ASTM E2275 – Metalworking Fluid Test

ASTM E2275 is a standard practice for evaluating water-miscible metalworking fluid bioresistance and antimicrobial preservative performance.

Metal Working Fluids (MWF) are regularly used in challenging environments and are often exposed to significant microbial populations. Untreated or untested, MWF’s ability to function properly can be compromised by microbial contamination.  ASTM E2275 is also used to determine the overall effectiveness of a biocidal formulation used in metalworking fluids.

A variety of issues can affect Metal Working Fluids; balancing the ability of a formulation to resist biological contamination while maintaining overall performance and cost is key.

The ASTM E2275 test method can be used for a quick kill and long-term preservation studies.  Quick kill studies are generally 48 hours and Preservation Challenge studies are generally a 4-week assessment. Results provide important data about antimicrobial efficacy during product development and can help manufacturers select an effective antimicrobial preservative concentration.

Although standard preservation testing is 4 weeks, many customers request a 3 month testing period or test their formulations until failure to determine when a formulation can no longer resist microbial contamination.

Testing Options

  • Preservation: Preservation Test for antimicrobial performance tests an additive generally over the course of 12 weeks. As with similar preservation testing, the additive in the MWF is subjected to a range of contamination until it no longer functions effectively. This approach is most commonly requested.  Customers commonly request a month to month analysis and testing can be terminated at a specific time or upon failure.
  • Bioresistance: Used for water-miscible metalworking fluids, the bioresistance option of the ASTM E2275 MWF test series provides data showing how the antimicrobial additive works over a course of 12 days. A range of mixed inoculum can be used to determine bioresistance.
  • Biocidal: Used for water-miscible metalworking fluids, the biocidal or ‘quick kill’ option provides laboratory procedures for evaluating microbicide performance. The standard biocidal test range is 5 days and the biocidal option can be used for fresh, aged, single and/or multi-dosed MWF.

For more information about ASTM E2275 and Performance testing, contact our antimicrobial lab at 847-483-9950 or