Your facility has a source testing requirement on the permit, and you've never been through one before. Maybe you inherited the permit from a previous manager. Maybe this is newly permitted equipment. Either way, you need to know what's going to happen and what your role is in making it go smoothly.
A stack test isn't complicated, but it does require coordination. Here's the full process from start to finish -- what happens before, during, and after the crew shows up.
Phase 1: Before the Test
The work starts well before anyone arrives with sampling equipment. This phase typically takes two to four weeks, sometimes longer depending on SCAQMD review timelines.
Permit Review and Method Selection
The first step is reviewing your SCAQMD permit conditions. Your permit specifies what pollutants must be tested, which test methods to use, and how often testing is required. Common pollutants include NOx, CO, O2, PM10, and VOC. The methods might be SCAQMD Method 100.1, EPA Method 5, or any number of others depending on the equipment.
Your testing company will pull your permit, identify the applicable conditions, and confirm the test methods. This is where errors get prevented. The wrong method means a rejected test.
Protocol Preparation and Agency Submission
Before any SCAQMD compliance test, a test protocol must be prepared and submitted to the district. The protocol documents the test methods, number of runs, sampling locations, operating conditions, and QA/QC procedures.
SCAQMD reviews the protocol and either approves it or requests modifications. This review can take one to three weeks. Don't schedule your test until the protocol is approved. Testing without an approved protocol creates compliance risk.
The protocol also needs specific information from your facility: stack dimensions, sampling port locations, number of ports, distance from flow disturbances, and expected operating conditions during the test. If you don't have this information readily available, your testing company will need a site visit to collect it.
Scheduling Around Production
Stack tests must be performed at representative operating conditions. That means the equipment being tested needs to be running at normal or maximum rated capacity, depending on what the permit requires.
This is a coordination exercise. You need to schedule the test on a day when:
- The equipment will be operating at the required load
- Production won't need to shut down unexpectedly
- The stack platform is accessible and safe
- Facility personnel are available for the safety orientation
If your boiler only runs at full load during certain shifts, or your process operates seasonally, that narrows your available test dates. Plan accordingly.
What You Need to Provide in Advance
Your testing company will send you a checklist. At minimum, expect to provide:
- Stack and duct dimensions -- diameter, cross-sectional area, and shape
- Sampling port locations -- number of ports, distances from bends and transitions
- Equipment operating data -- fuel type, firing rate, production rate
- Platform and access information -- ladder/stairway access, platform load capacity
- Safety requirements -- PPE requirements, site-specific hazards, confined space status
- Contact information -- who will be onsite during the test
If sampling ports don't exist or are in the wrong location, they'll need to be installed before the test. This is not a test-day problem you want to discover.
Phase 2: Test Day
Test day is where the planning pays off. Here's what happens hour by hour.
Crew Arrival and Setup (1-2 Hours)
The testing crew typically arrives by 6:00 or 7:00 AM. A straightforward boiler test with Method 100.1 analyzers might require two technicians. A multi-method test with particulate sampling and flow measurements could require three or four.
The crew completes your facility's safety orientation first. Then setup begins: transporting equipment to the platform, connecting analyzers to sampling ports, running calibration checks, and verifying stack conditions with facility personnel.
For particulate testing (EPA Method 5 or SCAQMD Method 5.1), setup includes assembling the sampling train -- probe, heated filter box, impinger train, and metering console. Each component gets leak-checked before the first run.
The Test Runs (3-6 Hours)
Most source tests require a minimum of three valid test runs. Each run duration depends on the method:
- SCAQMD Method 100.1 (analyzers for NOx, CO, O2): 15-30 minutes per run, plus stabilization time. This is the fastest method for boiler-type tests.
- EPA Method 5 (particulate): 60-120 minutes per run. Each run requires a multi-point traverse across the stack cross-section.
- EPA Method 201A (PM10/PM2.5): 60-180 minutes per run, depending on the number of traverse points and stack diameter.
- EPA Method 25A (VOC by FID): 30-60 minutes per run.
Between runs, the crew performs leak checks, calibration verifications, and data reviews. If a run fails QA/QC -- a leak develops, a filter breaks, or the analyzer drifts out of specification -- that run is invalidated and must be repeated.
What Operating Conditions Must Be Maintained
This is where facility cooperation is critical. During each test run, the equipment must operate at consistent, representative conditions. That means:
- Firing rate stays steady. Don't ramp the boiler up or down mid-run.
- Production rate is documented. If it's a process source, log production throughput during each run.
- No unusual operations. Don't perform maintenance, blow soot, or change fuel mid-test.
- Provide operating data. The crew will ask for fuel flow readings, steam production, or other process data at intervals during each run.
If conditions change during a run, the crew may need to invalidate that run and start over. This extends the test day.
Common Surprises on Test Day
Even well-planned tests hit issues. A voided run extends a half-day test into a full day. Access problems -- undersized platforms, non-compliant ladders -- can force a postponement. If the equipment can't hold the required load, the test can't proceed. And for outdoor stacks, high winds affect isokinetic sampling while rain can damage equipment.
Phase 3: After the Test
The crew packs up and leaves, but the process isn't over. Data reduction, QA/QC review, and report preparation take time.
Data Reduction and QA/QC (1-3 Weeks)
Raw field data goes through a structured reduction process. Instrumental methods require calibration corrections, drift checks, and emission rate calculations. Gravimetric methods (particulate) send filters to the laboratory for weighing and analysis.
Every data point is checked against QA/QC criteria. Calibration drift, leak check results, and isokinetic variation must fall within method specifications. If something falls outside limits, the affected run may be invalidated.
Draft Report and Final Submission (1-2 Weeks)
Accurate Environmental Services provides a draft report for your review before finalizing. Review it carefully -- verify operating data matches your records and confirm equipment descriptions are accurate.
SCAQMD requires final source test reports within 60 days of the test date. Your testing company handles submission, but you should confirm it was received. A late submission can trigger a Notice of Violation even if the test results show compliance. Keep a copy in your facility records.
Timeline Summary
Here's a realistic timeline for the entire process:
| Phase | Duration |
|---|---|
| Permit review and protocol preparation | 1-2 weeks |
| SCAQMD protocol review and approval | 1-3 weeks |
| Test day | 1 day (typically 6-10 hours onsite) |
| Data reduction and QA/QC | 1-3 weeks |
| Draft report and client review | 1-2 weeks |
| Final report and SCAQMD submission | Within 60 days of test date |
Start-to-finish, plan for six to ten weeks from initial contact to final report submission. If your compliance deadline is approaching, don't wait. The protocol review alone can take three weeks.
How to Make Your First Test Go Smoothly
Know your permit conditions before the testing company calls. Provide stack information early. Schedule a day when the equipment will run at required conditions for a full shift. Assign a point of contact who can answer operating questions and authorize access. And don't wait until the deadline -- protocols need approval, weather happens, equipment breaks.
Your job is to make sure the conditions are right and the access is there. The testing company handles the rest.
Frequently Asked Questions
Plan for a full day. A straightforward boiler test with gas analyzers (SCAQMD Method 100.1) may be done in four to five hours, including setup and calibration. Particulate testing requires runs of at least 60 minutes each, and multi-method tests can take eight to ten hours overall. If runs need to be repeated due to QA/QC issues or operating condition changes, the test may extend into a second day.
The test crew will work with you to stabilize conditions, but if the equipment can't hold the required load or the process isn't operating normally, the test may need to be rescheduled. Testing at non-representative conditions produces results that SCAQMD will not accept. It's better to postpone than to generate invalid data.
Start the process at least six to eight weeks before your compliance deadline. Protocol preparation takes one to two weeks, SCAQMD review takes one to three weeks, and you need flexibility for scheduling around production and weather. Waiting until the last minute is the single most common reason facilities miss compliance deadlines.
The source testing company typically prepares and submits the report to SCAQMD on the facility's behalf. However, the compliance obligation belongs to the facility. You should confirm that the report was submitted within the 60-day window and keep a copy in your records. Accurate Environmental Services handles submission as part of our standard scope of work.
AccuEnviro has performed thousands of source tests across the SCAQMD jurisdiction. We handle protocol preparation, agency coordination, field testing, and report delivery. If this is your first test, we'll walk you through each step.
Call (714) 379-9200 or request a quote at accuenviro.com