Stellantis D45 5254 Radiant Combustion Heat Source Exposure Materials

The "Stellantis D45 5254 Materials Exposed to Radiant Combustion Heat Source" standard, published by Stellantis, a multinational automotive manufacturing company formed by the merger of Italian-American Fiat Chrysler Automobiles and the French PSA Group, aims to measure and observe the temperatures at which sound insulation materials or other materials (rubber type, heat shield) are exposed to a heat source (such as a muffler or engine compartment).

In principle, a sample of the material to be tested is exposed to heat radiation from a temperature-controlled infrared heater for a specific period of time. The temperatures reached are measured, and then the condition of the material is observed.

Samples must be representative of the quantity to be measured. To ensure this representativeness, it is necessary to know the basic characteristics of the study population. The sample selection criteria should be stated in the test report, the content of which is defined in the A10 0156 standard. If there is any doubt about the samples, Stellantis should be contacted for the procedures to be followed.

Depending on the type of part, the sample taken from the material to be tested consists of 3 test specimens of the same thickness as the material, measuring 300 mm x 100 mm. For pipes or casings, a sufficiently wide cross-section of material larger than the diameter of the infrared heater should be cut. Other dimensions should be specified in the test report. The test specimens should be conditioned in a climate chamber for 24 hours.

The steps to follow when conducting the test are as follows:

• It is placed inside the assembly test chamber.
• The infrared heater is mounted to the support using a clamp, with the emitter side facing down.
• The test specimen is secured with clamps using a support, with the viewing side facing upwards (towards the heat source = infrared heater).
• The thermocouple connected to the regulator is placed on the test specimen so that its surface side, exposed to the heat source, is in contact with the sample.
• Thermocouple 1, which will measure the temperature on the heat source side and control the required control temperature via the regulator, is attached to the viewing side.
• To measure the temperature on the colder side, a thermocouple is attached to the bottom, at the back, of the two test specimens.
• These thermocouples are positioned so that their rounded ends contact the surface of the material. They can be secured with clamps attached to sample holders.
• The distance between the visible side of the test specimen and the radiating side of the infrared heater is adjusted. By default, 20 mm plus/minus 2 mm is used. Other dimensions must be specified in the test report.
• Thermocouples 1 and 2 are connected to the recorder.
• The infrared heater is connected to the temperature regulator.
• The equipment is powered.
• The required control temperature is displayed.
• The temperatures of thermocouples 1 and 2 are continuously recorded.
• The timer is started when the control temperature is reached. The test continues for 30 minutes or a specified time.
• At the end of the exposure time, the thermocouples and control sensor are removed.
• The test sample is left in the reservoir for 1 hour.
• A cross-section is taken from the exposed area, and the condition of the material is examined in detail.
• During the test, the occurrence of any specific event (such as smoke, onset of combustion, flames, etc.) is noted.
• The test is stopped when the material starts to burn.

In short, the Stellantis D45 5254 standard involves a laboratory testing method to evaluate how non-metallic materials used in vehicle interiors and exteriors behave when exposed to radiant heat from a combustion source. The primary aim is to assess fire resistance and flammability risks and to ensure that materials do not readily ignite, spread flames, or excessively contribute to fire spread in real-world scenarios such as exposure to engine compartment heat or accidental fires.

The main objectives of this standard are:

• To measure the material's resistance to ignition under radiant heat flux.
• To evaluate the combustion rate, flame spread, and self-extinguishing characteristics.
• To simulate exposure to high-temperature radiant sources (e.g., exhaust systems, turbochargers, or external fire hazards).

This test method complements broader automotive flammability regulations such as the “FMVSS 302 U.S. Federal Motor Vehicle Safety Standard – Horizontal Burn Rate for Interior Materials” standard or the ISO 3795 standard, but focuses specifically on radiant heat from combustion rather than direct flame contact.

Automotive materials must balance lightweight design, cost, and aesthetics with stringent fire safety requirements. Stellantis D45 5254 and similar standards help prevent failures of very large dimensions.

• In engine compartments or underbody areas exposed to high temperatures.
• During accidents involving fuel leaks or electrical failures.
• Compliance helps meet global regulations (e.g., UN ECE R118 for bus interiors or EU end-of-life vehicle directives).

Suppliers must certify materials according to these standards during homologation, which contributes to overall vehicle fire safety ratings.

The Stellantis D45 5254 standard is a niche engineering specification rather than a consumer-facing one. This standard is commonly found in supplier databases, material approval lists, and older PSA standard catalogs.

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 in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services to businesses in accordance with the "Stellantis D45 5254 Materials exposed to radiant combustion heat sources" standard.