ASTM D120 Standard Specification for Rubber Insulating Gloves

The "ASTM D120 Standard Specification for Rubber Insulating Gloves" standard developed by the American Society for Testing and Materials (ASTM) describes the requirements for the manufacture of rubber insulating gloves to protect workers from electric shock and defines a test method.

This standard provides two types of gloves: Type I non-ozone-resistant and Type II ozone-resistant gloves. Ozone resistance refers to a material's ability to resist deterioration or cracking when exposed to ozone, a reactive oxygen species found in the atmosphere. Ozone is a highly reactive gas that can attack and break down the double bonds in rubber and other elastomers. Even low concentrations (as little as 0,01 ppm) can cause visible cracking in sensitive materials over time, especially under stress.

Type I gloves are not ozone resistant. They are made of natural rubber or other materials that can degrade in ozone-rich environments. Type II gloves are ozone resistant. They are typically made of synthetic rubber, such as ethylene propylene diene monomer (EPDM) or butyl rubber, formulated to resist ozone damage.

The ASTM D120 standard includes six glove classes with different electrical properties. Classifications are based on maximum operating voltage:

• Class 00: Maximum 500 Volts AC, 750 Volts DC
• Class 0: Maximum 1.000 Volts AC, 1.500 Volts DC
• Class 1: Maximum 7.500 Volts AC, 11.250 Volts DC
• Class 2: Maximum 17.000 Volts AC, 25.500 Volts DC
• Class 3: Maximum 26.500 Volts AC, 39.750 Volts DC
• Class 4: Maximum 36.000 Volts AC, 54.000 Volts DC

The following tests will be performed within the scope of this standard:

• AC endurance test
• AC disturbance test
• AC moisture absorption and durability test
• DC endurance test
• DC disturbance test
• Ozone resistance test
• Chemical tests
• Tensile strength
• Elongation resistance test
• Tear resistance test
• Puncture resistance test

Gloves must pass physical requirements for tensile strength, elongation, tear resistance, and puncture resistance. Each glove must pass a dielectric test at a specified voltage to ensure proper insulation. Gloves should be clearly marked with the class, size, manufacturer, and other compliance information. Gloves should be visually inspected and electrically retested regularly, typically every 6 months (or as required by OSHA or the employer's safety protocols).

This standard is commonly required by electricians, line workers, and utility workers who use high-voltage equipment or systems.

The ASTM D120 standard is important because it ensures that rubber insulating gloves that protect workers from electric shock and arc flash meet stringent safety and performance requirements. These gloves are often the last line of defense between a worker and a deadly electric current. Therefore, consistent, tested quality is critical.

The ASTM D120 standard is considered important for the following reasons:

• Protects human life: High-voltage work is inherently hazardous. Gloves covered by this standard are designed to withstand thousands of volts without failure, preventing fatal injuries.
• Defines critical performance requirements: This standard specifies the minimum electrical, physical, and chemical properties that gloves must meet. This includes resistance to: high voltage (AC/DC), physical damage (tear, puncture), ozone (Type II), humidity, and aging.
• Supports OSHA and NFPA compliance: This standard is referenced by OSHA 29 CFR 1910.137 and NFPA 70E for electrical personal protective equipment. Employers must provide gloves that comply with ASTM D120 for employees exposed to live parts. Failure to comply may result in legal penalties or liability in the event of an accident.
• Standardizes production and testing: This standard provides a universal benchmark for glove manufacturers, safety officers, and buyers. It ensures gloves are tested under consistent methods, particularly dielectric testing (electrical insulation), accelerated aging, and marking and traceability.
• Ensures product reliability in the field: Real-world conditions (weather, ozone, stretching) can degrade gloves. This standard's ozone resistance and thickness requirements help gloves remain reliable over time.

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 D120 Standard Specification for Rubber Insulating Gloves" standard.