The peak expiratory flow (PEF), also called peak expiratory flow rate (PEFR), is a person’s maximum speed of expiration, as measured with a peak flow meter, a small, hand-held device used to monitor a person’s ability to breathe out air. Peak expiratory flow is typically measured in units of liters per minute (L/min).Click to see full answer. Keeping this in consideration, what are normal fev1 FVC and PEF values?The normal value for the FEV1/FVC ratio is 70% (and 65% in persons older than age 65). When compared to the reference value, a lower measured value corresponds to a more severe lung abnormality. (See table below.) Restrictive lung diseases can cause the FVC to be abnormal.Furthermore, what is a good reading on a peak flow meter? Green Zone: 80 to 100 percent of the usual or normal peak flow readings are clear. A peak flow reading in the green zone indicates that the lung function management is under good control. Yellow Zone: 50 to 79 percent of the usual or normal peak flow readings indicates caution. Moreover, what is normal PEF? Peak Expiratory Flow Rate. Normal Values. In men, readings up to 100 L/min lower than predicted are within normal limits. For women, the equivalent figure is 85 L/min.What is a normal reading on a spirometer?The Measured column represents the total volume exhaled during the first second, in liters. Normal values in healthy males aged 20-60 range from 4.5 to 3.5 liters, and normal values for females aged 20-60 range from 3.25 to 2.5 liters.