DBL 5404 Delivery Specification for Thermoplastic Parts Used in Vehicle Interiors

The “DBL 5404 Delivery Specification for Thermoplastic Parts Used in Vehicle Interiors” standard, developed by Daimler, the owner of the Mercedes-Benz brand, describes the technical requirements and test methods for parts made from thermoplastic materials used in vehicle passenger compartments. This standard applies to unpainted and galvanized/coated components made from common interior thermoplastics such as the following:

• ABS
• ABS+PC (ABS/polycarbonate blends)
• PA (polyamides)
• PP (polypropylene)
• PPO (modified polyphenylene oxide)
• PMMA (acrylic)

These parts are designed for the following:

• Direct and indirect areas of the passenger compartment
• Passenger compartment heating and ventilation systems
• Trim panels, housings, control elements, and functional interior components.

This standard does not cover painted exterior parts, under-hood/engine compartment components, or other material types (e.g., thermosets or metals). These fall under standards such as DBL 5416 (exterior thermoplastics) or DBL 5403 (engine-related thermoplastics).

This specification ensures that interior plastic components meet high Mercedes-Benz standards in the following areas:

• Durability and long-term performance under typical in-vehicle conditions.
• Resistance to environmental factors, chemicals, and mechanical stress.
• Maintaining appearance (color, brightness, texture)
• Security and user interaction (e.g., avoiding excessive disruption that could affect functionality or create a hazard)

Parts must undergo a comprehensive series of tests before being approved for use in Mercedes-Benz vehicles. This standard includes numerous test sections. General evaluation areas include:

• Resistance to chemicals and care products: Tests against cosmetics, sunscreens, and cleaning agents (usually referring to DBL 5399 test environments and evaluated according to DIN EN ISO 4628-1 standard)
• Scratch and abrasion resistance: Including color and gloss measurements following scratch tests.
• Climate/aging resistance: Heat aging, humidity, thermal cycling, light exposure (xenon arc weathering exposure)
• Mechanical properties: Tensile strength, impact, bending behavior (before and after aging)
• Odor and emissions: Low volatile organic compound/fogging behavior (typically referred to as the DBL 1000 series)
• Color fastness and surface stability
• Specific requirements for certain material groups or applications (e.g. § 18.7 scratch resistance)

Different material types or applications may require slightly different testing intensities or acceptance criteria.

In short, the DBL5404 standard is a company-specific quality and delivery specification for thermoplastic parts used in automotive interiors. It is not an international standard like ISO or ASTM, but rather a corporate material and component standard that vehicle suppliers must adhere to when delivering interior plastic parts.

The DBL5404 standard specifically covers the following:

• Parts made from thermoplastics.
• Components designed for direct and indirect areas of the passenger compartment (including trim pieces, housings, panels and parts related to heating and ventilation systems).

The purpose of this standard is to ensure consistent material quality, physical performance, and durability of plastic parts used in vehicle cabins. It defines the physical tests and thresholds that manufacturers must meet before their parts are accepted into mass production.

The DBL5404 standard provides both material-level specifications and component testing procedures. Typical areas covered include:

• Material properties: The following tests have been identified:
• Density (e.g., EN ISO 1183-1)
• Post-ignition residue (ash content)
• Mechanical strength and deformation behavior (e.g., tensile, bending tests)
• Impact resistance at different temperatures (EN ISO 179)
• Vicat softening temperature and heat deviation
• Moisture and water content
• Performance criteria: The parts must meet the following performance limits:
• Impact resistance at both room temperature and low temperatures.
• Tensile strength and elongation
• Thermal resistance (heat aging and hot storage)
• Condensation and volatile emissions (related to indoor air quality)
• Fragrance and cosmetic resistance (e.g., to chemicals such as cosmetics)

These requirements ensure that thermoplastic parts do not degrade, emit odors, emit excessive volatile substances, or otherwise degrade in a real vehicle interior environment.

The DBL 5404 standard divides the tests into sections that apply to different product versions and part types. Examples include:

• § 4.2 Resistance to maintenance products
• § 7.1 Density
• § 7.2 Ash (post-ignition residue)
• § 7.3 Bending stress
• § 7.4 Impact bending / impact resistance
• § 7.6 Pulling behavior
• § 7.14 Resistance to cosmetics
• § 7.15 Resistance to maintenance products
• § 18.7 Scratch resistance followed by color measurement

These tests are generally performed according to well-known test methods (usually ISO or DIN standards).

The DBL 5404 standard is considered important for the following reasons:

• They provide repeatable performance across parts from different suppliers.
• They establish minimum acceptance criteria for material and part behavior under real-world stresses.
• They help ensure passenger safety, comfort, and the durability of automotive interior components.

Consequently, the DBL 5404 standard plays a critical role in ensuring that the plastic interior components of Mercedes-Benz vehicles remain attractive, functional, and safe throughout the vehicle's lifespan. This is a significant aspect of the brand's renowned interior quality.

For many years, our organization, with its competent and experienced team, 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 DBL 5404 standard.