2. Display Elements Note L Parts Per Million; % v /v M Maximum Gas Exposure N Time-Weighted Average Exposure The display backlight automatically activates for 3 seconds whenever there is insufficient light to view the display and during alarm conditions. Any pushbutton reactivates the backlight for 6 seconds. 7

8 Users Manual Table 5. Pushbuttons Pushbutton Description A To turn on the detector, press A. To initiate the Confidence Beep, press B while pressing A at startup. D CAL C TWA MAX B OK To turn off the detector, press A and hold for 5 seconds. To decrement the displayed value, press D. To initiate calibration and setting alarm setpoints, press B and D simultaneously. To increment the displayed value, press C. To view the TWA and maximum gas exposures, press B and C simultaneously. To initiate calibration and setting alarm setpoints, press B and D simultaneously. To save the displayed value, press B. To initiate the Confidence Beep, press B while pressing A at startup. 8

9 Activating the Detector* Activating the Detector* To activate the detector, press A. 5. The display shows the High Alarm setpoint: The detector begins a self-test. Self-Test The detector performs the actions in steps 1-5. Manually check that all actions occur. 1. The display shows all elements. 2. The audible alarm beeps and visual alarm flashes.* 3. The detector briefly turns on the backlight. The detector then begins a 30-second countdown. During this time, the detector tests the sensor and the battery. If the sensor test fails, the audible alarm emits a slow modulating tone and the visual alarm flashes slowly. 4. The display shows the Low Alarm setpoint: *GasAlert with Internal Vibrator Alarm (Optional Model, Prefix "GAA-"): Activating the Detector - 1 vibration. 9

10 Users Manual If the battery test fails, the audible alarm beeps and the visual alarm flashes once every 5 seconds. The display shows: Self-Test Pass* If the detector passes the self-test, the detector begins normal operation. The display shows the ambient gas reading: Note If the Confidence Beep is on, the audible alarm beeps if the battery has sufficient power and stops if the battery power is low. (See the section, Confidence Beep. ) Then the detector starts recording the maximum gas exposure and calculating the TWA (time-weighted average). Self-Test Fail* If the detector fails the self-test, see the section, If the Detector Does Not Work. 10

11 Deactivating the Detector* Deactivating the Detector* To turn off the detector, press A and hold for 5 seconds. The audible alarm beeps four times and the visual alarm flashes four times.* The display shows: Confidence Beep The Confidence Beep tells you the battery has sufficient power to appropriately respond to a hazardous level of gas and emit an alarm. Instead of beeping when the battery s power is low, the audible alarm beeps to advise you the battery has sufficient power. The Confidence Beep stops when the battery power is low. You can only activate the Confidence Beep at startup. To turn on the Confidence Beep: 1. If the detector is on, deactivate the detector. After 3 additional seconds, the display turns off and the detector stops normal operation. Note If A is held down for less than 5 seconds, the detector will not shut down 2. Press A and B simultaneously. After the self-test completes, the detector continuously beeps once every 5 seconds.* To turn off the Confidence Beep, turn off, and then restart the detector. *(GasAlert with Internal Vibrator Alarm: See pages 12, 13, 17). 11

12 Users Manual Alarms Table 6 describes detector alarms and shows how the display looks for each alarm. Table 7 describes the computed gas exposures. Table 6. Alarms Alarm Display Alarm Display Low Alarm: Slow modulating tone. Slow flash. ALARM flashes. *Slow vibrations. TWA Alarm: Fast modulating tone. Fast flash. ALARM flashes. *Fast vibrations. High Alarm: Fast modulating tone. Fast flash. ALARM flashes. *Fast vibrations. *GasAlert with Internal Vibrator Alarm (Optional Model, prefix "GAA-"): Alarms and advice. Sensor Alarm: Slow modulating tone. Slow flash. ALARM flashes. *Vibrates along with beeps/flashes. 12

13 Alarms Table 6. Alarms (cont.) Alarm Display Alarm Display Low Battery Alarm: 1 beep and 1 flash every 5 seconds. (Confidence Beep disabled) *1 quick vibration every 5 seconds. Automatic Shutdown Alarm: 8 beeps and flashes. M displays periodically. *1 long vibration at start of Alarm. Confidence Beep: 1 beep every 5 seconds. *1 quick vibration per minute. Normal Shutdown: 4 beeps and flashes. *1 long vibration. Note During an alarm condition, the detector activates the backlight and the display shows the current ambient gas reading. The High Alarm overrides a TWA Alarm and a TWA Alarm overrides a Low Alarm. 13

14 Users Manual Computed Gas Exposures WWarning To avoid possible personal injury, do not turn off the detector during a workshift. The detector automatically resets the TWA and maximum gas exposures at startup. If you restart the detector during a workshift, these values will not reflect the entire workshift. Gas Exposure Table 7. Computed Gas Exposures Description TWA Time-weighted average based on an 8-hour work day. Accumulated value. Maximum* Highest gas level encountered during the period the detector is turned on. *Maximum gas exposure describes both very high and very low levels of oxygen. 14

15 Alarms Viewing Gas Exposures Press B and C simultaneously. The display first shows the TWA gas exposure: Gas Alarm Setpoints The detector s gas alarm setpoints trigger the gas alarms, which are described in Table 8. Table 8. Gas Alarm Setpoints The display then shows the maximum gas exposure: Alarm Low Alarm TWA Alarm High Alarm Condition Toxic Gases: Ambient gas level above Low Alarm setpoint. O 2: Ambient gas level may be set to above or below 20.9%. TWA above Low Alarm setpoint (O 2: Not applicable). Ambient gas level above High Alarm Setpoint. O 2: Ambient gas level may be set to above or below 20.9%. 15

16 Users Manual Resetting Gas Alarm Setpoints Table 9 lists the factory-set alarm setpoints. Table 9. Factory Set Alarm Setpoints Gas Low High CO 35 ppm (parts per million) 200 ppm H 2S 10 ppm 15 ppm SO 2 2 ppm 5 ppm Cl ppm 1.0 ppm Note You can disable an alarm by setting the alarm setpoint to 0. Setting the Low Alarm setpoint to 0 turns off the Low and TWA Alarms. Stopping a Gas Alarm The Low and High Alarms stop when the ambient gas level returns to the acceptable range. The detector computes the TWA value up to the Low Alarm setpoint. At that time, the detector activates the TWA Alarm. You can only stop the TWA Alarm by deactivating the detector. NH 3 25 ppm 50 ppm HCN 4.7 ppm 10.0 ppm NO ppm 5.0 ppm O % 23.5% To change the factory-set alarm setpoints, refer to the section Calibration and Setting Alarm Setpoints. 16

17 Alarms Sensor Alarm The detector tests for a missing or defective sensor during the activation self-test. See the section, "If the Detector Does Not Work." Low Battery Alarm The detector tests the battery during the activation selftest and continuously thereafter. If the battery voltage is low, the detector activates the Low Battery Alarm. The Low Battery Alarm continues until you replace the battery or the battery power is almost depleted. If the battery voltage drops too low, the detector executes an Automatic Shutdown. Note If the Confidence Beep is on, the audible alarm does not beep during a Low Battery alarm. (See the section, "Confidence Beep.") Automatic Shutdown Alarm* If the battery voltage is in immediate danger of dropping below the minimum operating voltage, the audible alarm beeps 8 times and the visual alarm flashes 8 times.* After 3 seconds, the display blanks out and the detector stops normal operation. The display shows M LOW periodically until the battery power is depleted. *(GasAlert with Internal Vibrator Alarm: Automatic Shutdown Alarm - 1 long vibration at start of Alarm) Replace the battery. (See the section, "Replacing the Battery or Sensor.") Note Typically, the Low Battery Alarm continues for 30 minutes before Automatic Shutdown. 17

18 Users Manual Calibration and Setting Alarm Setpoints Guidelines When calibrating the detector, adhere to the following guidelines. Recommended gas mixture: CO: 50 to 500 ppm balance N 2 H 2S: 10 to 100 ppm balance N 2 SO 2: 10 to 50 ppm balance N 2 Cl 2: 5 to 10 ppm balance N 2 NH 3: 50 to 200 ppm balance N 2 HCN: 10 to 20 ppm balance N 2 NO 2: 10 to 20 ppm balance air O 2: Clean Air Calibration accuracy is never better than the calibration gas accuracy. BW Technologies recommends a premium-grade calibration gas. Gases with NIST (National Institute of Standards and Technology) traceable accuracy will improve the validity of the calibration. Do not use a gas cylinder beyond its expiration date. Calibrate a new sensor before use. Allow the sensor to stabilize before starting calibration (used: 60 seconds; new: 5 minutes). Calibrate the detector once every 1 to 3 months, depending on use and sensor exposure to poisons and contaminants. Calibrate the detector if the ambient gas display varies at startup. It is best to calibrate the sensor before changing alarm setpoints. Calibrate only in a clean atmosphere, which is free of background gas. To disable an alarm, set its alarm setpoint to 0. If you require a certified calibration, contact BW Technologies using one of the numbers on page 2. 18

19 Calibration and Setting Alarm Setpoints Test Cap The Test Cap and hose, which are shipped with the detector, simplify sensor testing and calibration. Table 10 and Figure 3 show how to use the Test Cap and hose when applying gas to the sensor. 1 2 Table 10. Test Cap Item A B C Description Test Cap Hose Regulator and Gas Cylinder 3 Figure 3. Test Cap 19

20 Users Manual Calibration Procedure To calibrate the detector and set its alarm setpoints, perform the following 8-step procedure. Auto Zero (O2 Calibrate in Clean Air) The display flashes auto zero while the detector automatically zeroes the sensor. Start Calibration To quit at any point, press A. The detector retains any saved values, and the audible alarm beeps four times before the detector returns to normal operation. 1. Press B and D simultaneously. The display shows: The audible alarm beeps once. Factory Password-Protected (Optional Model, suffix -5 ) If the detector is password protected, after a successful Auto Zero, the detector will ask for the password before proceeding to Auto Span and Alarm Setpoints. If the password is not entered within 8 seconds the detector will automatically return to normal operation. The audible alarm then beeps twice. Note Do not apply the calibration gas until the display shows a flashing gas cylinder; otherwise, the auto zero step will fail. If the sensor fails the auto zero step, the display shows no and the detector skips the sensor span steps. Press A to exit. Then restart calibration in an atmosphere that is clear of the targeted gas. If the step fails a second time, restart the detector to test the sensors. 20

21 Calibration and Setting Alarm Setpoints Set Span The display shows the current calibration gas setting: The up and down arrows flash, prompting you to input a new calibration gas concentration or use the displayed value for the span (sensitivity adjustment). Note If you do not press any pushbuttons within 10 seconds of viewing this display, the detector automatically saves the displayed concentration of the calibration gas. If you change the calibration gas concentration but pause for 10 seconds before pressing B, the detector rejects the new value. The display shows no and the audible alarm beeps six times. The display then shows the original calibration gas concentration, which will be used in the next step. 2. To change the calibration gas setting, press C or D until the display matches the concentration of the calibration gas. 3. Press B to save the displayed value. 21

22 Users Manual Span The display shows a flashing gas cylinder, prompting you to apply a calibration gas to the sensor or skip the span. 4. Apply gas to the sensor at a flow rate of 250 to 500 ml/min. Or, press B now to skip the span. When the detector senses approximately one-half of the expected gas concentration (30 seconds), the audible alarm beeps once. The detector then begins spanning the sensor (2 minutes; 30 seconds O 2). The audible alarm beeps three times at the end of the span. Note The detector will not span a sensor if: You do not apply gas to the sensor. The sensor fails to detect at least one-half of the expected gas concentration in the first 30 seconds. The gas concentration drops below one-half of the expected gas level during the 2- minute span. If the detector fails to span a sensor, the display shows no and the audible alarm beeps six times (unless you pressed B to skip the span). If you apply gas to a sensor and the detector fails to span the sensor, repeat the calibration process using a new gas cylinder. If the sensor fails the span a second time, replace the sensor. (See the section, Replacing the Battery or Sensor. ) 22

23 Calibration and Setting Alarm Setpoints Setting the Low Alarm Setpoint The display shows the Low Alarm setpoint: The up and down arrows flash, prompting you to input a new Low Alarm setpoint. Note If you do not press any pushbuttons within 10 seconds, the detector automatically retains the Low Alarm setpoints. If you change a displayed value but pause for 10 seconds before pressing B, the detector rejects the new value. The display shows no and the audible alarm beeps six times. The display then shows the unchanged Low Alarm setpoint. 5. If you want to change the Low Alarm setpoint, press C or D until the display shows the new value. 6. Press B to save the displayed value. 23

24 Users Manual Setting the High Alarm Setpoint The display shows the High Alarm setpoint: The up and down arrows flash, prompting you to input a new High Alarm setpoint. 7. If you want to change the High Alarm setpoint, press C or D until the display shows the new value. 8. Press B to save the displayed value. Note If you do not press any pushbuttons within 10 seconds, the detector automatically retains the High Alarm setpoint. If you change the High Alarm setpoint but pause for 10 seconds before pressing B, the detector rejects the new value. The display shows no and the audible alarm beeps six times. The display then shows the unchanged High Alarm setpoint. At the end of step 8, the audible alarm beeps four times and the detector returns to normal operation. Verification (optional) Test the detector using a gas cylinder other than the one used in the calibration steps. The gas concentration should not exceed the sensor's detection range. Confirm that the display shows the expected concentration. 24

25 Maintenance Maintenance To keep the detector in good operating condition, perform the following basic maintenance as required: Calibrate, test, and inspect the detector at regular intervals. Keep an Operations Log of all maintenance, calibrations, and alarm events. Clean the exterior with a soft damp cloth. Do not use solvents, soaps, or polishes. Do not immerse the detector in liquids. Cleaning a Sensor Screen Remove the screen. Clean using a soft, clean brush and clean, warm water. Let the screen dry before replacing it. Cleaning a Sensor Remove the sensor. Clean using a soft, clean brush and no water. Clearing a Sensor The sensor has a high degree of resistance to common vapors and gases. The sensor will most likely clear itself if you remove the detector to a clean environment and wait 10 to 30 minutes. Do not expose a sensor to the fumes of inorganic solvents (such as, paint fumes) or organic solvents. 25

26 Users Manual Replacing the Battery or Sensor WWarning To avoid possible personal injury: Replace the battery as soon as the detector emits a Low Battery Alarm. Use only the following batteries: Energizer CR2. Use only the sensor specifically designed for your GasAlert model. Othewise, the detector will not monitor the target gas. (See the section, "Replacement Parts and Accessories.") Figure 4 and Table 11 illustrate how to replace the battery or sensor. If the detector is on, shut down the detector before replacing the battery or sensor. Use a Phillips head screwdriver to loosen and tighten any screws. Do not use excessive force when removing or inserting the sensor, or the sensor may be damaged. Gently rocking the sensor back and forth may help free a tightly held sensor. The battery lasts 3 years, assuming 8 hours of average use per day. To preserve battery life, turn the detector off when you are not using it. The sensor provides consistent and accurate ambient gas readings. The sensor lasts 2 years under normal operation. The section, If the Detector Does Not Work describes problems caused by a sensor in need of calibration or replacement. 26

27 Replacing the Battery or Sensor Table 11. Replacing the Battery or Sensor 1 Item Description A Detector Back Screws B Detector Back + 2 C D Battery Main Board Screws E F Main Board Sensor G Detector Front 6 7 Figure 4. Replacing the Battery or Sensor 27

28 Users Manual If the Detector Does Not Work The detector s electronics are protected from variations in humidity and corrosive atmospheres. If you encounter a problem, try the solutions listed in Table 12. If you still are unable to correct the problem, contact BW Technologies using one of the numbers on page 2. Table 12. Troubleshooting Tips Problem Possible Cause Solution Detector does not turn on. No battery. Install battery. Depleted battery. Replace battery. Damaged or defective detector. Contact BW. (See page 2.) Reversed battery Reinstall battery correctly. Detector enters alarm immediately when turned on. Sensor needs to stabilize. Used sensor: wait 60 seconds New sensor: wait 5 minutes Low Battery alarm. Replace battery. Sensor alarm. Replace sensor. 28

29 If the Detector Does Not Work Table 12. Troubleshooting Tips (cont.) Problem Possible Cause Solution Activation self-test fails during one of the first five steps. General fault. Alarm setpoints are incorrect. Contact BW. (See page 2.) Reset alarm setpoints. Detector does not display normal ambient gas reading after activation self-test. Sensor not stabilized. Detector requires calibration. Used sensor: wait 60 seconds New sensor: wait 5 minutes Calibrate detector. Targeted gas is present. Detector is operating properly. Use caution in suspect areas. Detector does not respond to pushbuttons. Battery is depleted. Detector is performing operations that do not require user input. Replace battery. Pushbutton operation restores automatically when the operation ends. Detector does not accurately measure gas. Detector requires calibration. Detector is colder/hotter than ambient gas. Calibrate sensor. Allow detector to acquire ambient temperature before use. Sensor screen is blocked. Clean sensor screen. 29

30 Users Manual Table 12. Troubleshooting Tips (cont.) Problem Possible Cause Solution Detector does not enter alarm. Alarm setpoint(s) are set incorrectly. Reset alarm setpoints. Alarm setpoint(s) set to zero. Reset alarm setpoints. Detector is in calibration mode. Complete the calibration procedure. Detector intermittently enters alarm without apparent reason. Ambient gas levels are near alarm setpoint or the sensor is exposed to a puff of the targeted gas. Detector is operating normally. Use caution in suspect areas. Check maximum gas exposure reading. Alarms set incorrectly. Reset alarm setpoints. Missing or faulty sensor. Replace sensor. Detector automatically shuts off. Automatic Shutdown feature activated due to weak battery. Replace battery. Unit will not auto zero or calibrate O 2 sensor reading is erratic. O 2 sensor replacement may not be compatible. Change O 2 sensor. GA-2X, GAA-2X: 2 year O 2 (#O2-A2) GA-X, GAA-X: 1 year O 2 (#O2-A1) 30

31 Replacement Parts and Accessories Replacement Parts and Accessories WWarning To avoid personal injury or damage to the detector, use only specified replacement parts. To order any parts or accessories listed in Table 13, contact BW Technologies. (See page 2.) Table 13. Replacement Parts and Accessories Model No. Description Quantity PS-RH04 Replacement H 2S sensor 1 PS-RM04 Replacement CO sensor 1 PS-RS04 Replacement SO 2 sensor 1 PS-RC10 Replacement Cl 2 sensor 1 PS-RA10 Replacement NH 3 sensor 1 Model No. Description Quantity D4-RX06 Replacement O 2 (1 Year) sensor 1 (compatible with: GA-X; GAA-X) GA-SS Sensor Screens 10 GA-TC-1 Test Cap and Hose 1 REG-0.5 Gas Regulator (0.5 L/min) 1 G0042-H25 Calibration Gas, H 2S 1 CG2-M-200 Calibration Gas, CO 1 CG2-S-25 Calibration Gas, SO 2 1 CG2-C-5 Calibration Gas, Cl 2 1 CG2-A-50 Calibration Gas, NH 3 1 CG2-Z-10 Calibration Gas, HCN 1 CG2-D-10 Calibration Gas, NO 2 1 PS-RZ10 Replacement HCN sensor 1 PS-RD04 Replacement NO 2 sensor 1 SR-X10 Replacement O 2 (2 Year) sensor (compatible with: GA-2X; GAA-2X) 1 31

32 Users Manual Specifications Operating temperature: -20 C to +50 C H 2S: -40 C to +50 C *Vibrator Alarm Models (all): -20 C to +45 C Operating humidity: 5 % to 95 % Relative humidity (non-condensing) Detection Ranges: GasAlert CO: 0 ppm 999 ppm (1 ppm increments) GasAlert H 2S: 0 ppm ppm (1 ppm increments) GasAlert SO 2: 0 ppm ppm (1 ppm increments) GasAlert Cl 2: 0 ppm - 50 ppm (0.1 ppm increments) GasAlert NH 3: 0 ppm 999 ppm (1 ppm increments) GasAlert HCN: 0 ppm - 30 ppm (0.1 ppm increments) GasAlert NO 2: 0 ppm 99.9 ppm (0.1 ppm increments) GasAlert O 2: 0 30 % (0.1% increments) Sensor type: Plug-in electrochemical cells Calibration: Automatic zero and span. Alarm Conditions: Low Alarm, TWA Alarm, High Alarm, Sensor Alarm, Low Battery Alarm, Confidence Beep, Automatic Shutdown Alarm. Visual alarm: Red light-emitting diode (LED) Display: Alpha-numeric liquid crystal display (LCD) Backlight: Automatically activates for 3 seconds whenever there is insufficient light to view the display and during alarm conditions. Any pushbutton reactivates the backlight for 6 seconds. Self-test: Initiated at activation. Calibration: Auto zero, set span, and span sensor. Battery: 3 V lithium CR2-series battery. Typical battery life: (assuming 8 hours per day of average use) Standard Models: 3 years Vibrator Alarm Models: 1 year (Note: Battery drains faster if Confidence Beep is used constantly) Intrinsic safety: Classified by UL to both U.S. and Canadian Standards as intrinsically safe for Class I, Division 1, Group A, B, C, D and Class I, Zone 0, Group IIC Cenelec EEx ia IIC Audible alarm: 90 db at 1 ft (0.3 m) variable pulsed beeper. 32