The word "helipad" is used to describe a helicopter landing pad, which is a landing area for helicopters. Even though helicopters can usually land on any flat surface, a fabricated helipad provides a clearly marked, designated, hard surface area away from obstacles on which a helicopter can land. Helipads are often constructed out of concrete and are marked with a circle and/or a letter "H", so that rotorcraft can spot them from the air.
Helipads may be located at heliports or airports where fuel, air traffic control, and service facilities for aircraft are available. In addition, helipads may also be located away from such facilities and are commonly placed on the roofs of hospitals to facilitate MEDEVACs and/or even on corporate office buildings. Large ships and sea vessels sometimes have a helipad onboard to allow people to board or deboard the vessel while it is still at sea. This is particularly useful in the event of any emergency.
Helipads are not always constructed out of concrete and can be set-up in remote areas to allow rotorcraft to land in hard to reach areas. For example, helipads may be constructed in extreme conditions such as frozen ice or on mountain tops. Most rooftop helipads often display a large two-digit number that represents the weight limit (in thousands of pounds) of the helipad. In addition, a second number may also be present, which represents the maximum rotor diameter in feet.