Volatile Oraganics Compounds Emissions in Captured Stream – USEPA Method 204B

USEPA Method 204B is used for the determination of the volatile organic compounds (VOC) content of captured gas streams.  It is used in the development of a gas/gas protocol for determining VOC capture efficiency (CE) for surface coating and printing operations.
 
A CE test consists of at least three sampling runs.  Each run covers at least one complete production cycle, but is at least 3 hours long.  The sampling time for each run need not exceed 8 hours, even if the production cycle is not completed.  Alternative sampling times are used with the approval of the Administrator.
 
A gas sample is extracted from the source though a heated sample line and, if necessary, a glass fiber filter to a flame ionization analyzer (FIA).
 
The amount of VOC captured (G) is calculated as the sum of the products of the VOC content (C_Gj), the flow rate (Q_Gj), and the sample time (Ø_C) from each captured emissions point.
 
The procedure is not acceptable in certain site-specific situations:

• if direct-fired heaters or other circumstances that affect the quantity of VOC at the control device inlet;
• if particulate organic aerosols are formed in the process and are present in the captured emissions.