a guide to radio frequency hazards with electric...
TRANSCRIPT
A Guide to Radio
Frequency Hazards
with Electric Detonators
J. Hugh Strong, James H. Turner,and Michael W. Wortham
Sydney Cheryl SuttonEditor
N.C. Department of LaborDivision of Occupational Safety and Health
4 W. Edenton St.Raleigh, NC 27601-1092
Cherie K. BerryCommissioner of Labor
N.C. Department of LaborOccupational Safety and Health Program
Cherie K. BerryCommissioner of Labor
OSHA State Plan Designee
To obtain additional copies of this book, or if you havequestions about N.C. occupational safety and healthstandards or rules, please contact:
N.C. Department of LaborBureau of Education, Training and Technical Assistance
4 W. Edenton St.Raleigh, NC 27601-1092
Phone: (919) 807-2875 or 1-800-NC-LABOR____________________
Additional sources of information are listed on theinside back cover of this book.
____________________The projected cost of the OSHNC program for federal fiscal year 2002–2003is $13,130,589. Federal funding provides approximately 37 percent($4,920,000) of this total.Printed 3/98, 2M
Acknowledgments
A Guide to Radio Frequency Hazards withElectric Detonators was prepared for the NorthCarolina Department of Labor by the Mine andQuarry Bureau of the North Carolina Departmentof Labor. The Mine and Quarry Bureau gratefullyacknowledges the cooperation of the Institute ofMakers of Explosives (IME), Washington, D.C., inthe preparation of this guide. All of the tables inpart 2 of this guide were taken from IME SafetyLibrary Publication No. 20.
ContentsPart Page
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1iiv
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1ivi
1 Electric Detonators and Hazards Posedby Radio Frequency Energy . . . . . . . . . . . . . . .1ii1Initiation of Electric Detonatorsby Radio Frequency Energy . . . . . . . . . . . .1ii1
Radio Frequency Energy Sources . . . . . . .1ii2Radio Frequency Pickup Circuits. . . . . . . .1ii8General Precautions against RFEnergy Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . ii12
Transportation of Electric Detonators . . . ii13Citizens Band Transmitters andCellular Telephones. . . . . . . . . . . . . . . . . . . . . . ii14
2 Tables of Distances—RF Sources andElectric Detonators . . . . . . . . . . . . . . . . . . . . . . . . . ii15I. Recommended Distances for Commercial
AM Broadcast Transmitters . . . . . . . . . ii15II. Recommended Distances for
Transmitters up to 50 MHz . . . . . . . . . . ii16III. Recommended Distances for VHF TV
FM Broadcasting Transmitters . . . . . . ii16IV. Recommended Distances for UHF TV
Transmitters . . . . . . . . . . . . . . . . . . . . . . . . . . . ii17V. Radio Transmitting Stations . . . . . . . . . . ii18
VI. Recommended Distances of MobileTransmitters Including Amateurand Citizens Band. . . . . . . . . . . . . . . . . . . . . ii20
iii
Appendix—Standards and Regulationsfor the Use of Electric Detonators aroundRadio Frequency Hazards . . . . . . . . . . . . . . . . . ii22
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii26
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii28
iv
ForewordThe Mine and Quarry Bureau of the North Carolina
Department of Labor prevents work-related injuriesand illnesses by offering training in the safe use ofexplosives and blasting devices. A Guide to RadioFrequency Hazards with Electric Detonators contributesto that objective. It describes hazards of radio frequencyenergy to the loading and firing of electrically initiatedblasting operations and sets forth precautions thatshould be taken during such operations. Many of thesehazards are covered by the state’s Occupational Safetyand Health Division’s (OSHNC) standards.
In this state, the North Carolina Department ofLabor consultants and inspectors administer the federalOSHA laws through a plan approved by the U.S.Department of Labor. All current OSHA standards areenforced. Many educational programs, publications(including this guide), and other services are alsooffered to help inform people about their rights andresponsibilities regarding OSHA.
As you look through this guide, please remember thatOSHA’s mission is greater than just enforcement. Anequally important goal is to help citizens find ways tocreate safe and healthy workplaces. Reading and usingthe information in this booklet, like other educationalmaterials produced by the North Carolina Departmentof Labor, can help.
Cherie K. BerryCommissioner of Labor
v
vi
IntroductionThe purpose of this guide is to promote safe work
practices by assisting persons who use electric detona-tors in assessing hazards of the initiation of commercialelectric detonators by radio frequency (RF) energy. Thisguide also provides tables of safe distances from RFsources for the use of electric detonators.
Part 1 identifies major RF sources. Part 2 offerstables for safe distances between particular RF sourcesand the use of electric detonators. Adherence to thetables in part 2 provides the user of electric detonatorsa high degree of assurance that the blasting layoutshould be safe from RF initiation.
This guide applies to commercial electric detonators.It does not apply to military electric firing devices. lt isrecommended that, prior to market introduction, anyimported electric detonators be tested for safety proper-ties by an authorized United States laboratory, such asthe U.S. Bureau of Mines or Bureau of Explosives.
Information in this guide derives from sources reflect-ing competent analysis and research and is believed to beaccurate. Nevertheless, the reader cannot be guaranteedthat the guide will apply to every application or variationin the use of electric detonators. The references section ofthis guide includes additional sources of information forunusual situations in which electric detonators are used.
The information contained in this guide is basedupon many years of practical experience and the latestand most widely accepted publications available in thefield. As such, it is believed that all data presented areboth accurate and reliable. However, the NorthCarolina Department of Labor makes no warranties,expressed or implied, to the user of this publication.All risks associated with the use of the informationare assumed by the user, and the North Carolina
Department of Labor hereby expressly denies any andall liability for use of this information. This publicationis not to be taken as a license to operate or recommen-dation to infringe any patent.
Though this guide is not intended to be incon-sistent with OSH or MSHA standards, if an area isconsidered by the reader to be inconsistent, thestandard should be followed.
vii
1Electric Detonators andHazards Posed by Radio
Frequency EnergyThe normal method of firing an electric detonator is
to apply electric energy from a power source such as ablasting machine or power line to the blasting circuit orto the open ends of the detonator wires. This electricalenergy flows through the wires to the detonator andcauses the resistance wire inside the detonator to heatthe primary explosives to the burning (explosion) tem-perature.
Initiation of Electric Detonators byRadio Frequency Energy
The possibility of premature explosions of electric det-onators due to RF energy is remote. Each year through-out the continental United States approximately 100million such detonators are used with few mishaps.However, there have been authenticated cases in whichdetonators were prematurely initiated by RF transmis-sion to the detonator wires. Subsequent investigationsrevealed that the instances would not have occurred ifproper safe distances from the RF sources had beenmaintained.
How RF Energy Initiates Electric Detonators
If the electric detonator wires are located in a strongRF field (near a transmitter that is radiating RF power),the usually insulated but unshielded leg wires or circuitwires will act as an antenna similar to that on a radioor TV set. That is true whether the circuit wires areconnected to a blasting machine or not, or whether theyare shunted (short circuited ends) or not shunted (open
1
ends). This antenna will absorb RF energy from thetransmitter RF field and the electric current transmittedto the detonator wires will flow into the detonator. (Seefigure 1.) Depending on the strength of the RF field andthe antenna configuration formed by the detonator wiresand its orientation, sufficient RF energy may be inducedin the wires to fire the electric detonator.
Figure 1
RF Energy Absorbed by Detonator Leg Wires
Radio Frequency Energy SourcesRadio frequency transmitters include citizens band (CB)
radios, cellular telephones, AM and FM radios, radar, andtelevision. These transmitters create powerful electromag-netic fields, which decrease in intensity with distance fromthe transmitter antenna. Tests have demonstrated thatelectric detonator wires, under particular conditions and
2
Electric Detonator
RF Ene
rgy
AM
Ant
enna
circumstances, may absorb enough electrical energy fromsuch fields to cause their explosion.
Mobile cellular telephones and CB radios pose unusualproblems. In recent years their use has greatly expanded.Mobile cellular telephones transmit RF energy duringsending and receiving. Additionally, modern technologyhas provided pages that transmit and receive RF energy.Safe distances are recommended for the Federal Com-munications Commission-approved, double sideband (4watts maximum output power) and single sideband (12watts peak envelope power) units in table VI.
Commercial AM Broadcast Transmitters
Commercial AM broadcast transmitters [0.535 to1.605 MHZ (Megahertz)] are potentially the most haz-ardous RF energy source. They combine high power andlow frequency so that there is little loss of induced RFenergy in the detonator lead wires. (See figure 2.)
Figure 2
Commercial AM Broadcast Transmitter(Vertically Polarized)
3
Frequency-modulated FM and TV Transmitters
Frequency-modulated FM and TV transmitters arenot likely to create hazardous situations. Although theirpower is extremely high and the antennas are horizon-tally polarized, their high frequency currents are rapid-ly attenuated in the detonator or leg wires. This RFsource employs antennas on very high towers, whichhave the additional effect of reducing the electromag-netic field at ground level. (See figure 3.)
Figure 3
Frequency-modulated FM and TV Transmitters(Horizontally Polarized)
4
Figure 4
Mobile Radios
Mobile Sources of RF Energy
Mobile radios and cellular telephones that transmitRF energy must be rated as a high potential hazardbecause, although their power is low, they can bebrought directly into a blasting area. (See figure 4.)Transmitting pagers also need to be considered.
5
HF and VHF Mobile Station(Citizens Band)
UHF Mobile Station(Long Range)
Figure 5 depicts other types of antennas associatedwith radio services.
Figure 5
Antennas Associated with Radio Services
6
Mobile Service Base StationMobile Service Base Station
Microwave Relays
The hazards of RF energy from microwave relays aresmall because they operate at a very high frequency,have a restricted radiation pattern, and are not normal-ly located within a blasting area. (See figure 6.)
Figure 6
A Microwave Relay
7
Radar Installations
Radar installations pose a hazard if blasting is donewithin the radar beam range. Radar installations radi-ate high power levels through the use of high gainantennas. (See figure 7.)
Figure 7
Radar Installations
Radio Frequency Pickup CircuitsElectric detonator wire layout can act as RF pickup
circuits for the radio frequencies used in AM radiobroadcasting and mobile operations. Two sensitive RFpickup circuits that might be created by lead wire con-figuration at electric blasting operations are known asthe dipole circuit and the long wire circuit.
8
Radar Service(Directional)
Radar Service(Revolving)
Dipole Pickup Circuit
The dipole circuit is depicted in figure 8. The dipolecircuit presents the most hazardous conditions when:
• The circuit wiring and/or electric detonator legwires are elevated several feet off the ground
• The length of this wiring is equal to one-half thewave length of the radio wave
• The electric detonator is located at a point where theRF current in the circuit wiring is at a maximum
Figure 8
Dipole Pickup Circuit
9
Several Feet
Ground
Long Wire
Detonator Wire
Detonator Wire
ElectricDetonator
Long Wire Pickup Circuit
The long wire circuit is shown in figure 9. The longwire circuit condition occurs when the electric detonatoris at one end of the wiring that:
• Is elevated in the air
• Has a length equivalent to one-quarter of thewavelength of the radio wave
• Is grounded to the earth through the electricdetonator
To determine the approximate radio wavelength, thetransmitter frequency in megahertz (MHz) is dividedinto 1,000. For example, a CB transmitter operates on afrequency of 26.96 to 27.33 MHz. This, divided into1,000, yields a wavelength of 36.6 to 37.1 feet.
Both of the previous circuits require that the leadline or detonator wires be suspended above the ground.Both of the circuits (antennas) achieve their maximumcurrent pickup when they are (1) parallel to a horizon-tal transmitting antenna (FM, TV, or amateur radio) or(2) pointed toward a vertical antenna (AM, mobile, etc.).
Figure 9
Long Wire Pickup Circuit
10
Several Feet
Detonator Wire Detonator Wire
Dipole
Ground
Electric Detonator
Loop Pickup Circuit
Another sensitive RF pickup circuit, and one com-monly encountered in blasting operations, is the loopcircuit. This circuit is sensitive to the magnetic portionof the electromagnetic wave. The loop circuit receivesthe maximum pickup when its long axis is placed in thedirection of the transmitting antenna. Safe distancetables for AM broadcast transmitters and mobile trans-mitters (both using vertical antennas) were derivedfrom the loop configuration. Figure 10 shows a pre-ferred case loop pickup circuit.
Figure 10
Loop Pickup Circuit—Preferred Case
11
Vertically Polarized
Transmitting Antenna
To Rest ofBlasting Layout
Charged HoleLong Axis
Blasting MachinePickup Area
Figure 11 shows an acceptable but less desirable con-figuration of loop and transmitting antenna. In general,the loop areas can be reduced by picking up both leadwires as in a duplex wire circuit and making all wiresplices as close to the ground as possible.
Figure 11
Loop Pickup Circuit—Acceptable but Less Desirable
General Precautions against RFEnergy Sources
The following list of precautions will reduce hazardsand increase safety for employees associated with blast-ing operations near RF energy sources.
12
Vertically PolarizedTransmitting Antenna
Blasting Machine
Charged Hole
Electric Detonator
Pickup Area
To Rest ofBlasting Layout
Long
Axis
1. When blasting electrically at a fixed location suchas a mine, quarry, or construction site, check to seewhether any radio transmitters are located closer toyour blasting site than the applicable separationrecommended in part 2 of this guide. Always be onthe alert for new transmitters. If possible, check eachtransmitter before it goes into service, to ensure itwill not pose a hazard to your blasting operation.
2. Keep mobile transmitters away from blastingareas. If transmitters are allowed on or near theblasting area, a strict policy must be set to ensurethat the transmitters are always turned off. Thisprecaution should be followed no matter what fre-quency or energy (watts) the transmitter employs.
3. If there is a choice, use the higher frequency bands(450-470 MHz) for mobile transmitters. RF pickupis less efficient at these frequencies than at thelower frequencies.
4. Avoid large loops in blasting wiring by running thelead wires parallel to each other and close together.
5. If loops are unavoidable, keep them small andorient them broadside towards the transmittingantenna.
6. Keep wires on the ground in blasting layouts. Bareconnecting points should be elevated slightly toprevent current leakage.
7. Arrange all lead lines out of the beam of directionaldevices such as radar or microwave relay stations.
8. If there is any doubt as to the RF hazards in relationto your blasting operations, a non-electric blastingsystem should be used until you have consulted witha person qualified in RF energy as it relates to blast-ing operations.
13
Transportation of Electric DetonatorsThe transportation of electric detonators does not cre-
ate a hazard from radio energy as long as the detona-tors are in their original containers. In their originalcontainers, the leg wires of the detonators are folded orcoiled so as to provide effective protection against cur-rent induction. Also, the metal body of a vehicle virtual-ly eliminates the penetration of RF energy.
If vehicles equipped with radio transmitters are usedto transport electric detonators to and from a job: (1)the caps should be carried in an enclosed metal boxlined with a non-sparking material and (2) the trans-mitter should be turned off when the caps are removedfrom the box.
Citizens Band Transmitters andCellular Telephones
CB radios are the most common radio communicationin existence today, but cellular telephone use is rapidlyincreasing. These radios often are in operation in bothmobile and base units within close proximity of blastingoperations. The units are used constantly on the high-ways, which are at times close to blasting operations.CBs are used by haul truck drivers, employees, andcompany officials.
Although the power (maximum 5 watts) is low on CBradios and cellular telephones, precautions should betaken in their use around electric blasting operations.CB radios and cellular telephones should not be operat-ed by anyone on the property during blast hole loadingoperations. In areas close to public roads where it isimpossible to control their usage, mine operators andconstruction crews should restrict the use of electricdetonators and use a non-electric blasting system.
14
2Tables of Distances—RF
Sources and Electric DetonatorsThe tables in this part of the guide are offered to
assist mine and quarry operators and commercialblasters. The tables include all of the obvious type of RFtransmitters that would be encountered around mines,quarries, and other blasting operations.
The tables were derived from analytical “worst case”calculations. They are based on an assumed 40-milli-watt no-fire level of commercial detonators. Field testshave shown the tables to be conservative, as would beexpected. There are numerous uncertainties involved infield tests respecting the efficiency of RF energy pickupand its delivery to the detonator. Thus, both the NorthCarolina Department of Labor and the Institute ofMakers of Explosives strongly recommend that thetables in this guide be followed.
Table I
Recommended Distances for CommercialAM Broadcast Transmitters
15
(0.535 to 1.605 MHz)
Transmitter Powera Minimum Distance
(watts) (feet)
Up to 4,000 8005,000 900
10,000 1,30025,000 2,00050,000b 2,900
100,000 4,100500,000 9,100
a. Power delivered to antennab. Maximum power of U.S. broadcast transmitters in this frequency
range
16
Table II
Recommended Distances for Transmitters up to 50 MHz
– – – – – – –
Table III
Recommended Distances for VHF TV and FMBroadcasting Transmitters
(Excluding AM Broadcast—Calculated for aSpecific Loop Pickup Configuration)a,b
Transmitter Powerc Minimum Distance
(watts) (feet)
100 800500 1,700
1,000 2,5005,000 5,500
50,000 17,000500,000d 55,000
a. Based on the configuration shown in figure 11 using 20.8 MHz,which is the most sensitive frequency
b. This table should be applied to international broadcast transmittersin the 10–25 MHz range
c. Power delivered to antennad. Present maximum for international broadcast
Effective Radiated Minimum Distance (feet)Power (watts) Channels 2 to 6 FM Radio Channels 7 to 13
Up to 1,000 1,000 800 60010,000 1,800 1,400 1,000
100,000a 3,200 2,600 1,900316,000b 4,300 3,400 2,500
1,000,000 5,800 4,600 3,30010,000,000 10,200 8,100 5,900
a. Present maximum power channels 2 to 6 and FMb. Present maximum power channels 7 to 13
17
Table IV
Recommended Distances for UHF TV Transmitters
Effective Radiated Power Minimum Distance
(watts) (feet)
Up to 10,000 6001,000,000 2,0005,000,000a 3,000
100,000,000 6,000
a. Present maximum power channels 14 to 83
18
Tab
le V
Ra
dio
Tra
nsm
itti
ng
Sta
tion
sa
Max
imu
mF
req
uen
cyW
avel
eng
thT
ran
smit
ter
Po
wer
Ref
eren
ce T
able
Typ
e(M
egah
ertz
)(f
eet)
(wat
ts)
for
Saf
e D
ista
nce
Com
mer
cial
Sta
ndar
d B
road
cast
(A
M)
0.53
5–1.
605
1,82
0–61
550
,000
IF
requ
ency
Mod
ulat
ion
(FM
)88
–108
11.2
–9.1
550,
000b
IIIT
V (
Cha
nnel
s 2–
6)54
–88
18.2
–11.
210
0,00
0bIII
TV
(C
hann
els
7–13
)17
4–21
65.
6–4.
531
6,00
0bIII
TV
(C
hann
els
14–8
3)47
0–89
02.
1–1.
15,
000,
000b
IV
Am
ateu
r16
0-M
eter
Ban
d1.
8–2.
054
5–49
01,
000
II18
0-M
eter
Ban
d3.
5–4.
028
0–24
61,
000
II14
0-M
eter
Ban
d7.
0–7.
314
0–13
51,
000
II12
0-M
eter
Ban
d14
.0–1
4.4
70.0
–68.
21,
000
II11
5-M
eter
Ban
d21
.10–
21.2
546
.3–4
6.0
1,00
0II
Citi
zens
Ban
d26
.96–
27.2
336
.6–3
6.0
5V
I11
0-M
eter
Ban
d•
Mob
ile28
.0–2
9.7
35.1
–33.
01,
000
VI
• F
ixed
28.0
–29.
735
.1–3
3.0
1,00
0II
116-
Met
er B
and
50.0
–54.
019
.7–1
8.2
1,00
0V
I11
2-M
eter
Ban
d14
4–14
86.
8–6.
651,
000
VI
111 ⁄4
-Met
er B
and
220–
225
4.46
–4.3
61,
000
VIc
19
Aut
omob
ile T
elep
hone
VH
F F
ixed
Sta
tion
150–
160
2.0–
1.87
510
0V
IV
HF
Mob
ile S
tatio
n15
91.
8930
VI
UH
F F
ixed
Sta
tion
450–
470
0.67
–0.6
417
5V
IU
HF
Fix
ed S
tatio
n47
0–51
20.
64–0
.59
60V
IU
HF
Mob
ile S
tatio
n45
90.
6535
VI
Cel
lula
r (a
lso
othe
rs in
420
–30,
000
MH
z ra
nge)
825–
890
0.36
–0.3
33
VI
2-W
ay C
omm
unic
atio
nsH
F R
ange
Cen
tral
Sta
tion
25–5
039
–20
500
IIM
obile
Uni
t25
–50
39–2
050
0V
IV
HF
Ran
ge C
entr
al S
tatio
n14
8–17
46.
6–5.
660
0V
IM
obile
Uni
t14
8–17
46.
6–5.
618
0V
IU
HF
Ran
ge C
entr
al S
tatio
n45
0–47
02.
2–2.
118
0V
IM
obile
Uni
t45
0–47
02.
2–2.
118
0V
ILF
Ran
ge (
Avi
atio
n)0.
2–0.
45,
000–
2,50
02,
000
IH
F R
ange
(A
viat
ion)
4–23
250–
4450
,000
IIV
HF
Ran
ge (
Avi
atio
n)11
8.0–
135.
98.
3–7.
250
100
feet
UH
F R
ange
(A
viat
ion)
225–
500
4.4–
2.0
100
50 fe
etR
adio
Tel
egra
ph6–
2316
4–43
50,0
00II
a.P
artia
l lis
tb.
Pre
sent
max
imum
effe
ctiv
e ra
diat
ed p
ower
c.U
se 1
50.8
–161
.6 M
Hz
colu
mn
20
Tab
le V
I
Rec
omm
end
ed D
ista
nce
s of
Mob
ile
Tra
nsm
itte
rs I
ncl
ud
ing
Am
ate
ur
an
d C
itiz
ens
Ba
nd
(Min
imum
Dis
tanc
e [fe
et])
VH
FU
HF
35–3
6 M
Hz
450–
470
MH
zP
ublic
Use
Pub
lic U
se42
–44
MH
zV
HF
Cel
lula
r, A
uto-
MF
HF
Pub
lic U
se14
4–14
8 M
Hz
mob
ile T
ele-
Tra
nsm
itte
r P
ow
era
1.6–
3.4
MH
z28
–29.
7 M
Hz
50–5
4 M
Hz
150–
161.
6 M
Hz
phon
es a
bove
(wat
ts)
Indu
stria
lA
mat
eur
Am
ateu
rP
ublic
Use
800
MH
z
530
7060
2010
1040
100
8030
2050
9023
018
070
4010
012
032
026
010
060
180b
170
430
350
130
8025
020
050
041
016
090
500c
280
710
580
220
120
600d
300
780
640
240
140
1,00
0e40
01,
010
820
310
180
10,0
00f
1,24
03,
200
2,60
099
056
0
21
Cit
izen
s B
an
d, C
lass
D T
ran
smit
ters
, 26.
96-2
7.41
MH
z
Rec
om
men
ded
Min
imu
m D
ista
nce
Typ
eH
and
-Hel
dV
ehic
le-M
ou
nte
d
Dou
ble
Sid
eban
d, 4
wat
ts m
axim
um tr
ansm
itter
pow
er5
ft.65
ft.
Sin
gle
Sid
eban
d, 1
2 w
atts
pea
k en
velo
pe p
ower
20 ft
.11
0 ft.
a.P
ower
del
iver
ed to
ant
enna
b.P
rese
nt m
axim
um p
ower
for
two-
way
mob
ile u
nits
in V
HF
(15
0.8–
161.
6 M
Hz
rang
e) a
nd fo
r tw
o-w
ay m
obile
and
fixe
dst
atio
n un
its in
UH
F (
450–
460
MH
z ra
nge)
c.P
rese
nt m
axim
um p
ower
for
maj
or V
HF
two-
way
mob
ile a
nd fi
xed
stat
ion
units
in 3
5–44
MH
z ra
nge
d.P
rese
nt m
axim
um p
ower
for
two-
way
fixe
d st
atio
n un
its in
VH
F (
150.
8–16
1.6
MH
z ra
nge)
e.P
rese
nt m
axim
um p
ower
for
amat
eur
radi
o m
obile
uni
tsf.
Pre
sent
max
imum
pow
er fo
r so
me
base
sta
tions
in 4
2–44
MH
z ba
nd a
nd 1
.6–1
.8 M
Hz
band
Due
to r
ecen
t cha
nges
mad
e in
am
ateu
r ra
dio,
1,5
00 w
atts
of p
eak
pow
er o
utpu
t is
now
per
mis
sibl
e on
all
radi
o fr
eque
n-ci
es a
ssig
ned
to th
e am
ateu
r ra
dio
serv
ice.
Add
ition
al h
igh
freq
uenc
y ba
nds
have
als
o be
en a
ssig
ned
to th
e 30
-met
er b
and.
22
Ap
pen
dix
Sta
nd
ard
s a
nd
Reg
ula
tion
s fo
r th
e U
se o
f E
lect
ric
Det
ona
tors
aro
un
d R
ad
io F
req
uen
cy H
aza
rds
Sub
part
U—
Bla
stin
g an
d th
eU
se o
f Exp
losi
ves:
29
CF
R19
26.9
00(k
)—D
ue p
reca
utio
nssh
all b
e ta
ken
to p
reve
nt a
cci-
dent
al d
isch
arge
of e
lect
ricbl
astin
g ca
ps fr
om c
urre
ntin
duce
d by
rad
ar, r
adio
tran
s-m
itter
s, li
ghtn
ing,
adj
acen
tpo
wer
lines
, dus
t sto
rms,
or
othe
r so
urce
s of
ext
rane
ous
elec
tric
ity. T
hese
pre
caut
ions
shal
l inc
lude
: (1)
Det
onat
ors
shal
l be
shor
t-ci
rcui
ted
inho
les
whi
ch h
ave
been
prim
edan
d sh
unte
d un
til w
ired
into
the
blas
ing
circ
uit.
(3)(
i) T
hepr
omin
ent d
ispl
ay o
f ade
quat
esi
gns,
war
ning
aga
inst
the
use
of m
obile
rad
io tr
ansm
itter
s,on
all
road
s w
ithin
1,0
00 fe
et
No
rth
Car
olin
aO
ccu
pat
ion
al S
afet
y an
dH
ealth
Sta
nd
ard
s fo
r th
eC
on
stru
ctio
n In
du
stry
Sub
part
H—
Haz
ardo
usM
ater
ials
: 29
CF
R19
10.1
09(e
)(vi
i)—D
ue p
reca
u-tio
ns s
hall
be ta
ken
to p
reve
ntac
cide
ntal
dis
char
ge o
f ele
c-tr
ic b
last
ing
caps
from
cur
rent
indu
ced
by r
adar
, rad
io tr
ans-
mitt
ers,
ligh
tnin
g, a
djac
ent
pow
erlin
es, d
ust s
torm
s, o
rot
her
sour
ces
of e
xtra
neou
sel
ectr
icity
. The
se p
reca
utio
nssh
all i
nclu
de: (
b) T
he p
ostin
gof
sig
ns w
arni
ng a
gain
st th
eus
e of
mob
ile r
adio
tran
smit-
ters
on
all r
oads
with
in 3
50fe
et o
f the
bla
stin
g op
erat
ions
.
No
rth
Car
olin
aO
ccu
pat
ion
al S
afet
y an
dH
ealt
h S
tan
dar
ds
for
Gen
eral
Ind
ust
ry
Sam
e as
N.C
. Occ
upat
iona
lS
afet
y an
d H
ealth
Sta
ndar
dsfo
r G
ener
al In
dust
ry, 2
9 C
FR
1910
.109
(e)(
vii)
and
(e)(
vii)(
b)an
d th
e N
.C. O
ccup
atio
nal
Saf
ety
and
Hea
lth S
tand
ards
for
the
Con
stru
ctio
n In
dust
ry,
29 C
FR
192
6.90
0(k)
.
Fed
eral
Occ
up
atio
nal
Sa
fety
an
d H
ea
lth
Sta
nd
ard
s
Cha
pter
7—
Use
of E
xplo
sive
Mat
eria
ls fo
r B
last
ing:
7-1
.15
Pre
caut
ions
sha
ll be
take
n to
prev
ent a
ccid
enta
l dis
char
geof
ele
ctric
det
onat
ors
from
curr
ent i
nduc
ed b
y ra
dar
and
radi
o tr
ansm
itter
s, li
ghtn
ing,
adja
cent
pow
erlin
es, d
ust
stor
ms,
or
othe
r so
urce
s of
extr
aneo
us e
lect
ricity
. The
sepr
ecau
tions
sha
ll in
clud
e: (
a)T
he p
ostin
g of
sig
ns w
arni
ngag
ains
t the
use
of m
obile
radi
o tr
ansm
itter
s on
all
road
sw
ithin
350
feet
(10
7 m
) of
blas
ting
oper
atio
ns. (
b)O
bser
vanc
e of
the
late
st r
ec-
omm
enda
tions
with
reg
ard
tobl
astin
g in
the
vici
nity
of r
adio
tran
smitt
ers
or p
ower
lines
, as
Nat
ion
al F
ire
Co
de
23
of b
last
ing
oper
atio
ns. W
hen-
ever
adh
eren
ce to
the
1,00
0fo
ot d
ista
nce
wou
ld c
reat
e an
oper
atio
nal h
andi
cap,
a c
om-
pete
nt p
erso
n sh
all b
e co
nsul
t-ed
to e
valu
ate
the
part
icul
arsi
tuat
ion,
and
alte
rnat
ive
prov
i-si
ons
may
be
mad
e w
hich
are
adeq
uate
ly d
esig
ned
to p
re-
vent
any
pre
mat
ure
firin
g of
elec
tric
bla
stin
g ca
ps. A
desc
riptio
n of
any
suc
h al
ter-
nativ
es s
hall
be r
educ
ed to
writ
ing
and
shal
l be
cert
ified
as
mee
ting
the
purp
oses
of t
his
subd
ivis
ion
by th
e co
mpe
tent
pers
on c
onsu
lted.
The
desc
riptio
n sh
all b
e m
ain-
tain
ed a
t the
con
stru
ctio
n si
tedu
ring
the
dura
tion
of th
ew
ork,
and
sha
ll be
ava
ilabl
e
No
rth
Car
olin
aO
ccu
pat
ion
al S
afet
y an
dH
ealth
Sta
nd
ard
s fo
r th
eC
on
stru
ctio
n In
du
stry
No
rth
Car
olin
aO
ccu
pat
ion
al S
afet
y an
dH
ealt
h S
tan
dar
ds
for
Gen
eral
Ind
ust
ry
Fed
eral
Occ
up
atio
nal
Sa
fety
an
d H
ea
lth
Sta
nd
ard
s
set f
orth
in IM
E S
afet
y Li
brar
yP
ublic
atio
n N
o. 2
0, S
afet
yG
uide
for
the
Pre
vent
ion
ofR
adio
Fre
quen
cy H
azar
ds in
the
Use
of E
lect
ric B
last
ing
Cap
s.Nat
ion
al F
ire
Co
de
24
for
insp
ectio
n by
rep
rese
nta-
tives
of t
he C
omm
issi
oner
of
Labo
r. (
3)(ii
) S
peci
men
s of
sign
s w
hich
wou
ld m
eet t
here
quire
men
ts o
f sub
divi
sion
(i)
of th
is s
ubpa
ragr
aph
(3)
are
the
follo
win
g:
(4)
Ens
urin
g th
at m
obile
rad
iotr
ansm
itter
s w
hich
are
less
than
100
feet
aw
ay fr
om e
lec-
tric
bla
stin
g ca
ps, i
n ot
her
than
orig
inal
con
tain
er, s
hall
bede
ener
gize
d an
d ef
fect
ivel
ylo
cked
.No
rth
Car
olin
aO
ccu
pat
ion
al S
afet
y an
dH
ealth
Sta
nd
ard
s fo
r th
eC
on
stru
ctio
n In
du
stry
No
rth
Car
olin
aO
ccu
pat
ion
al S
afet
y an
dH
ealt
h S
tan
dar
ds
for
Gen
eral
Ind
ust
ry
Fed
eral
Occ
up
atio
nal
Sa
fety
an
d H
ea
lth
Sta
nd
ard
sN
atio
nal
Fir
e C
od
e
BL
AS
TIN
GZ
ON
E10
00 F
T
TU
RN
OF
F2-
WA
YR
AD
IO
Abo
ut 4
8" X
48"
Abo
ut 4
2" X
36"
25
(5)
Com
plia
nce
with
the
rec-
omm
enda
tions
of t
he In
stitu
teof
Mak
ers
of E
xplo
sive
s w
ithre
gard
to b
last
ing
in th
e vi
cini
-ty
of r
adio
tran
smitt
ers
as s
tip-
ulat
ed in
Rad
io F
requ
ency
Ene
rgy—
A P
oten
tial H
azar
din
the
Use
of E
lect
ric B
last
ing
Cap
s IM
E P
ublic
atio
n N
o. 2
0.
No
rth
Car
olin
aO
ccu
pat
ion
al S
afet
y an
dH
ealth
Sta
nd
ard
s fo
r th
eC
on
stru
ctio
n In
du
stry
No
rth
Car
olin
aO
ccu
pat
ion
al S
afet
y an
dH
ealt
h S
tan
dar
ds
for
Gen
eral
Ind
ust
ry
Fed
eral
Occ
up
atio
nal
Sa
fety
an
d H
ea
lth
Sta
nd
ard
sN
atio
nal
Fir
e C
od
e
GlossaryAmateur Service. A service of intercommunications andtechnical investigations carried on by duly authorizedpersons interested in radio techniques.
Aviation Services. Services of fixed and land stations andmobile stations on land and on board aircraft primarilyfor the safe expedition and economical operation of air-craft.
Broadcasting Service. A radio communication service inwhich the transmissions are intended for direct recep-tion by the general public.
Citizens Band Radio. A radio communication service offixed, land, and mobile stations intended for personal orbusiness radio communication, radio signaling, (and)control of remote objects or devices.
Fixed Service. A service of radio communication betweenspecified fixed points.
Fixed Station. A station in the fixed service.
International Broadcast Service. A service whosetransmissions are intended to be received directly bythe general public in foreign countries.
Land Station. A station in the mobile service intendedto be used while in motion or during halts at unspeci-fied points.
Maritime Services. Services intended for maritime radiocommunication and including fixed stations, land sta-tions, and mobile stations on land and on board ships.
Megahertz. 1,000,000 cycles per second.
Mobile Service. A service of radio communicationbetween mobile and land stations, or between mobilestations.
26
Mobile Station. A station in the mobile service intendedto be used while in motion or during halts at unspeci-fied points.
Standard Frequency Terms and Bands.High Frequency Band (HF): 3–30 MHzGigahertz (GHz): 1 GHz = 1,000,000,000 cycles per secondMedium Frequency Band (MF): 0.3–3 MHzMegahertz (MHz): 1 MHz = 1,000,000 cycles per secondUltra High Frequency Band (UHF): 300–3,000 MHzVery High Frequency Band (VHF): 30–300 MHz
27
ReferencesAtlas Powder Company. Handbook of Electric Blasting.
Dallas, Texas, 1985.
E.I. Dupont de Nemours. Dupont’s Blasters’ Handbook.175th Anniversary Ed. Wilmington, Delaware, 1977.
Institute of Makers of Explosives. Safety LibraryPublication No. 20. Washington, D.C., 1988.
National Fire Code. Use of Explosive Material forBlasting. Chapter 7.
North Carolina OSHA Standards for General Industry.29 CFR 1910.
North Carolina OSHA Standards for the ConstructionIndustry. 29 CFR 1926.
28
The following industry guides are available from the N.C. Depart-ment of Labor’s Division of Occupational Safety and Health:1#1. A Guide to Safety in Confined Spaces1#2. A Guide to Procedures of the Safety and Health Review Board of North
Carolina1#3. A Guide to Machine Safeguarding1#4. A Guide to OSHA in North Carolina1#5. A Guide for Persons Employed in Cotton Dust Environments1#6. A Guide to Lead Exposure in the Construction Industry1#7. A Guide to Bloodborne Pathogens in the Workplace1#8. A Guide to Voluntary Training and Training Requirements in OSHA
Standards1#9. A Guide to Ergonomics#10. A Guide to Farm Safety and Health#11. A Guide to Radio Frequency Hazards With Electric Detonators#12. A Guide to Forklift Operator Training#13. A Guide to the Safe Storage of Explosive Materials#14. A Guide to the OSHA Excavations Standard#15. A Guide to Developing and Maintaining an Effective Hearing
Conservation Program#17. A Guide to Asbestos for Industry#18. A Guide to Electrical Safety#19. A Guide to Occupational Exposure to Wood and Wood Dust#20. A Guide to Crane Safety#21. A Guide to School Safety and Health#23. A Guide to Working With Electricity#25. A Guide to Personal Protective Equipment#26. A Guide to Manual Materials Handling and Back Safety#27. A Guide to the Control of Hazardous Energy (Lockout/Tagout)#28. A Guide to Eye Wash and Safety Shower Facilities#29. A Guide to Safety and Health in Feed and Grain Mills#30. A Guide to Working With Corrosive Substances#31. A Guide to Formaldehyde#32. A Guide to Fall Prevention in Industry#33. A Guide to Office Safety and Health#34. A Guide to Safety and Health in the Poultry Industry#35. A Guide to Preventing Heat Stress#36. A Guide to the Safe Use of Escalators and Elevators#37. A Guide to Boilers and Pressure Vessels#38. A Guide to Safe Scaffolding#39. A Guide to Safety in the Textile Industry#40. A Guide to Emergency Action Planning#41. A Guide to OSHA for Small Businesses in North Carolina
Occupational Safety and Health (OSH)Sources of Information
You may call 1-800-NC-LABOR to reach any division of the N.C.Department of Labor; or visit the NCDOL home page on the World WideWeb, Internet Web site address: http://www.nclabor.com.N.C. Division of Occupational Safety and Health
Mailing Address: Physical Location:4 W. Edenton St. 111 Hillsborough St.Raleigh, NC 27601-1092 (Old Revenue Building, 3rd Floor)Local Telephone: (919) 807-2900 Fax: (919) 807-2856
For information concerning education, training and interpretations of occupationalsafety and health standards contact:Bureau of Education, Training and Technical Assistance
Mailing Address: Physical Location:4 W. Edenton St. 111 Hillsborough St.Raleigh, NC 27601-1092 (Old Revenue Building, 4th Floor)Telephone: (919) 807-2875 Fax: (919) 807-2876
For information concerning occupational safety and health consultative servicesand safety awards programs contact:Bureau of Consultative Services
Mailing Address: Physical Location:4 W. Edenton St. 111 Hillsborough St.Raleigh, NC 27601-1092 (Old Revenue Building, 3rd Floor)Telephone: (919) 807-2899 Fax: (919) 807-2902
For information concerning migrant housing inspections and other related activi-ties contact:Agricultural Safety and Health Bureau
Mailing Address: Physical Location:4 W. Edenton St. 111 Hillsborough St.Raleigh, NC 27601-1092 (Old Revenue Building, 2nd Floor)Telephone: (919) 807-2923 Fax: (919) 807-2924
For information concerning occupational safety and health compliance contact:Safety and Health Compliance District Offices
Raleigh District OfficeTelephone: Safety (919) 662-4597 Fax: (919) 662-4709
Health (919) 662-4711Charlotte District Office(901 Blairhill Road, Suite 200, Charlotte, NC 28217-1578)Telephone: Safety (704) 342-6163 Fax: (704) 342-5919Winston-Salem District Office(901 Peters Creek Parkway, Winston-Salem, NC 27103-4551)Telephone: Safety (336) 761-2700 Fax: (336) 761-2326
Health (336) 761-2700 Fax: (336) 761-2130Wilmington District Office(1200 N. 23rd St., Suite 205, Wilmington, NC 28405-1824)Telephone: (910) 251-2678 Fax: (910) 251-2654Asheville District Office(204 Charlotte Highway, Suite B, Asheville, NC 28803-8681)Telephone: (828) 299-8232 Fax: (828) 299-8266
***To make an OSHA Complaint, OSH Complaint Desk: (919) 807-2796***For statistical information concerning program activities contact:Planning, Statistics and Information Management
Mailing Address: Physical Location:4 W. Edenton St. 111 Hillsborough St.Raleigh, NC 27601-1092 (Old Revenue Building, 2nd Floor)Telephone: (919) 807-2950 Fax: (919) 807-2951
For information about books, periodicals, vertical files, videos, films, audio/slidesets and computer databases contact:N.C. Department of Labor Library
Mailing Address: Physical Location:4 W. Edenton St. 111 Hillsborough St.Raleigh, NC 27601-1092 (Old Revenue Building, 5th Floor)Telephone: (919) 807-2848 Fax: (919) 807-2849
N.C. Department of Labor (Other than OSH)4 W. Edenton St.Raleigh, NC 27601-1092Telephone: (919) 733-7166 Fax: (919) 733-6197