Herbert Saffir, a consulting engineer who specializes in wind damage to buildings, and Robert Simpson, who was then director of the National Hurricane Center, invented the scale during the 1970s. The table below is a breakdown of the average wind and pressure values and the likely level of damage for each of the five hurricane categories. Two lower storm classes are listed also. Pressure is given in inches of mercury. The average sea-level atmospheric pressure is 29.92 inches of mercury.
Wind speed is given in miles per hour.