Editors Note: The following is a reprint of a letter regarding VOC testing. The letter is self-explanatory but is reprinted here as a source of information to our readers. It would be helpful for laboratories to assist in the testing as noted at the end of the letter.

July 18, 2006

Subject: Round Robin Testing of a Supplement to D 2369 for Determining the VOC of Multi-Component, High-Solids, Addition or Free-Radical Cured Resin Systems

To: ASTM D-01.21.24 (Task Group for Fast Cure Multi-Component Paints)

Cc: ASTM D-01.21 (Chemical Analysis of Paints) and D-01.46 (Industrial Protective Coatings)

From: Fred Gelfant, Chair, Task Group 21.24

Background

ASTM D 2369, Standard Test Method for Volatile Content of Coatings, and EPA's Reference Method 24 (RM 24) are cited as the compliance method in a variety of state and local air pollution regulations. At one time, the two were very similar. Over the last decade, however, the EPA has extended its recognition of appropriate test methods beyond the provisions embodied in 2369.1

There are now three glaring differences between EPA's test guidance and D 2369. D 2369 limits the sample size to 0.3 grams (as RM 24 once did), specifies that a diluent be added to the sample to ensure flow to form a uniformly thin film, and specifies the cure time at a maximum of one hour.2 EPA, on the other hand, has always allowed up to 24 hours for the cure to proceed and, as the Agency has learned more about various polymer chemistries and their application, has authorized larger sample sizes and eliminated the diluent requirement for three different polymer chemistries.

It is now clear that a much larger number of "ultra high" solids (>90% non-volatiles), multi-component, addition or free-radical polymer chemistries measure an artificially high VOC content when diluted with a solvent. These include epoxy, urethane, vinyl ester, polyester, acrylic and polyurea resins. Historically, this has not been an issue since the VOC contents of these very-high solids materials (that are neither "solventborne" nor "waterborne") are so low that even the unrepresentative, VOC measure of adulterated samples comply by a significant margin.

Issues

1. The margin of compliance of high solids, multi-component, solvent-adulterated samples will disappear on July 1 when the South Coast Air Quality Management District (SCAQMD) of California is scheduled to implement a "100 grams per liter" limit for industrial maintenance coatings.

2. D 2369 is no longer consistent with Federal guidance on testing for compliance with VOC regulations.

3. RM 24 has not yet extended the applicability of its larger sample, dilution-free, alternative test method to the additional chemistries noted above.3

Action Taken by D-01.21 (Chemical Analysis of Paints) at June Meeting

After reviewing a draft of a revised D 2369, in which instructions for VOC analysis of "ultra-high" solids had been incorporated via nine footnotes, attendees voiced concern that an analyst might find the instructions confusing. After some deliberation, it was agreed that the new material should be incorporated directly into the Procedures portion (Section 7) of D 2369 by separating it into four distinct parts. The first three would merely be a rearrangement of the existing instructions for waterborne, solventborne and multicomponent coatings. The fourth would provide instructions for "ultra-high" solids (those with > 90 % non-volatile). The fourth section will also reference those recent pronouncements by EPA for specific coatings that omit the requirement for diluent and sizes the sample in terms "representative of how the product is used," a term used by the EPA.

The new draft is expected to be complete in August. Afterward, the Task Group must determine the inter- and intra-laboratory reproducibility of the new test procedure by:

1. Identifying at least five laboratories that will participate (Assume five samples will be tested.)

2. Implementing the round robin test.

3. Presenting the rearranged D2369 for ballot approval.

Request

By this letter, Task Group 21.24b invites laboratories to volunteer their participation in a round robin study to examine the repeatability and reproducibility of the alternative test for ultra-high solids coatings. (The test, in essence is a typical D 2369 analysis but of a larger sample that is not diluted and undergoes a longer cure induction period.)

With the SCAQMD poised to make its rules more stringent and other air quality regulatory groups (including the North Central and Northeast consortiums of States and Environment Canada) considering adoption of the new rules, the need for an accurate VOC test method could increase dramatically in the near future. If your laboratory is willing to participate in the round robin, notify Jim Berry, Berry Environmental, 5021 Yadkin Drive Suite 202, Raleigh, NC 27609, JimBerryEC@aol.com, phone 919/785.9631.