SES N 2405 Odor Test for Materials

Developed by Suzuki Motor Corporation as part of its environmental/chemical management standards, the “SES N 2405 Odor Test for Materials” standard is part of Suzuki’s efforts to control and minimize unpleasant odors in vehicle cabins and contributes to overall vehicle interior air quality.

The SES N 2405 standard defines a standardized method for the sensory (human panel-based) evaluation of odors emitted by non-metallic materials and components used in vehicle interiors. This standard primarily applies to components with a surface area greater than 400 cm². For example,

Dashboard
Door trims
Upholstery materials
Ceiling tiles
Carpets and floor coverings
Other plastic, textile or composite interior elements

The aim is to ensure that the materials do not emit strong or unpleasant odors, especially under heat or over time. This can affect passenger comfort and perceived quality.

This standard is often used in conjunction with the closely related SES N 2403 standard, which concerns the quantitative determination and control of volatile organic compound (VOC) emissions from similar types of materials.

This testing process basically follows these steps:

Sample preparation: Materials are pre-conditioned (e.g., exposed to controlled temperature and humidity) and sometimes heated to simulate real-world conditions inside a vehicle.
Odor chamber or bag method: Samples are placed in sealed containers, heated (usually around 60-80 degrees Celsius), and allowed to release volatile substances.
Panel evaluation: A trained human panel (typically 3-10 evaluators) smells the gas in the head cavity and rates the odor intensity and quality on a standardized scale. Common scales range from 1 (no odor/pleasant) to 6 (very strong/unpleasant), and acceptance criteria usually require a rating below a certain threshold (e.g., a maximum of 3 or 2,5 depending on the part category).
Odor types: The panels can identify specific character notes (e.g., chemical, plastic, moldy, fishy, sweet) to help pinpoint sources.
Replications and checks: Multiple replications and blank/reference samples ensure reliability.

SES N 2405 standard test results are included in supplier reports, material certificates, and homologation documents for Suzuki vehicles. For example, test reports typically indicate compliance after specific curing or ventilation times (e.g., 11 days at room temperature).

Odor problems in vehicle interiors have been a long-standing complaint among consumers. Standards like SES N 2405 help manufacturers in the following areas:

To meet regulatory requirements in markets sensitive to volatile organic compounds and emissions.
Improving customer satisfaction by reducing new car smell complaints or long-term gas emissions.
Supporting green sourcing and sustainability goals (linked to relevant standards such as SES N 2402 for restricted substances).

Independent testing laboratories provide accredited services for SES N 2405 compliance, confirming their role in global supply chains for Suzuki and its partners.

In short, the Suzuki SES N 2405 standard defines odor evaluation requirements for materials and components used in vehicle cabins. This standard is part of a broader Suzuki engineering standards system that ensures all materials used in vehicles meet stringent quality, safety, and comfort requirements.

The main objectives of the SES N 2405 standard are as follows:

To assess odor emissions from interior materials.
To ensure passenger comfort and a perception of quality.
To prevent unpleasant or harmful odors in the vehicle cabin.
To support compliance with environmental and health expectations.

This standard is particularly important because many modern vehicles use synthetic materials that can release odors over time.

The SES N 2405 standard applies to the following:

Interior plastic parts
Textiles and upholstery
Adhesives and sealants
Foam materials
Trim components

This standard is typically used for vehicle interior parts with a significant surface area (e.g., over 400 cm²).

The SES N 2405 standard is based not entirely on instrumental measurement, but on sensory (human) assessment. The basic characteristics of this method are as follows:

Samples are conditioned under controlled conditions.
A trained panel evaluates the intensity and quality of the odor.
Fragrances are rated using a defined scale (e.g., 1-6 or similar).
Both intensity and acceptability are evaluated.

In this way, the test becomes highly relevant to actual customer perception.

The SES N 2405 standard is generally used in conjunction with the SES N 2403 standard. The SES N 2403 standard measures volatile organic compound (VOC) emissions, while the SES N 2405 standard assesses odor perception. Together, these two standards provide a complete assessment of indoor air quality.

Chemical analysis (objective)
Sensory evaluation (subjective)

The importance of the SES N 2405 standard in the automotive industry is as follows:

Passenger comfort: Unpleasant odors can negatively affect the following:
Driving experience
Brand perception
Customer happiness
Health considerations: Odors may indicate the following:
Presence of VOCs
Potential irritants or harmful substances
Quality assurance: A neutral or pleasant cabin scent is now an important indicator of quality in modern vehicles.

Materials tested under the SES N 2405 standard are evaluated according to the following criteria:

Fragrance intensity
Type of smell (e.g., chemical, musty, sweet)
Level of acceptability
Permanence over time

Only materials that meet the specified threshold values are approved for use.

In conclusion, the SES N 2405 standard plays a critical role in ensuring that vehicle interiors are comfortable, safe, and enjoyable for passengers. This standard represents Suzuki's commitment to providing a pleasant and healthy interior environment by rigorously evaluating and controlling material odors. Along with complementary standards relating to volatile organic compound emissions, this standard also ensures a comfortable, low-odor cabin experience for drivers and passengers worldwide. Suppliers to Suzuki are required to demonstrate compliance with this standard in their material approval processes.

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 SES N 2405 standard.