Unshielded (Open) Installations

T.O. 33B-1-1 frequency not to exceed six months. A log, initialed by the individual making the inspection, shall be maintained. g. A qualified radiographer shall be present at the console panel during all radiographic exposures and will be the only person authorized to operate radiography equipment. A calibrated survey instrument shall be available for immediate use by the radiographer during all radiographic operations. h. Except when conducting daily verification of safety interlock operation and in emergencies, door interlocks will not be used to terminate the exposure. The exposure shall be terminated at the control panel. i. When radiographic exposures have been completed, the power safety-switch key shall be removed from the control panel. The radiation-producing equipment and power safety-switch key shall be placed in secure areas separate from one another. Only radiographers authorized by the Unit Commander shall have access to the storage area. 6.9.18.3 Unshielded (Open) Installations. 6.9.18.3.1 Features. a. This class shall be selected only if operational requirements prevent the use of either of the other classes. For radiography its use should be limited mainly to mobile and portable equipment where fixed shielding cannot be used. Fluoroscopy shall be done only by remote observation, such as by closed circuit television. b. The operational requirements of other types of installations may necessitate use of this class. c. The protection of personnel and public depends almost entirely on strict adherence to safe operating procedures. With this adherence, unshielded installations may provide a degree of protection similar to the other classes. d. The lack of inherent shielding necessarily increases the importance of an effective ALARA program. Additionally, lack of interlock and engineered access to high radiation areas increases the importance of unauthorized use of devices. 6.9.18.3.2 Requirements. NOTE High Radiation Area boundaries shall be calculated only. Verification surveys shall not be performed unless such surveys can be accomplished (using devices such as those, which integrate dose) without additional, unnec- essary exposure to personnel. An installation shall be classified as ‘‘unshielded’’ if due to operational requirements it cannot be provided with the inherent degree of protection specified for either Army ‘‘protective’’ or ‘‘enclosed’’ and Air Force shielded installations. Such installations include fenced or ‘‘roped-off’’ areas located either in the open or inside buildings such as hanger bays. An installation so classified shall conform to all of the following mandatory requirements: a. The source and all objects exposed thereto shall be within a conspicuously posted perimeter that limits the area in which the exposure can exceed 100 mR (1 mSv) in any 1 hour. This area will be conspicuously coated with ‘‘Danger, High Radiation Area’’ or ‘‘Caution, High Radiation Area’’ signs. No person shall have access to the ‘‘High Radiation Area’’ within this perimeter nor may remain in the area during irradiation. b. A second perimeter delineating a ‘‘Radiation Area’’ shall be calculated, posted with sufficient ‘‘Caution, Radiation Area’’ signs so as to be conspicuous from any direction of approach, and radiation levels verified by radiation surveys. Such radiation surveys shall be documented in operating logs and shall include a minimum of two readings for each side of the radiation boundary. (A ‘‘Radiation Area’’ is defined as any area accessible to individuals in which ionizing radiation dose rate levels Change 2 6-147