This standard defines performance parameters for an inst rument to measure absorbed dose and absorbed dose rate to air during emergency situations. For the measurement of beta radiation, the absorbed dose to tissue at a depth of 7 mg/cm 2 of tissue shall be used. Wherever the term «dose» or «dose rate» is used in this standard, it means absorbed dose or absorbed dose rate to air in air. This standard does not specify which instruments are required nor does it consider numbers or specific locations of such inst ruments. These determinations are made by qualified individuals and appropriate regulatory authorities. If national regulations require other isotropic dose or exposure quantities (e.g. ambient or directional dose equivalent) to be used for the purposes above, this standard applies to the performance characteristics of the equipment intended to measure these other quantities. For example, the same numerical values for the requirements for the radiation characteristics would still apply but the conventionally true values would be expressed in the other quantity and not in absorbed dose rate. Specifications for instruments for measuring dose rate less than the minimum detectable absorbed dose rate level specified in this standard are contained in I EC Publications 395 and 532. Where such inst ruments are also to be used for emergency measurements, they shall also meet the requirements of this standard. Primary emphasis is placed on the selection of inst ruments and systems and on their ability to provide data rapidly as the basis for making appropriate emergency action decisions. This standard only applies to portable instruments (herein referred to as "instruments"). (See I E C Publication 951-3.) Although this standard specifies the requirements for equipment primarily for emergency use, such equipment may also be used for on-site measurements at other times. If the instrument has a remote detector and if an additional detector is provided in the measuring assembly to measure the dose rate at the location of the operator, the requirements of this standard shall apply to both of the detectors.