IAQ Building Education and Assessment Model (I-BEAM)
Visual Reference Modules
Mouse over the animated pictures below to see messages which are referenced in more detail below.
Pressure relationships between rooms is designated at the bottom of each room (with a plus for positive and minus for negative pressure).
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| 1. Balanced Flows are Precarious |
- [KITCHEN EXHAUST] Exhaust fans in the kitchen are on manual switch. In the early morning and late afternoon hours, a small set of exhaust fans are operating to accommodate light cooking for lunch. This places the kitchen and cafeteria area under slight negative pressure that draws some transfer air from the office area.? What happens at noon?
- [COPY ROOM] The exhaust is maintaining a slight negative pressure which draws some transfer air from the office space during the early morning and late afternoon. What happens during the lunch?
- [OFFICE SUPPLY] The office supply air flow is sufficient in the morning and late afternoon to keep the office under slight positive pressure relative to the copy room and kitchen. Neither copy room pollutants nor kitchen pollutants are entering the office area. All is well in the morning. What happens during the lunch?
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| 2. Unbalanced Flows Pollutes Office |
- [KITCHEN EXHAUST] It's lunch time. When preparing lunch, the main exhaust fans in the kitchen are turned on. These are drawing a large volume of air out the exhaust so that the kitchen and cafeteria area under greater negative pressure that draws more transfer air from the office area. What happens in the office area?
- [OFFICE AREA] Since the kitchen exhaust fans are running full, the kitchen is drawing enough transfer air from the office area to place the office under negative pressure relative to the copy room. This draws copy room exhaust into the office environment. Complaints occur only around lunch and only if the copy room is being heavily used. By the time the building engineer arrives to investigate in the late afternoon, the kitchen exhaust fans are turned down, and the problem has gone away. Other offices in the building think that the IAQ was actually better than other times of the day. The problem recurs only periodically. The engineer thinks these particular occupants are just periodic complainers. Sound familiar?
- [COPY ROOM] Copy room exhaust and supply are operating normally. But since the kitchen exhaust fans are running at full load, the draw from the kitchen is sufficient to draw copy room contaminants into the office area and generate complaints.
- [OUTDOOR AIR] The flow of outdoor air into the building automatically increases when the kitchen exhaust fans are turned on full. The extra outdoor air replaces the air removed by the added exhaust from the kitchen area. However, although the building itself has added dilution ventilation, giving rise to improved IAQ elsewhere in the building, air the office next to the copy room becomes more polluted when the copy machines are heavily used during the lunch period.
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