Ventilation to Ensure Good Air Quality in Offices

Index

01 Interesting and Health Data

02 Regulations and Health

03 Types of Ventilation

03.1 Controlled Mechanical Ventilation

03.2 Hygrometrically Regulated Mechanical Ventilation

03.3 Controlled Double Flow Ventilation

04 Most Common Air Conditioning Systems

04.1 Constant Flow

04.2 Variable Flow

05 Causes of Deterioration in Air Quality

06 Tips for Good Air Quality in Offices

Offices are closed spaces where millions of people around the world spend a large part of their time. Therefore, the air quality in offices must be taken care of for health and well-being reasons. When the environment is polluted, it must be renewed from the outside to the inside. To achieve this, adequate ventilation contributes to improving habitability, while reducing humidity levels. Similarly, with controlled mechanical ventilation systems, especially double flow systems, we prevent risks from the action of dangerous or toxic gases.

If that were not enough, adequate ventilation and energy efficiency are closely related. The mentioned systems are optimal to reduce energy consumption in offices and save on the electricity or gas bill.

01 Interesting and Health Data

City inhabitants spend about 90% of our time indoors. Workplaces, housing, or transportation are the main environments where we live. Throughout the 24 hours of the day, we breathe about 15,000 liters of air. Therefore, if it is not in good conditions, our health is at real risk.

Offices are spaces that remain closed most of the time, even with windows or doors. Temperature regulation is done through air conditioning devices and other ventilation systems. At first glance, we might believe that air quality in these places is good. Surely, most people would say it is much better than in open spaces. However, the World Health Organization states that it is up to eight times worse in terms of pollution levels.

What are the reasons for this to happen? The main reason is poor or nonexistent ventilation, which leads to the concentration of pollutants. What may be more surprising is that the indoor pollution rate is higher in open-plan offices. That is, the so-called open spaces contain more harmful substances than individual offices or small ones. In these cases, indoor air can be up to ten or twenty times more polluted than the exterior.

02 Regulations and Health

Aware of this reality, both the European Union and Spain have mandatory regulations. They regulate the ventilation conditions that certain spaces must meet, including office buildings. The main norms are as follows:

• Technical Building Code (CTE). Basic document HS3 - Habitability and Health - Indoor Air Quality.
• Regulation of Thermal Installations in Buildings (RITE).
• Royal Decree 235/2013.
• European Directive 2010/31/EU.

The CTE is the normative framework that marks the conditions of habitability and safety that buildings must meet. This document is based on the Law 38/1999 of November 5, on Building Regulation (LOE). In addition to ventilation conditions, it also establishes many other issues, such as accessibility, energy savings, or structural safety.

On the other hand, the RITE establishes the technical requirements of facilities regarding thermal well-being and hygiene. That is, it sets criteria for air conditioning, heating, or hot water installations.

Among the issues covered by the RITE are:

• Indoor air quality.
• Acoustic environment quality.
• Thermal environment quality.
• Hygiene.

In this regard, it sets requirements that pursue, among others, the following objectives:

• Optimization of energy performance of heat and cold generators.
• Improvement of thermal fluid insulation and conduction.
• Use of renewable energies, especially photovoltaic and biomass.
• Use of energy recovery subsystems and exploitation of residual energies.
• Accounting systems for consumption in collective installations.
• Progressive elimination of the most polluting solid fuels.
• Gradual elimination of less efficient generating equipment.

03 Types of Ventilation

Offices can be equipped with various types of ventilation. It is advisable in these cases to update the systems to optimize energy efficiency. Similarly, the adequate conservation of the building must be taken into account. For this, it is necessary to choose systems that guarantee good indoor air quality. Lastly, but not least, there are considerations about the health of the people working inside.

Natural ventilation is not sufficient to renew indoor air quality in offices. Wind and movement caused by thermal differences can help. The different density of indoor and outdoor air can drive external air through the building envelope openings. However, this requires specially designed designs, and even so, it is not something that is sufficient to guarantee the best ventilation conditions. It all depends on the climate, building design, and human behavior. To ensure clean air, we can resort to the following systems:

03.1 Controlled Mechanical Ventilation

It is a predominant option in new constructions and in building renovations, including offices. The reason is that it helps to renew the air while reducing energy consumption. This system can be of double or single flow. Thanks to the use of the appropriate mechanisms, they mechanically extract the polluted air from the room and direct it outside.

In the case of double flow, they also extract and renew the indoor air with a flow coming from outside. In this last case, the presence of a high-efficiency heat exchanger allows the two opposite flows to exchange heat. This process, which does not exchange air particles, but only temperature, ensures maximum energy efficiency. In this way, temperature control systems, such as heating or cooling, consume much less than conventional solutions.

At any time of the year, double flow heat recovery systems treat the air before reusing it. This is achieved, regardless of outside temperature, through filtration and dehumidification.

This air treatment system is very effective and has great advantages. Among them, the office will be healthier for those who work there. In addition, it will last longer from an architectural perspective. The reason is that problems such as mold or condensation can be solved.

An office design with maximum comfort and energy efficiency has systems that offer the following features:

• Air filtration.
• Controlled ventilation.
• Free cooling.
• Dehumidification and heat recovery.
• Temperature control systems.

03.2 Hygrometrically Regulated Mechanical Ventilation

This method is designed to extract poor quality air and renew it depending on humidity levels. This means that the main factor it takes into account is humidity. It works by following the principle of air sweeping within the office.

The most humid areas of the installation, such as bathrooms or toilets, are the places from which polluted air is extracted. This process is carried out through hygro-regulable vents. Their opening occurs depending on the humidity detected by the system. Another option for them to open is timers located in the vents that are connected to the equipment through ducts.

The flow of clean air is introduced through hygro-regulable inlets. Normally, they are located in the windows of the office or the building in which they are installed. If it is in a dwelling, they will be in the living room or lounge, for example. The duct network is placed in false ceilings, as it happens in many other cases.

03.3 Controlled Double Flow Ventilation

It is a controlled mechanical system that integrates extraction and delivery flow systems. Its advantages are numerous, although energy savings and air quality stand out. Furthermore, it regulates indoor temperature with a minimum energy cost.

The heat emitted by the polluted air that exits outdoors is used to raise the temperature of the air that is introduced. There is a zone of the installation where both ducts coincide, one that carries air outside and the other that introduces it. It is there that a temperature exchange occurs, although the ducts are completely isolated. Therefore, there is no contact between both flows. An extractor fan draws air from outside to the inside. On the other hand, an induction fan expels air from the inside to the outside.

Installations of this type are somewhat more expensive than controlled single flow mechanical ventilation systems. A larger number of ducts are required to channel the incoming and outgoing air. However, this provides significant savings on the energy bill. How do we achieve this?

• We recover up to 70% of the energy contained in the extracted residual air. In the case of high-efficiency systems already available on the market, up to 90% recovery is achieved.
• We use the heat released from the kitchen or bathroom.

04 Most Common Air Conditioning Systems

An air conditioning system is a device capable of regulating the temperature and humidity of the air. It can do so in both a dwelling or office and any other facility. In addition, it affects circulation and purity, thus reducing the amount of suspended toxic particles. With it, we also improve thermal comfort.

The air-to-air system is what we know as air conditioning. It consists of the following elements:

• Compressor.
• Condenser.
• Evaporator.
• Expansion valve.
• Pipes.

In addition to the aforementioned, there are three other types:

• air-to-air
• water-to-water
• water-to-air

In the case of the first type, air-to-air, there are two types: constant flow and variable flow.

04.1 Constant Flow

Air is introduced into the office or the relevant premises with a flow that is always at the same level. It is regulated by the temperature at which it exits and the time it operates.

04.2 Variable Flow

We adjust the amount of energy provided. On the other hand, we modify the amount of air introduced into the space that is being climatized. This can be an office or any other place.

05 Causes of Deterioration in Air Quality

There are numerous factors that can influence the levels of pollution and toxicity in the air. Among them are indoor pollutants:

• Humidity.
• Carbon dioxide.
• Volatile organic compounds.

On the other hand, there are also outdoor pollutants:

• Fine particles.
• Pollen grains.
• Radon.

06 Tips for Good Air Quality in Offices

The health of workers, their productivity, their well-being, and the good conditions of the office are affected by this factor. To maintain it, here are some tips:

• Resort to natural ventilation as much as possible, without blocking windows, doors or ventilation openings.
• Perform regular maintenance of ventilation, air conditioning, and refrigeration devices.
• Monitor humidity levels. When they oscillate between 30% and 50%, they help keep dust mites, mold, and other allergens under control. However, excessive humidity can be detrimental to building preservation, furniture, and human health.
• Resort to controlled ventilation systems, especially double flow ones. This allows optimizing air quality, temperature, and energy savings.
• Monitor radon levels. Perform tests to check if there is a real risk from this substance that increases the chances of suffering lung cancer.

As we have seen, energy quality and air quality in an office affect humans and the building itself. Therefore, taking care of it is crucial to maintain health and well-being levels. If you want to learn more about this topic, you might be interested in this article: Cleaning the ventilation ducts: what we need to know.