This Newsletter released by the Chartered Institution of Building Services Engineers (CIBSE) Natural Ventilation Group (NVG) Management Committee, aims to inform members and potential members of the work being undertaken by the Group to benefit the discipline of natural ventilation within CIBSE.

Contents include:

• Overheating corridors: Performance of mitigation actions measured;
• Using the new CIBSE design summer years to assess overheating in London;
• UK joins the Air Infiltration and Ventilation Centre.

The paper at hand collects research findings on the impact of air flow on the thermal performance of pitched roof assemblies. Air flows in these components are typically a mixture of: 1) in/exfiltration, 2) natural convection and 3) wind-washing. In the current building practice the necessity of an air barrier to guarantee the thermal and hygric performance of roofs is well established. Yet the need for a continuous wind barrier to avoid wind-washing of the insulation layer is still often underestimated in practice.

Against the background of increased global demands for energy efficiency, property owners should raise the standards of ductwork systems for ventilation, heating and air conditioning. This would not only save energy, but also mean lower installation costs, shorter assembly times and better air quality thanks to less leakage. The importance of energy-efficient buildings will increase in the future, not only due to rising electricity prices, but also due to increased environmental awareness.

This presentation will explain what exactly calibration should mean. It will also look into the hierarchy of and the differences between the calibration labs of national standards, accredited labs (like DAkkS, a national government-appointed accreditation body in Germany, or Cofrac – Comité français d’accréditation – in France), and manufacturer’s calibration labs. Even the labs themselves must have their own measuring devices checked in order to guarantee what is known as traceability to national standards, and to determine the measurement uncertainty of their testing devices.

We conducted observations of wind velocity profiles above a high-density area in Tokyo, Japan, using a Doppler LIDAR system. Obtained data of the exponent index for the power law, which is commonly used to describe the wind velocity profile, displayed diurnal variation, decreasing in the daytime, which is expected in unstable atmospheric conditions. This paper provides information on the uncertainty in the calculated ventilation airflow rate due to the use of a constant value for the exponent index.

The objective of this paper is to assess the impact of the envelope airtightness on airflow patterns for single detached dwellings depending on the ventilation system.

The Net Zero Energy Residential Test Facility (NZERTF) was constructed at the National Institute of Standards and Technology (NIST) to support the development and adoption of cost-effective net zero energy designs and technologies. Key design objectives included providing occupant health and comfort through adequate ventilation and reduced indoor contaminant sources.

Constructions joints occur everywhere where several construction materials meet. That’s many meters that need to be taken care off, respecting the function that the materials or the joint need to fulfill. Typically a joint filled with sealing material has to account for water tightness, or is applied for esthetical reasons. Insulating materials can also be injected for thermal or acoustical insulation. A combination of joint materials often guarantees more advanced functions, fire resistance is a typical example.