T.O. 33B-1-1
6-151
6.9.18.3.3.4 Operations.
a. Once the restricted area is identified, it shall be adequately posted to assure against inadvertent entry.
In some buildings it may be feasible to lock appropriate doors or limit access to very large work areas as
a simple means of radiation area control. In other locations it may be necessary to establish boundaries
by roping off or barricading passageways at appropriate locations. In any event, sufficient control in the
form of posting, use of safety monitors and use of access limiting devices shall be in place to guarantee
that no individual can enter the area inadvertently.
b. In general, when radiographic operations are conducted without benefit of shielding it is necessary to
erect a rope barrier around X-ray tube head at a distance of 70 meters (230 feet) or more for vertical
beam orientation. For exposures requiring near horizontal or horizontal beams, the barrier may have to
be extended in the direction of the beam for several hundred meters to achieve exposure rates at the
barrier that are less than or equal to the maximum limits. (Fixed or portable shielding should be used
whenever practicable to reduce the size of area which must be controlled.) Obvious1y, if the exposures
can be made in an area completely isolated, and unauthorized entry into the radiation area can be
absolutely guaranteed, these barriers can be relaxed. However, all entrances into the isolated area shall
be secured and posted, and any uncontrolled area must not contain exposure rates that would allow
personnel to receive in excess of 2 mrem (20 mSv) in any one hour. All positions around the barrier
must be in view of one of the radiographers or radiation monitors during exposures.
c. Place radiation warning signs along the barrier so that at least one can be seen from any direction of
approach.
d. Extend the power cable from the tube head to the controls so that the operator is located as far as
possible from the radiation source, usually at least 75 feet (23 meters). Place the controls so that all
monitors or the entire perimeter of the barrier can be seen by the radiographer. If this is not possible,
adequate means of communication shall be specified by either a consultant health physicist or Nuclear
Medicine Science Officer or other qualified individual during a survey of the unshielded operation.
Adequate means of communications may includes two-way radios, whistles, electronic/propellant-
activated noise alarms or ultrasonic infrared intrusion barriers but need not be limited to these methods.
e. Place the sign “X-RAY ON”, when lit, near the X-ray tube and connect to the X-ray interlock circuit.
f. Illuminate the area for night operation.
g. Insure that no one is INSIDE the object being radiographed.
h. Prior to making an exposure, the area shall be surveyed by the radiographers to establish pattern of any
radiation fields that may be present and to determine the adequacy of rope barrier placement.
i. Upon completion of the survey and modification of the barrier, if needed, put the film in place and
proceed with the radiographic exposure.
j. If the barrier is penetrated by anyone during the exposure, the radiation source shall be turned off
immediately and the incident reported to the radiography supervisor.
k. The radiographic apparatus shall NOT be left unattended when operating nor shall it be operated by
unauthorized personnel. This equipment shall always be stored in secure area. A key lock shall be
installed on all radiographic unit consoles. While in storage or unattended by an authorized
radiographer, the power safety-switch key shall be removed from the console and securely maintained
separate from the apparatus. Only radiographers authorized by the Unit Commander shall have access
to the industrial radiographic unit power safety-switch key storage areas.
