The Protocol Gas Verification Program (PGVP) is an EPA initiative established in March 2011 to ensure the accuracy of calibration gases used in continuous emissions monitoring systems (CEMS). Facilities subject to 40 CFR Part 75 emissions monitoring and reporting requirements must procure EPA protocol gases from a production site listed as a PGVP participant on the date of purchase—or from a vendor selling unaltered protocol gases from a PGVP-approved production site. Full requirements are outlined in 40 CFR 75.12(g)(6) and (7). These gases and their associated QA/QC checks are what make emissions data defensible. EPA relies on that data to assess compliance with emission reduction requirements under the Clean Air Act—and the integrity of that data starts with the calibration gas in your CEMS. PGVP Objectives and EPA Requirements The Clean Air Markets Division (CAMD) administers the PGVP with four core objectives: Ensure that EPA protocol gases meet the accuracy requirements of 40 CFR Part 75 Help calibration gas consumers make informed purchasing decisions Give well-performing vendors an incentive to maintain good practices Encourage underperforming vendors to make measurable improvements CAMD maintains a current list of approved PGVP participants and vendor IDs on its program website. Verify you're referencing the most current list—vendor approval status changes, and purchasing from a lapsed site has real consequences for your data. How the PGVP Affects Part 75 Facilities EPA conducts blind audits of gas vendors and does not typically notify individual facilities when a vendor loses approved status. That means calibration gas from a lapsed vendor can go undetected—until it shows up as invalid data during a QA/QC event. Facilities should check the approved vendor list at the start of each year and confirm their gas supplier is still on it. The Emissions Collection and Monitoring Plan System (ECMPS) includes a built-in feature that lets sites verify their cylinders were produced at an approved vendor site—use it as part of your routine QA/QC workflow. PGVP Compliance Support from Alliance Technical Group Calibration gas is one piece of a larger compliance picture. Alliance partners with Part 75 facilities to deliver dependable emissions testing, continuous monitoring expertise, and strategic compliance guidance that strengthens data reliability, simplifies reporting, and helps facilities meet the highest regulatory standards—from CEMS shelter construction and system maintenance to DAS software, stack testing, and ongoing QA/QC support.

Calibration drift checks are time-consuming, difficult to perform manually, and in some facility environments, genuinely hazardous. For anyone responsible for maintaining CEMS, COMS, or CPMS, automating daily validations is one of the most straightforward ways to reduce workload, improve data accuracy, and eliminate the human error that comes with manual processes. This guide covers what daily validation automation involves, why it matters for compliance, and how a data acquisition system handles it. What Are Daily Calibration Validations? The EPA defines calibration as comparing a measurement instrument against a standard of higher accuracy to detect, quantify, and where necessary, eliminate inaccuracies through adjustment. That last part is worth noting: because calibration involves adjustment, frequent corrections can actually introduce additional measurement uncertainty. Quality control procedures that include verification checks and multi-point calibration verifications are designed as "checks without correction" — confirming the instrument is operating within tolerance without making unnecessary adjustments each time. Why Daily Validations Matter EPA quality assurance regulations require CEMS operators to challenge and verify the accuracy of their monitors periodically — typically once every 24 hours. These checks use gas cylinders of known concentrations prepared to EPA protocol specifications. Done manually, that process depends on someone remembering to perform it, performing it consistently, and performing it the same way each time. A capable DAS removes those variables. The system is pre-configured to run the same check sequence every time, on a timer set approximately 24 hours after the last check, so the comparison is always apples-to-apples — or more precisely, Granny Smith-to-Granny Smith. If a unit is offline when a scheduled check is due, StackVision queues a startup calibration check automatically. When the unit comes back online, the DAS waits a defined interval and initiates the calibration cycle without operator intervention. Every regulation governing continuous monitoring systems requires that accuracy be verified and proven. Automation ensures that requirement is met consistently, not just when someone has time for it. How StackVision Handles Daily Validation Automation StackVision's DAS architecture addresses daily validations at both the hardware and software level. The 8864 Data Controller handles data collection from monitored sources, performs initial validation, generates compliance averages, and stores data locally before passing values to StackVision. That two-layer structure means validation logic is embedded at the point of data acquisition — not applied after the fact. From there, StackVision manages the full calibration workflow: scheduling, initiation, data reduction, status tracking, and recordkeeping. Automated checks run at consistent intervals, flag anomalies, and produce the documentation your facility needs without requiring manual intervention at each step. For facilities running multiple monitoring systems across different streams or regulatory programs, that consistency matters. Manual validation processes scale poorly. Automated ones don't. Getting Started With Automated Daily Validations If your facility is new to automated calibration validation — or if you're evaluating whether your current DAS is handling it correctly — Alliance Technical Group's CEMS & DAS team can walk through your monitoring configuration and identify where automation can close gaps.