ASTM Biocide Selection


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by Fred Passman, Ph.D., BCA, Inc.,  Princeton,  NJ


If you’ve ever wondered about how biocides are chosen for particular metalworking fluids or applications.  If you’ve every tried to figure out why no single biocide is the best choice all the time.  If you seem to get conflicting advice from different biocide manufacturers, then you will find tons of useful information in ASTM’s newly released E-2169 Standard Practice for Selecting Antimicrobial Pesticides for use in Water-Miscible Metalworking Fluids.

In November 2000, during their semi-annual meeting, members of ASTM Subcommittee E.34.50, Health and Safety of Metalworking Fluids determined that the metalworking industry needed a clear concise review of the considerations involved in biocide selection and use.  Shortly thereafter, Dr. John Howell, the Subcommittee’s Chair, invited me to lead a task force chartered to create the new document.  With the able assistance of folks representing the major metalworking fluid biocide manufacturers and coolant compounders, we had a first draft prepared in time for our May, 2001 Task Force meeting.  After incorporating a few revisions, we were able to send our proposed Practice to ballot during the summer of 2001, and received Society approval in October, 2001.

Following ASTM convention, E-2169 is divided into twelve sections.  The first section “Scope” identifies what the rest of the Practice is about:

“1. Scope
            “1.1 This practice provides recommendations for selecting antimicrobial pesticides (microbicides) for use in water-miscible metalworking fluids (MWF).  It presents information regarding regulatory requirements, as well as technical factors including target microbes, efficacy and chemical compatibility.
            “1.2 This guide is not an encyclopedic compilation of all the concepts and terminology used by chemists, microbiologists, toxicologists, formulators, plant engineers and regulatory affairs specialists involved in antimicrobial pesticide selection and application.  Instead, it provides a general understanding of the selection process and its supporting considerations.”

The next two sections provide a list of references and a glossary of terms that might be unfamiliar to non-technical readers.  Except for the last section, a list of keywords, the balance of the Practice steps through the process of biocide selection.  By the way, although biocide is the tradition term used for the products designed to kill microbes, the EPA prefers replacing biocide with the more politically correct antimicrobial pesticide.  EPA argues that biocide is too general a term and may seem too threatening to employees who have to handle these products.

E-2169 steps through the process of defining your microbicide performance objectives and testing candidate product abilities to meet those objectives.  The Practice reviews registration and other regulatory issues such as hazardous material handling and disposal.  It includes a list of the 57 microbicides currently approved for use in MWF in the U.S.

This seven-page document is packed with background information that helps both technical and non-technical stakeholders understand why it’s important to match microbicides with performance needs and coolant chemistry.  It also guides readers through the product evaluation process.

Taking much of the mystery out of biocide selection and use, ASTM E-2169 is available on-line at and can be purchased from the web site directly.