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Note: Where applicable, see State of California, Department of Transportation, Traffic Manual, Chapter 5, Traffic Controls for Construction and Maintenance Work Zones for specific sign requirements.
(b) Signs shall be posted approximately 1,000 feet from the blasting area on all public access.
(c) Electric blasting operations shall not be conducted closer to any operating mobile or fixed radio, television, or radar transmitter than the distances shown in the following tables:
Table 1
Recommended Table of Distances for
Commercial AM Broadcast Transmitters
(0.535 to 1.605 MHz)
Transmitter Power Minimum Distance
(Watts) (Feet)
Up to 4,000................................................ 750
5,000...................................................... 850
10,000................................................... 1,300
25,000................................................... 2,000
50,0001.................................................. 2,800
100,000.................................................. 3,900
500,000.................................................. 8,800
150,000 watts is the present maximum power of U.S. broadcast transmitters in this frequency range.
Table 2
Recommended Table of Distances for HF Transmitters
Other Than AM broadcast Worse Case Calculated at 20.8 MHz1
for a Loop Pickup Configuration
Transmitter Power Minimum Distance
(Watts) (Feet)
100.......................................... 750
500........................................ 1,700
1,000...................................... 2,400
5,000....................................... 5500
50,000.................................... 17,000
500,0002.................................. 55,000
1 It is at this frequency that the proposed pickup loop, shown in Figure 2 achieves its maximum efficiency. This table should be applied to International Broadcast Transmitters in the 10-25 MHz range.
2 Present maximum for International Broadcast.
Table 3
Recommended Table of Distances of Mobile Transmitters
Including Amateur and Citizens Radio
MINIMUM DISTANCE (Feet)
VHF
35 to 36 MHz
Public Use VHF
42 to 44 MHz 144 to 148 MHz
Transmitter MF MF Public Use Amateur UHF
Power 1.6 to 3.4 MHz 28 to 39.7 MHz 50 to 54 MHz 150.6 to 161.6MHz 450 to 460 MHz
(Watts) Industrial Amateur Amateur Public Use Public Use
10 40 100 40 15 10
50 90 220 90 35 20
100 125 310 130 50 30
1801 65 40
250 200 490 205 75 45
5002 295
6003 300 760 315 115 70
1, 0004 400 980 410 150 90
10,0005 1,250 1,300
Citizens Band Radio 26.96 to 27.23 MHz 5 watts--Minimum Distance 5 ft.
1 Maximum power for two-way mobile units in VHF (150.8 or 161.6 MHz range) and for two-way mobile and fixed station units in UHF (450 to 460 MHz range).
2 Maximum power for major VHF two-way mobile and fixed station unit in 35 to 44 MHz range.
3 Maximum ower for two-way fixed station units in VHF (150.8 to 161.6 MHz range).
4 Maximum power for amateur radio mobile units.
5 Maximum power for some base stations in 42 to 44 MHz band and 1.6 to 1.8 MHz band.
Table 4
Recommended Table of Distances for VHF TV and FM Broadcasting Transmitters
Effective Radiative Power Minimum Distance(Feet)
(Watts) Channels 2 to 6 and FM Channels 7 to 13
Up to 1,000..................... 1,000 750
10,000.......................... 1,800 1,300
100,0001........................ 3,200 2,300
316,0002........................ 4,300 3,000
1,000,000....................... 5,800 4,000
10,000,000..................... 10,200 7,4001
1 Present maximum power channels 2 to 6 and FM100,000 watts.
2 Present maximum power channels 7 to 13--316,000 watts.
Table 5
Recommended Table of Distances from UHF TV Transmitters
Effective Radiative Power Minimum Distance
(Watts) (Feet)
Up to 10,000.................................. 600
1,000,000................................... 2,000
5,000,0001.................................. 3,000
100,000,000................................. 6,000
1 Present maximum power channels 14 to 83--5,000,000 watts.
RECOMMENDED TABLES OF DISTANCES
These tables of distances are designed for the convenience of the commercial blaster. The selected groupings include all the obvious types of RF transmitters that will be encountered around blasting sites.
These tables were derived from analytical worse case calculations. They are based on an assumed 40-milliwatt no-fire level of commercial blasting caps. Actual field tests have shown that these tables are conservative as would be expected. Because of the uncertainties involved in field tests as to the efficiency of RF energy pickup and its delivery to the blasting cap, we strongly recommend that these tables be followed. If these tables present distances which are operationally inconvenient to use, we suggest field tests be made by expert consultants and the procedures detailed for providing minimum RF pickup be adhered to.
The data upon which these tables are based were derived by the Franklin Institute Research Laboratories for the Institute of Makers of Explosives.
NOTE: Authority and reference cited: Section 142.3, Labor Code.
HISTORY
1. Amendment of subsection (a) filed 7-8-81; effective thirtieth day thereafter (Register 81, No. 28).
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