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In a sealed building with tight facades, conditions for a good indoor air quality and comfortable conditions must be guaranteed all the time especially for employees. This paper deals with the case of a specific retrofitted building without any openings that immediately shows many difficulties to maintain good indoor air quality in some parts of the occupied volume. An assessment of ductwork and HVAC system performance was first realized, conducted by the SNIA (National Airport Engineering Service).

An accurate temperature gradient calculation is essential for displacement ventilation (DV) system design, since it directly relates to the calculation of supply air flow rate. Several simplified nodal models were developed and implemented in the various building simulation programmes in order to estimate the temperature stratification in rooms with displacement ventilation. However, the most commonly used models do not count the types and locations of the typical heat loads in rooms with displacement ventilation.

The real performances of ventilation systems on site remains a challenge in practice. One of the most common reasons for complaints by the building occupants is the acoustic discomfort. Mechanical ventilation often produces too high levels of noise, mainly coming from the fans. 

Although several good practice recommendations are theoretically known to limit the noise generation by mechanical ventilation systems, the acoustical performance of real ventilation systems on site seems uncontrolled and unexpected.  

Noise remains a major concern for building occupants, both in their home and workplace. Ventilation system is one of the noise sources in buildings. Usually, the main issue is the resulting noise level in the room. It is generated by the fan and the ductwork components, travels inside ducts, and is then radiated into the room by air diffusers, air inlets, and air outlets. But ducts also go through other indoor spaces. Airborne noise will pass through the duct wall and radiate in the surrounding space. This can be an issue for occupants. 

International there are many different requirements and regulations for ventilation.  Sometimes the variation is more than a factor of five. There are strong drivers to reduce energy consumption for HVAC, and therefore the spread in requirements and regulation is worthwhile to study. To reduce ventilation flows there is a necessity to understand the reasons behind. Demand control to reduce this flows is in many countries growing but the control parameters are quite different, for instance humidity versus CO2 control.

Particulate matter with a diameter of ≤2.5µm (PM2.5) has been shown to be present in many buildings at concentrations that are harmful to human health. Accordingly, they should be used as metrics of indoor air quality (IAQ) and included in standards or norms. This paper uses measurements of PM2.5 concentrations made in three different environments using three different devices to show that there are barriers that must be before they can be considered viable diagnostics. Optical particle counters (OPCs) are a common device used to measure temporal changes in PM2.5 concentration.

A systematic and efficient strategy is needed to assess and manage the potential risks to human health that arise from the manufacture and use of thousands of chemicals.  For both volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs), exposure is strongly influenced by the types of materials and products in which the VOC or SVOC occur, the concentration of the VOC or SVOC in the material or product, the way in which the material or product is used or applied indoors, and the ventilation rate within the room or building.

In March 2016 a new regulation came into force in Belgium regarding the wellbeing at work, with specific requirements on the indoor air quality (IAQ). The requirement is expressed as a maximum absolute CO2 concentration of 800 ppm in all working spaces. Compared to the previous requirement, i.e.

As a result of new inquiries in 20 countries the ventilation requirements will be presented for different rooms in dwellings, offices and schools. These rooms are differentiated between wet rooms such as toilets, bathroom and kitchen and typical rooms for these buildings for instance classrooms and office rooms. The results show big differences between countries. Climate and building style can have an effect on ventilation requirements. Some countries have to only requirements for specific rooms but also for whole house and whole building ventilation.

Airtightness is the most important property of building envelopes to understand the ventilation. Airtightness refers to the flow measurement through the building envelope as a function of pressure across the building envelope. This relationship often fits to a power law, which is the most common way of expressing data. However, pressure homogeneity during airtightness tests can crop up, especially in large buildings.