Gastec 138 Instructions

GASTEC
No.138
Instructions for
Methylene Chloride Detector Tube
FOR SAFE OPERATION :
Carefully read this manual and the instruction manual of your Gastec Gas Sampling Pump.
&WARNING:
1. Use only Gastec detector tubes in a Gastec pump.
2. Do not interchange or use non-Gastec parts or components in Gastec's detector tube and
pump system.
3. Using non-Gastec parts or components in Gastec's detector tube and pump system or using
a non-Gastec detector tube with a Gastec pump or using a Gastec detector tube with a non-
Gastec pump may damage your detector tube and pump system, or may cause serious
injuries, or death to the end-user. It will also void all warranties, and guarantees regarding
performance and data accuracy.
&
CAUTION : If you do not observe the following precautions, you may
suffer injuries or damage the product.
1. When breaking the tube ends, keep away from eyes.
2. Do not touch the broken glass tubes, broken pieces and reagent with bare hand(s).
3. The sampling time represents the time necessary to draw the air sample through the tube.
The tube must be positioned in the desired sampling area for the entire sampling time or until
the flow finish indicator indicates the end of the sampling.
6.NOTES : For maintaining performance and reliability of the test
results, observe the following.
1. Use Gastec Gas Sampling Pump together with Gastec Detector Tubes only for the purposes
specified in the instruction manual of the detector tube.
2. Use this tube within the temperature range of 0 - 40°C (32 - 104°F).
3. Use this tube within the relative humidity range of 0 - 90%.
4. This tube may be interfered with by the coexisting gases. Please refer to the table
"INTERFERENCES" below.
5. If this tube is exposed under the direct sunlight, the reagent of the tube may be turned to pale
yellow, however, this colour change does not affect the tube reading.
6. The shelf life and storage condition of the tube are marked on the label of the tube box.
APPLICATION OF THE TUBE :
Use this tube for detecting Methylene Chloride in the air or in industrial areas and for
determining the environmental atmospheric condition.
SPECIFICATION:
(Because of Gastec's commitment to continued improvement, specifications are subject to
change without notice.)
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Detecting Layer
Measurinq Ranae 30-50 ppm 50-500 ppm
Number of Pump Stroke
2 1
Stroke Correction Factor
0.6
1
SamplinQ Time
3 minutes per pump stroke
Detectina Limit 10 ppm (n=2)
Colour Chanae
White
-+
Pale pink
CH2Cl2
+
CrO3
+
H2S2O7
-+
Cl2
Reaction Principle
Cl2
+
3 3' 5 5'-Tetramethvlbenzidine
-+
Holoauinone
Coefficient of Variation: 15% (for 50 to 100 ppm), 10% (for 100 to 500 ppm)
**Shelf Life : Please refer to the validity date printed on the tube box.
**Store the tubes in a dark and cool place
CORRECTION FOR TEMPERATURE, HUMIDITY AND PRESSURE:
Temperature : Correct for temperature with the table below.
Temperature °C(°F)
0 5 10 15 20 25 30 35 40
(32) (41) (50) (59) (68) (77) (86) (95) (104)
Correction Factor 2.5* 2.0* 1.6* 1.2 1.0 0.9 0.8 0.7 0.6
*If the value of the Tube Reading multiplied by the Temperature Correction Factor is higher
than 700ppm a measurement cannot be performed.
Humidity : No correction is required between 0 - 90% R.H.
Pressure :
To correct for pressure, use the formula below.
Tube Reading* (ppm)
x
1013 (hPa)
Atmospheric Pressure (hPa)
*
This value is after other correction(s), if any, are applied.
MEASUREMENT PROCEDURE:
1. For checking the leakage of the pump, insert a freshly sealed detector tube into the pump.
Follow the instructions provided with the pump operation manual.
2. Break the tips off the fresh primary tube and analyser tube by snapping off each tube end in
the tube tip breaker of the pump.
3. Connect the© marked ends with rubber tubing after snapping off each end.
4. Insert the analyser tube securely into pump inlet with the arrow ( G► ) on the tube pointing
toward the pump.
5. Make certain the pump handle is all the way in. Align the guide marks on the pump body with
the guide marks on the handle.
6. Pull the handle all the way out until it locks at one pump stroke (100 ml). Wait three minutes
and confirm the completion of the sampling.