www.skcltd.com
770-300M Issue E
Page 25
Setting a Custom Scale Factor
The Split2 monitor is calibrated using ISO 12103-1 A2 Fine Test Dust. The different dust types
present in actual workplace locations will have different reflection and refraction properties
from those of the test dust and will therefore have different light scattering properties within
the Split2 monitor sensor head.
If sampling is to be performed regularly in the same workplace locations a custom scale
factor can be set on the Split2 monitor so that it’s reading more closely correlates with the
actual dust concentration in that environment. Note that different custom scale factors may
be required for different workplace locations.
In order to calculate a custom scale factor a sample must first be taken with the Split2 monitor
in the workplace location, along with a concurrent filter sample for gravimetric analysis.
The filter and IOM cassette must be pre and post weighed and a T.W.A. (Time Weighted
Average) concentration calculated for the filter sample.
The filter T.W.A. and the T.W.A. from the Split2 monitor review data (see page 23/24) are then
used to calculate the custom scale factor as follows -
Custom Scale Factor = Filter T.W.A. Result
Split2 T.W.A. Result
Example -
Filter T.W.A. = 5 mg/m³
Split2 T.W.A. = 4 mg/m³
Custom Scale Factor = 5 mg/m³
4 mg/m³
= 1.25
Important Note:
Applying a custom scale factor to the Split2 monitor should not be done
using only a single filter sample result. It is strongly recommended that a minimum of 10
filter samples should be undertaken and the calculated scale factors averaged to obtain a
typical scale factor for that workplace location.
To set the custom scale factor, on the main menu
screen press the up and down keys to highlight the
Special Functions menu item and press enter to show
the new screen.
Run
Review Data
Special Functions
Auto-Zero
On the Special Functions menu screen press enter to
select the System Options menu item and show the
new screen.
System Options
Date/Time
Set Alarm
Cancel
On the System Options menu screen press enter to
select the Extended Options menu item and show the
new screen.
Extended Options
Sample Rate
Erase Memory
Cancel