WS/T 676-2020Measuring method of radon injection coefficient of building materials (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

Drafting organizations of this standard. Institute of Radiation Protection and Nuclear Safety Medicine, Chinese Center for Disease Control and Prevention, Hefei Cement Research and Design Institute, South China University learn.

1 Scope

This standard specifies the method for measuring the radon coefficient of building materials by circulating air.

This standard is applicable to the measurement of radon coefficient in building materials.

2 Normative references

The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this document.

For undated references, the latest version (including all amendments) applies to this document.

GB 6566 Radionuclide limits for building materials GB/T 11743 Analytical method of radionuclides in soil by gamma energy spectrum GBZ/T 182 Indoor radon and its decay products measurement specification

3 Terms and definitions

The following terms and definitions apply to this document.

Radon concentration

The radioactivity of radon-222 per unit volume of air.

Radon Emission Coefficient in a unit time interval, the ratio of the concentration of radon released from building materials to the total concentration of radon formed in building materials at the same time, commonly used the symbol e indicates that its value varies from 0 to 1.

Ra specific activity the ratio of the radioactivity of the nuclide 226Ra in a substance to the mass of the substance.

Measuring chamber

A regular container made of materials that are not easy to absorb radon, such as stainless steel or plexiglass, has good air tightness and has air inlets and outlets.

Measuring system radon leakage rate the rate of radon leakage in the loop of the entire measurement system due to the air tightness of the measurement chamber or leakage of the pipeline interface.

Note. The SI unit is h-1.

4 Measuring system

5 Sample preparation and measurement

6 Uncertainty requirements and evaluation

6.1 When reporting the test results, an evaluation of uncertainty should be given. Refer to Appendix B for the method.

6.2 The components of the evaluation uncertainty shall be given in the following categories.

a) Type A evaluation of uncertainty. the uncertainty evaluated by the method of statistical analysis of the measured value of the repeatability condition;

b) Type B evaluation of uncertainty. Uncertainty evaluated by non-statistical analysis method.

6.3 If this standard is complied with, under laboratory conditions, the relative expanded uncertainty of the measurement system for measuring the radon coefficient of building materials should be better than 35% Appendix A (Informative appendix) A brief schematic diagram of the measurement system for the radon coefficient of building materials refer to Figure A.1 for the construction and pipeline connection of the building material radon coefficient measurement system.

Appendix B

(Informative appendix)

Example of Uncertainty Evaluation for Measurement of Radon Coefficient of Building Materials B.1 The uncertainty evaluation of the measurement and calculation of the radon coefficient includes the A and B evaluations B.1.1 The main sources of Type A uncertainty components are as follows.

a) Deviation of radon concentration measurement, bu;

b) The uncertainty component introduced by the measurement of the free gas volume of the measurement system, vu;

c) The uncertainty component introduced by the quality measurement of the constant weight state of the building material sample, mu.

B.1.2 The main sources of Type B uncertainty components include.

a) The uncertainty component introduced by the effective attenuation coefficient, du;

b) The uncertainty component introduced by the 226Ra specific activity measurement system of building materials samples, Rau;

c) Calibration deviation of continuous radon meter, Rnu.

B.2 Relative expanded uncertainty the relative expanded uncertainty of the measurement results of the radon coefficient of building materials can be calculated using equation (B.1), and the inclusion factor is k=2.

B.3 Calculation example