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More on Those Mysterious Odors |
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Here's another question we were asked recently. Perhaps it reminds you of concerns you've heard about in your own buildings.
Q. We have an occasional vomit-like odor occurring in our building. When the complaints come in, we respond, but the odors are usually gone when we arrive. We don't find any obvious source of the odor. What can it be?
A. Butyric acid produces a distinct vomit-like odor.
We have encountered certain manufacturers who have replaced ceiling tiles in the past due to indoor air quality (IAQ) problems. Butyric acid is a substance which is routinely analyzed by ceiling tile manufacturers during the manufacturing process. Ceiling tile batches with butyric acid content of less than 100 parts per million are accepted.
The ceiling tile manufacturing process works similar to this.
1) Fiber used in the tile is mixed with water and pressed into forms.
2) As the tile is compressed, the water is removed from the tile and recycled for use in the next batch.
3) After several cycles, this water becomes contaminated with impurities including bacteria and algae.
4) The water is then treated with various chemicals to remove the impurities.
5) One of the by-products of this pricess is butyric acid.
6) As the purified water is reused, it can contain butyric acid, some of which can become lodged in the tiles.
7) As batches are made, less and less of the acid remains in the tile until the water is again treated and the cycle starts over.
8) The odor is normally dormant until the tile becomes exposed to water or humid enivornment conditions.
Therefore, the odor can exist. Its strength can vary significantly from batch to batch. It can be intermittent depending on humidity, temperature, or the rate of water leakage. In addition, the odor can be concentrated in a space for short periods of time. When air movement patterns change in the space, the odor can seem to disappear.
Some recent experience showed that from 25-50% of the population will notice a mild odor while the rest will not. Of those who do notice the odor, up to 25% will be significantly affected and will seek to remove themselves from the environment.
Put simply, vomit-like odors can be caused by ceiling tiles exposed to the unique situation noted above. |
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