ASTM D 7520 : 2013

1.1This test method describes the procedures to determine the opacity of a plume, using digital imagery and associated hardware and software. The aforementioned plume is caused by particulate matter emitted from a stationary point source in the outdoor ambient environment.

1.2The 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.

1.3This method is suitable to determine the opacity of plumes from zero (0) percent to one hundred (100) percent.

1.4This test method is not applicable to stacks with internal diameters greater than 7.0 ft (2.13 m).²

1.5Conditions 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).

1.6This standard describes the procedures to certify the DCOT, hardware, software, and method to determine the opacity of the plumes.

1.7This 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.