Heath Consultants Odorator - Manual (Page 22)

Appendix C
13
Elevation Corrections for the Methane ODORATOR
The methane ODORATOR mixes air with natural gas to allow the user to
determine the percent gas level at which odorant is readily detectable. As
elevation is increased or decreased, the air density changes and must be
accounted for. Use the Elevation Change Correction Chart as follows:
1. Use the ODORATOR to determine the readily detectable level per
the instructions in this manual.
2. Write down the readily detectable reading from the LCD on the
ODORATOR.
3. Write down the elevation at which the ODORATOR was last
calibrated as found on the label on the inside of the exhaust port
cover.
4. Determine the elevation at which the reading was taken.
5. Subtract the calibration elevation from the reading elevation and
round off to the nearest 1000’.
6. Positive elevation differences correspond to the “UP” columns in
the chart while negative elevation differences correspond to the
“DOWN” colunms. Determine which elevation change correction
chart column to be used.
7. Use the ODORATOR reading and either look up the actual % gas
value from the chosen column or interpolate the actual % gas value
for the readings between the values on the chart and write the actual
% gas value down.
Interpolation Example 1: UP Column
An ODORATOR reading of .23 is taken at 3000’. The calibration elevation
is 50’ so the elevation difference is 3000 - 50 = 2950, which is rounded
off to 3000’. The difference is positive so the UP 3000 correction column
will be used.
A reading of .23 lies between chart readings of .20 and .30. This reading
also lies between actual values of .19 and .28 using the UP 3000 correction
column.