Segregation distances.

  1. Law
  2. CFR 49
  3. Transportation
  4. Other Regulations Relating to Transportation
  5. Pipeline and Hazardous Materials Safety Administration, Department of Transportation
  6. Hazardous Materials Regulations
  7. Carriage by Vessel
  8. Detailed Requirements for Radioactive Materials
  9. Segregation distances.

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§ 176.708 Segregation distances.

(a) Table IV lists minimum separation distances between radioactive materials and spaces regularly occupied by crew members or passengers, or between radioactive materials and undeveloped photographic film. It expresses the separation distances as a function of the sum of the TIs of all packages in a single consignment, in the case of 0 or 3 feet of intervening cargo of unit density for persons, and 0, 3, or 6 feet of intervening cargo of unit density for undeveloped film. Cargo of unit density is stowed cargo with a density of 1 long ton (2240 lbs.) per 36 cubic feet. Separation distances may be interpolated from the table where appropriate.

(b) Table IV is to be used to determine the separation distance for undeveloped film.

(c) Category YELLOW-II or YELLOW-III packages or overpacks must not be transported in spaces occupied by passengers, except those exclusively reserved for couriers specially authorized to accompany such packages or overpacks.

(d) The separation distances for crew members and passengers may be determined by one of two methods:

(1) By using Table IV to determine the minimum distances between the radioactive material packages and regularly occupied spaces or living quarters; or

(2) For one or more consignments of Class 7 (radioactive) material to be loaded on board a vessel under the exclusive use conditions described in § 176.704(f), by demonstration through direct measurement, made and documented by a suitably qualified person, that for the indicated exposure times the dose rate in regularly occupied spaces or living quarters is less than -

(i) For the crew: 7.0 µSv/h (0.70 mrem/h) up to 700 hours in a year, or 1.8 µSv/h (0.18 mrem/h) up to 2750 hours in a year; and

(ii) For the passengers: 1.8 µSv/h (0.18 mrem/h) up to 550 hours in a year, taking into account any relocation of cargo during the voyage.

(e) Any departure from the segregation provisions should be approved by the competent authority of the flag state of the ship and, when requested, by the competent authority at each port of call.

(f) Table IV is as follows:

Expand Table

Table IV

Sum of transport indexes of the packages Minimum distance in feet from living accommodation or regularly occupied working space Minimum distance in feet from undeveloped film and plates
1 day voyage 2 day voyage 4 day voyage 10 day voyage 20 day voyage 30 day voyage 40 day voyage 50 day voyage
Cargo thickness in feet (unit density)
Nil 3 Nil 3 6 Nil 3 6 Nil 3 6 Nil 3 6 Nil 3 6 Nil 3 6 Nil 3 6 Nil 3 6
0.1 to 0.5 5 X 6 X X 8 X X 11 X X 17 4 X 25 6 X 30 7 X 35 8 X 39 9 X
0.6 to 1 6 X 8 X X 11 X X 16 4 X 25 6 X 35 8 X 42 10 X 50 12 X 55 13 X
1.1 to 2 9 X 11 X X 16 4 X 22 5 X 35 8 X 50 12 X 61 14 X 70 17 X 78 19 X
2.1 to 3 10 X 14 X X 19 5 X 27 6 X 42 10 X 61 14 X 74 18 X 86 20 X 96 23 X
3.1 to 5 13 X 17 4 X 25 6 X 35 8 X 55 13 X 78 19 X 96 23 X 110 26 X 124 29 7
5.1 to 10 19 4 25 6 X 35 8 X 50 12 X 78 19 X 110 26 X 135 33 8 155 37 9 175 42 10
10.1 to 20 26 6 35 8 X 50 12 X 69 17 X 110 26 X 155 37 9 190 46 11 220 53 13 250 59 14
20.1 to 30 32 8 43 10 X 61 14 X 85 20 X 135 32 8 190 45 11 235 56 13 270 65 16 305 72 17
30.1 to 50 42 10 55 13 X 78 19 X 110 26 X 175 42 10 245 58 14 300 73 17 350 84 20 390 94 22
50.1 to 100 59 14 78 19 X 110 26 X 155 37 9 245 59 14 350 82 20 430 105 24 515 118 28 550 130 32
100.1 to 150 72 17 96 23 X 135 32 8 190 46 11 300 72 17 425 100 24 525 125 30 600 145 35 (7 ) 165 39
150.1 to 200 84 20 110 26 X 155 37 9 200 53 13 350 84 20 490 115 28 600 140 35 (7 ) 165 40 (7 ) 190 45
200.1 to 300 105 24 135 32 X 190 46 11 270 64 15 425 105 25 600 145 35 (7 ) 180 42 (7 ) 205 49 (7 ) 230 55
300.1 to 400 120 28 160 37 9 220 53 13 310 75 18 500 120 28 (7 ) 165 40 (7 ) 205 49 (7 ) 235 57 (7 ) 265 63

Note:

(1) X - indicates that thickness of screening cargo is sufficient without any additional segregation distance.

(2) By using 6 feet of intervening unit density cargo for persons and 10 feet for film and plates, no distance shielding is necessary for any length of voyage specified.

(3) Using 1 steel bulkhead or steel deck - multiply segregation distance by 0.8. Using 2 steel bulkheads or steel decks - multiply segregation distance by 0.64.

(4) “Cargo of Unit Density” means cargo stowed at a density of 1 ton (long) per 36 cubic feet; where the density is less than this the depth of cargo specified must be increased in proportion.

(5) “Minimum distance” means the least in any direction whether vertical or horizontal from the outer surface of the nearest package.

(6) The figures below the double line of the table shall be used in those cases where the appropriate provisions of this class permit the sum of the transport indices to exceed 200.

(7) Not to be carried unless screening by other cargo and bulkheads can be arranged in accordance with the other columns.

[Amdt. 176-15, 48 FR 10245, Mar. 10, 1983, as amended by Amdt. 176-37, 60 FR 50334, Sept. 28, 1995; 69 FR 3695, Jan. 26, 2004]


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