Air diffusion in tertiary and industrial buildings: A practical guide for installers
This comprehensive guide provides support for managing air diffusion in tertiary and industrial buildings. Discover the types of diffusers, the selection criteria and best practices for successful installation.
1 – The basic principles of air diffusion
Air diffusion consists of supplying, distributing and evacuating air to/from a space so as to ensure thermal comfort and good air quality. The key to a high-performance air diffusion system lies in understanding certain principles, such as fluid dynamics and types of air flow.
a. Fluid dynamics: what is it?
Although invisible, air is subject to specific physical laws, especially two phenomena which play a major role in air diffusion:
- The Coanda effect: The supply air tends to adhere to nearby surfaces, such as ceilings or walls. This makes it possible to direct the air flow, while preventing uncomfortable direct air currents.
In the case of a wall diffusion unit, the distance between the air stream and the ceiling must be small (around 30 cm). For a ceiling diffusion unit, the Coanda effect is guaranteed as long as the diffusion angle is 45° or less. - Induction: When the supply air enters a space, it draws in the ambient air with it, which increases the moving air volume, and promotes a homogeneous mixture.
b. Types of air flow
Today’s diffusion systems are based on two types of air flow:
- Turbulent flow: Characterised by irregular movements, it enables the conditioned air to mix quickly with the ambient air.
- Laminar flow: This more stable and direct flow is used in environments where clean air is vital, such as white rooms or operating theatres.
2 – The various types of air diffusion system
Choosing the ideal diffusion system for your project guarantees you optimal comfort and efficient distribution. But what are the main air diffusion categories available?
a. Mixing diffusion
Mixing diffusion is the most common type of system in offices, schools or commercial spaces. It consists of a high-speed air supply, creating a turbulent flow to mix the fresh air with the ambient air. It ensures a homogeneous temperature (though it can generate air currents if incorrectly configured). Similarly, mixing diffusion is not ideal for some applications where the ambient air is heavily polluted.
b. Displacement air diffusion
Ideal for environments where air quality is the priority, this system supplies the air at low speed. The fresh air is generally cooler than the room air, so this process causes controlled and uniform air displacement towards the top of the room. Hence the pollutants and contaminants rise quickly above the occupied space, and the air is extracted from the room via the ceiling space. This is a highly efficient solution, but requires space for the diffusers.
c. Swirl diffusion
Suited to large spaces, this system can blow air at high speed over very long distances. Although this system covers vast areas, it can be noisy and creates strong air currents. This system can be found in specific installations such as industrial applications, and large spaces such as airports.
3 – How to select your diffuser The key criteria for a successful installation.
Selecting the right diffuser is essential to ensure the air quality and optimal comfort in your project. Here are the main criteria to consider when choosing your diffuser ⬇️
a. Types of diffusers
- Ceiling diffusers: Available in circular, rectangular or linear versions. They provide uniform air diffusion, adjustable from 1 direction to 360°, and are ideal for large open spaces.
- Wall grilles: Versatile and economic, these are suitable for the air return or a targeted air supply.
- Stream diffusers: Used for long-range applications, these are perfect for warehouses or rooms with high ceilings.
- Air displacement diffusers: Used in large spaces to maintain an excellent interior air quality while providing optimal comfort
b. Selection parameters to consider for air diffusion
- Air flow: The diffuser must be able to manage the requisite air volume without generating excessive noise, or uncomfortable air currents.
- Range and drop: You need to ensure that the air stream can cover the necessary distance while adhering to comfortable areas for the occupants.
- Induction: The diffuser’s capacity to mix the supply air with the ambient air is crucial in order to prevent air stagnation.
c. Select a design according to its architectural integration
The choice of air diffuser is not limited to its technical performances: it also plays an essential role in the aesthetics and harmony of the interior spaces.
Our air diffusers are available in a range of elegant modern models designed to fit into any architectural style perfectly. Thanks to their streamlined shape and a variety of finishes, each CAIROX diffuser becomes a discreet but crucial feature.
We also offer more technical solutions to blend into the air diffusion system designs, such as our textile plenum PLUMBOX.
At CAIROX, we have a wide range of diffusers able to meet a variety of needs and applications, whether in terms of performance or design.
But perhaps you could do with some expert advice?
4 – Good practice for installing grilles and diffusers
Here is our advice for successful air diffuser installation:
- Positioning: Make sure that the diffusers are placed so as to prevent direct air currents aimed at the occupants, while ensuring uniform coverage of the space.
- Spacing: Adhere to the recommended spacing between the diffusers to ensure homogeneous air distribution.
- Setting: Adhere to the experts’ recommendations for your project, and the recommended configurations for your diffuser.
5 – Cairox: Your air diffusion partner
CAIROX’s mission is to bring you products meeting the air diffusion challenges inherent in tertiary and industrial buildings. Thanks to our network of subsidiaries in Europe, we are able to supply our customers with local stock suited to their needs and standards.
Our technical teams, backed up by simulation tools, are there to support you throughout your project, whether small-scale or more complex installations.
✉️ Contact an expertYour questions about air diffusion and choosing diffusers
Air diffusion not only ensures the thermal comfort of the occupants, but also good air quality, essential for their health and productivity.
The main types include ceiling diffusers, wall grilles, floor diffusers and air stream diffusers, each of which is suited to specific needs in terms of air flow and aesthetics.
The choice depends on several factors: the requisite air flow, the range, the permissible noise level and the building’s aesthetics. To make the right choice, it is advisable to use the selection tools supplied by the manufacturers.
It is important to follow the recommendations in terms of spacing, setting and positioning of the diffusers, to prevent unpleasant air currents and ensure uniform air distribution.
Cairox offers comprehensive support thanks to its local teams, its air stream simulation and product selection tools, as well as its large stock available to quickly meet your on-site needs.