kJm2

KJm2, commonly written as kJ/m^2 or kJ m^-2, is the unit of energy per unit area represent ing kilojoules per square meter. It expresses how much energy has been delivered to or released from a surface over a specified area. It is not an SI base unit; it is a derived unit formed from the joule and the square meter. In practice, it is used to quantify cumulative energy input, such as solar irradiation received by a surface during a time interval, or the energy deposited during a thermal or fire exposure test.

To avoid ambiguity, the standard notation uses a slash or exponent: kJ/m^2 or kJ m^-2. When you see "kJm2" in some sources, it is shorthand for kilojoules per square meter.

One can convert to related units: 1 kJ/m^2 equals 1000 J/m^2. In terms of energy over time, solar or radiant energy might be quoted as a daily insolation of a few kWh/m^2, which corresponds to several thousand kJ/m^2. Specifically, 1 kWh/m^2 equals 3.6 MJ/m^2 or 3600 kJ/m^2.

Applications include solar energy assessments, building thermal simulations, and standardized material tests where exposure is described by energy per area rather than flux rate. It contrasts with units of flux, such as W/m^2, which measure rate, whereas kJ/m^2 measures total energy over a period.