Spirometry: Forced Vital Capacity This procedure measures Forced Vital Capacity which requires a maximal inhalation and maximal, forced exhalation. FVC + Residual Volume (not measure here) is = Total Lung Volume. FEV 1.0 is the amount expired in one second. The ratio of FEV 1.0 to FVC is clinically relevant. A ratio of 80% or greater is considered normal. Less than 80% could indicate conditions such as asthma or COPD (emphysema).  Rating 0/10 Views 617 Duration 00:20