California Code of Regulations
Title 8 - Industrial Relations
Division 1 - Department of Industrial Relations
Chapter 4 - Division of Industrial Safety
Subchapter 7 - General Industry Safety Orders
Group 18 - Explosive Materials
Article 116 - Handling and Use of Explosive Materials in Blasting Operations
Section 5306 - Electric Blasting in Proximity to Radio, Television or Radar Transmitters

Universal Citation: 8 CA Code of Regs 5306

Current through Register 2024 Notice Reg. No. 38, September 20, 2024

(a) Blasting area warning signs shall be posted approximately 1,000 feet from the blasting area along all access routes. These signs shall be in accordance with all requirements of the California Manual on Uniform Traffic Control Devices for Streets and Highways, September 26, 2006, published by the State Department of Transportation (CA-MUTCD), Part 6, Temporary Traffic Control, Sections 6 F.38 through 6F.41, which are hereby incorporated by reference.

(b) 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(1) (Watts)	Minimum Distance (Feet)
Up to 4,000..........................	..........................720
5,000..........................	..........................800
10,000..........................	..........................1,130
25,000..........................	..........................1,790
50,000(2)..........................	..........................2,500
100,000..........................	..........................3,600
500,000..........................	..........................8,000
__________

1 Power delivered to the antenna.

2 50,000 watts is the present maximum power of U.S. broadcast transmitters in this frequency range.

Table 2 Recommended Distances for Transmitters Up to 50 MHz (Excluding AM Broadcast) Calculated for a Specific Loop Pickup Configuration(1)(2)

Transmitter Power(3) (Watts)	Minimum Distance (Feet)
100..........................	..........................790
200..........................	..........................1,120
500..........................	..........................1,770
1,000..........................	..........................2,500
1,500..........................	..........................3,070
5,000..........................	..........................5,590
50,000..........................	..........................17,700
500,000(4)..........................	..........................55,900
__________

(1) Based on the configuration with the blasting machine being the component of the blasting circuit closed to the transmitter, using 20.8 MHz, which is the most sensitive frequency.

(2) This table should be applied to International Broadcast Transmitters in the 10-25 MHz range.

(3) Power delivered to the antenna.

(4) Present maximum for International Broadcast.

Table 3 Recommended Distances of Mobile Transmitters and Cellular Telephones Including Amateur and Citizens' Band MINIMUM DISTANCE (Feet)

Transmitter(1) Power (Watts)	MF 1.7 to 3.4 MHz Industrial	HF 28 to 29.7 MHz Amateur	VHF 35 to 36 MHz Public Use 42 to 44 MHz Public Use 50 to 54 MHz Amateur	VHF 144 to 148 MHz Amateur 150.8 to 161.6 MHz Public Use	UHF 450 to 470 MHz Public Use Cellular Telephones Above 800 MHz
1	15	47	37	12	8
5	33	105	82	27	18
10	46	148	116	38	25
50	102	331	259	85	55
100	144	468	366	120	78
180(2)	193	627	491	161	104
200	204	661	518	170	110
250	228	739	579	190	123
500(3)	322	1,045	818	268	174
600(4)	353	1,145	897	294	190
1,000	455	1,478	1,157	379	245
1,500(5)	557	1,810	1,417	464	300
10,000(6)	1,438	4,673	3,659	1,198	775

Citizens Band, Class D Transmitters, 26,965 MHz (Channel 1)-27,405 MHz (Channel 40)

	Type	Recommended Minimum Distance
		Hand-Held	Vehicle-Mounted
	Double Sideband - 4 watts maximum transmitter power	5 ft.	65 ft.
	Single Sideband - 12 watts peak envelope power	20 ft.	110 ft.
__________

(1) Power delivered to antenna.
(2) 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).
(3) Maximum power for major VHF two-way mobile and fixed station units in 35 to 44 MHz range.
(4) Maximum power for two-way fixed station units in VHF (150.8 to 161.5 MHz range).
(5) Maximum power for amateur radio mobile units.
(6) 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 Radiated Power		Minimum Distance (Feet)
(Watts)	Channels 2 to 6	FM Radio	Channels 7 to 13
Up to 1,000	820	667	502
10,000	1,450	1,190	892
100,000(1)	2,580	2,115	1,585
316,000(2)	3,450	2,820	2,130
1,000,000	4,600	3,770	2,820
10,000,000	8,190	6,690	5,020
__________

(1) Present maximum effective radiated power channels 2 to 6 and FM--100,000 watts.
(2) Present maximum effective radiated power channels 7 to 13--316,000 watts.

Table 5 Recommended Table of Distances from UHF TV Transmitters

Effective Radiative Power (Watts)	Minimum Distance (Feet)
Up to 10,000..........................	..........................600
1,000,000..........................	..........................2,000
5,000,000(1)..........................	..........................3,000
100,000,000..........................	..........................6,000
__________

(1) Present maximum power channels 14 to 69--5,000,000 watts.

NOTE: RECOMMENDED TABLES OF DISTANCES

These tables of distances are designed for the convenience of the licensed 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.

(d) The specified distances in the tables may be reduced provided special precautions, acceptable to the Division are taken.

1. Amendment of subsection (a) filed 7-8-81; effective thirtieth day thereafter (Register 81, No. 28).
2. Amendment of section and NOTE, including transfer of section 1938, App. B, Plate B-15 to section 5306, tables 1-5, filed 7-11-2003; operative 8-10-2003 (Register 2003, No. 28).
3. Amendment of section heading and subsection (a), repealer of subsection (b) and subsection relettering filed 10-26-2009; operative 11-25-2009 (Register 2009, No. 44).

Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.

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