EN 13129: New Comfort & Air Quality Standards For European Rail

EN 13129: Air Conditioning and Comfort Parameters for Main Line Rolling Stock

EN 13129 is a fundamental European standard that specifies the comfort parameters and type testing procedures for air conditioning systems installed in main line railway rolling stock. The primary goal of the standard is to define a set of verifiable criteria to ensure a comfortable and healthy environment for passengers and crew during a journey, regardless of external weather conditions.

This standard provides manufacturers, operators, and procurement agencies with a common technical language and a framework for designing, testing, and accepting heating, ventilation, and air conditioning (HVAC) systems. It harmonizes expectations for performance across the European railway network.

Scope and Objective of EN 13129

The scope of EN 13129 is specifically focused on main line rolling stock. This includes passenger coaches, driving cabs, restaurant cars, sleeping cars, and couchettes. It is important to note that the standard generally excludes urban and suburban vehicles such as metros, trams, and light rail vehicles, which are often covered by different standards due to their unique operational profiles (e.g., frequent door openings, shorter travel times).

The core objectives of the standard are:

• To Define Comfort: To translate the subjective feeling of “comfort” into objective, measurable physical parameters.
• To Ensure Performance: To establish standardized test procedures (type tests) that verify an HVAC system’s ability to meet these parameters under simulated operational conditions.
• To Promote Interoperability: To create a baseline for HVAC performance, ensuring a consistent level of passenger experience on interoperable rail services.

Key Comfort Parameters Defined by EN 13129

EN 13129 breaks down passenger and crew comfort into several critical technical parameters. An HVAC system’s performance is evaluated against its ability to maintain these parameters within specified ranges.

Thermal Comfort (Temperature and Humidity)

This is the most critical aspect of comfort. The standard defines acceptable ranges for the operative temperature, which is a composite measure of air temperature and radiant heat from surfaces like windows and walls. It also specifies a comfortable range for relative humidity.

• Internal Temperature: Typically, the system must maintain an internal temperature between 20°C and 24°C, depending on the operational mode (heating or cooling) and the external ambient temperature.
• Relative Humidity: The acceptable range for relative humidity is generally between 30% and 70%. Excessively dry or humid air can cause discomfort and health issues.
• Temperature Uniformity: The standard sets limits on temperature variations, both vertically (between head and ankle level) and horizontally throughout the passenger area, to avoid cold or hot spots.

Air Velocity and Distribution

Proper air distribution is crucial to avoid the sensation of draught, which can cause significant discomfort even if the temperature is correct. The standard sets maximum allowable air speeds in occupied zones.

• Maximum Air Speed: In seated passenger areas, the air velocity should typically not exceed 0.25 m/s to prevent draughts. The limits may vary slightly based on the air temperature and location.
• Air Distribution System: The design of air outlets (diffusers) and the overall airflow pattern are critical for achieving uniform temperature and velocity distribution.

Air Quality and Fresh Air Supply

Maintaining good air quality is essential for both comfort and health. This is primarily achieved by supplying a sufficient amount of fresh (outside) air and limiting the concentration of CO₂.

• Fresh Air Flow Rate: The standard specifies a minimum volumetric flow rate of fresh air per person to dilute bio-effluents and other contaminants.
• CO₂ Concentration: The concentration of carbon dioxide (CO₂) is used as a key indicator of indoor air quality. EN 13129 sets a maximum limit, often around 1500 ppm (parts per million) above the external ambient level, to prevent feelings of stuffiness and fatigue.

Acoustic Comfort (Noise Levels)

The HVAC system is a significant source of background noise inside a railway vehicle. The standard specifies maximum permissible noise levels generated by the air conditioning system when operating in different modes (e.g., full cooling, ventilation) to ensure a quiet and relaxing travel environment.

The Role of Type Testing in EN 13129

A “type test” is a procedure performed on a representative HVAC unit or a complete vehicle under controlled laboratory conditions to verify that its design meets the requirements of the standard. These tests are fundamental to EN 13129 and are typically conducted in a specialized climatic chamber capable of simulating a wide range of external temperatures, humidity, and solar radiation.

Common Type Tests Performed

• Heating Performance Test: Verifies the system’s ability to heat the vehicle from a cold-soaked condition (e.g., -25°C) to a comfortable internal temperature within a specified time.
• Cooling Performance Test: Measures the system’s capacity to cool the vehicle down from a high ambient temperature (e.g., +40°C) with simulated solar load and full passenger occupancy.
• Air Distribution Test: Involves measuring air velocities and temperatures at numerous points within the vehicle to ensure uniformity and compliance with draught limits.
• Fresh Air Supply Test: Confirms that the system delivers the required amount of fresh air under various operating conditions.
• Demisting and Defrosting Test: A specific test for the driver’s cab HVAC to ensure it can quickly clear the front windscreens of fog or ice for safe visibility.

Comparison Table: Comfort Categories in EN 13129

The standard often defines different comfort categories (e.g., A, B, C) to allow for different levels of service. Below is a simplified, representative table illustrating how these categories might differ.

Importance for the Railway Industry

EN 13129 is a cornerstone document for the railway sector. For rolling stock manufacturers, it provides clear design targets and a standardized method to prove their HVAC systems’ performance. For train operating companies, it ensures they procure vehicles that will deliver a high level of passenger satisfaction and a safe working environment for their crew. Ultimately, the standard contributes directly to making rail travel a more attractive and comfortable mode of transport by setting a high, consistent benchmark for the onboard climate.