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EPA Method 9 Certification- Opacity Reading -Smoke School- High Winds - Wind Changes- and Outhouses

Using the outhouse during  high winds can be hazardous to your health. If you don't believe it, then just ask me- Uncle George.


Now I know why they call Chicago the Windy City.

Changing wind directions can make reading opacity of smokestacks more difficult while performing EPA Method 9 Visibility Readings in the field. You always have to stand in a position that is perpendicular to the wind and the plume direction. Get a cross sectional view. If the wind changes direction during a normal 6-minute observation period, then you need to stop the readings and wait for the winds to change back to normal. If the winds don't change back to their formal direction, then you will have to move to a new location so the winds will be perpendicular. This would be one reason why a 6-minute reading would take more than six minutes to complete. You need to explain any condition that requires you to read for more time than the six minute set. Explain this in the comments section of the EPA Method 9 form. Example: Comments: Paused 4 minutes for wind change. Moved to a new location. Indicate wind direction changes on the form where it says wind direction start, end.

High winds can also make opacity readings more difficult. The winds may shear off the emissions. If this happens, then read the opacity at the point where the plume touches the stack. The exception to this rule of course is when steam or water vapor is present in the plume. When the plume cools down the steam will evaporate all at once. You can almost see a line where the steam stops and the readable emissions start. Your observation point will be the densest part of the plume after the steam stops. Steam looks like a white fluffy cloud. You usually can not see through it, it usually has shadows at the bottom because the sun can not penetrate the steam easily. Do not read the opacity of the steam.

You can not stand under the smokestack and read steam that extends from the stack. You have to get in your truck and go down to the end of the steam. Set up an observation position to observe the steam at the observation point, the densest point in the plume after the steam stops. Treat the steam as if it were an extension of the smokestack. Stand with the winds blowing perpendicular to your position with the wind blowing  through one of your ears. Face the observation point with your nose like a Mississippi Bird Dog. Hold both hands out to your side. The sun has to be  behind your hands. Stand back at least 3 times the height of the steam related to where your eyeballs are. If the end of the steam is 100 feet above your eyeballs, then you have to stand back 300 feet. This will give you a vertical angle of at least 18 degrees. The maximum distance for accurate readings is a quarter of a mile.

High winds make our job of presenting the opacity Method 9 certification test difficult. Your job is to watch the plume for changes in wind direction. Holler scratch if the wind changes and we will redo the reading after the wind settles. In some cases if the wind change is persistent, we will need to stop the test and ask you to move so you can stay in a position that is perpendicular to the wind direction. If this happens we will show the standards 25%, 50%, and 75% again. Then we will resume the test. We work hard to make the test as easy to pass as possible.

If this story made you smile, then you need to read the rest of my stories about life the way it is or the way it should be.

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