SKC Limited SPLIT2 - Manual (Page 18)

18
TAG: 002 * STATS *
Date: THURS 04-NOV-99
Start: 10:57:09
Stop: 11:35:19
Statistics
Download
Cancel
Once the Tag has been selected and the ENTER button pressed
you may see a screen stating ‘SCANNING MEMORY’ for a time.
This will change to the first of 5 information screens. The first
screen shows the Start and Stop time, date and Tag number.
Press the DOWN arrow to display the next screen, which will
detail the MAXIMUM Concentration in mg/m
3 .
Press the DOWN arrow again for the next screen which will
detail the MINIMUM concentration in mg/m3. Next comes the
TWA screen followed by the STEL screen. To view a STEL the
unit must have run for at least 30 minutes.
** MAXIMUM **
Date: THURS 04-NOV-99
Time: 10:57:09
Conc: R 0.45 mg/m
3
A final press of the DOWN button will return to the STATISTICS
screen.
Downloading data to a PC:
To download the data to a PC scroll the arrow down to the
DOWNLOAD option and press the ENTER button. Make sure
the SPLIT2 is connected to the computer and follow the
instruction on screen, while referring to the SPLITCOMM
SOFTWARE users Guide provided with the instrument.
Downloading can take several minutes to complete. Please be
patient during this operation.
Statistics
Download
Cancel
DOWNLOADING TO A PC
Correction of dust concentrations for
different types of dust:
Why do we need to correct for dust type?
Light scattering instruments are calibrated to the NIOSH 0600
method using Arizona Road Dust. This type of dust is very regular
in shape and gives a good correlation for calibration purposes.
However, as different types of dust have different reflection and
defraction properties that may differ from Arizona Road Dust
the ability to correct for this difference allows the SPLIT2 to be
‘tuned’ to the type of dust your are monitoring. For example;
Wood dust has different light scattering properties than coal dust
even if the concentrations are the same.
The theory:
By collecting the dust that has passed through the sensor onto a
preweighed filter we are doing a basic calibration of the light
scattering system to a gravimetric (mass of dust) sample. Once the
monitoring exercise has finished, the filter is post weighed giving a
Time Weighted Average result in mg/m3.
This TWA is then used to correct the readings on the SPLIT2 by
entering a SCALE factor into the units software. The TWA can
also be applied to the SPLITCOMM software package to correct
the real time data and hence correct the graphic display of time
against concentration.
If this is done a number of times in the same monitoring situation.
e.g. a work process an average SCALE factor can be obtained for
that particular circumstance. Subsequently this scale factor can be
applied to similar work situations.
The COSHH regulations advise that after monitoring has been
carried out in compliance with the appropriate methodology, in
this case MDHS 14/n, (Gravimetric using a pump, IOM sampler
and filter), providing the material or the process does not change
it can be assumed exposure will remain at or around that level.
The SCALE factor system with the SPLIT2 works on the same
principle. A final note: At this time light scattering instruments
cannot be used to show compliance to Occupational Exposure
Standards in the UK.
To correct the concentration reading on the instrument to the
dust cloud in your particular circumstance the following
procedure is advised.