EPA Method 24: Determination of Volatile Organic Compound (VOC) content in Paints, Inks, and Related Coating Products

What is EPA Method 24 testing?

EPA method 24 is the only method currently accepted by EPA and U.S. state/local regulatory bodies for the measurement of volatile organic compound (VOC) content in paints, inks, and related coating products.  This method however is known and documented to have large measurement errors especially with coating with VOCs below 50g/L.  The major sources of VOC error were found to be in the water and non-volatile determinations.  This is shown in an article published in the Journal of Coatings Technology “Sources of Error in VOC Determination via EPA Method 24”. Due to this level of error, different methods for determining VOC directly by Gas Chromatography (GC) are currently being pursued, such as ASTM D6886 and SCAQMD method 313.

What are volatile organic compounds?

According to 40 CFR 51.1000, volatile organic compounds refer to any compound of carbon which participates in atmospheric photochemical reactions. However, this definition excludes carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates and ammonium carbonate.

A list of the exempt solvents are found in the CFR, including some popular coating solvents such as acetone, t-butyl acetate, dimethyl carbonate, propylene carbonate, parachlorobenzotrifluoride (Oxol 100), methyl acetate, methylene chloride, and most recently 2-amino-2-methyl-1-propanol (AMP-95).

Which industries and companies need EPA 24 testing?

EPA 24 is used by many manufacturing industries for reporting emissions of coating and related products to local regulatory bodies, with some of the most common being the CASE industries (coatings, adhesives, sealants, and elastomers).  This would include both coating manufacturers and coating operations, such as automotive, appliance, furniture and can lining manufacturers. The coating operation industry is subject to emission controls which can range from 0.4 #/gal to as much as 5.5#/gal and are advised to consult the state or local regulations for details of such limits.

Different variations of EPA Method 24

While at times the EPA Method 24 may appear to be simple, there are many different tests that cover the large array of sample types. For this reason, it is very important to know your sample type and application to assure the correct testing is being performed to suit your needs. Typically, the VOC is reported as mass of VOC per Unit Volume of coating less water and exempt solvents; however, in some cases it needs to be reported out at mass of VOC per unit volume of coating solids which requires additional volume solids testing as shown below.

VOC content expressed as the Mass of VOC per Unit Volume of Coating Less Water and Exempt solvents (pound per gallon or grams per liter)

• ASTM Practice D3960 - Standard Practice for Determining Volatile Organic Compound (VOC) Content of Paints and related coatings.
• ASTM D 1475 - Standard Test Method for Density of Paint, Varnish, Lacquer, and Related Products
• ASTM D 2369 - Standard Test Method for Volatile Content of Coatings
• ASTM D 3792 - Standard Test Method for Water Content of Water Reducible Paints by Direct Injection into a Gas Chromatograph.
• ASTM D 4017 - Standard Test Method for Water in Paints and Paint Materials by the Karl Fischer Titration Method.
• ASTM D 4457 - Standard Test Method for Determination of Dichloromethane and 1,1,1-Trichloroethane in Paints and Coatings by Direct Injection into a Gas Chromatograph
• ASTM D5095 - Standard Test Method for Volatile Content of Silanes, Siloxanes, and Silane-Siloxane blends
• ASTM D 5200 - Standard Test Method of Volatile Content  of Solvent-borne Aerosol Paints
• ASTM D 5325 - Standard Test Method of Volatile Content  of Water-Borne Aerosol Paint

VOC content expressed as the mass of VOC per unit Volume of Coating Solids

• ASTM D 2697 - Standard Test Method for Volume Nonvolatile Matter of Clear or Pigmented Coatings