Nominal ventilation is a key term in ventilation technology that is often used but may not be familiar to everyone. So what is behind this term? In this blog post, we take a deep dive into the world of ventilation systems to shed light on the meaning, functionality and technical requirements of nominal ventilation. Let’s explore together the different aspects of this important component of indoor air technology and understand how it helps to create a healthy and comfortable indoor climate.
What is nominal ventilation?
Definition and delimitation of terms Nominal ventilation is a key term in ventilation technology that describes the standardised amount of air that is exchanged per period of time in a particular room. It ensures that the air quality in living spaces, offices and other buildings remains constant even without manual intervention. In contrast to minimum ventilation , which specifies the minimum required air supply, nominal ventilation defines a certain amount of air that should ideally be provided during normal operation. Nominal ventilation is an important factor for the indoor air quality and energy consumption of a building. It makes it possible to maintain a pleasant and healthy indoor climate by ensuring a sufficient supply of fresh air and removing stale air.
When defining the term, it is important to understand that nominal ventilation can vary depending on the area of application and room size. It is usually measured in cubic metres per hour (m³/h) and takes into account factors such as the use of the room, the number of people and the specific air quality requirements. Nominal ventilation can be realised by various ventilation systems and technologies, with the aim always being to ensure optimum air exchange and improve the comfort of the room users. By clearly defining and calculating the nominal ventilation, planners and operators can ensure that the ventilation system works efficiently and fulfils the individual requirements of the building.
Ventilation levels in detail: How nominal ventilation fits in Ventilation systems must always be in harmony with the specific requirements of the respective building and its utilisation. Nominal ventilation is an important part of ventilation management, but it is not the only ventilation stage.
1. ventilation for moisture protection (minimum ventilation) As the lowest level, the primary aim of ventilation for humidity protection is to regulate humidity indoors. Excessive humidity caused by breathing, showering or cooking can result in mould growth and damage the building fabric. This is where ventilation systems come into play, which specifically reduce the humidity in order to prevent such damage. This ventilation level must be taken into account particularly in damp rooms such as bathrooms, kitchens or washrooms. Ventilation for moisture protection is less about a constant supply of fresh air and more about the targeted control unit of air circulation to keep the room humidity below a critical level. A permanently high moisture content in rooms can be harmful to health and damage the building fabric. Nominal ventilation plays a supporting role in this context, as it ensures that fresh air is continuously supplied to dilute and remove the humidity.
2. reduced ventilation Reduced ventilation is used in situations where ventilation is not dependent on the full level of nominal ventilation, but where a certain amount of basic ventilation is still necessary. A typical example is rooms that are not in constant use, such as storerooms, cellar rooms or guest rooms. In these cases, reduced ventilation is sufficient to maintain the air quality without the system having to rely on the full nominal ventilation values. Reduced ventilation is particularly advantageous in terms of energy efficiency, as it minimises air exchange and thus reduces heat loss through ventilation.
3. nominal ventilation Nominal ventilation ensures that there is always a sufficient supply of fresh air in a room to keep the air quality at a healthy level. It describes the specified amount of air that must be supplied to a room in order to ensure an optimum oxygen supply and the dilution of pollutants such as CO2, odours or VOCs (volatile organic compounds). Nominal ventilation is therefore particularly important in frequently used rooms such as living rooms, offices or classrooms. In contrast to ventilation at previous levels, nominal ventilation ensures constant air circulation, which ensures stable indoor air quality under ‘normal conditions’ in a home.
4. intensive ventilation Intensive ventilation is the highest ventilation level and is used when particularly high demands are placed on air quality or when rapid air exchange processes are required. This often occurs in areas where there is a high level of pollutants or moisture, such as in commercial kitchens, laboratories or during renovation work. With intensive ventilation, a significantly higher volume of air is supplied in the shortest possible time in order to quickly relieve the indoor air and ensure high air quality. It is often used in combination with powerful exhaust air systems or in ventilation systems with heat recovery (HRV) in order to maintain energy efficiency at the same time. In some cases, intensive ventilation can also be used as a temporary measure, for example when very humid air needs to be extracted.
These four ventilation stages represent a flexible system for ensuring air quality, which is used depending on the room and situation. Nominal ventilation forms the central basis, as it constantly ensures fresh and low-pollutant room air. Technical requirements and calculation principles Nominal ventilation is an essential concept in ventilation technology, which entails certain technical requirements and calculation principles. Nominal ventilation defines the standard air volume required to ventilate and extract air from rooms in order to ensure optimum air quality.
The calculation of nominal ventilation is based on various factors such as the size of the room, the utilisation of the room, the number of people present and the required air quality. The aim is to supply the right amount of fresh air to ensure a comfortable indoor climate and to effectively remove pollutants and odours. The technical requirements relate to the selection and design of the ventilation system in order to ensure nominal ventilation in accordance with the individual needs and requirements of the building. Aspects such as air volume flows, filter efficiency, sound insulation and energy efficiency must be taken into account. In order to calculate the nominal ventilation correctly, specific key figures and formulae are used to enable precise dimensioning of the ventilation system.
The DIN standard plays a decisive role here in defining and complying with the qualitative requirements for the ventilation systems. The precise determination of the nominal ventilation is of great importance in order to create a healthy and comfortable indoor climate that meets individual requirements and legal specifications. Professional planning and design of the ventilation system ensures an efficient and reliable ventilation solution.
Important terms in connection with nominal ventilation
In connection with nominal ventilation, certain terms are of central importance in order to fully understand the concept.
Supply air and exhaust air: Supply air refers to the fresh air that flows into a room, while exhaust air is the stale air that leaves the room. A balanced exchange between supply air and exhaust air is crucial for a good indoor climate.
Air flow: The air flow indicates how much air is transported through a ventilation system per unit of time. It is measured in cubic metres per hour (m³/h) and is an important value for assessing the efficiency of the ventilation system.
Air exchange rate: The air exchange rate describes how often the air in a room is exchanged within an hour. A high air exchange rate is particularly important to ensure fresh air and reduce pollutants.
Sound level: The sound level in conjunction with the nominal ventilation rate provides information about the volume generated by the ventilation system. A low sound level is crucial for comfort in a building.
Hygienic filter: Hygienic filters help to filter pollutants, dust and pollen from the incoming air. They help to improve air quality and protect the health of the occupants.
Heat recovery: Heat recovery is an important aspect of nominal ventilation, where the heat from the exhaust air is used to heat the supply air. This saves energy and helps to reduce heating costs.
Legal requirements and standards in detail
Legal requirements and standards are of crucial importance when planning and implementing ventilation systems. Nominal ventilation plays a central role here and must be designed in accordance with the regulations. The directives specify how indoor air quality is guaranteed and energy efficiency ensured. The statutory regulations must be complied with, particularly in new builds and refurbishment projects.
Nominal ventilation ensures that a constant exchange of air is guaranteed and that pollutants and humidity are efficiently removed. Specific legal requirements apply to nominal ventilation, which installers and planners must observe. DIN 1946-6 regulates the requirements for the ventilation of residential buildings and describes the minimum requirements for air exchange. This standard ensures that nominal ventilation not only meets health standards, but also energy efficiency standards. The Energy Saving Ordinance (EnEV) stipulates that new buildings and extensively renovated buildings must fulfil certain requirements in terms of energy consumption and therefore also in terms of ventilation systems. Nominal ventilation in combination with heat recovery plays a key role here. Other relevant regulations are the Building Regulations and the Technical Building Regulations, which specify how ventilation systems are to be planned, installed and operated.
It is important to keep an eye on all relevant regulations in order to create an optimum indoor climate and minimise energy consumption at the same time. Compliance with legal requirements and standards is therefore essential for a functioning and efficient ventilation system.
Decentralised ventilation systems as a solution for meeting nominal ventilation requirements
In the context of ventilation technology, decentralised ventilation systems can be a convincing solution for meeting nominal ventilation requirements. With this approach, ventilation systems are installed locally in the respective rooms, enabling individualised and needs-based ventilation. Technologically, these systems are often equipped with modern humidity sensors, CO2 sensors and heat exchangers, which enable needs-based control units. A major advantage of decentralised ventilation systems is their flexibility and modularity. They can be adapted to the specific requirements and conditions of a building and therefore offer a customised solution for nominal ventilation. In addition, decentralised ventilation systems offer a good opportunity for noise reduction and can therefore create a pleasant and quiet room environment. This is particularly important in living areas, offices or schools where optimum acoustics are required. The integrated heat recovery in many decentralised ventilation systems contributes to energy efficiency, as the exhausted air preheats the incoming fresh air. This results in a reduction in energy consumption and thus also supports the fulfilment of sustainability goals. Overall, decentralised ventilation systems can be considered an innovative and effective solution for meeting nominal ventilation requirements. It offers numerous advantages in terms of efficiency, comfort and environmental compatibility and therefore represents a forward-looking option in the field of ventilation technology.
Correct calculation and implementation of nominal ventilation is crucial to ensure energy efficiency and air quality. It is also important to observe legal requirements and standards to ensure that everything meets the required standards. By integrating modern decentralised ventilation solutions, many requirements can be effectively met. So, always keep nominal ventilation in mind to plan an optimal indoor climate and an efficient ventilation system.
