Practical Workshop on U-Value Calculations for Walls

Introduction

• Focus: Practical application of U-value calculations for walls using a specific process.
• U-value: Represents the transmittance of heat through a material, considering depth and resistance.

Key Concepts

• Resistance of Materials: Essential for calculating U-value.

  • Given resistances for surfaces and air gaps.
  • Need to calculate resistances for materials like bricks, blocks, and plaster.

• Conductivity and Resistance:

  • Conductivity is the measure of heat transfer capability.
  • Resistance can be calculated by inversing conductivity and multiplying by material depth.

Calculation Process

1. Determine Resistances:
   • Calculate resistances using the formula: Resistance = Inverse of Conductivity x Depth.
2. Calculate U-Value:
   • Add all material resistances.
   • Use the U-value formula to find the final U-value (e.g., 1.49 W/m²·°C).

Tools and Applications

• Utilization of an app for calculating thermal transmittance (U-value) with accurate input data.
• Many manufacturers offer their own tools for evaluating materials.

Temperature Units

• Use either Kelvin or Celsius consistently.
• U-value consistency is maintained regardless of Kelvin or Celsius usage, provided the same units are used throughout.

Regulatory Considerations

• Importance of adhering to regulations that may change over time.
• Part L documentation: L1B (2018) for existing buildings, L1A (2016) for new buildings.
  • Minimum U-value requirements differ for walls: 0.28 for some walls, 0.3 for others.
• Not all calculated U-values meet current regulatory standards.

Conclusion

• Ensure calculations align with both the material properties and regulatory requirements.

• Note: Regularly check for updates in regulations and standards to ensure compliance.

These notes summarize the practical workshop focusing on calculating U-values for building walls, providing a clear methodology and highlighting important considerations regarding temperature units and regulatory compliance.