Heath Consultants Odorator User Manual

Page 23

Appendix C

The reading as a percentage between the adjacent chart readings can be

used to determine the actual value using the same percentage between

chart actuals.

The reading of .23 is 30% of the difference in the chart higher reading from

the chart lower reading. The lower chart reading and actual will be used as

the base or reference.

.23 - .20

.3 or 30%

.30 - .20

Therefore the actual value will be 30% of the difference in the chart higher

actual from the chart lower actual. Again, the lower value will be the base

or reference.

30% of (.28 - .19) = .3 x .09 = .027 which is rounded off to .03

Since the actual value base is .19, the actual value will be .19 + .03 = .22% gas.

Interpolation Example 2: DOWN Column

An ODORATOR reading of .23 is taken at 2700’. The calibration elevation is

5500’ so the elevation difference is 2700-5500 = -2800 which is rounded of to

-3000’. The difference is negative so the DOWN 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 .15 and .22 using the DOWN 3000 cor-

rection column.