What is a flow regulator: installation and operation

A flow regulator is an element located inside the duct in order to achieve a constant flow within a pressure range that typically ranges from 50 to 200 Pa. It is a mechanism used in both ventilation and air conditioning, as well as in the extraction of air and injection processes. This flow circulates through the ventilation ducts and is defined as the amount of air flowing through the duct. Its mathematical expression is:

• Q = V x S

where Q is the flow (m3/h), V is the velocity (m/s) and S is the section (m2).

The circulation of a certain amount of air through a ventilation duct is heavily conditioned by the pressure loss, which is the pressure needed to overcome the friction inside a duct. This pressure determines the energy expenditure needed to circulate the air flow through the ducts, that is, the pressure drop. This depends on several factors, including the air velocity, its density, and the roughness of the duct walls. It should be noted that air ducts are not always composed of straight sections, but often present bends, deviations, inlets, and outlets. All these elements offer resistance to the flow of air, causing pressure losses. To know the total resistance of a duct system, it is necessary to calculate the pressure drops in each of the obstacles in its layout and add them to those of the straight sections.

Installation and maintenance of the flow regulator

The flow regulator is installed by simple installation inside the ventilation duct, whether vertical or horizontal. A seal gasket prevents flow loss when the air flows through the regulator. Occasionally, the regulator may be associated with an air diffusion mouth. The minimum distance between the two must be at least once the diameter at the extraction points and three times the diameter at the injection points.

Required renovation flows in the C.T.E. DB-HS3

The Technical Building Code in its Basic Document HS3. "Air Quality" defines the renovation flow for each room in l/s, based on the number of occupants in each one. In bedrooms, it considers one occupant for single bedrooms and two for double bedrooms. In each dining room and living room, it considers the total number of occupants counted in all bedrooms of the house, following these parameters to define the minimum ventilation flow for each local:

• Bedrooms: 5 l/s per occupant

• Living rooms and dining rooms: 3 l/s per occupant

• Bathrooms and toilets: 15 l/s per local

• Kitchens: 50 l/s per local

• Storage rooms and common areas: 0.7 l/s per m2 of usable surface

• Parks and garages: 120 l/s per parking space

• Waste storage areas: 10 l/s per m2 of usable surface