The Yoon-Nelson
model is a descriptive model that uses experimental data to calculate parameters that are
then entered into the model.
- Yoon, Y.H., J.H. Nelson,
Breakthrough Time and Adsorption Capacity of Respirator Cartridges, American Industrial
Hygiene Association Journal, 53:303-316 (1992).
- The basic
equation for the model is:
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t = breakthrough time (min)
t =
50% contaminant breakthrough time (min)
k' = rate constant (min-1)
P = probability of
contaminant breakthrough. |
- The value of t is determined from experimental
data.
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The value of k' has been shown to be
related to t by the following
formula:
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k = proportionality constant that is constant
independent of concentration and varies only slightly with humidity. |
- The value of t is related to the contaminant concentration by
the equation:
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K", a = constants
that can be derived from
experimental data. They vary with humidity, but for humidities £ 50% they are essentially constant.
CI = contaminant assault
concentration. (ppm)
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- It is possible to determine the constants k, K", and a from a minimum of 3 experimental
data points. However, the inclusion of additional data points increases the accuracy of
the model.
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