SKC Limited AirChek 3000 Deluxe Pump Step By Step Guide - Manual (Page 3)

www.skcltd.com 224-G1 Issue D Page 1
What is air sampling?
What is air sampling?
Put simply, air sampling is capturing the
contaminant from a known volume of air,
measuring the amount of contaminant
captured, and expressing it as a concentration.
The air is passed through a filter medium
(normally a paper for solid contaminants and
a sorbent for gases). The volume of air is
measured against the amount of contaminant captured. This gives the concentration, which
is expressed either as milligrams per cubic
metre (mg/m
3 ) or parts per million (ppm).
The volume of air is calculated by multiplying
the flow rate through the filter medium by the
time in minutes. Calibration of the flow rate is
important and should be carried out before
and after each sample is taken.
How is it done?
There are many different methods of taking
air samples, but by far the most widely used
and preferred is to connect a battery operated
pump to a filter medium. The pump should be
capable of drawing air through the filter at a
constant rate for a time in excess of 8 hours,
even in adverse conditions such as extreme
cold.
This
criteria is based around the
recommendations that samples should be
taken on a personal basis for an 8 hour Time
Weighted Average (TWA). Other types of
sampling, notably the Short Term Exposure
Limit (STEL) present no problems for the pump
sampler.
It is also worth remembering that a sample by
definition is a very small part of the whole. For
example: taking one or two parts from a batch
of one hundred and checking them does not
necessarily mean that the other ninety eight
parts will be the same. Do not assume that a
result from your air sample is exactly what is in
the atmosphere all the time.
30cm
Diameter
Breathing
Zone
I.O.M.
Sampler
Sample
Pump