Method 4 : Determination of Moisture Content in Stack Gases

In this method, a gas sample is extracted at a constant rate from the source; moisture is removed from the sample stream and determined either volumetrically or gravimetrically.

The method contains two possible procedures: a reference method and an approximation method.

The required equipment is shown in the table below.

Type of sampling →
Equipment ↓
Reference Method Approximation Method
Probe Stainless steel or glass tubing, sufficiently heated to prevent water condensation, and equipped with a filter, either in-stack or heated out-of-stack to remove particulate matter.
Condenser As required in Method 5 Two midget impingers, each with 30-ml capacity, or equivalent.
Cooling Systems An ice bath container, crushed ice, and water (or equivalent), to aid in condensing moisture.
Drying Tube - Tube packed with new or regenerated 6- to 16-mesh indicating-type silica gel (or equivalent desiccant), to dry the sample gas and to protect the meter and pump.
Pump - Leak-free, diaphragm type, or equivalent, to pull the gas sample through the train.
Volume Meter - Dry gas meter, sufficiently accurate to measure the sample volume to within 2 percent, and calibrated over the range of flow rates and conditions actually encountered during sampling.
Flow rate Meter - To measure the flow range from 0 to 3 liters/min
Vacuum Gauge - to be used for the sampling leak check.
Flow rate Meter - To measure the flow range from 0 to 3 liters/min
Barometer - -
Graduated Cylinder - -

We manufacture and / or supply all equipment required for implementation of Method 4 and much more.