Indoor Air Quality Measurement by Belimo
Humans spend around 90% of their lifetimes inside closed rooms, so a good room climate is important. Air quality in particular has a huge impact on our health and well-being. Air tight building shells may well be superior in terms of energy, but they prevent natural air exchange. However, they can be fully automated using appropriate ventilation systems and sensors.
A Good Room Climate is Essential
People can survive around thirty days without food, up to four days without water, but only a matter of minutes without air. The most important component of air, i.e. oxygen, is needed to burn nutrients. The brain is particularly sensitive to a lack of oxygen. In rooms without ventilation, the concentration of CO2 increases, performance drops rapidly, we are unable to concentrate, feel tired, suffer from headaches and much more. But it's not just oxygen as well as the CO2 content of the air which indicates a good room climate. The air humidity (ideally 40-60%), air temperature, differential temperature, air ions, air quality and air velocity are also important for a healthy room climate.
There Are Very Few Specifications Governing Indoor Areas
While there are statutory requirements for outdoor air and compliance with them is monitored carefully, there are few binding limit values for indoor air. The WHO and Swiss Lung Association believe that, in 2020, chronic obstructive pulmonary disease (COPD) will be one of the most common causes of death worldwide. Therefore, indoor air needs to be "clean" if our health and well-being are not to be jeopardised. This can be achieved with a good ventilation system. Belimo's solutions for the heating, ventilation and air conditioning industry are making a vital contribution towards this. Belimo provides an entire range of sensors for measuring the most important factors affecting room climates, such as air quality, temperature, air humidity and flow. Our Variable Air Volume (VAV) technology and pressure-independent control valves ensure a perfectly balanced flow of air and water at all times, resulting in optimum comfort.
Good Air Quality for Greater Performance
The air around us comprises 21% oxygen, 78% nitrogen, 0.04% carbon dioxide (CO2), as well as traces of noble gases, water vapour and pollutants. Today, one of the most important indicators of air quality in closed rooms is the CO2 value. Because humans also produce CO2 by breathing and add this to the air, the concentration of CO2 continually increases in closed rooms where people are present. An air tight building shell means that the air exchange rate falls, resulting in an increased concentration of harmful substances in the indoor air. This can be counteracted by regularly venting rooms or, if this isn't possible, by fitting a ventilation system to take on this task. Because a ventilation system can also reliably remove air pollutants, it improves the air quality of rooms in which people are present over the long term. If such rooms are equipped with sensors, which provide the ventilation plant room with a permanent supply of data, the system will run in a reliable and independent manner.
Air Quality Measurements in Over 250 Classrooms
Currently, more than 30% of children in Europe suffer from allergy-related illnesses, such as asthma, hay fever or neurodermatitis. A link with pervasive environmental pollution cannot be ruled out. After all, in closed rooms in particular, pollutants can accumulate and also enter the body through the air inhaled. In addition to chronic illnesses, "poor air" also has further implications for our well-being. In order to discover how air quality affects pupils and teachers, the MeineRaumluft.ch platform joined forces with the Zurich Teachers' Association (Züricher Lehrerverband) and the Zurich Lung Organisation (Organisation Lunge Zürich) to install measuring devices in over 250 classrooms, which have been in place since November 2016. One positive effect was that simply installing the measuring devices affected the ventilation habits of teachers and pupils, because as soon as the concentration of CO2 in the room got too high, the windows were opened to let air in.
Despite this, Figure 1 of the image below shows that CO2 levels were found to be excessively high. In over 13% of the measurements taken at the end of the lesson, the CO2 level was above 2000 ppm, which is the upper limit value for CO2 concentrations in occupied rooms according to the SIA 180 standard. Figure 2 shows that the relative humidity was below 30% in a quarter of the measurements. This may result in health complications, such as a drying out of the airways' mucous membranes. Dust, dirt and germs are then not removed from the airways quickly enough. If these spend a long time in the respiratory tract, the risk of respiratory illnesses increases. Typical consequences include coughs, bronchitis, colds and sinus infections. The only good news is that from Figure 3 it can be seen that, with a few exceptions, the temperature in degrees Celsius was in an acceptable range.
Achieving Good Air Quality With Smart HVAC Components
Standardised guidelines exist for the composition of indoor air. To a great extent, these correspond to the feel-good factor. HVAC building automation is key to maintaining these. The ventilation plant room is networked with controllers and sensors. Air values in the rooms can be automatically optimised if the components that are fitted with sensors communicate reliable information to the plant room in order to control fans and regulate temperature, CO2 content and air humidity. The building management technology then automatically compares the incoming information about the actual and nominal status in the room and gives the actuators the corresponding command to open or close dampers and valves or move them to an intermediate position. This enables the desired supply of air at a comfortable temperature, with the ideal level of humidity and a rich oxygen content.
Belimo Sensors – The Foundation of Comfort
Belimo HVAC sensors offer superior reliability, easy installation and seamless integration with major building automation systems. The innovative housing design allows for quick and tool-free installation, easy commissioning and provides NEMA 4X/IP65 protection. The product range includes accurate sensors for measuring temperature, humidity, pressure, CO2, volatile compounds (VOCs), and flow in pipe and duct application.
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