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JICOSH Home > Laws > Ordinance on Prevention of Ionizing Radiation Hazards
Ordinance on Prevention of Ionizing Radiation Hazards

Ministry of Labour Ordinance No. 41 of September 30, 1972
Latest Amendments:
Ministry of Health, Labour and Welfare Ordinance No. 172 of July 16, 2001


Chapter VII.  Working Environment Measurement

(Workshops Where the Working Environment Measurement Shall Be Done)

Article 53.  The workshops as established by the Ministry of Health, Labour and Welfare Ordinance based on the item 6 of Article 21 of the Cabinet Order are as given below:

(1)  The portion which corresponds to the controlled area of workshops therein to carry out the radiation work.

(2)  Work rooms for handling radioactive substances.

(3)  Workshops therein to carry out work as listed in item 7 of Attached Table 2 of the Cabinet Order.

(Measurement, etc., of Dose Equivalent Rate)

Article 54.  The employer shall periodically measure the dose equivalent rate or dose equivalent due to the external radiation in the controlled area designated in item 1 of the preceding article by using radiation measuring instrument at least monthly (at least in every 6 months where the stationary radiation equipment is provided with the fixed shield or where the radiation equipment is loaded with the radioactive substance of less than 3.7 GBq) and record the following matters for each measurement and file for at least five years.

(1)  Time and date of measurement.

(2)  Method of measurement.

(3)  Kind, type and performance of radiation measuring instrument.

(4)  Measured parts.

(5)  Conditions of measurement.

(6)  Result of measurement.

(7)  Name of measurer.

(8)  Outline of the measures taken according to the result of the measurement.

2.  Notwithstanding the provision of the preceding paragraph, the dose equivalent rate and dose equivalent set forth in the preceding paragraph may be determined by calculation where measurement by the measuring instrument is extremely difficult.

3.  The measurements specified in paragraph 1 or the calculations specified in the preceding paragraph shall be made for a 1-cm dose equivalent rate or 1-cm dose equivalent. However, in places where a 70-micrometer dose equivalent rate may exceed 10 times the 1-cm dose equivalent rate, or a 70-micrometer dose equivalent may exceed 10 times the 1-cm dose equivalent among the controlled areas prescribed in item 1 of the preceding article, the same shall be made for the 70-micrometer dose equivalent rate or the 70-micrometer dose equivalent as well.

4.  The employer shall inform workers who enter the controlled area of the result of the measurement provided for in paragraph 1 or the result of calculation provided for in paragraph 2 by posting it, etc., in an easily visible location.

(Measurement of Concentrations of Radioactive Substances)

Article 55.  In terms of the workshops as provided for by item 2 or 3 of Article 53, the employer shall make measurements of contaminations of radioactive substances in the air periodically, once at an interval which is shorter than a month by radiation measuring instruments, and shall make records on the matters as given in the respective items of paragraph 1 of the preceding Article and keep the records in custody for a period of five years.

I / II / III / IV / IV-II / V
Supplementary Provisions
Attached Table