ASTM D3945-93 PDF

Full title and description

St ASTM D3945-93 — Standard Test Methods for Shear Stability of Polymer-Containing Fluids Using a Diesel Injector Nozzle. Test methods that evaluate percent viscosity loss of polymer-thickened lubricants caused by mechanical shear at a diesel injector nozzle; includes two apparatus procedures (Procedure A: European diesel injector apparatus; Procedure B: Fuel Injector Shear Stability Test, FISST).

Abstract

ASTM D3945-93 specifies two diesel-injector-based procedures for measuring the shear stability of polymer-containing fluids by determining percent loss in kinematic viscosity at 100 °C after exposure to nozzle shear. The measured viscosity loss is used as an index of polymer degradation under high‑shear conditions representative of fuel-injection and other high‑pressure orifices. The standard documents apparatus, calibration, test cycles, and reporting conventions, and identifies limitations and comparability issues between procedures.

General information

• Status: Withdrawn (1998); procedures later published as separate test methods.
• Publication date: January 1, 1993 (designation D3945-93).
• Publisher: ASTM International (American Society for Testing and Materials).
• ICS / categories: 75.100 (Lubricants, industrial oils and related products) / Petroleum products and lubricants testing.
• Edition / version: 1993 edition (D3945-93).
• Number of pages: 11 pages (standard test method document).

Scope

The standard covers two diesel injector nozzle apparatus procedures to evaluate shear stability of polymer-containing fluids by measuring percent viscosity loss at 100 °C. Procedure A uses European diesel injector test equipment; Procedure B uses FISST (Fuel Injector Shear Stability Test) equipment. The results reflect polymer degradation due to nozzle shear and are intended for laboratory comparison and quality-control purposes rather than to predict every field outcome.

Key topics and requirements

• Measurement endpoint: percent loss of kinematic viscosity at 100 °C (viscosity loss % = (KVinitial − KVfinal) / KVinitial × 100).
• Two apparatus/procedures: Procedure A (European diesel injector apparatus) and Procedure B (FISST nozzle apparatus).
• Defined test cycles, sample handling, and viscosity measurement references (viscometry per ASTM D445 or equivalent).
• Calibration and apparatus severity considerations; acknowledgement that procedures may produce different results and are not directly interchangeable without correlation.
• Statements of limitations and safety responsibilities for laboratory use.
• Reporting conventions (single determinations, test conditions, and percent viscosity loss).

Typical use and users

Used by lubricant formulators, additive manufacturers, engine and component developers, independent test laboratories, and quality‑control groups to assess the shear sensitivity of polymer-thickened oils (multigrade engine oils, hydraulic fluids, and other polymer-containing lubricants). Typical applications include R&D screening, batch quality checks, comparative performance testing, and specification support where nozzle-shear degradation is a concern.

Related standards

Closely related or successor standards and referenced methods include ASTM D2603 (sonic shear stability methods), ASTM D5275 (FISST, originally published as Procedure B of D3945), ASTM D6278 (European diesel injector apparatus procedure, later developed separately), ASTM D445 (kinematic viscosity measurement), CEC L-14 and related CEC procedures, and various ISO/DIN methods that address viscosity loss and shear stability of polymer-containing lubricants.

Keywords

shear stability; viscosity loss; diesel injector nozzle; polymer-containing fluids; FISST; European diesel injector method; lubricant testing; VI improvers; kinematic viscosity; nozzle shear.

FAQ

Q: What is this standard?

A: ASTM D3945-93 is a test method that defines two diesel-injector-based procedures for measuring the shear stability of polymer-containing fluids by determining percent viscosity loss at 100 °C after nozzle shear.

Q: What does it cover?

A: It covers apparatus descriptions, test cycles, calibration notes, sample preparation, viscosity measurement procedures, limitations, and reporting for two nozzle-shear test procedures (European diesel injector apparatus and FISST).

Q: Who typically uses it?

A: Lubricant and additive formulators, QC and R&D laboratories, engine and fuel‑system component developers, and independent testing organizations interested in polymer degradation under high-shear nozzle conditions.

Q: Is it current or superseded?

A: D3945-93 was withdrawn in 1998. Its two procedures were subsequently issued or revised as separate standards (for example, the FISST procedure is now covered by ASTM D5275 and European-injector procedures by later ASTM methods such as D6278). Users should consult those current test methods for up-to-date procedures and calibration requirements.

Q: Is it part of a series?

A: It is part of ASTM's portfolio of lubricant shear‑stability methods and is historically linked with other ASTM sonic and injector shear tests (D2603, D5275, D6278) and with industry committee procedures (CEC and DIN/ISO equivalents).

Q: What are the key keywords?

A: Shear stability, diesel injector nozzle, FISST, viscosity loss, polymer-containing fluids, lubricant testing, kinematic viscosity, VI improvers.