DS EN 50267-2-3:1998 Common Test Methods For Cables Under Fire Conditions - Tests On Gases Evolved During Combustion Of Material From Cables - Part 2: Procedures - Section 3: Determination Of Degree Of Acidity Of Gases For Cables By Determination Of The Weighted Average Of Ph And Conductivity Defines the test method and procedure for the determination of the degree of acidity of gases evolved during the combustion of electric or optical cables by determination of the weighted average of pH