The two reference immersion oils described in this practice are required for the development of oil-resistant rubber compounds for use in environments where contact with petroleum-based solvents and oils is encountered. Tests for tensile strength, percent elongation at break, hardness, and percent volume swell are performed after a specified immersion time period (at a specified temperature) in the evaluation of oil-resistant rubbers. The results of such testing by rubber product manufacturers and their customers are used to develop oil-resistant rubbers or compounds, or both.

Testing with ASTM Oils No. 2 and No. 3 is used to verify compliance with purchase specifications which reference the oil-resistant classes of rubbers and elastomers listed in Table 6 of Classification D 2000. These oils are also used in comparative performance evaluation testing of O-rings and O-ring compounds as cited in Test Methods D 1414. The use of these reference oils is required for the development and selection of oil-resistant rubber compounds having acceptable or optimum performance characteristics, or both.

1.1 This practice covers two new immersion oils to be used as replacements for ASTM No. 2 and No. 3 immersion oils as called for in Test Method D 471. The new immersion oils will be designated as IRM 902 as a replacement for ASTM No. 2 oil and IRM 903 as a replacement for ASTM No. 3 oil. The new reference oils have been developed under a new committee D-11 policy on reference materials (see practice D 4678 for background on the new policy and procedures).

1.2 The new oils, IRM 902 and IRM 903, are similar but not fully equivalent to ASTM No. 2 and ASTM No. 3 oil, respectively.

1.3 This practice gives the necessary background and details on the changeover from the previous oils to the new oils. See Annex A1 for additional information on the commercial oils selected to replace the two ASTM oils and the test program conducted for this selection process. The changeover from ASTM to IRM oils is proposed in two steps:

1.3.1 Step 1—A transition phase that makes use of the Equivalent Volume Swell (EVS) for each of the two replacement oils. EVS(902) is the ASTM No. 2 percent volume swell value calculated from the measured percent volume swell value using IRM 902 as the immersion liquid. A similar calculation can be used to calculate the analogous EVS(903) value. Either EVS value is obtained as a correction of the measured IRM 902 or 903 percent volume swell value. The EVS values may be used to determine if volume swell specifications are met when the specifications are expressed in terms of ASTM No. 2 or No. 3 limits and

1.3.2 Step 2— A longer term policy change or conversion of specifications from ASTM No. 2 and No. 3 values to IRM 902 and 903 values.

1.4 The EVS values are calculated on the basis of "correction equations" derived from one of two sources.

1.4.1 Correction equations derived from the results of the comprehensive evaluation program conducted to select each of the two replacement oils from a group of three candidate oils for each ASTM oil. This program is described in Annex A1.

1.4.2 Correction equations derived from in-house customized or specific testing programs to make direct comparisons of the volume swell (and other important properties) of the two IRM and ASTM oils. These programs should be conducted in each laboratory of those organizations that engage in producer-user specification testing for rubber immersion performance.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.