No.1D
Instructions for
Carbon Monoxide Passive Dosi-Tube
FOR SAFE OPERATION :
Carefully read this manual before use.
⚠
CAUTION : If not observed, injuries to the operator or damage to the
product may result.
1. When breaking the Passive Dosi-Tube, keep the tube away from eyes.
2. Do not touch any broken glass tubes, pieces and reagents with bare hand(s).
3. Keep tubes out of Direct Sunlight, which fades the discolouration of the tube.
△
NOTES : For maintaining performance and reliability of the test
results.
1. Use this tube within the temperature range of 0 - 40
℃
(32 - 104
℉
).
2. Use this tube within the relative humidity range of 0 - 90%.
3. This tube may be interfered with by coexisting gases. Please refer to the “INTERFERENCES”.
4. The shelf life and storage condition of the Passive Dosi-tube are marked on the label of the
tube box.
APPLICATION OF THE TUBE :
Use this tube for detecting Carbon monoxide in the air or the industrial areas and
environmental atmospheric condition.
SPECIFICATION :
(As a result of Gastec’s commitment to continued improvement, specifications are subject to
change without notice.)
This tube measures TWA (time-weighted average) gas concentration by utilizing natural
diffusion of the target gas without a gas sampling pump.
Measuring Range
1.04 – 2000 ppm
Sampling Hours
0.5 – 48 hours
Detecting Limit
2 ppm (10 hours)
Colour Change
Pale Yellow
→
Brown
Reaction Principle
CO
＋
Na
2
Pd (SO
3
)
2
→
Pd
＋
CO
2
＋
SO
2
＋
Na
2
SO
3
Coefficient of Variation: 10% (for 50 to 1000 ppm·hr)
**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 :
No correction is required.
Humidity :
No correction is required.
Pressure :
No correction is required.
MEASUREMENT PROCEDURE :
1. Break a Dosi-tube at the breaking line of the tube by the optional Passive Dosi-Tube Holder
No.710.
2. Set the Dosi-tube into the tube holder firmly so the broken tip doesn’t appear from the edge of
the tube holder. Record the measurement starting time on a peel-off numbered label supplied
with each box of the tubes and put the label on the Dosi-tube in the tube holder.
3. Clip the tube holder to the clothing (e.g. shirt collar) for personal sampling or place the Dosi-
tube in the workplace where the measurement is required. When the sampling is finished,
record the measurement finishing time on the label on the Dosi-tube.
4. Average gas concentration can be obtained from half an hour to 48 hours sampling.
Calculate the actual sampling time and the average gas concentration can be obtained by the
following formula:
Average Concentration =
Dosi-Tube Reading (ppm
·
hour)
Actual Sampling Time (hours)
5. To protect the tube holder at the shirt collar from dropping during operation, it is advisable to
support the tube holder with a string through the small hole of the tube holder.
INTERFERENCES :
Substance
Concentration Interference
Interference gas only
Chlorine
No
No discolouration
Nitrogen dioxide
≧
5 ppm
−
No discolouration
Hydrogen sulphide
+
Reddish brown
The table of the interference gases primarily expresses the interference of each coexisting
gas in the gas concentration range that is equivalent to the target gas concentration.
Therefore, the test result may be affected by other substances not listed in the table.
For more information, please contact us or your Gastec representatives.
DANGEROUS AND HAZARDOUS PROPERTIES :
Threshold Limit Value-Time Weighted Average by ACGIH (2014) : 25 ppm
Explosive Range : 12.5 – 74 %
G PASSIVE DOSI-TUBE
GASTEC
G
②
③
①
Detecting Layer
Breaking Line
50
100
200
300
400
600
800
1000
ppm
･
hr
1D
