But its potential to kill workers in or near confined spaces should never be underestimated. On Nov. 5, 2005, two contractors working at Valero Energy Corp.'s Delaware City, Del., oil refinery died from nitrogen asphyxiation.
The hertz (symbol Hz) is the unit of frequency in the International System of Units (SI) and is defined as one cycle per second. It is named for Heinrich Rudolf Hertz, the first person to provide conclusive proof of the existence of electromagnetic waves.ach musical note corresponds to a particular frequency which can be measured in hertz. An infant's ear is able to perceive frequencies ranging from 20 Hz to 20,000 Hz; the average adult human can hear sounds between 20 Hz and 16,000 Hz.
In English, hertz is also used as the plural form. As an SI unit, Hz can be prefixed; commonly used multiples are kHz (kilohertz, 10 3 Hz), MHz (megahertz, 10 6 Hz), GHz (gigahertz, 10 9 Hz) and THz (terahertz, 10 12 Hz).adio frequency radiation is usually measured in kilohertz (kHz), megahertz (MHz), or gigahertz (GHz). Light is electromagnetic radiation that is even higher in frequency, and has frequencies in the range of tens (infrared) to thousands (ultraviolet) of terahertz.