This International Standard specifies the minimum characteristics of instruments for measuring physical quantities characterizing an environment as well as the methods for measuring the physical quantities of this environment. It does not aim to define an overall index of comfort or thermal stress but simply to standardize the process of recording information leading to the determination of such indices. Other International Standards give details of the methods making use of the information obtained in accordance with this standard. This International Standard is used as a reference when establishing specifications for manufacturers and users of instruments for measuring the physical quantities of the environment; a written contract between two parties for the measurement of these quantities. It applies to the influence of hot, moderate, comfortable or cold environments on people.