Maintenance of ventilation ducts: a regulatory issue
superadmin
December 16, 2016
In this article, we will explain the causes of microbial contamination present in ventilation systems and the regulatory framework that mentions maintenance issues related to maintenance of the elements that are part of these installations (ventilation ducts, filters, and openings).
Ventilation systems, the gateway to microbial contamination
Do you know the main hazards of indoor air pollution in the space you inhabit or work in? Let’s take a closer look at its origin. Fungi can infiltrate unnoticed into the habitable areas of our domestic environment, either due to damage from moisture, the presence of domestic animals, through contaminated air humidifiers, and of course, due to the existence of ventilation and air conditioning devices that have not been properly maintained.What does this deficient maintenance, which you should avoid if you seek good indoor air quality in your home or workplace, consist of? It can be due to different causes:
- Poor quality of the installed filters, or poor selection of them based on the conditions of use of the space and required maintenance. The filters retain a good part of the particles carried by the air. Since they can also carry microorganisms, they represent a good medium for the development of such organisms.
- Deficient maintenance and cleaning. Proper maintenance and cleaning of air conditioning, ventilation, humidifiers, or cooling towers must be ensured.
- Lack of tightness and accumulated dirt in the air ducts.
- Improper placement of outdoor air extraction points. These extraction points should not be installed in locations where, from a microbiological point of view, there is particularly specific external contamination.
Maintenance and cleaning of ventilation ducts: do you know the regulations that address this issue?
According to the CTE DB HS 3 Indoor Air Quality, the ducts, whether for admission, extraction for hybrid ventilation or for mechanical ventilation, will have a finish that makes them difficult to soil. Additionally, they must be accessible for registration and cleaning. In the case of the former, every 10 m at most, throughout their course; for the second, at the top and at the start; and for the third, at the top and at the start of the vertical sections. The basic document also warns that different maintenance operations must be performed. Thus, ducts, openings, and filters will be cleaned every year (in the case of filters, their replacement should be assessed), the tightness of the ducts will be checked every five years and the condition of the filters will be reviewed every six months.According to RITE, the interior lining of the ducts must withstand the aggressive action of disinfection products. Moreover, their inner surface must have a mechanical resistance that allows them to withstand the stresses imposed by mechanical cleaning operations stipulated by the UNE 100012 standard regarding the hygienization of air conditioning systems.
According to the standard UNE-EN 13403:2003, regarding building ventilation, different cleaning systems (contact suction, pressurized air, or brushing and pressurized air) can be used. If the cleaning method used is brushing, it is important to note that metal brushes are prohibited. Regarding the panels of insulating material in the ducts, these must withstand cleaning operations equivalent to a 20-year service life, so that the material of the inner surface of the duct does not show detachment, chipping, or evident signs of erosion.
Finally, the UNE 100030 IN:2005 standard, Guide for the prevention and control of proliferation and dissemination of legionella in installations, reminds us that in ducts for air transportation where dirt can accumulate in areas with low air velocity, there are turbulence and water introduced due to leaks, or condensation occurs, there is a risk of microorganism proliferation, particularly legionella. The standard, like the previous ones, recommends using ducts with a smooth surface, made with materials that resist corrosion and the mechanical action of cleaning. As for the section of the ducts, as much as possible, the standard stipulates that circular, oval, or rectangular sections with rounded corners should be chosen to facilitate cleaning operations.
Ensure that your ventilation system complies with the demands of current regulations and do not allow the elements of your ventilation system to endanger the health and well-being of your family.
Siber Ventilation
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