ASTM D2112-15 (2023) PDF

Full title and description

ASTM D2112 − 15 (Reapproved 2023) — Standard Test Method for Oxidation Stability of Inhibited Mineral Insulating Oil by Pressure Vessel. This procedure defines an accelerated, controlled test to evaluate the oxidation stability (induction period of oxidation inhibitors) of new mineral insulating oils that contain synthetic antioxidant inhibitors, using a rotating pressure vessel with oxygen, a copper catalyst coil, and water at elevated temperature.

Abstract

This test method provides a rapid, repeatable laboratory procedure to assess the continuity of oxidation-inhibitor performance in inhibited mineral insulating oils. The method measures the time to oxidation under accelerated conditions (elevated temperature, oxygen pressure, catalyst and agitation) and is intended primarily for quality control and batch-to-batch consistency checks rather than as a direct predictor of field life.

General information

• Status: Published — current edition reapproved 2023 (active).
• Publication date: Current edition approved December 1, 2023 (published December 2023).
• Publisher: ASTM International.
• ICS / categories: 29.040.10 — Insulating oils; Committee D27 (Electrical Insulating Liquids and Gases).
• Edition / version: D2112-15 (Reapproved 2023).
• Number of pages: 6 pages.

Scope

The method is intended as a rapid procedure for evaluating the oxidation stability of new mineral insulating oils that contain synthetic oxidation inhibitors (for example, 2,6-ditertiary-butyl para-cresol or 2,6-ditertiary-butyl phenol). Test conditions are accelerated (elevated temperature, oxygen pressure, agitation and a copper catalyst in the vessel) to determine an induction period. The procedure is primarily intended for checking continuity of oxidation stability from shipment to shipment. Applicability to inhibited oils with viscosity greater than about 12 cSt at 40 °C is not established. The test is not proven to directly predict field performance, and safety precautions for oxygen and high-temperature operation must be observed.

Key topics and requirements

• Purpose: determine induction period / oxidation stability of inhibited mineral insulating oils under accelerated conditions.
• Test apparatus: rotating pressure vessel (stainless steel or copper body), glass test specimen container, copper catalyst coil, pressure gauge/transducer, bath and agitation system.
• Typical test conditions: sample mass ~50 g, added water (5 mL), rotation at ~100 rpm at 30° angle, initial oxygen pressure ≈ 620 kPa (90 psi), bath temperature 140 °C.
• Key reagents/materials: high-purity oxygen (≥99.5%), copper wire catalyst (AWG No. 14, 99.9% Cu), specified solvents/cleaning reagents.
• Measurement/endpoint: time until prescribed pressure/indicator changes (induction period) that signify oxidation under the test conditions.
• Limitations: accelerated lab test — limited correlation with in-service life; not validated for higher-viscosity inhibited oils.
• Safety: warnings regarding the use of pressurized oxygen at elevated temperature and need for appropriate controls.

Typical use and users

Used by oil testing laboratories, transformer and electrical equipment manufacturers, utilities, lubricant producers and quality-control groups to check batch-to-batch consistency of antioxidant performance in mineral insulating oils. Also used by specifications authors and procurement teams when verifying supplier conformity and by research groups comparing inhibited oil formulations in accelerated oxidation screening.

Related standards

Standards commonly referenced alongside or related to D2112 include ASTM D2272 (modified rotating pressure vessel procedure at a higher temperature), ASTM D2440 (oxidation stability of mineral insulating oil), ASTM D3487 (specification for mineral insulating oil used in electrical apparatus), ASTM D117 (guide for sampling/test methods for insulating liquids), and newer specifications addressing less-flammable and rerefined insulating liquids. D2112 is maintained under ASTM Committee D27 (Electrical Insulating Liquids and Gases).

Keywords

oxidation stability, inhibited mineral insulating oil, pressure vessel, rotating vessel, induction period, transformer oil, antioxidant, copper catalyst, accelerated oxidation test, ASTM D2112

FAQ

Q: What is this standard?

A: ASTM D2112 − 15 (Reapproved 2023) is a standardized laboratory test method for assessing the oxidation stability (induction period) of mineral insulating oils that contain synthetic antioxidants using a pressurized, rotating vessel.

Q: What does it cover?

A: It covers apparatus, reagents, specimen preparation, test conditions (oxygen pressure, temperature, agitation), procedure and reporting for a rapid, accelerated evaluation of inhibited mineral insulating oils. It specifies typical test conditions (e.g., 140 °C, ~620 kPa O2, 100 rpm) and notes limitations for higher-viscosity oils.

Q: Who typically uses it?

A: Oil test laboratories, transformer manufacturers, utilities, lubricant producers, standards authors and procurement/quality teams use this method for quality control, acceptance testing and comparative screening of antioxidant performance.

Q: Is it current or superseded?

A: The standard is current in its reapproved 2023 edition (designation D2112-15 with reapproval in 2023). Users should check for any subsequent revisions or active work items that may update apparatus details or test parameters.

Q: Is it part of a series?

A: Yes. D2112 sits within the ASTM D27 series (Electrical Insulating Liquids and Gases) and is commonly used alongside related methods and specifications such as D2272 (related rotating pressure vessel test variant), D2440, D3487 and other D27 committee documents.

Q: What are the key keywords?

A: Oxidation stability, inhibited mineral insulating oil, pressure vessel, rotating vessel, induction period, transformer oil, antioxidant, copper catalyst, accelerated test.