# Title 40

## SECTION 53.63

### 53.63 Test procedure: Wind tunnel inlet aspiration test.

§ 53.63 Test procedure: Wind tunnel inlet aspiration test.(a) *Overview.* This test applies to a candidate sampler
which differs from the reference method sampler only with respect
to the design of the inlet. The purpose of this test is to ensure
that the aspiration of a Class II candidate sampler is such that it
representatively extracts an ambient aerosol at elevated wind
speeds. This wind tunnel test uses a single-sized, liquid aerosol
in conjunction with wind speeds of 2 km/hr and 24 km/hr. The test
atmosphere concentration is alternately measured with the candidate
sampler and a reference method device, both of which are operated
without the 2.5-micron fractionation device installed. The test
conditions are summarized in table F-2 of this subpart (under the
heading of “wind tunnel inlet aspiration test”). The candidate
sampler must meet or exceed the acceptance criteria given in table
F-1 of this subpart.

(b) *Technical definition.* Relative aspiration is the
ratio (expressed as a percentage) of the aerosol mass concentration
measured by the candidate sampler to that measured by a reference
method sampler.

(c) *Facilities and equipment required.* The facilities and
equipment are identical to those required for the full wind tunnel
test (§ 53.62(c)).

(d) *Setup.* The candidate and reference method samplers
shall be operated with the PM 2.5 fractionation device removed from
the flow path throughout this entire test procedure. Modifications
to accommodate this requirement shall be limited to removal of the
fractionator and insertion of the filter holder directly into the
downtube of the inlet.

(e) *Test procedure* - (1) *Establish the wind tunnel
test atmosphere.* Follow the procedures in § 53.62(d)(1) through
(d)(4) to establish a test atmosphere for one of the two wind
speeds specified in table F-2 of this subpart.

(2) *Measure the aerosol concentration with the reference
sampler.* (i) Install the reference sampler (or portion thereof)
in the wind tunnel with the sampler inlet opening centered in the
sampling zone. To meet the maximum blockage limit of § 53.62(c)(1)
or for convenience, part of the test sampler may be positioned
external to the wind tunnel provided that neither the geometry of
the sampler nor the length of any connecting tube or pipe is
altered. Collect particles for a time period such that the relative
error of the measured concentration is less than 5.0 percent.

(ii) Determine the quantity of material collected with the reference method sampler using a calibrated fluorometer. Calculate and record the mass concentration as:

Equation 15 where: i = replicate number; Mref = mass of material collected with the reference method sampler; Q = reference method sampler volumetric flow rate; and t = sampling time.(iii) Remove the reference method sampler from the tunnel.

(3) *Measure the aerosol concentration with the candidate
sampler.* (i) Install the candidate sampler (or portion thereof)
in the wind tunnel with the sampler inlet centered in the sampling
zone. To meet the maximum blockage limit of § 53.62(c)(1) or for
convenience, part of the test sampler may be positioned external to
the wind tunnel provided that neither the geometry of the sampler
nor the length of any connecting tube or pipe is altered. Collect
particles for a time period such that the relative error of the
measured concentration is less than 5.0 percent.

(ii) Determine the quantity of material collected with the candidate sampler using a calibrated fluorometer. Calculate and record the mass concentration as:

Equation 16 where: i = replicate number; Mcand = mass of material collected with the candidate sampler; Q = candidate sampler volumetric flow rate; and t = sampling time.(iii) Remove the candidate sampler from the wind tunnel.

(4) Repeat steps in paragraphs (d) (2) and (d)(3) of this section. Alternately measure the tunnel concentration with the reference sampler and the candidate sampler until four reference sampler and three candidate sampler measurements of the wind tunnel concentration are obtained.

(5) *Calculations.* (i) Calculate and record aspiration
ratio for each candidate sampler run as:

(ii) Calculate and record the mean aspiration ratio as:

Equation 18 where: i = replicate number; and n = total number of measurements of aspiration ratio.(iii) Precision of the aspiration ratio. (A) Calculate and record the precision of the aspiration ratio measurements as the coefficient of variation as:

Equation 19 where: i = replicate number; and n = total number of measurements of aspiration ratio.(B) If the value of CVA exceeds 10 percent, the entire test procedure must be repeated.

(f) *Evaluation of test results.* The candidate method
passes the inlet aspiration test if all values of A meet the
acceptance criteria specified in table F-1 of this subpart.