Appendix A - Scaling; Introduction; Scaling Procedure - Pentair GOYEN MECAIR PEM Manual

APPENDIX A – SCALING
A.1 INTRODUCTION
The readings from a PEM sensor can be scaled to show the dust concentration in mg/m³. The sensor readings are scaled
with reference to an isokinetic extractive sample, carried out to standards defined by your local environmental authority
or government agency.
NOTE: Scaling of each sensor is necessary on an annual basis as a minimum and should be carried out either by
Goyen | Mecair or an authorized representative.
The Scaling procedure is carried out to calculate a Scaling Factor used to multiply the raw sensor readings into a true
dust concentration directly in mg/m³. The use of a simple scaling factor is possible since the response of the instrument is
directly proportional to the dust concentration over a predefined range.
CALCULATING THE SCALING FACTOR
The basic method to calculate a new Scaling Factor (SF) a sensor uses the following formula:
New SF = Current SF × (Test Result/Sensor Average)
where
• The is the result obtained from a single stack emission test.
Test Result
• The
Current Scaling Factor
• The is the average of the readings displayed using the
Sensor Average
Example:
• Sampling test result =
• Current Scaling Factor setting = 2.5
• Instrument average =
• New Scaling Factor =
A.2 SCALING PROCEDURE
To obtain a valid, new Scaling Factor, carry out the following procedure:
1. Ensure that the sensor is running correctly and that the plant is running normally with representative conditions.
2. Record the sensor's Display Smoothing [DISP] setting, then change the DISP setting to match the length of the
sampling run to be carried out (in seconds; see section 7.4.1 on page 18 for details).
3. Record the current Scaling Factor.
4. Carry out an isokinetic test. At the end of the isokinetic test immediately record the sensor average from the display of
the sensor ('Sensor Average').
5. Reset the Display Smoothing [DISP] setting (as noted in step 2; the default is 0005 = 5 seconds).
6. Obtain the isokinetic sampling result ('Test Result'; usually available in 2–4 weeks).
7. Calculate the new Scaling Factor (see box above).
8. Enter the new Scaling Factor (see section 7.5.1 on page 18 for details).
INSTALLATION AND OPERATION MANUAL – OWNER'S RECORD PEM MANUAL – PARTICULATE EMISSION MONITOR
is the SF entered into the instrument at the time of sampling. (The default setting is 1.0.)
50 mg/m³
20 units
2.5 × (50/20) = 6.25
Current Scaling Factor
.
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