ISO 20843:2003 specifies a test method to determine the pH value of non-flammable fluids within categories HFAE, HFAS and HFC, as classified in ISO 6743-4:1999.
BS ISO 20843:2003 history
2003BS ISO 20843:2003 Petroleum and related products - Determination of pH of fire-resistant fluids within categories HFAE, HFAS and HFC