Atmos Tightness Monitor is a statistical tightness monitoring system used to test for leaks in airport hydrants. It uses sequential probability ratio test (SPRT) to detect changes in the overall pressure. SPRT analyzes the pressure variation over a high pressure and then a lower pressure to confirm the tightness of a test section. The system does not require temperature sensors for leak confirmation. Wave Gen acquisition units provide leak location. Compliant with EI 1540, EI 1560, JIG2, and JIG4.