Method to calculate fit factor and protection factor with a dynamically changing background challenge
View Patent ↗A method for quantitatively evaluating the protective efficacy of a respiratory protection mask in an environment with a dynamic pollutant concentration, including providing a first air sampling unit and a second air sampling unit both electronically connected to a data acquisition system, obtaining a first pollutant reading of the environment with the dynamic pollutant concentration using the first air sampling unit, obtaining a second pollutant reading of the respiratory protection mask in the environment using the second air sampling unit, and determining a fit factor of the respiratory protection mask using the data acquisition system by dividing the first pollutant reading by the second pollutant reading. The method additionally includes determining a correction factor between the first air sampling unit and the second air sampling unit and applying the correction factor to the second air sampling unit using the data acquisition system.
1 . A method for quantitatively evaluating the protective efficacy of a respiratory protection mask in an environment with a dynamic pollutant concentration, the method comprising:
providing a first air sampling unit and a second air sampling unit, both the first air sampling unit and the second air sampling unit electronically connected to a data acquisition system;
determining a correction factor between the first air sampling unit and the second air sampling unit and applying the correction factor to the second air sampling unit using the data acquisition system;
positioning the respiratory protection mask in the environment with the dynamic pollutant concentration, the respiratory protection mask forming a seal with a substrate;
obtaining a first pollutant reading of the environment with the dynamic pollutant concentration using the first air sampling unit;
obtaining a second pollutant reading of the respiratory protection mask using the second air sampling unit; and
determining a fit factor of the respiratory protection mask using the data acquisition system by dividing the first pollutant reading by the second pollutant reading.
2 . The method of claim 1 , wherein determining the correction factor comprises:
recording a plurality of voltage values of each of the first air sampling unit and the second air sampling unit at various time intervals in the environment with the dynamic pollutant concentration as the pollutant concentration inside is increased;
calculating a percent difference in the plurality of voltage values of the first air sampling unit and the plurality of voltage values of the second air sampling unit to determine the correction factor between the first air sampling unit and the second air sampling unit.
3 . The method of claim 1 , wherein the pollutant is an aerosol, a vapor, or a combination thereof.
4 . The method of claim 1 , wherein the first air sampling unit and the second air sampling unit are photometers.
5 . The method of claim 4 , wherein the photometers are laser photometers.
6 . The method of claim 4 , wherein the photometers are TSI 8587 A aerosol photometers.
7 . The method of claim 1 , wherein the data acquisition system includes software configured to control the operation of the first air sampling unit and the second air sampling unit.
8 . The method of claim 7 , wherein the software of the data acquisition system instructs the first air sampling unit and second air sampling unit to switch to clear where zero voltages for both the first air sampling unit and second air sampling unit are recorded, instructs the first air sampling unit and second air sampling unit to switch to downstream where a downstream voltage for the first air sampling unit is recorded and a downstream voltage of the second air sampling unit is recorded, and then calculates the fit factor according to:
Fit
Factor
=
(
(
Downstream
Volatge
of
first
unit
-
Zero
Voltage
of
first
unit
)
(
Downstream
Volatge
of
second
unit
-
Zero
Volate
of
second
unit
)
⋆
Correction
Factor
)
9 . The method of claim 1 , wherein the substrate is a human subject.
10 . The method of claim 9 , wherein the subject performs movements inside the environment with the dynamic pollutant concentration as the protective efficacy of the respiratory protection mask is evaluated.
11 . The method of claim 1 , wherein the dynamic pollutant concentration of the environment is varied overtime to simulate a plurality of test scenarios.
12 . The method of claim 1 , wherein the environment with the dynamic pollutant concentration is not necessarily compliant with test standards for fit factor testing.
13 . A method for quantitatively evaluating the protective efficacy of a respiratory protection mask in an environment with a dynamic pollutant concentration, the method comprising:
providing a first air sampling unit and a second air sampling unit, both the first air sampling unit and the second air sampling unit electronically connected to a data acquisition system, wherein the data acquisition system includes software configured to control the operation of the first air sampling unit and the second air sampling unit;
positioning the respiratory protection mask in the environment with the dynamic pollutant concentration, the respiratory protection mask forming a seal with a substrate;
obtaining a first pollutant reading of the environment with the dynamic pollutant concentration using the first air sampling unit;
obtaining a second pollutant reading of the respiratory protection mask using the second air sampling unit; and
determining a fit factor of the respiratory protection mask using the data acquisition system by dividing the first pollutant reading by the second pollutant reading, wherein the software of the data acquisition system instructs the first air sampling unit and second air sampling unit to switch to clear where zero voltages for both the first air sampling unit and second air sampling unit are recorded, instructs the first air sampling unit and second air sampling unit to switch to downstream where a downstream voltage for the first air sampling unit is recorded and a downstream voltage of the second air sampling unit is recorded, and then calculates the fit factor according to:
Fit
Factor
=
(
(
Downstream
Volatge
of
first
unit
-
Zero
Voltage
of
first
unit
)
(
Downstream
Volatge
of
second
unit
-
Zero
Volate
of
second
unit
)
⋆
Correction
Factor
)
14 . The method of claim 13 , wherein the pollutant is an aerosol, a vapor, or a combination thereof.
15 . The method of claim 13 , wherein the first air sampling unit and the second air sampling unit are photometers.
16 . The method of claim 15 , wherein the photometers are laser photometers.
17 . The method of claim 13 , wherein the substrate is a human subject and wherein the subject performs movements inside the environment with the dynamic pollutant concentration as the protective efficacy of the respiratory protection mask is evaluated.
18 . The method of claim 13 , wherein the dynamic pollutant concentration of the environment is varied overtime to simulate a plurality of test scenarios.
19 . The method of claim 13 , wherein the environment with the dynamic pollutant concentration is not necessarily compliant with test standards for fit factor testing.