ASTM D1120 Standard Test Method for Boiling Point of Engine Coolants

Get Certified ASTM D1120 Testing for Reliable Coolant Performance

ASTM D1120 provides a standardized method for determining the EBP of engine coolants. The test aids manufacturers in evaluating the performance of a coolant formulation under test and comparing it with other formulations and production batches. An accurate boiling point is important for selecting coolants and can be used by engineers to determine if a formulation is suitable for the applicable product specifications. Engine coolants will help to maintain the proper engine temperature and carry heat from critical parts of the engine. Once a coolant reaches its boiling point, vapor development can have an impact on the cooling system and heat transfer. 

The ASTM D1120 standard: 

• Calculates the vapor pressure of engine coolants in equilibrium.
• Works on concentrated and prediluted coolant solutions.
• Utilizes controlled heating and refluxing to set up boiling equilibrium.
• Uses a partial immersion thermometer to measure the temperature of a liquid.
• Compensates for the influence of barometric pressure on the measured temperature.
• Supports the quality control and comparison of coolant formulations.
• Works with the SI (metric) system of measurement. 

What are the Uses of ASTM D1120 Testing?

ASTM D1120 testing can be used by manufacturers and laboratories to determine the boiling properties of engine coolant products. The results are used for product development, quality assurance, and verification with pertinent technical specifications. 

This standard:

• Tests the boiling point of automotive cooling compounds.
• Assists in quality control of coolant manufacturing.
• Assists in comparing various forms and concentrations of coolants.
• Supplies information to research and development.
• Helps manufacturers conduct thermal performance assessments.
• Ensures that product requirements can be verified if the method is mentioned in the specification
• Sets up a uniform reporting format for boiling point determinations. 

Which Materials Can Be Tested Under ASTM D1120?

ASTM D1120 is for engine coolants in concentrated and/or prediluted samples. The method can be used in laboratories to test appropriate liquid coolant formulations, such as glycol-based ones, within the method’s applicability. Technicians are able to take a representative sample prior to testing and avoid contamination that may impact the test result. If an antileak additive is present in a coolant, ASTM D1176 outlines the procedure for obtaining a representative test sample. Conventional specimen dimensions are not specified, as the method tests liquids instead of solid specimens. Rather, the number of technicians is determined by the number needed for the prescribed test apparatus and procedure.

Why is ASTM D1120 Important?

The ASTM D1120 is a standard method for obtaining the equilibrium boiling point of engine coolants. This property helps engineers predict how a coolant behaves at high temperatures under atmospheric pressure. A good boiling point will assist in product comparison and in quality control. This could be due to a formulation difference, a problem with dilution, contamination, or some other possible reason and should be investigated. Technicians will have to consider the makeup of the coolant, the specifications they are working with, and the operating conditions the product is subjected to; however, they should do so before interpreting any results. The test is not a complete test of the cooling system performance and does not allow prediction of the boiling point at engine operating pressure.

ASTM D1120 Equipment and Sample Preparation Guide

The equipment needed to conduct ASTM D1120 testing includes a water-cooled reflux condenser, a heat-resistant glass flask, boiling stones, an electric heating mantle, and a partial immersion thermometer. Technicians take a representative sample of the coolant and examine the equipment prior to heating. They also use them to measure barometric pressure to correct the observed boiling temperature. 

ASTM D1120 Testing Process and Data Collection

The ASTM D1120 testing process starts with the sample identification and preparation. Technicians check the apparatus, place the thermometer properly, and join the reflux condenser assembly with the test flask. They put the boiling stones provided in the flask and pour the corresponding amount of coolant. The technician then brings the sample to the desired temperature by using the electric heating mantle and keeps the temperature constants necessary for the method. Vapor is returned to the flask by the condenser so the sample comes to equilibrium while it is being boiled. When the test is completed to the prescribed measurement condition, the technician records the temperature of the liquid and records the barometric pressure. The analyst uses the pressure correction specified to calculate the equilibrium boiling point. The laboratory records the corrected result and any observations made that are relevant. Technicians use these records for comparing batches of coolants, forming a basis for investigation of unexpected results and for an analysis of compliance with applicable product requirements. 

Common Challenges and Troubleshooting

For ASTM D1120 testing, use clean equipment, a representative sample, an accurate temperature measurement, and the proper atmospheric pressure correction. These errors may occur in any of these areas and impact the boiling point reported. The wrong heating method can also make it impossible for the sample to attain the desired equilibrium condition. These difficulties can be minimized by checking the temperature and barometer, examining the glassware and condenser, and by following the recommended heating. They should also be used to avoid contamination of the sample and to make sure the reflux apparatus works. If a result is inconsistent with previous measurements or product specifications, the condition of the sample, instrument performance, test conditions, and calculation should be investigated by the laboratory before accepting the result. 

• The sample identification and preparation details are recorded by the technicians.
• The laboratory records the temperature of the liquid under the conditions indicated by the method.
• During testing, technicians will record the barometric pressure.
• The analyst applies the correction as per the calculated pressure and reports the equilibrium boiling point.
• The laboratory compares the corrected result to the product specification or acceptance criteria.
• Analysts examine unexpected differences among samples and/or production batches.
• The laboratory records the result and the conditions of the test in order to ensure quality control and traceability.

Link to ASTM D1120