No. S 29
Radiation Protection Act
(Chapter 262)
Radiation Protection (Ionising Radiation) Regulations 2000
In exercise of the powers conferred by section 28 of the Radiation Protection Act, the Minister for Health hereby makes the following Regulations:
PART I
PRELIMINARY
Citation and commencement
1.  These Regulations may be cited as the Radiation Protection (Ionising Radiation) Regulations 2000 and shall come into operation on 1st February 2000.
Definitions
2.  In these Regulations, unless the context otherwise requires —
“absorbed dose” means the amount of energy, expressed in gray, imparted to matter by ionising radiation per unit mass of the irradiated material at the place of interest;
“annual limit on intake” or “ALI” means the activity of a radionuclide which, if taken alone into the human body, would irradiate an individual to the dose limit specified in Part I of the Second Schedule;
“approved” means approved in writing by the Director;
“becquerel” means the unit of radioactivity defined as one disintegration per second, and may be designated by the symbol “Bq”;
“committed effective dose” means the time integral of the effective dose rate following an intake of radioactive material into the body based on —
(a)the time period that has elapsed after the intake; and
(b)if the time that has elapsed after the intake is not known, the time period shall be deemed to be 50 years for above and a time period of up to his attainment of 70 years of age for an intake by an individual below 18 years of age;
“effective dose” means the sum of the weighted equivalent doses in all tissues and organs of the human body;
“equivalent dose” means the sum of the product of the absorbed dose in gray and the radiation weighting factor for all the different types of radiation incident on a tissue or an organ, and is expressed in sievert;
“full blood examination” means —
(a)an estimation of the haemoglobin in grams per 100 millilitres of whole blood;
(b)an estimation of the number of red blood cells present per cubic millimetre of whole blood;
(c)an estimation of the number of white blood cells present per cubic millimetre of whole blood;
(d)a differential white cell count;
(e)a platelet count;
(f)a search for abnormal cells and description of any seen; and
(g)any other blood examination as the Director may from time to time require;
“gigabecquerel” means one thousand million becquerels and may be designated by the symbol “GBq”;
“gray” means the unit of absorbed dose and is equal to one joule per kilogramme of irradiated material and may be designated by the symbol “Gy”;
“individual” means any natural person;
“installation” means the area of radiation hazard under the administrative control of the person possessing the source of radiation;
“ionisation chamber smoke detector” means a detector, using radioactive materials, sensitive to combustion products capable of affecting ionisation currents within the detector;
“irradiating apparatus” means —
(a)any apparatus that is capable of producing ionising radiation; or
(b)any component of or accessory to an apparatus described in paragraph (a);
“kilobecquerel” means one thousand becquerels and may be designated by the symbol “kBq”;
“leakage radiation” means all radiation other than the useful beam;
“licensee” means a person who holds a licence under the Act;
“megabecquerel” means one million becquerels and may be designated by the symbol “MBq”;
“microsievert” means one millionth part of a sievert and may be designated by the symbol “µSv”;
“millisievert” means one thousandth part of a sievert and may be designated by the symbol “mSv”;
“non-single station ionisation chamber smoke detector” means an ionisation chamber smoke detector which is intended for, and capable of, connection to one or more other smoke detector units as part of a fire detection system with a centrally located alarm and power supply unit;
“primary radiation” means radiation coming directly from any radioactive substances or irradiating apparatus;
“radiation” or “ionising radiation” means energy that is propagated in the form of X-rays, gamma-rays, alpha and beta particles, high speed electrons, neutrons, protons and other nuclear particles, but does not include energy in the form of sound and radiowaves, or visible, infra-red, or ultra-violet light;
“radiation dose” means effective dose or equivalent dose received by an individual;
“radiation hazard” means the danger to the health of an individual arising from exposure to ionising radiation, whether due to external radiation or to radiation from radioactive substances within the body;
“radiation level” means the corresponding equivalent dose rate;
“radiation weighting factor” means a dimensionless factor, selected for the type and energy of radiation incident on the body or from sources within the body, by which the absorbed dose in a tissue or an organ is weighted to give the equivalent dose;
“radiation work” means work which —
(a)involves the use or handling of any radioactive substance;
(b)involves the use or operation of any irradiating apparatus; or
(c)is required to be carried out in proximity to any irradiating apparatus or radioactive substance or both,
and which is liable to result in the receiving by the individual engaging in it of a radiation dose in excess of one-tenth of the appropriate dose limit for radiation workers as specified in Part I of the Second Schedule;
“radiation worker” means any individual who is engaged in or is employed for part or whole or his working time to do radiation work;
“scattered radiation” means radiation which, during its passage through a substance —
(a)has been deviated in direction; or
(b)has been modified by an increase in wave length;
“sealed source” means any radioactive material that is firmly bonded within material or sealed in a capsule of adequate mechanical strength so as to prevent the escape of any part of the radioactive material under foreseeable conditions of use and wear but so designed as to allow the emission of ionising radiation for use as required;
“secondary radiation” means radiation other than primary radiation that is emitted by any matter irradiated by primary radiation;
“sievert” means the unit of equivalent dose and may be designated by the symbol “Sv”;
“single station ionisation chamber smoke detector” means a self-contained ionisation chamber smoke detector in which the alarm is incorporated in the ionisation chamber smoke detector itself and which does not need to be linked to any other external fire detection or alarm system in order to function;
“specific activity”, in relation to —
(a)a radionuclide, means the activity of the radionuclide per unit mass of that nuclide; and
(b)a material in which the radionuclides are essentially uniformly distributed, means the activity per unit mass of the material;
“stochastic effects” means those effects for which the probability of an effect occurring, regarded as a function of dose, is without threshold;
“tissue weighting factor” means the proportion of the risk arising from stochastic effects resulting from tissue to the total risk, when the whole body is irradiated uniformly;
“transfer record” means a record prepared on the termination of any individual’s employment of radiation dose received by him being a record prepared in accordance with requirements for the time being imposed under these Regulations;
“unsealed source” means any radioactive material which is not a sealed source;
“useful beam” means that part of the primary and secondary radiation that passes through the aperture, cone or other device for collimating the beam.
Made this 12th day of January 2000.
MOSES LEE
Permanent Secretary,
Ministry of Health,
Singapore.
[RPI 01/91:07; AG/LEG/SL/262/98/1 Vol. 1]