STACK SAMPLING 1109
methods, testing should be performed only by personnel
trained and experienced with the sampling train and the ion
chromatograph used for this method.Test Method 7BTest Method 7B is used for the determination of nitrogen
oxide (NO x ) emissions from nitric acid plants. This method
is very similar to Method 7 except that in this method the
NO x concentration of the grab sample is measured using
an ultraviolet spectrophotometer. Audit samples, available
through EPA’s Quality Assurance Division, are required for
each set of compliance samples.
The EPA Test Method 7B write-up contains detailed
instructions, along with a list of references. It should be read
in detail before the Method is attempted. As with all of these
methods, testing should be performed only by personnel
trained and experienced with the equipment and spectropho-
tometer used for this method.Test Method 7CTest Method 7C is used to determine NO x from fossil-fuel
fired steam generators, electric utility plants, nitric acid
plants, or other sources as specified in the regulations. In
this method, an integrated sample is collected in alkaline-
permanganate solution. The NO and NO 2 in the stack gas are
oxidized to NO 2 and NO 3 by the permanganate. The NO 3 is
then reduced by cadmium to NO 2 , then the NO 2 from both
starting chemicals is measured colorimetrically.
The train used for Method 7C is similar to the one used
for Method 6 except that the three impingers are larger and
have restricted orifices at the tips. 200 ml of KMnO 4 /NaOH
solution is placed into each of the three impingers. The probe
is heated as necessary to prevent condensation. A sampling
rate of 400–500 cc/minute should be used since greater rates
will give low results. The sample run must be a minimum of
1 hour. Carbon dioxide should be measured during the run
with either an Orsat or Fyrite analyzer.
The EPA Test Method 7C write-up contains detailed
instructions for sample preparation, analysis and calibrations,
along with a list of references. It should be read in detail
before the Method is attempted. Testing should be performed
only by personnel trained and experienced with the equip-
ment and titrations specified in this method. The Method 7
audit samples are appropriate for this method as well.Test Method 7DTest Method 7D is used to determine NO x from stationary
sources. In this method, an integrated sample is collected
in alkaline-permanganate solution. The NO and NO 2 in the
stack gas are oxidized to NO 3 by the permanganate. The NO 3
is analyzed by ion chromatography.
The train and sample recovery procedure used for Method
7D is identical to the one used for Method 7C. The Method
describes the calibration and recommended chromatographic
conditions for the analysis by ion chromatography.The EPA Test Method 7D write-up contains detailed
instructions for sample preparation, analysis and calibration
along with a list of references. It should be read in detail
before the Method is attempted. Testing should be per-
formed only by personnel trained and experienced with the
equipment and ion chromatography used in this method. The
Method 7 audit samples are appropriate for this method.Test Method 7ETest Method 7E is an instrumental method for the determi-
nation of NO x from stationary sources. In this method, a gas
sample is continuously extracted from a stack and conveyed
to a chemiluminescence analyzed for determination of NO x.
The performance specifications and test procedures in
Method 6C are incorporated by reference to ensure data
reliability.
The chemiluminescence analyzer is based on the reac-
tion of NO with ozone to produce NO 2 and a photon of light.
This light is measured with a photomultiplier. If total NO x is
required, the NO 2 is thermally converted to NO before anal-
ysis. When the converter is used NO x is measured.
The EPA Test Method 7E write-up contains instruc-
tions for calibrations, along with a list of references. The
manufacturer’s instructions should be followed for set up of
the instrument. Testing should be performed only by trained
personnel.Test Method 8Test Method 8 will provide data on both the sulfur dioxide
and sulfuric acid mist from stationary sources. This method
is similar to Method 6 except that the sulfuric acid in the
isopropanol solution is also measured by the barium–thorin
titration method.
Instead of using the midget impingers as used in
Method 6, the full size impingers, as in Method 5, are used.
A filter is installed between the isopropanol impinger and
the first hydrogen peroxide impinger to catch any sulfuric
acid carry over.
The EPA Test Method 8 write-up contains detailed
instructions, along with a list of references. It should be
read in detail before the Method is attempted. As with all of
these methods, testing should be performed only by trained
and experienced personnel using equipment and materials
designed for this purpose.Test Method 9Test Method 9 is used for visually determining the opacity
of emissions from stacks or ducts. The specified procedures
are to be followed by human observers trained and certified
by procedures also contained in the method.
The training and certification portion of the method is
based on teaching observers to identify smoke of given opac-
ity between zero and 100% in increments of 5%. This is
accomplished using a smoke generator machine capable of
producing white and black smoke separately and identifyingC019_003_r03.indd 1109C019_003_r03.indd 1109 11/18/2005 11:07:16 AM11/18/2005 11:07:16 AM