(1) Wash-off method. Effectiveness is determined by measuring the aerosol mass deposited on the candidate sampler's after filter versus the aerosol mass deposited in the fractionator. The material deposited in the fractionator is recovered by washing its internal surfaces. For these wash-off tests, a fluorometer must be used to quantitate the aerosol concentration. Note that if this technique is chosen, the candidate must be reloaded with coarse aerosol prior to each test point when reevaluating the curve as specified in the loading test.

(2) Static chamber method. Effectiveness is determined by measuring the aerosol mass concentration sampled by the candidate sampler's after filter versus that which exists in a static chamber. A calibrated fluorometer shall be used to quantify the collected aerosol deposits. The aerosol concentration is calculated as the measured aerosol mass divided by the sampled air volume.

(3) Divided flow method. Effectiveness is determined by comparing the aerosol concentration upstream of the candidate sampler's fractionator versus that concentration which exists downstream of the candidate fractionator. These tests may utilize either fluorometry or a real-time aerosol measuring device to determine the aerosol concentration.

(1) Aerosol generation. Methods for generating aerosols shall be identical to those prescribed in § 53.62(c)(2).

(2) Particle delivery system. Acceptable apparatus for delivering the generated aerosols to the candidate fractionator is dependent on the effectiveness measurement methodology and shall be defined as follows:

(3) Particle concentration measurement -

(1) Remove the inlet and downtube from the candidate fractionator. All tests procedures shall be conducted with the inlet and downtube removed from the candidate sampler.

(2) Surface treatment of the fractionator. Rinsing aluminum surfaces with alkaline solutions has been found to adversely affect subsequent fluorometric quantitation of aerosol mass deposits. If wash-off tests are to be used for quantifying aerosol penetration, internal surfaces of the fractionator must first be plated with electroless nickel. Specifications for this plating are specified in Society of Automotive Engineers Aerospace Material Specification (SAE AMS) 2404C, Electroless Nickel Plating (Reference 3 in appendix A of subpart F).

(1) Clean the candidate sampler. Note: The procedures in this step may be omitted if this test is being used to evaluate the fractionator after being loaded as specified in § 53.65.

(2) Generate aerosol. Follow the procedures for aerosol generation prescribed in § 53.62(d)(2).

(3) Verify the quality of the test aerosol. Follow the procedures for verification of test aerosol size and quality prescribed in § 53.62(d)(4).

(4) Determine effectiveness for the particle size being produced.

(ii) Determine the quantity of material collected on the after filter of the candidate method using a calibrated fluorometer. Calculate and record the aerosol mass concentration for the sampler filter as:

Equation 20

where:

i = replicate number;

M_cand = mass of material collected with the candidate sampler;

Q = candidate sampler volumetric flowrate; and

t = sampling time.

(iii) Wash all interior surfaces upstream of the filter and determine the quantity of material collected using a calibrated fluorometer. Calculate and record the fluorometric mass concentration of the sampler wash as:

Equation 21

where:

i = replicate number;

M_wash = mass of material washed from the interior surfaces of the fractionator;

Q = candidate sampler volumetric flowrate; and

t = sampling time.

(iv) Calculate and record the sampling effectiveness of the test sampler for this particle size as:

Equation 22

where:

i = replicate number.

(vi) Calculate and record the average sampling effectiveness of the test sampler as:

Equation 23

where:

i = replicate number; and

n = number of replicates.

(vii)

(A) Calculate and record the coefficient of variation for the replicate sampling effectiveness measurements of the test sampler as:

Equation 24

where:

i = replicate number; and

n = total number of measurements.

(B) If the value of CV_E exceeds 10 percent, then steps in paragraphs (e) (2) through (e)(4) of this section must be repeated.

(5) Repeat steps in paragraphs (e) (1) through (e)(4) of this section for each particle size specified in table F-2 of this subpart.

(1) Generate aerosol. Follow the procedures for aerosol generation prescribed in § 53.62(d)(2).

(2) Verify the quality of the test aerosol. Follow the procedures for verification of test aerosol size and quality prescribed in § 53.62(d)(4).

(3) Introduce particles into chamber. Introduce the particles into the static chamber and allow the particle concentration to stabilize.

(4) Install and operate the candidate sampler's fractionator and its after-filter and at least four total filters.

(5) Calculate the aerosol spatial uniformity in the chamber.

(i) Determine the quantity of material collected with each total filter sampler in the array using a calibrated fluorometer. Calculate and record the mass concentration for each total filter sampler as:

Equation 25

where:

i = replicate number;

j = total filter sampler number;

M_total = mass of material collected with the total filter sampler;

Q = total filter sampler volumetric flowrate; and

t = sample time.

(ii) Calculate and record the mean mass concentration as:

Equation 26

where:

n = total number of samplers;

i = replicate number; and

j = filter sampler number.

(iii)

(A) Calculate and record the coefficient of variation of the total mass concentration as:

Equation 27

where:

i = replicate number;

j = total filter sampler number; and

n = number of total filter samplers.

(B) If the value of CV_total exceeds 10 percent, then the particle concentration uniformity is unacceptable, alterations to the static chamber test apparatus must be made, and steps in paragraphs (f)(1) through (f)(5) of this section must be repeated.

(6) Determine the effectiveness of the candidate sampler.

(i) Determine the quantity of material collected on the candidate sampler's after filter using a calibrated fluorometer. Calculate and record the mass concentration for the candidate sampler as:

Equation 28

where:

i = replicate number;

M_cand = mass of material collected with the candidate sampler;

Q = candidate sampler volumetric flowrate; and

t = sample time.

(ii) Calculate and record the sampling effectiveness of the candidate sampler as:

Equation 29

where:

i = replicate number.

(iv) Calculate and record the average sampling effectiveness of the test sampler as:

Equation 30

where:

i= replicate number.

(v)

(A) Calculate and record the coefficient of variation for the replicate sampling effectiveness measurements of the test sampler as:

Equation 31

where:

i = replicate number; and

n = number of measurements of effectiveness.

(B) If the value of CV_E exceeds 10 percent, then the test run (steps in paragraphs (f)(2) through (f)(6) of this section) is unacceptable and must be repeated.

(7) Repeat steps in paragraphs (f)(1) through (f)(6) of this section for each particle size specified in table F-2 of this subpart.

(1) Generate calibration aerosol. Follow the procedures for aerosol generation prescribed in § 53.62(d)(2).

(2) Verify the quality of the calibration aerosol. Follow the procedures for verification of calibration aerosol size and quality prescribed in § 53.62(d)(4).

(3) Introduce aerosol. Introduce the calibration aerosol into the static chamber and allow the particle concentration to stabilize.

(4) Validate that transport is equal for the divided flow option.

(i) With fluorometry as a detector:

(A) Install a total filter on each leg of the divided flow apparatus.

(B) Collect particles simultaneously through both legs at 16.7 L/min onto an appropriate filter for a time period such that the relative error of the measured concentration is less than 5.0 percent.

(C) Determine the quantity of material collected on each filter using a calibrated fluorometer. Calculate and record the mass concentration measured in each leg as:

Equation 32

where:

i = replicate number,

M = mass of material collected with the total filter; and

Q = candidate sampler volumetric flowrate.

(D) Repeat steps in paragraphs (g)(4)(i)(A) through (g)(4)(i)(C) of this section until a minimum of three replicate measurements are performed.

(iii)

(A) Calculate the mean concentration and coefficient of variation as:

Equation 33 Equation 34

where:

i = replicate number; and

n = number of replicates.

(B) If the measured mean concentrations through the two legs do not agree within 5 percent, then adjustments may be made in the setup, and this step must be repeated.

(5) Determine effectiveness. Determine the sampling effectiveness of the test sampler with the inlet removed by one of the following procedures:

(i) With fluorometry as a detector:

(A) Prepare the divided flow apparatus for particle collection. Install a total filter into the bypass leg of the divided flow apparatus. Install the particle size fractionator with a total filter placed immediately downstream of it into the other leg.

(B) Collect particles simultaneously through both legs at 16.7 L/min onto appropriate filters for a time period such that the relative error of the measured concentration is less than 5.0 percent.

(C) Determine the quantity of material collected on each filter using a calibrated fluorometer. Calculate and record the mass concentration measured by the total filter and that measured after penetrating through the candidate fractionator as follows:

Equation 35 Equation 36

where:

i = replicate number.

(iii) Calculate and record sampling effectiveness of the candidate sampler as:

Equation 37

where:

i = replicate number.

(6) Repeat step in paragraph (g)(5) of this section, as appropriate, to obtain a minimum of three replicate measurements of sampling effectiveness.

(7) Calculate the mean and coefficient of variation for replicate measurements of effectiveness.

(i) Calculate and record the mean sampling effectiveness of the candidate sampler as:

Equation 38

where:

i = replicate number.

(ii)

(A) Calculate and record the coefficient of variation for the replicate sampling effectiveness measurements of the candidate sampler as:

Equation 39

where:

i = replicate number; and

n = number of replicates.

(B) If the coefficient of variation is not less than 10 percent, then the test run must be repeated (steps in paragraphs (g)(1) through (g)(7) of this section).

(8) Repeat steps in paragraphs (g)(1) through (g)(7) of this section for each particle size specified in table F-2 of this subpart.

(1) Treatment of multiplets. For all measurements made by fluorometric analysis, data shall be corrected for the presence of multiplets as described in § 53.62(f)(1). Data collected using a real-time device (as described in paragraph (c)(3)(ii)) of this section will not require multiplet correction.

(2) Cutpoint determination. For each wind speed determine the sampler Dp₅₀ cutpoint defined as the aerodynamic particle size corresponding to 50 percent effectiveness from the multiplet corrected smooth curve.

(3) Graphical analysis and numerical integration with ambient distributions. Follow the steps outlined in § 53.62 (e)(3) through (e)

(4) to calculate the estimated concentration measurement ratio between the candidate sampler and a reference method sampler.