Washington Administrative Code › Title 296 - Labor and Industries, Department of › Chapter 296-62 - General occupational health standards › Part J-1 - PHYSICAL AGENTS › Section 296-62-09004 - Ionizing radiation

Current through Register Vol. 24-14, July 15, 2024
(1) 
				Definitions applicable to this section.
Note:
Definitions also appear in some subsections.
(a)
Radiation
.
Includes alpha rays, beta rays, gamma
				rays, X-rays, neutrons, high-speed electrons, highspeed protons, and other
				atomic particles; but such term does not include sound or radio waves, or
				visible light, or infrared or ultraviolet light.
(b)
Radioactive material.
Any
				material which emits, by spontaneous nuclear disintegration, corpuscular or
				electromagnetic emanations.
(c)
Restricted area.
Any area access to which is controlled by the
				employer for purposes of protection of individuals from exposure to radiation
				or radioactive materials.
(d)
Unrestricted area.
Any area access to which is not controlled by
				the employer for purposes of protection of individuals from exposure to
				radiation or radioactive materials.
(e)
Dose.
The quantity of ionizing radiation absorbed,
				per unit of mass, by the body or by any portion of the body. When the
				provisions in this section specify a dose during a period of time, the dose is
				the total quantity of radiation absorbed, per unit of mass, by the body or by
				any portion of the body during such period of time. Several different units of
				dose are in current use. Definitions of units used in this section are set
				forth in subdivisions (f) and (g) of this subsection.
(f)
Rad.
A measure of the dose
				of any ionizing radiation to body tissues in terms of the energy absorbed per
				unit of mass of the tissue. One rad is the dose corresponding to the absorption
				of 100 ergs per gram of tissue (1 millirad (mrad) = 0.001 rad).
(g)
Rem.
A measure of the dose
				of any ionizing radiation to body tissue in terms of its estimated biological
				effect relative to a dose of 1 roentgen (r) of X-rays (1 millirem (mrem) =
				0.001 rem). The relation of the rem to other dose units depends upon the
				biological effect under consideration and upon the conditions for irradiation.
				Each of the following is considered to be equivalent to a dose of 1 rem:
(i)  A dose of 1 roentgen due to x- or gamma
				radiation;
(ii)  A dose of 1 rad
				due to x-, gamma, or beta radiation;
(iii)
				 A dose of 0.1 rad due to neutrons or high energy
				protons;
(iv)  A dose of 0.05 rad
				due to particles heavier than protons and with sufficient energy to reach the
				lens of the eye;
(v)  If it is more
				convenient to measure the neutron flux, or equivalent, than to determine the
				neutron dose in rads, as provided in item (iii) of this subdivision, 1 rem of
				neutron radiation may, for purposes of the provisions in this section be
				assumed to be equivalent to 14 million neutrons per square centimeter incident
				upon the body; or, if there is sufficient information to estimate with
				reasonable accuracy the approximate distribution in energy of the neutrons, the
				incident number of neutrons per square centimeter equivalent to 1 rem may be
				estimated from the following table:
Neutron Flux Dose Equivalents
Neutron energy (million electron volts
							 (Mev))
Number of neutrons per square centimeter equivalent
							 to a dose of 1 rem (neutrons/cm2)
Average flux to deliver 100 millirem in 40 hours
							 (neutrons/cm2 per sec.)
Thermal ........
970 X 106
670
0.0001 ..........
720 X 106
500
0.005 ...........
820 X 106
570
0.02 ............
400 X 106
280
0.1 .............
120 X 106
80
0.5 .............
43 X 106
30
1.0 .............
26 X 106
18
2.5 .............
29 X 106
20
5.0 .............
26 X 106
18
7.5 .............
24 X 106
17
10 .............
24 X 106
17
10 to 30 .........
14 X 106
10
(h)
				 For determining exposures to X- or gamma rays up to 3 Mev., the
				dose limits specified in this section may be assumed to be equivalent to the
				"air dose." For the purpose of this section "air dose" means that the dose is
				measured by a properly calibrated appropriate instrument in air at or near the
				body surface in the region of the highest dosage rate.
(i)
Curie.
A unit of
				measurement of radioactivity. One curie (Ci) is that quantity of radioactive
				material which decays at the rate of 2.2 x 1012
				disintegrations per minute (dpm).
(i)  One
				millicurie (mCi) = 10-3Ci
(ii)  One microcurie (uCi) =
				10-6Ci
(iii)
				 One nanocurie (nCi) = 10-9Ci
(iv)  One picocurie (pCi) =
				10-12Ci