Section 120.422 - Appendix C - Design Requirements for an Operator's Booth(A)Space Requirements(1) The operator shall be allotted not less than 7.5 square feet (0.697 m2) of unobstructed floor space in the booth.(2) The operator's booth may be any geometric configuration with no dimension of less than two feet (0.61 m).(3) The space shall be allotted excluding any encumbrance by the x-ray control panel, such as overhang, cables or other similar encroachments.(4) The booth shall be located or constructed such that unattenuated direct scatter radiation originating in the examination table or at the wall cassette shall not reach the operator's station in the booth.(B)Structural Requirements(1) The booth walls shall be permanently fixed barriers of at least seven feet (2.13 m) high.(2) When a door or movable panel is used as an integral part of the booth structure, it must have an interlock which will prevent an exposure when the door or panel is not closed.(3) Shielding shall be provided to maintain exposure inside the booth equal to or less than two mR per week.(C)X-ray Control Placement. The x-ray exposure switch for the system shall be fixed within the booth and; (1) Shall be at least 40 inches (1.02 m) from any open edge of the booth and;(2) Shall allow the operator to use the majority of the available viewing windows.(D)Viewing System Requirements.(1) Each booth shall have at least one viewing device which will: (a) Be so placed that the operator can view the patient during any exposure; and,(b) The device should be so placed that the operator can have full view of any occupant of the room and should be so placed that the operator can view any entry into the room. If any door that allows access to the room cannot be seen from the booth, then that door must have an interlock controlling the exposure, which will prevent the exposure if the door is not closed.(2) When the viewing system is a window, the following requirements also apply: (a) The viewing area shall be at least one square foot (0.0929 m2).(b) The design of the booth shall be such that the operator's expected position when viewing the patient and operating the x-ray system is at least 18 inches (0.457m) from the edge of the booth.(c) The material constituting the window shall have at least the same lead equivalence as that required in the booth's walls in which it is mounted.(3) When the viewing system is by mirrors, the mirror(s) shall be so located as to accomplish the general requirements of 105 CMR 120.422: Appendix C(A)(4).(4) When the viewing system is by electronic means:(a) The camera shall be so located as to accomplish the general requirements of 105 CMR 120.421: Appendix C(A)(4); and,(b) There shall be an alternate viewing system as a backup for the primary system.(c) Means shall be provided for the operator to be able to orally communicate with the patient at all times.