EPA Method 2: Isokinetic Air Emission Testing

EPA Method 2 is for the determination of the average velocity and volumetric flow rate of a gas stream. This method employs the principals of EPA Method 1 in selecting an appropriate measurement location and determining the minimum number of measurement points to provide reliable velocity and volumetric flow rate determination. This method is not suitable for cyclonic or swirling gas streams as identified in EPA Method 1.

Determining the flue gas velocity and volumetric flow rate are necessary components to determine isokinetic sample rates and also to determine mass emission rates of air pollutant emissions from regulated sources. The measured velocity and calculated volumetric flow rate are also useful tools when designing and sizing control devices, as well as performing engineering studies.

Having an understanding of the purpose and motives establishes a base to comprehend the why and what’s of the procedures in the EPA Method 2. The desired objective is to relate the knowledge of the method to practical application in actual measurements. Initial discussion in this lesson will provide background information for EPA Method 2. The balance of the discussion is a step by step field procedures to be performed in actual application.

Some material of Method 2 is incorporated by reference from other methods. To obtain reliable results, persons using this method should have a thorough knowledge of at least Method 1. Method 2 is not applicable at measurement sites that fail to meet the criteria of Method 1. EPA Method 2 can be utilized for most gas flue streams. Experienced individuals can apply the knowledge and experience of this method to other reference methods such as EPA Method 2A, 2C, 2D, 2F, 2G, and 2H.