Prepare observers to make defensible visual opacity readings with practical training, documented qualification testing, and a clear six-month renewal process.
EPA Method 9 establishes a visual procedure for determining the opacity of emissions from stationary sources. Qualified observers use a consistent field position, background, lighting, timing, and recording process to make readings in five-percent increments.
The qualification procedure presents 25 black-smoke and 25 white-smoke readings in random order. To qualify, no individual reading may be off by more than 15 percentage points, and the average absolute error must not exceed 7.5 percentage points for either the black or white set.
A successful observer receives documentation of qualification. Certification remains valid for six months, after which the qualification procedure must be repeated. Companies should maintain accessible records and schedule renewals early enough to avoid gaps in qualified coverage.
Opaque supports first-time and returning observers through public classes, private onsite programs, an online lecture, and an eligible VR certification path. The right option depends on group size, timing, equipment, and the requirements that apply to the facility.
Confirm whether the observer is initial or renewing.
Complete the applicable instruction and practice.
Read 25 white and 25 black plumes.
Meet both Method 9 error criteria.
Save the qualification record and schedule renewal before six months.
No individual reading may differ by more than 15 percentage points, and average absolute error must be 7.5 percentage points or less for each set of 25 black and 25 white readings.
Every six months.
Training covers the observation principles, positioning, reading intervals, documentation, and practical skills needed for visible-emissions work.
The current method and supporting information are available from the U.S. EPA Emission Measurement Center.
Tell us who needs training, where they are located, and when their certification is due.