Nextteq Standard Airtec Regulator Kit - Manual (Page 22)

PACKING LIST SECTION IV:
Maintenance & Troubleshooting
22 NEXTTEQ LLC (Rev. 2) 4/09
Tips for Tube Reading
The following items will be helpful when reading and interpreting the Airtec detector
tubes.
1.) Always read the tubes and record the results immediately after testing. In some
cases stains may fade or “crawl” within a few hours.
2.) A tube may never be reused, even after a zero reading.
3.) The oil mist tube is normally used at 500 scc/min for 40 minutes. However,
reliable results can be obtained using shorter sampling periods and correcting the
reading with a multiplication factor (see below):
Test Duration
Multiply Reading By
20 minutes 2
4.) If at the end of a test you note that the stain has overshot the scale, the actual
concentration may be determined as follows:
a) Repeat the test with a new tube and observe the time required to reach the
highest calibration mark (full scale).
b) Multiply the full-scale concentration by the ratio of the recommended test
time to the actual test time.
Example
H2O tube reaches full scale (80 mg/m
3
) in 36 seconds. Recommended
time is 1 minute.
Ratio = 1 min/0.6 mins. = 1.66
Thus, the actual concentration is
80 x 1.66 = 133 mg/m
3
SECTION V: Sampling Tips