21 CFR 1020.40 is the Radiation Safety Performance Standard for Cabinet X-ray Systems developed by the US FDA (Food and Drug Administration),
applicable to cabinet X-ray equipment exported to or sold in the US market.
Scope of Application
Applicable object: Cabinet X-ray systems manufactured/assembled on or after April 10, 1975; The hand luggage inspection system is applicable to
equipment manufactured/assembled on or after April 25, 1974.
Not applicable to: systems specifically designed for material microscopy (such as X-ray diffraction, spectroscopy, electron microscopy equipment)
and systems intentionally exposing people to X-rays.
Common applicable products: airport/station baggage screening machines, industrial inspection X-ray machines, food inspection X-ray equipment, etc.
Radiation leakage limit (most critical indicator)
At a distance of 5 centimeters from the outer surface of the cabinet, the leakage radiation within 1 hour shall not exceed 0.5 mR/hr (0.5 milliradians per
hour).
Measurement conditions:
Measurement area: 10 cm ², maximum linear size not exceeding 5 cm
Under the conditions of tube voltage, current, beam direction, and scattered radiation that generate maximum X-ray exposure
The door and maintenance panel need to be tested separately when fully closed and fixed in any other position that allows for the generation of X-radiation
Floor requirements
Cabinet X-ray systems must have permanent flooring.
Port and aperture safety requirements
No port shall allow any part of the human body to be inserted into the primary X-ray beam. No aperture shall allow any part of the human body to
be inserted.
Requirements for safety interlocking devices
Each door shall be equipped with at least two safety interlocks.
One of the interlocks must ensure that the energy supply circuit of the high-voltage generator is physically disconnected when the door is opened.
Each maintenance panel shall have at least one safety interlock.
After the interlock is interrupted, specific controls need to be used to restore X-ray production.
Any single component failure shall not result in the failure of more than one required safety interlock.
Ground fault protection
Grounding faults shall not cause the generation of X-rays.
Control and indicator requirements
Key control: Ensure that no X-rays are generated after the key is removed.
Independent X-ray start/stop control.
Two independent X-ray generation indicators (sound/light), with at least one indicator labeled "X-Ray ON" visible from each door, maintenance panel,
and port.
Additional requirements for human access to the system
There must be emergency controls inside the cabinet to prevent and terminate the generation of X-rays, and they cannot be reset/bypassed from
the outside.
X-rays cannot be generated inside the cabinet.
At least 10 seconds of sound and light warning before the first activation after closing the door.
Continuous visible warning signals during X-ray generation.
Warning label requirements
The startup control must be marked with "Caution: X-Rays Produced When Energized"
Each port must be labeled with "Caution: Do Not Insert Any Part of the Body When System is Energized - X-ray Hazard"
Additional requirements for luggage inspection system
The operator must be able to monitor all ports and doors in the control area.
When the exposure time is ≥ 0.5 seconds, the operator can terminate the exposure at any time.
When the exposure time is less than 0.5 seconds, the operator can prevent subsequent exposures.
References to relevant regulations
21 CFR 1010.2: Product Certification Requirements
21 CFR 1020.40: Performance Standards for Cabinet X-ray Systems
FDA Guidance Document: Specific Instructions for Cabinet X-Ray Product Inspections and Tests
To obtain a testing report for export to the United States, it is usually necessary for a third-party laboratory recognized by the FDA to conduct testing
according to the above standards and issue a compliance report.
