ASTM D7520-09

Standard Test Method for Determining the Opacity of a Plume in the Outdoor Ambient Atmosphere

SIGNIFICANCE AND USE
Air permits from regulatory agencies often require measurements of opacity from stationary air pollution point sources in the outdoor ambient environment. Opacity has been visually measured by certified smoke readers in accordance with USEPA (USEPA Method 9). DCOT is also a method to determine plume opacity in the outdoor ambient environment.
The concept of DCOT was based on previous method development using Digital Still Cameras and field testing of those methods. , The purpose of this standard is to set a minimum level of performance for products that use DCOT to determine plume opacity in ambient environments.
SCOPE
1.1 This test method describes the procedures to determine the opacity of a plume. The aforementioned plume is caused by particulate matter emitted from a stationary point source in the outdoor ambient environment using digital imagery and associated software and hardware.
1.2 The opacity of emissions is determined by the application of a Digital Camera Opacity Technique (DCOT) that consists of a Digital Still Camera, Analysis Software, and the Output Function’s content to obtain and interpret digital images to determine and report plume opacity.
1.3 This method is suitable to determine the opacity of plumes from zero (0) percent to one hundred (100) percent.
1.4 This test method is not applicable to stacks with internal diameters greater than 7.0 ft.  
1.5 Conditions that shall be considered when using this method to obtain the digital image of the plume include the plume’s background, the existence of condensed water in the plume, orientation of the Digital Still Camera to the plume and the sun (see Section 8).
1.6 This standard describes the procedures to certify the DCOT, hardware, software, and method to determine the opacity of the plumes.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-Oct-2009
• ICS: 13.040.20 - Ambient atmospheres
• Technical Committee: D22 - Air Quality
• Drafting Committee: D22.03 - Ambient Atmospheres and Source Emissions

Relations

• Replaced By: ASTM D7520-13 - Standard Test Method for Determining the Opacity of a Plume in the Outdoor Ambient Atmosphere
• Effective Date: 01-Dec-2013

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D7520 − 09
StandardTest Method for
Determining the Opacity of a Plume in the Outdoor Ambient
Atmosphere
This standard is issued under the fixed designation D7520; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This test method describes the procedures to determine 2.1 ASTM Standards:
theopacityofaplume.Theaforementionedplumeiscausedby D1356 Terminology Relating to Sampling and Analysis of
particulate matter emitted from a stationary point source in the Atmospheres
outdoor ambient environment using digital imagery and asso- E691 Practice for Conducting an Interlaboratory Study to
ciated software and hardware. Determine the Precision of a Test Method
2.2 U.S. Environmental Protection Agency (USEPA) Docu-
1.2 The opacity of emissions is determined by the applica-
ment:
tion of a Digital Camera Opacity Technique (DCOT) that
USEPA Method 9 Visual Determination of the Opacity of
consists of a Digital Still Camera, Analysis Software, and the
Emissions from Stationary Sources, 40 CFR, Part 60,
OutputFunction’scontenttoobtainandinterpretdigitalimages
Appendix A-4
to determine and report plume opacity.
2.3 Institute of Electrical and Electronics Engineers (IEEE)
1.3 This method is suitable to determine the opacity of
Document:
plumes from zero (0) percent to one hundred (100) percent.
IEEE 12207-2008 Systems and Software Engineering—
1.4 This test method is not applicable to stacks with internal Software Life Cycle Processes (ISO/IEC 12207:2008(E)),
Edition: 2nd, Institute of Electrical and Electronics
diameters greater than 7.0 ft.
Engineers, 01-Feb-2008, 138 pages, ISBN:
1.5 Conditions that shall be considered when using this
method to obtain the digital image of the plume include the
2.4 Japanese Electronic and Information Technology Indus-
plume’s background, the existence of condensed water in the
tries Association (JEITA) Document:
plume, orientation of the Digital Still Camera to the plume and
Exchangeable Image File Format (EXIF) for Digital Still
the sun (see Section 8).
Cameras: Joint Photographic Experts Group: JPEG file
1.6 This standard describes the procedures to certify the
format version 2.21, JEITA CP-3451-1 (English version)
DCOT, hardware, software, and method to determine the
dated 2003-09; http://www.jeita.or.jp/english/standard/
opacity of the plumes.
list/list.asp?cateid=1&subcateid=4
1.7 This standard does not purport to address all of the 2.5 International Organization for Standardization (ISO)
safety concerns, if any, associated with its use. It is the Standard:
responsibility of the user of this standard to establish appro- ISO 9001:2000(s)
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
This test method is under the jurisdiction of ASTM Committee D22 on Air the ASTM website.
Quality and is the direct responsibility of Subcommittee D22.03 on Ambient Available from United State Environmental ProtectionAgency (USEPA),Ariel
Atmospheres and Source Emissions. Rios Bldg, 1200 Pennsylvania Ave., NW, Washington, DC 20460, http://
Current edition approved Nov. 1, 2009. Published January 2010. DOI:10.1520/ www.epa.org.
D7520-09. Available from Institute of Electrical and Electronics Engineers, Inc., (IEEE),
The 7.0 ft limitation was set as a reasonable boundary for the initial issuing of 1828 L St., NW, Suite 1202, Washington, DC 20036-5104, http://www.ieee.org.
this test method due to there being a limited amount of data for large diameter Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
stacks. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7520 − 09
3. Terminology 4.2 The following conditions must be followed to make a
valid opacity determination:
3.1 For definitions of terms used in this test method, refer to
4.2.1 The image must be captured in a JPEG format that
Terminology D1356.
adheres to the EXIF 2.1 (or higher) standard.
3.2 Definitions of Terms Specific to This Standard:
4.2.2 The image must be captured with the sun located
3.2.1 analysis software—software that when combined with
behind the Digital Still Camera and within a 140° sector
a defined operating environment: a) inputs images captured by
directly behind the Digital Still Camera (see Table 1 for
the Digital Still Camera image capture devices; b) produces
schematic).
opacity measurements from the combination of human
4.2.3 The image must be captured perpendicular to the
interaction, open or proprietary calculations and algorithms,
direction of plume travel.
and image content viewing; c) and then output said opacity
4.2.4 Digital enhancement capabilities of the Digital Still
measurement along with Analysis Software’s configuration,
Camera (that is, flash, optical filters, digital zoom, and image
image source documentation and other environmental param-
stabilization) shall not be used. However, the Digital Still
eters.
Camera’s optical zoom may be used when capturing the digital
3.2.2 certified—for the purpose of this standard, certified
still image.
refers to achieving or excelling the requirements described in 4.2.5 The ambient light must be sufficient to show a clear
this method.
contrast between the plume and its background.
4.2.6 The portion of the plume selected for opacity deter-
3.2.3 DCOT operator—refers to the human operating the
mination shall not contain condensed water vapor.
DCOT system who records the digital still images with the
4.2.7 The selected portions of each image representing the
Digital Still Camera and then determines plume opacity with
visible plume and the uniform background must contrast
the Analysis Software.
sufficiently for the software to differentiate between the plume
3.2.4 Digital Still Camera—animagecapturedeviceusedto
and its background.
collect store and forward digital still images to the Analysis
4.2.8 The portion of the plume selected for opacity deter-
Software for analysis as defined by the DCOT vendor’s
mination shall represent the part of the plume with the highest
certification documentation.
apparent opacity, excluding water vapor, as determined by the
3.2.5 image transfer file—an electronic file that contains the
DCOT operator.
image captured by the Digital Still Camera and its associated
4.2.9 The area of the digital image to be analyzed for
environment documentation that is consistent with EXIF 2.1
opacity shall be centered in the digital image when taking the
JPG (or higher) format and is input to the Analysis Software.
photograph.
All of the digital images obtained by a DCOT system shall be
4.2.10 Each DCOT vendor shall provide training for opera-
reviewed by a qualified human DCOT operator to assess if the
tors of their DCOT system. The training shall include the
digital images are acceptable (for example, no obvious errors
content of the “Principles of Visual Emissions Measurements
in the digital images).
and Procedures to Evaluate those Emissions Using the Digital
3.2.6 opacity—measurement of the degree to which particu-
Camera Optical Technique (DCOT)” (Annex A1) and a de-
lateemissionsreducetheintensityoftransmittedphotopiclight scription of how to operate that specific DCOT system that
and obscure the view of an object through an effluent gas
passed smoke school.
stream of a given path length in ambient air.
5. Significance and Use
3.2.7 opacity source—any source that produces emissions
that are visible to the human eye.
5.1 Air permits from regulatory agencies often require
measurements of opacity from stationary air pollution point
3.2.8 output function—human readable information docu-
sources in the outdoor ambient environment. Opacity has been
menting the image being analyzed and configuration of the
visually measured by certified smoke readers in accordance
AnalysisSoftwareused,theopacitymeasurementandtheother
with USEPA (USEPA Method 9). DCOT is also a method to
required environment variables defined (for example, view
determine plume opacity in the outdoor ambient environment.
angle, wind direction).
5.2 The concept of DCOT was based on previous method
4. Summary of Test Method
development using Digital Still Cameras and field testing of
7,8
those methods. The purpose of this standard is to set a
4.1 ADigital Still Camera is used to capture a set of digital
minimum level of performance for products that use DCOT to
images of a plume against a contrasting background. Each
determine plume opacity in ambient environments.
image is analyzed with software that determines plume opacity
by comparing a user defined portion of the plume image where
opacity is being measured in comparison to the background
providing the contrasting values. The Analysis Software is 7
Du, K., Rood, M. J., Kim, B. J., Kemme, M. R., Franek, B. J., and Mattison,
used to average the opacities from the series of digital images
K.,QuantificationofPlumeOpacitybyDigitalPhotography, Environmental Science
& Technology, 41, 3, DOI: 10.1021/es061277n, 2007a, pp. 928-935.
taken of the plume over a fixed period of time. The software is
Du,K.,Rood,M.J.,Kim,B.J.,Kemme,M.R.,Franek,B.J.,Mattison,K.,and
also used to archive the image set utilized for each opacity
Cook, J., Digital Optical Method to Quantify the Visual Opacity of Plumes in the
determination including the portion of each image selected by
Field, J. Air and Waste Management Association, DOI:10.3155/1047-
the operator. 3289.57.7.836, 57, 2007b, pp. 836-844.
D7520 − 09
TABLE 1 Example of Field Data Record when Determining Plume Opacity with DCOT
Company name:
Company location:
Test Identification No.:
Date:
Type of facility:
Process unit:
Operating capacity or mode for process:
Control device:
Operational status of control device:
Height of emission point and estimation method:
Operator name:
Operator affiliation:
DCOT certification date:
DCOT certified by:
Camera’s manufacturer, model, and serial number:
Initial Final
CLOCK TIME
CAMERA LOCATION
Distance to discharge
Vertical angle of emission point
to camera
Angle of sun to back of camera
Height of emission point relative
to camera
ENVIRONMENTAL CONDITIONS
Background of plume
Wind direction
Wind speed
Ambient temperature
Relative humidity
Sky condition (for example,
clear, partially cloudy, overcast)
PLUME DESCRIPTION
Color
Distance between discharge and
location where opacity
is determined
NUMBER CAPTURED IMAGES
ADDITIONAL INFORMATION
Operator signature: Date:
6. Interferences 6.3 Steam Plumes—Steam plumes (or condensed water
vapor) cause significant errors in measuring opacity, and occur
6.1 Contrast—As the contrast between the color of the
in two distinct modes as either attached plumes or detached
plume and the background decreases, the observed opacity
plumes. When either condition is noted to exist, the camera
decreases. To achieve maximum opacity, the opacity shall be
operator must record sufficient images to document the type of
measured at a point where the maximum contrast exists
plume observed and the relative position of the exhaust stack
between the plume and the background.
withrelationshiptothepointtheopacitymeasurementismade.
6.2 Luminescence—Low light levels adversely impact the
determinationofplumeopacity.Adequatenaturallightmustbe
available to illuminate the plume and background during the
Water droplets in steam plumes will scatter light resulting in increased plume
period the images are captured.This method shall only be used
opacity until the water evaporates, and shall not be included in the determination of
during daytime conditions. opacity.
D7520 − 09
6.3.1 Attached Steam Plumes—When condensed water va- requirements in Annex A2 of this standard the image capture
porispresentwithintheplumeasitemergesfromtheemission component is complete and the Analysis Software takes over.
outlet, opacity images shall be made beyond the point in the
The Digital Still Camera is dependent on the minimum image
plume at which condensed water vapor is no longer visible.
requirements of the associated Analysis Software and thus
The operator shall record the approximate distance from the
mustconformtotherequirementsforimagecaptureasdictated
emission outlet to the point in the plume at which the images
by the Analysis Software component.
are made (Table 1).
7.1.2 The second component of the DCOT is the Analysis
6.3.2 Detached Steam Plume—When water vapor in the
Software which reads the images captured by the Digital Still
plume condenses and becomes visible at a distinct distance
Camera, performs analysis of the image and calculates the
from the emission outlet, the opacity of emissions shall be
opacity level of the pictorially represented emission from the
evaluated at the emission outlet prior to the condensation of
Digital Still Camera. Analysis Software modifications are
water vapor and the formation of the steam plume.
subject to procedures established in Annex A3. The Analysis
6.4 Angle of View—The position of the camera operator
Software portion of the DCOT enforces the specific require-
with respect to the smoke plume and sun will impact the
ments of the Digital Still Camera (that is, JPEG 2.1 output, or
perceived contrast between the smoke plume and the back-
higher) and the minimum requirements of the system to
ground. Changes in apparent contrast will impact the measure-
support required output capabilities (that is, compliant with
mentofopacityusingthistechniqueandmustbeminimizedby
Method 9 and certification documentation (IEEE 12207-
following the procedures specified in Section 8 of this method.
2008)).TheconfigurationdocumentationdescribingtheAnaly-
sis Software must include a listing of all non-proprietary
6.5 Slant-Angle—The path length of the plume is length-
ened when a Digital Still Camera is too close to a stack. The components of the software, such as: (1) the required hardware
plume shall be observed at least three stack heights away, platform (that is, processors supported), (2) basic input output
where the slant-angle is 18° or less to reduce the effect of slant
system (BIOS) supported, (3) storage media req
...