Evidential Breath Testers (EBT’s) are engineered to automatically capture a breath sample when analyzing for the presence of alcohol. There are two critical conditions which must be met in order for an automatic breath sample to be taken. First, the subject must provide a minimum volume of breath (1200 cc’s of breath for the Alco-Sensor IV and 1350 cc’s of breath for the Alco-Sensor V). Second, the subject must reach a breath flow drop off point. When both conditions occur, the instrument’s fuel cell automatically opens to capture 1cc of breath sample. However, when your subject will not or cannot provide the minimum volume of breath and reach the breath flow drop off point, it is referred to as “insufficient breath sample” or “shy lung”. Here are the most common reasons for “insufficient breath sample” or “shy lung” and ways to overcome it: