The Essentials of Air Sampling

So what is an essential part of air sampling that does not include all the usual questions of Who, Where, When and What? The equipment!

The first is the sampling device, whether that may simply be a filter in a device such as the IOM sampler for dust and particulates or a sorbent tube for gases and vapours. The second is the sampling pump itself. Does it have the required Intrinsic Safety certifications, the performance requirements for the application in hand, and the necessary power to meet the required run time?

All very necessary and obvious, but what about ensuring that the flow rate is measured accurately?

This is where another essential part of the air sampling procedure comes in, the air flow calibrator and, more specifically, SKC’s chek-mate.

Most air sampling is performed under vacuum and is a volumetric flow measured in either litres per minute for aerosols or millilitres per minute for gases and vapours.

The current HSE MDHS 14/4 Gravimetric Methods for the Determination of Inhalable, Thoracic and Respirable aerosols refers to testing of sampling trains before and after sampling to a measurement uncertainty of +/- 2.5%.

With its accuracy specification of ±1% of reading and display resolution of 0.001 litre/min, or 1 ml/min, the chek-mate significantly exceeds the requirements of MDHS 14/4.

The unit displays continuous real time volumetric flow and is provided with a UKAS/NIST traceable calibration certificate.

If we look back just a couple of years, we will see that most air sampling pump calibrators whether electronic, bubble type or a Rotameter were, and most still are, stood on the bench. The reason being is that they have to be vertical to ensure accuracy and indeed, correct operation in order to work at all.

Several of these have some form of piston unit so are of large mass, which means that they need time to stabilise to room temperature, are sensitive to being moved around, and require a firm, stable base to sit on.

The SKC chek-mate is not of this type, it’s different. Being an orifice type flow meter, it is truly portable, can be held in the hand and is orientation free, so it is incredibly versatile without losing accuracy and takes significantly less time to stabilise for use.

The unit has no moving parts, so there is very little to possibly go wrong. It is very simple to use; just connect up, switch on with a press of the only button and take the readings.

The readings are displayed on a large liquid crystal display, showing a moving average and it utilises a standard 9 volt battery so does not need a mains power source.

CE and ROHS compliant, SKC chek-mate is calibration at its finest.

Contact us for further information by email or telephone: 01258 480 188