To allow natural ventilation in steel buildings, there are elements in the design that should be considered. This is a continuation of last Friday’s post. It talks about additional design considerations for steel buildings.

· Allowing airflow between rooms of steel buildings is important. Interior doors should always be open to allow for whole-building ventilation. However, for rooms that require privacy, installing louvers or transoms is one way of providing ventilation.

· For steel buildings with attics, ventilating the attic space creates a major reduction in heat transfer to air-conditioned rooms below. It has been found that a well ventilated attic is 30°F cooler than unventilated ones.

· Consider the use of motorized fans like ceiling and whole-building fans. This strategy can provide up to 9°F temperature drop at one tenth of the energy consumption of mechanical air-conditioning systems.

· Determine which of the two methods work well to achieve natural ventilation – closed-building approach or open-building approach. For hot and dry climates where there is a significant difference between day and night temperatures, a closed-building approach is ideal. A large building is open at night to allow cooler air to come in and closed during the day to keep out the hot daytime air.

For steel buildings in war and humid areas where there is not much difference between day and night temperatures, an open-building approach is best. An open-building approach means that daytime cross ventilation is encouraged to maintain comfortable indoor temperatures.

· Opt for open staircases because they provide stack effect ventilation for steel buildings.

Source: http://www.wbdg.org/resources/naturalventilation.php#

Our concern for finding ways to save the environment makes natural ventilation an attractive method for reducing energy consumption and at the same time providing healthy, comfortable, and productive indoor climate in steel buildings. In appropriate settings where natural ventilation is used as an alternative to air-conditioning, as much as 30% of the total energy consumption can be saved.

Natural ventilation would benefit the following types of steel buildings:

· Bus stations, picnic shelters, and other steel buildings where stringent space conditioning (space heating + space cooling) is not expected
· Barracks and other single- and multi-family housing projects
· Small, free standing steel buildings in warm and temperate climates
· Warehouses, maintenance pools, and other high-bay facilities in warm climates

The online encyclopedia defines natural ventilation as the process of supplying and removing air through an indoor space by natural means. Counting on natural forces such as wind and buoyancy, natural ventilation systems rely on variations of pressure to deliver fresh air through buildings. For steel buildings to have efficient natural ventilation, both types should be implemented.

Wind blows air through the openings in the wall on the windward side of steel buildings, and suck air out of openings on the leeward side and the roof. Temperature variations between warm air inside and cool air outside causes the air in steel buildings to rise and exit at the ceiling or ridge, and enter via lower openings in the wall.

In the same fashion, buoyancy caused by a difference in indoor-to-outdoor air density resulting from temperature and moisture differences allows a pressurized column of dense, cooled air to come in, and lighter, warmer, humid air to come out near the top of steel buildings.

(to be continued)

Source: http://www.wbdg.org/resources/naturalventilation.php#