Ventilation is a simple but effective method for ensuring cleaner, safer indoor air.
Poor indoor air quality is a workplace hazard that doesn't always get enough attention. On the milder end, it can result in some degree of discomfort and may cause people with sensitivities to experience symptoms. More severe air quality hazards, however, can result in chronic and persistent health conditions.
While there are a number of ways to control this hazard and protect workers from the harms associated with low indoor air quality, ventilation is almost always the first line of defense.
To put it simply, ventilation is the process of replacing indoor air with outdoor air. In some cases, this can be accomplished by installing vents or opening windows to create better airflow. In most workplaces, however, mechanical ventilation will be needed to keep indoor air quality at a safe and comfortable level.
The Benefits of Ventilation
Good ventilation will improve indoor air quality, yes. But what does that mean, exactly?
Well, it really means a few different things.
Ventilation can help control temperature, replenish oxygen, and remove pollutants from the air. It can also regulate moisture, clear dusts from the air, and reduce the levels of carbon dioxide inside a facility.
An effective ventilation system can also remove unpleasant odors, make the environment less hospitable to molds and mildew, and keep air circulating rather than letting it become stagnant.
Controlling Indoor Air Quality Hazards with Ventilation
In any indoor space, there can be a number of airborne pollutants harming the health of occupants. In most cases, those pollutants are both invisible and odorless, making it very difficult to identify them. In fact, they're often identified indirectly, like when the people who work in a space start to feel sick or uncomfortable with no clear cause.
Dusts and smoke are two common air quality hazards, but one that is perhaps not as well know are volatile organic compounds (VOCs). VOCs can contain carbon, hydrogen, oxygen, fluoride, chlorine, bromide, sulfur, or nitrogen. Moreover, VOCs easily convert to vapor or gas, making them a high risk for exposure through inhalation.
Creating air ventilation through a mechanical system is a highly effective way of controlling these hazards. Moreover, if you are using an HVAC system to improve ventilation, it will also heat, cool, and manage humidity levels.
People who don't work outdoors spend about 90% of their time indoors. This alone is enough to show that ventilation is an important safety concern, since indoor air typically harbors more pollutants than outdoor air.
Good ventilation also prevents various types of property damage, such as wood rot, peeling paint, insect infestations. It also keeps insulation from getting too damp, which allows greater heat retention and keeps heating bills low.
(Find out Why Winterization Is Important for Health and Safety)
Additional Considerations for Mechanical Ventilation Systems
Mechanical exhaust systems are common in kitchens and bathrooms as a way to control odors and humidity. For kitchens, these systems must also be a equipped to manage smoke and grease.
A ceiling fan can also improve air circulation with in a single room. This does not negate the need for ventilation, however, as it does not exchange indoor air with outdoor air.
While natural ventilation offers a simple and often quite effective solution to indoor air quality hazards, it is not recommended for basements and other spaces below ground level. In those cases, the outside air can cause excess humidity and condensation, resulting in additional problems that could have been avoided with mechanical ventilation.
High heat and low temperatures can also make natural ventilation inadvisable. Since it involves creating a flow of outdoor air into the indoor space, this can create discomfort if that outdoor air is either hot or frigid.
Ventilation guidelines are based on the minimum ventilation rate required to maintain acceptable levels of bio effluents. Since it is the gas with the highest emission rate at a relatively constant level, carbon dioxide is used as a reference point. The constant value for carbon dioxide is 0.005 L/s.
ANSI/ASHRAE Standard 62-89 has set a "comfort (odor) criteria are not to exceed 1,000 ppm CO2. OSHA has set a limit of 5000 ppm over 8 hours.