This standard contains specifications for use of climate indexes at the workplace at warm and hot climates outside the comfort ranges, taking into consideration work intensity and clothing. The climate indexes - basic effective temperature, BET - normal effective temperature, NET, - WBGT Index (Wet Bulb Globe Temperature) - required sweat rate swreq are described and the measurement conditions for their recording were given. For assessment of the climate at the workplace and in its environments, orientation ranges for climate expositions are given. They apply for workplaces where activities shall be carried out on a regular basis under climatic exposure, and only for heat-conditioned persons. The Committee responsible for this standard is NA 023-00-05 GA "Gemeinschaftsausschuss NAErg/NAM: Ergonomie der physikalischen Umgebung, ErgPhysU" ("Joint Working Committee NAErg/NAM: Ergonomics of the physical environment") at DIN.