GB 22448-2025Non-destructive testing instruments - Protection rules for industrial X-ray radiographic equipment below 500kV (English PDF)

1 Scope

GB 22448-2025 is the Chinese national standard on non-destructive testing instruments - protection rules for industrial x-ray radiographic equipment below 500kv, in the field of testing. It carries no /T suffix, which in the Chinese system means compliance is mandatory: a product or a practice within its scope has to meet it to be lawfully made, sold or carried out in China. It was issued on 1 August 2025 by the State Administration for Market Regulation; Standardization Administration of China, and has been in force since 1 August 2026. Classification: ICS 19.100, CCS N78. This page is published from the official record of the standard held by the Chinese standards administration: the identification, the dates, the classification and the issuing body are taken from there. The clause text, the tables and the numeric limits are in the document itself, which is delivered complete in English translation.

This document specifies the protection requirements for industrial X-ray flaw detectors below 500 kV, the protection requirements for X-ray flaw detection work sites, radiation protection monitoring during use, safe operation requirements for X-ray machines and radiation protection testing for X-ray machines, etc. This document applies to the design, manufacture, installation and use of industrial X-ray flaw detectors below 500 kV (including stationary, mobile and portable X-ray flaw detectors). Non- destructive testing equipment with the same radiation source range but not used for flaw detection may refer to this document for further information.

2 Normative References

The contents of the following documents constitute indispensable clauses of this document through the normative references in the text. In terms of references with a specified date, only versions with a specified date are applicable to this document. In terms of references without a specified date, the latest version (including all the modifications) is applicable to this document.

GB 18871 Basic Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources

GB/T 36416.2 Testing Machine Vocabulary - Part

3 Terms and Definitions

The terms and definitions defined in GB 18871 and GB/T 36416.2 are applicable to this document.

4 Protection Requirements for X-ray Machines

4.1 Ambient Dose Equivalent Rate Caused by Leakage Ray When industrial X-ray flaw detectors below 500 kV (hereinafter referred to as the "X-ray machines") are in operation, the main beam window of the X-ray tube shall be covered with a light shield. At the maximum operating value specified by the manufacturer, the ambient dose equivalent rate caused by leakage ray at a distance of 100 cm from the X-ray tube focal point shall be measured using a protective-level dosimeter. The measured results shall comply with panel key switch is turned on. The key shall only be removed when the machine is stopped or in standby mode.

4.4 X-ray Generator It shall be ensured that the controller can only issue a transmission command when the X-ray generator is on. When the X-ray generator is off, no X-rays shall be emitted. The connection status of the X-ray generator shall not be arbitrarily changed.

4.5 Shielding Material The thickness of the shielding material inside the X-ray tube shall meet the requirements of

4.1 regarding the ambient dose equivalent rate caused by leakage ray.

4.6 Connecting Cable The length of the connecting cable between the controller of the portable X-ray machine and the high-voltage generator shall be greater than or equal to 20 m.

6 X-ray Protection Monitoring During Use

6.1 Occupational Exposure Dose Limits Routine personal dose monitoring shall be conducted for personnel subject to occupational exposure, and personal dose and health management files shall be established. The monitored values shall meet the requirements of GB 18871 and include the following contents.

a) The average annual effective dose over five consecutive years;

b) The effective dose in any given year;

c) The annual effective dose to the lens of the eye;

d) The annual equivalent dose to the limbs (hands and feet) or skin.