Calibration / Recalibration
DIGIT
AL
INCLINOMETER
DIGIT
AL
INCLINOMETER
30.0
-30.0
Side B (R
2
)
Side A (R
1
)
Angle
- Negative
+ Positive
O
Angle
O
Figure 9 Reference Inclinometer Calibration
Recalibration
Recalibrate the probe either within 12 months of its first field use after its most recent calibration or
after 10 field tests, whichever occurs later. In addition, whenever there is visible damage to the probe
head, the probe shall be recalibrated before it is used again.
Calibration
Calibration of inclinometers pressure measuring devices, transducers and process meters/display are
required before initial use in the field.
To calibrate the inclinometer system, secure a calibration triangular block in a fixed position. Place the
inclinometer on one side of the block (side A) to measure the angle of inclination (R1). Repeat this
measurement on the adjacent side of the block (side B) using the inclinometer to obtain a second
angle reading (R2). The difference of the sum of the two readings shall be within ±2° of the known
angle.
Calibrate each pressure measuring device (except those used exclusively for yaw nulling) using the
three-point calibration procedure described in section 10.3.3 of US EPA Method 2F. The device shall
be recalibrated according to the procedure in section 10.3.3 no later than 90 days after its first field
use following its most recent calibration. At the discretion of the tester, more frequent calibrations
(e.g., after a field test) may be performed. No adjustments, other than adjustments to the zero setting,
shall be made to the device between calibrations. A single-point calibration check shall be performed
on each pressure-measuring device after completion of each field test. At the discretion of the tester,
more frequent single-point calibration checks (e.g., after one or more field test runs) may be
performed. It is recommended that the post-test check be performed before leaving the field test site.
The check shall be performed at a pressure between 50 and 90 percent of upper scale by taking a
common pressure reading with the tested probe and a reference pressure measuring device.
At each pressure setting, the readings made must agree to within ± 2% of full scale of the device
being calibrated or 0.5mm H2O (0.02in H2O), whichever is less restrictive. Differential pressure
devices not meeting this requirement shall not be used.
180
°
- |R
1
+ R
2
| = +/-2
°
120
°
Revision:01 Page 13 of 23 9/26/2017