CLO Value: Understanding Clothing Insulation Testing and Research

Winter Clothing Thermal Insulation Testing and Research for CLO Values

CLO value is a crucial metric in the textile and apparel industry, representing the thermal insulation provided by clothing. As consumers and industries increasingly prioritize comfort, safety, and energy efficiency, the accurate measurement and understanding of CLO value have become essential. This article delves into the importance of CLO value, the methods used for clothing insulation testing, and how research in this area contributes to advancements in apparel design and performance.

What is CLO Value?

The CLO value is a unit of measurement that quantifies the thermal insulation of clothing. It indicates how well a garment can maintain body heat in different environmental conditions. One CLO is defined as the insulation needed to keep a resting person comfortable at an indoor temperature of 21°C (70°F) with air movement of 0.1 m/s and humidity less than 50%.

The CLO value is essential for understanding how clothing can protect against cold and maintain thermal comfort, especially in extreme environments such as outdoor activities, military operations, and space exploration.

Importance of CLO Value in Clothing

1. Thermal Comfort: The primary function of clothing is to provide thermal comfort by regulating body temperature. Understanding the CLO value helps designers create garments that keep the wearer warm in cold conditions and cool in hot environments.
2. Safety: In professions where workers are exposed to extreme temperatures, such as construction, firefighting, and outdoor sports, clothing with the appropriate CLO value is vital for safety. Proper insulation reduces the risk of hypothermia, frostbite, and other cold-related injuries.
3. Energy Efficiency: In building design and energy management, CLO values are used to optimize heating and cooling systems. By understanding the insulation provided by clothing, building managers can adjust indoor temperatures to save energy while maintaining occupant comfort.
4. Product Development: For apparel manufacturers, CLO value testing is critical in the development of outdoor and performance wear. Accurately measured CLO values ensure that garments meet the needs of consumers, whether for everyday wear or specialized activities.
5. Regulatory Compliance: In some industries, such as military and aerospace, clothing must meet specific insulation standards. Understanding and testing for CLO values ensure that garments comply with these regulations, protecting users in extreme environments.

Laboratory Methods of CLO Value Testing

Accurate measurement of CLO value requires specialized testing methods that simulate real-world conditions. The following are common methods used in clothing insulation testing:

1. Manikin Testing:
   • Overview: A thermal manikin is a human-shaped model with temperature sensors placed throughout its surface. The manikin is dressed in the clothing to be tested and exposed to controlled environmental conditions.
   • Procedure: The manikin is heated to a typical body temperature, and the power required to maintain this temperature is measured. The CLO value is calculated based on the difference in power consumption with and without the clothing.
   • Applications: Manikin testing is widely used in research and product development, providing accurate and repeatable measurements of clothing insulation. It is particularly useful for testing complex garments and layered clothing systems.
2. Hot Plate Testing:
   • Overview: A guarded hot plate simulates the human skin and is used to measure the thermal resistance of fabrics. The hot plate is placed in contact with the fabric, and the heat flow through the material is measured.
   • Procedure: The fabric is placed on the hot plate, and a known amount of heat is applied. The temperature difference between the top and bottom of the fabric is measured, and the CLO value is calculated based on the heat transfer rate.
   • Applications: Hot plate testing is commonly used for testing individual fabrics and materials before they are assembled into garments. It provides a quick and cost-effective way to assess insulation properties.
3. Field Testing:
   • Overview: Field testing involves measuring the CLO value in real-world conditions by monitoring the thermal comfort of human subjects wearing the clothing. This method provides data on how clothing performs in actual use.
   • Procedure: Test subjects wear the clothing in various environmental conditions, and their thermal comfort is assessed through physiological measurements (e.g., skin temperature, sweating) and subjective feedback (e.g., perceived warmth).
   • Applications: Field testing is valuable for validating lab-based CLO measurements and understanding how clothing performs in different weather conditions and activities.
4. Climatic Chamber Testing:
   • Overview: A climatic chamber simulates a wide range of environmental conditions, allowing for controlled testing of clothing insulation. The chamber can replicate different temperatures, humidity levels, and wind speeds.
   • Procedure: The clothing is tested on a thermal manikin or human subjects within the climatic chamber, and the CLO value is determined based on the thermal response.
   • Applications: Climatic chamber testing is used to evaluate the performance of clothing in extreme conditions, such as arctic environments or high-altitude settings. It is also used for testing the durability of insulation over time.

Challenges in CLO Value Testing

While CLO value testing is essential for ensuring the effectiveness of clothing insulation, it presents several challenges:

1. Variability in Human Physiology: Individual differences in metabolism, body composition, and activity levels can affect thermal comfort, making it difficult to standardize CLO measurements across different populations.
2. Environmental Factors: Factors such as wind, humidity, and physical activity can influence the insulation properties of clothing, making it challenging to replicate real-world conditions in a lab setting.
3. Complexity of Garments: Multi-layered clothing systems, varying fit, and different fabric combinations can complicate CLO value testing. Ensuring that all elements of the garment are accurately measured requires sophisticated testing methods.
4. Time and Cost: Comprehensive CLO value testing, particularly using manikins and climatic chambers, can be time-consuming and expensive. Balancing the need for accurate data with the cost of testing is a challenge for manufacturers.

Research and Innovations in CLO Value Testing

Ongoing research in CLO value testing focuses on improving the accuracy and relevance of insulation measurements. Some key areas of innovation include:

1. Smart Textiles: Research into smart textiles that adapt to environmental conditions is advancing the field of clothing insulation. These fabrics can change their insulation properties based on temperature or humidity, providing dynamic thermal comfort.
2. 3D Scanning and Modeling: Advanced 3D scanning and modeling techniques are being used to create more accurate thermal manikins and simulate the effects of clothing fit and movement on insulation.
3. Wearable Sensors: The development of wearable sensors allows for real-time monitoring of thermal comfort and insulation performance in the field. These sensors provide valuable data on how clothing behaves during actual use.
4. Sustainable Materials: Research into sustainable and biodegradable insulation materials is gaining traction as the industry seeks to reduce its environmental impact. These materials must be tested for their insulation properties to ensure they meet performance standards.

How Contract Laboratory Can Assist with CLO Value Testing

Contract Laboratory is a global platform that connects apparel manufacturers with accredited laboratories specializing in CLO value testing. Whether you need to test new materials, validate garment insulation, or conduct research, Contract Laboratory can help you find the right testing partner.

Services Offered by Contract Laboratory:

• Comprehensive Laboratory Network: Access a global network of laboratories with expertise in CLO value testing, ensuring accurate and reliable results.
• Customized Testing Solutions: Receive tailored testing services that match your specific product needs, from initial research to final product validation.
• Expert Consultation: Get assistance navigating the complexities of CLO value testing and ensuring your products meet industry standards.

Conclusion

CLO value testing is a critical aspect of clothing design and performance, ensuring that garments provide the necessary insulation for comfort and safety. By employing advanced testing methods and staying informed about the latest research, manufacturers can deliver high-quality products that meet the needs of consumers and comply with industry regulations. Contract Laboratory offers valuable resources to help businesses find the right testing solutions, ensuring that their clothing meets the highest standards of thermal insulation.

If your company manufactures clothing or other outdoor gear and needs a third-party independent laboratory for measuring the CLO value of its gloves, sweaters, jackets, snow pants, socks, or boots, we can help. Simply, Submit a Laboratory Test Request