IEC 60052 sets forth recommendations concerning the construction and use of standard air gaps for the measurement of peak values of the following four types of voltage: a) alternating voltages of power frequencies; b) full lightning impulse voltages; c) switching impulse voltages; d) direct voltages. Air gaps constructed and used in accordance with this publication are IEC standard measuring devices in accordance with IEC 60060-2 and primarily intended for performance checks of high voltage measuring systems.