MS940-01 Flammability Resistance for Electrical and Electronic Components

Developed by Hyundai Motor Company and Kia Corporation, the “MS940-01 Fire Resistance for Electrical and Electronic Components” standard is an automotive engineering standard designed to evaluate the fire resistance of plastic materials used in vehicle electrical and electronic components. This standard specifies flammability testing methods, performance requirements, and acceptance criteria to ensure that electronic components do not contribute to fire spread under normal operating or malfunction conditions.

As modern vehicles increasingly incorporate complex electronic components (including infotainment systems, advanced driver assistance systems, ADAS, electric powertrains, and battery management systems), the use of flame-resistant materials has become a critical safety requirement. The MS940-01 standard helps manufacturers select appropriate polymer materials and verify that they meet the required fire performance for their intended applications.

The main objectives of this standard are:

• To reduce the risk of fire from electrical or electronic components.
• To prevent the flames from spreading throughout the vehicle.
• To define standardized flammability testing procedures.
• To specify minimum flame-retardant performance for different categories of automotive electronic components.
• To enhance passenger safety during electrical failures or overheating incidents.
• To ensure consistent material quality across suppliers and production sites.

The MS940-01 standard applies primarily to plastic materials used in automotive electrical and electronic components. These include:

• electrical connectors
• Injection molded cable harness components
• Electronic control units (ECU)
• Information, entertainment and multimedia systems
• instrument panels
• Sensors
• Camera modules
• Communication devices
• High voltage connectors
• Battery management components
• Electric motor components
• DC/DC converters
• In-car chargers
• junction boxes
• Other electronic enclosures and boxes

This standard is particularly important for hybrid and battery electric vehicles due to the increasing number of high-energy electric systems.

Electrical systems can become ignition sources for the following reasons:

• Electrical short circuits
• Overloaded conductors
• Component overheating
• Arc errors
• Connector failures
• Battery failures
• Power semiconductor failures

If flammable plastics ignite, flames can quickly spread to nearby wiring, insulation, or internal materials. The MS940-01 standard minimizes these risks by requiring plastics to self-extinguish or burn slowly enough to prevent the spread of fire.

The MS940-01 standard requires flame-retardant plastic materials to meet the following criteria:

• To maintain flame resistance throughout the vehicle's service life.
• To exhibit resistance to deterioration after production processes and vehicle use.
• To prevent the formation of defects such as cracking or corrosion.
• Complying with hazardous materials restrictions.
• Excluding prohibited flame-retardant chemicals where required by regulations.

The MS940-01 standard adopts flammability (performance) classifications similar to those used in the UL 94 standard, depending on the application and the associated fire risk. Typical classifications include:

• HB - Horizontal burn-in: General electronic housings and connectors.
• V-2 - Vertical combustion with limited requirements: Low-risk applications.
• V-1 - Improved self-extinguishing performance: Medium risk electronics.
• V-0 - Highest commonly required rating: High voltage and critical safety components.

High-risk electrical systems typically require V-0 performance, while many conventional components may only require HB performance.

The horizontal burn test evaluates the following:

• Burning rate
• Flame spread distance
• The time required for the flame to spread.
• Ability to extinguish spontaneously

These standard test samples are exposed to a controlled flame for a specified period of time. The material is considered successful if:

• It goes out on its own.
• Flame spread remains below the specified limits.
• Alternatively, the measured combustion rate remains within the permitted values ​​depending on the sample thickness.

The vertical burn test is more rigorous. The sample is placed vertically and exposed twice to a standardized flame. The evaluation includes:

• Post-flame period
• Post-cranberry period
• Flame propagation
• Ignition of the cotton placed under the sample
• Burning droplets

Performance determines whether the material meets the following criteria:

• V-2
• V-1
• V-0

V-0 represents the highest level of flame resistance among these classifications because the material extinguishes quickly without igniting the cotton gauge through flaming droplets.

The MS940-01 standard defines different flammability requirements depending on the component type. Examples are as follows:

• General connectors: HB rating
• High-voltage connectors: V-0 rating.
• Electric drive components: V-0 rating
• Battery charging systems: V-0 rating
• Electronic control modules: Typically HB or higher, depending on circuit power and ignition risk.
• Communication modules: Requirements vary depending on the power level and the presence of potential ignition sources.

The MS940-01 standard refers to several widely accepted fire testing standards, including:

• ASTM D635 Standard test method for determining the rate of burning and/or degree and duration of burning of plastics in horizontal position.
• ASTM D3801 Standard test method for measuring the comparative combustion properties of solid plastics in a vertical position.
• UL 94 Flammability tests for plastic materials used in appliances and tools.
• IEC 62368-1 Audio/video, information and communication technology equipment - Part 1: Safety requirements
• MS201-02 Prohibition of the use of heavy metals in automotive parts and materials.

The MS940-01 standard is widely used in the development of the following:

• Electric vehicle battery systems
• High-voltage connectors
• Vehicle control modules
• instrument panels
• Information and entertainment systems
• Body control modules
• Camera systems
• Radar sensors
• Wireless charging units
• Power electronics
• Motor controllers
• Charging equipment
• junction boxes
• Cabling system components

Compliance with the MS940-01 standard provides the following advantages:

• Improving vehicle fire safety
• Reducing the risk of flame spread.
• Enhancing passenger protection.
• Consistent material availability among suppliers.
• Support for regulatory compliance.
• Increasing the reliability of electrical and electronic systems.
• Improved durability of flame-retardant materials throughout the product's lifespan.

Consequently, modern vehicles, especially hybrid and electric vehicles, contain hundreds of electronic modules and increasingly complex electrical architectures. If the surrounding materials are not sufficiently flame-resistant, a single electrical malfunction can become a source of ignition.

The MS940-01 standard provides a standardized method for characterizing plastic materials used in automotive electrical and electronic components, ensuring their resistance to ignition, limitation of flame spread, and self-extinguishing under controlled test conditions. By combining horizontal and vertical flammability tests with application-specific performance requirements, this standard plays a vital role in improving vehicle fire safety, supporting regulatory compliance, and enhancing the long-term reliability of automotive electrical systems.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting them in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services compliant with the MS940-01 standard.