ASTM G21-15(2021)e1 PDF

Overview

ASTM G21-15(2021)e1 is an internationally recognized standard outlining a practice for determining the resistance of synthetic polymeric materials to fungal growth. Developed by ASTM International, this standard is crucial for assessing how various plastics and polymer-based materials withstand exposure to fungi, particularly under conditions that encourage microbial attack. The method is applicable to molded or fabricated articles, tubes, rods, sheets, and films made from synthetic polymers. It provides a systematic approach for evaluating changes in mechanical, optical, and electrical properties after fungal exposure, ensuring material reliability and safety in environments where fungal contamination is a risk.

Key Topics

• Scope and Applicability

  • Covers synthetic polymeric materials in forms such as films, sheets, rods, and fabricated items.
  • Focuses on materials where the polymer base is typically fungus-resistant; additives like plasticizers or stabilizers can make materials susceptible to fungal growth.
  • Establishes test conditions favorable for fungal proliferation: temperature from 2 to 38°C (35 to 100°F), and high relative humidity (60-100%).

• Expected Effects of Fungal Exposure

  • Surface deterioration, discoloration, and loss of optical transmission.
  • Removal or breakdown of additives, leading to changes in stiffness, weight, and dimensions.
  • Electrical property degradation, including reduced insulation resistance and dielectric strength, often due to surface colonization and associated moisture.
  • Pronounced effects on films or coatings due to high surface-to-volume ratios.

• Test Methodology

  • Inoculation of specimens with selected test fungi and incubation under controlled environmental conditions.
  • Visual assessment and rating of fungal coverage after up to 28 days.
  • Optional mechanical, optical, or electrical evaluations using relevant ASTM methods to determine property changes.

• Reporting and Reproducibility

  • Requires detailed reporting of test organisms, incubation times, visual ratings, and property changes.
  • Emphasizes importance of noting maximum observed degradation due to potential variability in fungal attack.

Applications

• Quality Control for Manufacturers

  • Essential for plastic and polymer product manufacturers to confirm resistance to fungal deterioration, especially for materials intended for humid or biologically active environments.
  • Commonly applied in industries producing insulation, films, electrical components, medical devices, and coatings.

• Material Selection and Product Development

  • Supports engineers and designers in selecting suitable polymers and additives to enhance fungal resistance.
  • Informs the formulation of new plastic blends and surface treatments to minimize biosusceptibility.

• Regulatory and Safety Compliance

  • Useful for certifying products for use in environments where fungal contamination poses health or reliability risks, such as healthcare, food packaging, and construction.
  • Supports procurement and quality assurance processes with standardized assessment criteria.

Related Standards

• Mechanical and Physical Property Tests

  • ASTM D638: Tensile Properties of Plastics
  • ASTM D785: Rockwell Hardness of Plastics
  • ASTM D882, D1708: Tensile Properties of Thin Plastic Sheeting and Films

• Electrical Property Tests

  • ASTM D149: Dielectric Breakdown Voltage
  • ASTM D150: Dielectric Constant and Power Factor
  • ASTM D257: DC Resistance or Conductance of Insulating Materials

• Optical and Transmission Tests

  • ASTM D1003: Haze and Luminous Transmittance of Transparent Plastics
  • ASTM E308: Computing the Colors of Objects by Using the CIE System

• Water Vapor Transmission

  • ASTM E96/E96M: Water Vapor Transmission of Materials

By adhering to ASTM G21-15(2021)e1, organizations can ensure consistent, reliable evaluation of their synthetic polymeric materials’ fungal resistance, boosting product longevity and safety in demanding applications. For further guidance, consult the latest ASTM standards and referenced test methods to ensure comprehensive material assessment.