ASTM E1135 Standard Test Method for Comparing the Brightness of Fluorescent Penetrants

The standard "ASTM E1135 Standard Test Method for Comparing the Brightness of Fluorescent Penetrants," developed by the American Society for Testing and Materials (ASTM), describes techniques for comparing the brightness of penetrants used in fluorescent dye penetrant processing. This comparison is conducted under controlled conditions that eliminate many of the variables found in actual penetrant inspection. This allows the brightness factor to be isolated and measured independently of other factors affecting the performance of a penetrant system.

The brightness of a penetrant indicator is affected by the developer it is used in. However, this test method measures the brightness of a penetrant on a suitable filter paper substrate, which replaces the developer. The resulting brightness measurement is color corrected to approximate the color response of the average human eye. Since most inspections are performed with the human eye, this number has more practical value than a measurement in units of emitted energy. Furthermore, comparisons are expressed as a percentage of some selected standard penetrant, as no absolute measurement system currently exists.

The measurements made by this standard compare the gloss of a candidate penetrant with the gloss of a standard penetrant when tested according to the technique. There is no known correlation between the results obtained and the gloss of actual flaw indications obtained during inspection using the penetrant.

For the purposes of this standard, the terms and definitions given in ASTM E1316 apply.

Simulated indicators are prepared by impregnating filter paper with a specific amount of the penetrant being tested. Samples and similarly prepared standards are then measured in a fluorometer equipped to excite the penetrant with near-ultraviolet light and induce a color response similar to that experienced by the human eye under normal conditions during an examination. The fluorometer must be equipped with a special sample holder to accept the samples used.

Sample test results are not indicative of overall system performance, but are useful as a batch acceptance test and are used to compare the condition of the penetrant in use with an unused sample. A known amount of penetrant is diluted with a specified amount of a volatile solvent, pieces of filter paper are dipped into the mixture, the paper is dried at room temperature under specified conditions, placed in a sample holder, and measured with a fluorometer.

The primary use of this procedure is to compare the brightness of batches of fluorescent penetrant against a specified standard as a batch quality control test. The procedure is also used to monitor the brightness of an in-use penetrant against the brightness of an unused sample of the same material.

The significance of results is not absolute values ​​but relative comparisons made by a particular laboratory or operator on a particular fluorometer at a particular time point.

Prepare a set of four standard sample papers and four test sample papers. Mark the papers accordingly with a pencil. Pipette 1,0 mL of the selected standard penetrant into a 25 mL stoppered volumetric flask. Pipette 1,0 mL of test penetrant into a 25 mL stoppered volumetric flask. Fill the flasks to the top with the selected solvent, stopper, and mixture. Pour the standard penetrant-solvent mixture into a 50 mL beaker, and pour the test sample mixture into another 50 mL beaker.

Using forceps, dip four papers one at a time into the beaker, pull them out of the beaker opening to remove excess liquid, and clip them to the paper drying holder. The clip should cover as little of the paper as possible. All papers should be oriented vertically or horizontally in the same direction and should not touch anything other than the drying clip. This preparation should not be delayed, as the liquid in the beaker can evaporate, increasing the concentration. Allow the papers to air-dry at room temperature for 8 to 12 minutes.

The ASTM E1135 standard is essential because it provides a standard method for testing and evaluating the performance of protective clothing materials against liquid penetration, particularly under conditions simulating exposure to hazardous substances such as chemicals or biological agents.

The main reasons why this standard is important are:

• Ensures safety and reliability: This standard establishes consistent testing procedures to evaluate how well materials resist liquid penetration and ensures that protective clothing can protect workers in high-risk environments such as chemical plants or medical environments.
• Standardizes performance criteria: By defining clear measurements (e.g., penetration resistance under specific pressures), this standard enables manufacturers, regulators, and users to objectively compare materials and ensures that only effective products are used.
• Protects against hazardous exposure: This standard helps verify that clothing materials can withstand contact with hazardous liquids and reduces the risk of skin exposure to toxic or infectious substances.
• Supports regulatory compliance: Many industries rely on ASTM standards to meet occupational safety regulations (e.g., OSHA or European Union directives), ensure compliance, and avoid legal or safety violations.
• Facilitates innovation and quality control: Provides a benchmark for manufacturers to develop and test new materials, encouraging innovation while maintaining quality and consistency in protective clothing.

Without this standard, there is no uniform way to evaluate protective materials, resulting in inconsistent levels of safety, increased exposure risk, and potential harm to workers.

Our organization, which has been supporting businesses across all sectors for years through a wide range of testing, measurement, analysis, and evaluation activities, has a strong team of employees who closely follow global developments in science and technology and are constantly improving themselves. In this context, we also provide testing services in accordance with the "ASTM E1135 Standard Test Method for Comparing the Brightness of Fluorescent Penetrants" standard.