TA-03 | EPA Method 21 Leak Detection

Introduction

EPA Method 21 is the standard procedure for detecting fugitive VOC emissions from leaking joints, valves, and pipelines in industrial facilities.

This technical article demonstrates how ION SENSE^®‘s MiniPID 2 PPM WR sensor meets and exceeds all EPA Method 21 instrument specifications, including detection range, response time, calibration precision, and intrinsic safety requirements.

The article clarifies common misconceptions about calibration requirements—particularly the widespread but incorrect belief that 10,000 ppm methane calibration is mandatory—and provides practical guidance on selecting appropriate calibration gases and concentrations based on leak definitions and response factors.

Whether you’re implementing a leak detection and repair (LDAR) programme or ensuring compliance with 40 CFR regulations, this guide explains how to configure and calibrate PID-based instruments for reliable Method 21 compliance.