AEMC Instruments
®
HAZMAT Ground Resistance
Testing
Static Ground System Installation and testing
Copyright © 2010-2016 Chauvin Arnoux ®, Inc. d.b.a. AEMC® Instruments
Training Program
Working a Hazardous Materials Incident can be
difficult.
Without a good understanding of containers or
vehicles and Incident objectives, it can make
working with this type of incident harder than it
has to be.
Electrostatic Discharge
Electrostatic discharge (ESD) is the sudden flow of electricity between two electrically
charged objects caused by contact, an electrical short, or dielectric breakdown. A buildup of
static electricity can be caused by trirbocharging (friction) or by electrostatic induction. The
ESD occurs when differently-charged objects are brought close together or when the
dielectric between them breaks down, often creating a visible spark.
Static Build up
• Caused by energy trapped on surface
of non conductive molecules.
Can be created by the movement of
solids, liquids, and gases.
Can be caused by contaminants such as:
• Rust
• Dirt
• Dust
Bonding Vs Grounding
• What is a Bond?
• What is a Ground?
• The act of joining two electrical
• A conducting connection, whether
conducting materials together.
intentional or accidental, between
These may be two wires, a wire and
an electrical circuit or equipment
a pipe, or these may be two pieces
and the earth, or to some
of equipment or vehicles. Bonding is
conducting body that serves in
done by connecting of all the metal
place of the earth.”
parts that are not supposed to be
carrying current during normal
operations to bringing them to the
same electrical potential.
Rule of 3
# 1 There are clues. Do you understand them.
 What Happened?
 What’s Happening Now?
 What’s Likely to Occur?
Rule of 3
# 2 CONTAINERS are they:
 Non –Pressurized
 Pressurized
 Cryogenic
Rule of 3
# 3 STATE OF MATTER
 Solid
 Liquid
 Gas
And is it going to change it’s physical state of
matter during it’s release from it’s container.
Hazard Classifications
Understand the hazard class indicated by the
placards on the damaged vehicle
All damaged vehicles transporting Hazardous
materials must be grounded first, except those
transporting Radioactive material, before
transferring the material
Damaged Tanker (Cow)
How to properly ground and test before
transferring combustible material
Transfer Tanker (Nurse)
• Should be stationed
uphill and up wind
from the damaged
tanker
• Should be positioned
outside of the hot zone
• Should be grounded
first
• Should be bonded to
the damaged tanker
after grounding
HAZMAT Ground
Resistance Testing
• Why do you need a static ground a static
ground test kit?
– You are required to minimize static electricity
before transferring combustible fluid from a
road or rail accident
– NFPA standards adopted by all US fire
departments require static grounding and
testing before transferring flammable
substances
HAZMAT Ground
Resistance Testing
• What you needed
– A total solution to installation and testing
– A very simple system that could be installed quickly
without complicated instructions
– Testing had to be as basic as and quick as possible
(not a lot of dials to turn or buttons to press)
– The equipment had to be packaged in such a way
that it could all be easily deployed and then
accounted for at the completion of the operation
HAZMAT Ground
Resistance Testing
• What Are the NFPA standards that
apply?
 The two standards that you have to meet are:
 NFPA 472 -defined
the need to ground
and test
 NFPA 77 – defined
the acceptable
resistance value
Installation and Testing
Minimum Equipment Needed
Ground Resistance Meter and kit
Optional Intrinsically Safe Ohm Meter
(3 to 6) ½” dia. or larger Copper Grounding Rods
(3) 50 ft Stainless Steel braided cables with appropriate
Pinpoint
connecting clips for connecting tankers Cable clip
and pump to the ground rods
3 to 6 – Stainless Steel braided jumper cables (cable clips)
for connection multiple rods together
1 – 50 ft Stainless Steel braided
Bonding Cable (Pinpoint clamps)
for connecting the tankers together
Static Ground and Test Kit
Static Ground and Test Kit
Static Ground and Test Kit
What is in the Kit?
What is in the Kit?
To establish the ground
50 ft grounding cable
Driver/Extractor
50 ft bonding cable
3 ft ground rod
Ground rod coupler
10 ft jumper cable
What is in the Kit?
To test the ground
AEMC 3640 Kit
150 ft. 3-Point Ground
Resistance Testers
Hot Zone
uphill
Step 1
Install The Grounding System
1. Install a separate grounding
system for the distressed
tanker (Cow), recovery tanker
(Nurse) and pump in an area
that is up hill, up wind and
outside of the hot zone of the
distressed tanker
NOTE: One or more rods may
be needed for each grounding
system to obtain an
acceptable resistance
Ground Rods
To Cow
To Pump
To Nurse
10 foot separation
minimum between rods
Step 2
Test The Grounding System
To conduct a Fall of Potential test
separately on each of the
grounding systems
1. Insert auxiliary test electrode Z
into the ground at a distance of
50 to 80 feet from the ground
rod X
2. Insert auxiliary test electrode Y
into the ground at a distance
approximately 30 to 45 feet
from the ground system X and
in a straight line between the Z
electrode and the ground
system
3. Connect the Red, Blue and
Green wires to the rod(s),
electrodes and instrument as
shown
4. Press the test button to
measure the resistance
X
Y
Z
Readings
should be
below
1000
at minimum
and
preferably
below
25
Step 2
Test The Grounding System
Inject a known current at a known frequency through the Z electrode
Measure the voltage drop at Y electrode
X
Y
Z
Calculate and display
the resistance R = E/I
Desired Resistance
R less than 25 Ohms
or
R less than 1000 Ohms
R Earth
Connect To The Grounding System
1. Connect a grounding cable to
the distressed tanker first and
then to its grounding system
2. Connect a grounding cable
from the recovery tanker first
and then to its grounding
system
3. Connect a grounding cable
from the transfer pump first
and then to its grounding
system
4. Connect the bonding cable
from the distressed tanker first
and then to the recovery
tanker and connect the hoses
to the pump and tankers
5. Begin the transfer process
1
2
3
4
Grounding the Site
uphill
Test Set Up
NFPA 77 states “If the purpose of the
temporary grounding system is to dissipate static electricity, a total
resistance of up to 1K ohm (1000 ohms) in the ground path to
earth is considered adequate. “
Others prefer 100 ohms or even 25 ohms. The lower the better!
It will bleed off the static electricity faster
X
Y
Z
Error Indicators
X-Z Fault
When lit indicates that the voltage
measured between the Red (Z) and
green (X) terminals is above 30 volts
Causes
• Resistance is too high
• Interference voltage is too high
• Fuse is blown
• Lead not connected
Corrective actions
• Wet the area around the Z electrode
• Drive more ground rods for your grounding system
• Move the red, blue and green test leads away from any live power lines
• Check all test lead connections
• If these actions do not eliminate the problem, check and replace the fuse
Error Indicators
Xv-Y High Resistance
When lit indicates that the voltage
measured between the Blue (Y ) and
green (X) terminals is too high
Causes
• Resistance is too high
• Interference voltage is too high
• Lead not connected
Corrective actions
• Wet the area around the Z and Y electrodes
• Drive more ground rods for your grounding system
• Move the red, blue and green test leads away from any live power lines
• Check all test lead connections
Error Indicators
Xv-Y High Noise
When lit indicates that electrical
noise voltage measured between
the Blue (Y ) and green (X) terminals
is too high
Cause
• Interference voltage is too high
Corrective actions
• Move the red, blue and green test leads away from any live power lines
• Twist the red and blue lead around each other
• Shield the leads and tie the shield to the ground rod(s)
HAZMAT Ground
Resistance Testing
HAZMAT Ground
Resistance Testing
I/R Camera model 1950 now available