Issue
Date: March 10, 2000
Revision Date: April 17, 2002
Linde Services, Inc.
(Formally Praxair Services, Inc., originally listed as Tracer Research Corp.)
Tracer
ALD 2000 Automated Tank Tightness Test
BULK
UNDERGROUND STORAGE TANK LEAK DETECTION METHOD (50,000 gallons
or greater)
Certification
|
Leak
rate of 0.1 gph with PD = 100% and PFA = 0%.
|
Leak
Threshold
|
A
tank system should not be declared tight when tracer chemical
or hydrocarbon greater than the background level is detected
outside of the tank system.
|
Applicability
|
Gasoline,
diesel, aviation fuel, fuel oil #4, waste oil.
Other fluids which are compatible and soluble with an
acceptable tracer chemical may be tested after consultation
with the manufacturer.
|
Tank
Capacity
|
Not
limited by capacity.
|
Waiting
Time
|
Ranges
from 7 to 30 days (normally 2 weeks) after tracer is added
to tank.
|
Tracer
Dosage
|
Tracer
is added to tank manually at tank fill or automatically
using a metered injection pump at pipeline flowing into
tank.
Manual dosage of tracer is based on tank size, product
volume in tank, and frequency and volume of tank refills
according to manufacturer's recommendations.
Automated dosage at pipeline flowing into tank is based
on pipeline size and flow rate.
All tanks and piping downstream of the injection point
are dosed with tracer compound.
|
Permeability
|
Soil
permeability must readily allow tracer movement through
the tank excavation backfill (greater than 1 Darcy).
|
Probe
|
Radius
of influence of each tracer sampling probe is maximum
10 feet.
All tank surfaces must be within the zone of influence
of a sampling probe.
Probes must be installed per Manufacturer's guidelines.
|
Groundwater
|
Depth
to groundwater in tank excavation backfill must be determined.
For test method to detect a release of tracer chemical
below groundwater, the hydrostatic pressure of product
in the tank must exceed the hydrostatic pressure of groundwater
during test.
To accomplish this, product level must be maintained at
least 6 inches above groundwater for a minimum of 17 hours
during the first three days following addition of tracer
to the tank.
At the discretion of the regulatory agency, water ingress
measuring devices may be used to supplement test method
in high groundwater conditions.
|
Comments
|
The
presence of a layer of water saturated soil, that is also
frozen, above the location where a leak may exist, may
inhibit the effectiveness of the method by impeding the
transport of the tracer labeled product into the unsaturated
zone.
Groundwater above bottom of tank may limit effectiveness
of test method (e.g. when applied to tanks containing
water-miscible products or products whose specific gravity
is greater than 1).
Test method may not be effective in some tank excavation
backfill (such as clay) because it may plug holes in tank
and retard tracer movement through the soil.
Third party evaluation of the ALD 2000 System tested the
device's ability to collect a sample, transport sample
through 2700 feet of 3/32 inch tubing, and analyze sample.
Sample collection, analysis, data storage, and alarm activation
is controlled by system's computer.
Prior evaluations tested PD, PFA, leak threshold, dose,
tracer movement through soil, and waiting times.
|
Linde Services, Inc.
|
Evaluator: Ken Wilcox Associates
|
3755 N. Business Center Dr.
|
Tel: (816) 443-2494
|
Tucson, AZ
85705
|
Dates of Evaluation:
10/04/90
,
06/19/99
|
Tel: (844) 445-4633
|
Evaluator: Control Strategies Engineering
- out of
business
|
E-mail: contactus@linde.com
|
Tel: Contact Linde Services, Inc.
|
URL: www.lindeservices.com
|
Date
of Evaluation: 05/92
|
Formerly Praxair Services, Incorporated. LG 113 name changed on October 1, 2020.
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