Putting Pressure on Your Ventilation Systems

Finding the Right System for Your Building.

Choosing the ventilation systems for a plant or factory can be an extremely important decision when designing a new building or repurposing an old one. A building’s ventilation system will have a major impact on the interior temperature, humidity, noise level, airborne dust, and many other elements within the facility. Proper ventilation will also help maintain the structural integrity of the building itself by reducing the damage caused by heat and humidity such as corrosion or rust.

The manner in which a ventilation system controls the aforementioned factors such as heat and humidity can vary depending on the system type. Many ventilation systems operate by affecting the pressure inside the building in order to create airflow. Different systems have different configurations, which in turn can have very different effects on the building’s overall ventilation.

Negative Pressure – Powered Exhaust Systems

powered ventilation systemsA negative pressure system creates negative air pressure inside the building. By using exhaust fans to suck the air out of the building a negative pressure system is created. Due to the negative pressure, fresh air is continually drawn into the building through wall vents known as louvers. This constant movement of air is good for ventilation, however, this system does not work effectively in large facilities due to the effective air capture distance of the fans.

Positive Pressure – Pressure Gravity Systems

pressure gravity ventilation systemsPositive pressure systems work in the exact opposite way; Fans blow fresh air into the building, while the hot interior air exhausts from the building via roof vents. Fresh air replenishes the air at floor level. This has the added effect of creating a “breeze” that provides an evaporative cooling effect as it flows along the workers’ skin.

Neutral Pressure – Natural Ventilation Systems

natural venitlation systemsNeutral pressure systems utilize fans can work in one of two ways. The first includes using more fans to blow air both into and out of the building simultaneously. The second includes using a natural ventilation system to allow for the natural flow of air to ventilate a building. Natural ventilation helps maintain neutral pressure while ventilating the building. This involves balancing the air entering and leaving the building; creating a system that uses neither positive or negative pressure to move the air.

Ventilation Systems Pressure

The level of neutral pressure within in the building controls the amount of fresh air that drawn into the building. By controlling the air pressure within a building, the fresh air can be directed to enter at the rate and direction required to achieve optimal airflow in the building.

The fresh air may not mix adequately if the calculations for the proper pressure levels are incorrect. When air does not mix, this leads to poor air flow. This can result in a stratification of air inside the building. Stagnant air, whether it is hot or cold, will have a negative impact on any ventilation system.

Call a Moffitt representative today to learn more about how air pressure can affect a ventilation system.

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