OBSERVING AIR FLOW IN BUILDINGS INTRODUCTION The movement of air in a building affects the thermal comfort of occupants, influences the rates of heat gain or loss through the building envelope, and determines whether good-quality indoor air will be present. How a building designer lays out a building, chooses materials, defines building details, and participates in the construction process will influence the nature and magnitude of subsequent air movement in the building. Thermally-comfortable environments depend on four environmental parameters and two personal parameters. The four environmental parameters are the dry-bulb temperature of the air surrounding the occupant; the relative humidity of the air; the (net) radiant exchange between the occupant and the surrounding surfaces; and the rate of air movement around the occupant. Further, the two personal parameters are the metabolic rate for the activity in the occupant is engaged and the insulative value for the occupant’s clothing ensemble. Thus, one determinant of whether a building occupant will feel thermally comfortable is how rapidly or slowly air moves in the vicinity of the individual. For example, on a day when the air in a building is warm and humid, air flow around an occupant can improve how comfortable the individual will be. Alternatively, when interior air is cool and flows around an occupant, then s/he will perceive the air motion as a draft and may be made uncomfortable by this motion. Second, air movement can induce significant heat exchange through the building envelope. For instance, the infiltration of cold air through the envelope can require that heat be furnished by some internal source to maintain the inside air temperature at a comfortable level. Thus, to reduce heating requirements for building operation, the infiltration of cold air should be curtailed. Conversely, cool external air will often be intentionally admitted into an internal space (by active air-handling systems) to offset or dilute heat build-up that results from internal heat production sources. Supplying good-quality air to building spaces is also a requisite for maintaining healthy and comfortable conditions. The air within a building should be free of dust, dirt, allergens, and any potentially toxic substances; it should be clean-smelling and free from possibly offensive odors; and its humidity should be within acceptable ranges, so that stuffiness will not be experienced by occupants. Further, this good-quality air should be distributed uniformly and at acceptable velocity rates throughout each occupied space.
OBSERVING AIR FLOW IN BUILDINGS INTRODUCTION The movement of air in a building affects the thermal comfort of occupants, influences the rates of heat gain or loss through the building envelope, and determines whether good-quality indoor air will be present. How a building designer lays out a building, chooses materials, defines building details, and participates in the construction process will influence the nature and magnitude of subsequent air movement in the building. Thermally-comfortable environments depend on four environmental parameters and two personal parameters. The four environmental parameters are the dry-bulb temperature of the air surrounding the occupant; the relative humidity of the air; the (net) radiant exchange between the occupant and the surrounding surfaces; and the rate of air movement around the occupant. Further, the two personal parameters are the metabolic rate for the activity in the occupant is engaged and the insulative value for the occupant’s clothing ensemble. Thus, one determinant of whether a building occupant will feel thermally comfortable is how rapidly or slowly air moves in the vicinity of the individual. For example, on a day when the air in a building is warm and humid, air flow around an occupant can improve how comfortable the individual will be. Alternatively, when interior air is cool and flows around an occupant, then s/he will perceive the air motion as a draft and may be made uncomfortable by this motion. Second, air movement can induce significant heat exchange through the building envelope. For instance, the infiltration of cold air through the envelope can require that heat be furnished by some internal source to maintain the inside air temperature at a comfortable level. Thus, to reduce heating requirements for building operation, the infiltration of cold air should be curtailed. Conversely, cool external air will often be intentionally admitted into an internal space (by active air-handling systems) to offset or dilute heat build-up that results from internal heat production sources. Supplying good-quality air to building spaces is also a requisite for maintaining healthy and comfortable conditions. The air within a building should be free of dust, dirt, allergens, and any potentially toxic substances; it should be clean-smelling and free from possibly offensive odors; and its humidity should be within acceptable ranges, so that stuffiness will not be experienced by occupants. Further, this good-quality air should be distributed uniformly and at acceptable velocity rates throughout each occupied space.
ARC-05-5633%20-%20Olaogunode%20-%20Air%20Flow%20through%20Buildings%20in%20Nigeria.docx