ASTM C148-17(2022) PDF

Overview

ASTM C148-17(2022): Standard Test Methods for Polariscopic Examination of Glass Containers is an internationally recognized standard developed by ASTM for evaluating the annealing quality of glass containers. The standard outlines two reliable test methods for determining the degree of annealing by measuring the relative optical retardation in soda-lime-silica glass containers. Ensuring proper annealing is critical for product safety, durability, and quality control in glass manufacturing and related industries.

Key Topics

• Annealing Verification: The document provides two independent methods for assessing the state of anneal in glass containers, which is vital for preventing residual stresses that could lead to container failure.
• Test Method A (Polariscope): Used for optical retardation measurements below 150 nm, this method involves comparing sample containers to reference standards using a polariscope.
• Test Method B (Polarimeter): Suitable for measurements up to 565 nm, this polarimeter-based method measures the analyzer's rotation to determine optical retardation and thus evaluate annealing quality.
• Measurement Considerations: Both test methods take into account factors such as residual stress, glass thickness, and composition. For typical soda-lime-silica glass, composition has negligible effect, while accurate measurement of glass thickness at the point of maximum retardation is essential.
• Quality Assurance: The results help production facilities maintain high standards in the manufacture of glass products by identifying and addressing annealing irregularities.

Applications

ASTM C148-17(2022) plays a central role in quality control processes for manufacturers and suppliers of glass containers and similar products. Key practical applications include:

• Glass Container Manufacturing: Frequent testing ensures bottles and jars are properly annealed, minimizing internal stress and risk of cracking or breakage during filling, transport, or consumer use.
• Research and Development: Supports R&D and process optimization in glass production by providing standardized assessment tools.
• Safety Compliance: Meeting industry and regulatory safety requirements. Proper annealing is directly linked to product reliability in critical sectors such as food and beverage, pharmaceuticals, cosmetics, and chemical packaging.
• Supplier Evaluation: Offers a reference method for qualifying and auditing glassware suppliers for consistent product quality.

Related Standards

Several related ASTM standards enhance the effective implementation of ASTM C148-17(2022):

• ASTM C162: Terminology of Glass and Glass Products - Provides standardized definitions relevant to glass testing.
• ASTM C224: Practice for Sampling Glass Containers - Details best practices for collecting representative samples for testing.
• ASTM C1426: Practices for Verification and Calibration of Polarimeters - Ensures that polariscopes and polarimeters used in testing are properly calibrated for accurate results.

Summary

Adhering to ASTM C148-17(2022) ensures that glass containers meet international standards for annealing and structural quality. Its test methods are widely recognized for their accuracy, reliability, and practical application across industries, making it an essential resource for glass manufacturers, quality assurance professionals, and suppliers seeking to uphold high standards in glass container production.

Keywords: ASTM C148-17, polariscopic examination, glass containers, annealing verification, quality control, soda-lime-silica glass, polariscope, polarimeter, optical retardation, residual stress, glass manufacturing standards.