Issue Date: March 10, 2000
Revision Date: December 4, 2002

Praxair Services, Inc.
(originally listed as Tracer Research Corp.)

Tracer ALD 2000 Automated Line Tightness Test

Line Leak Detection Method for Airport Hydrant and Field Constructed Systems

Certification Leak rate of 0.1 gph with PD = 100% and PFA = 0%.
The USEPA has not set a minimum detectable leak rate for large diameter pipeline systems (airport hydrant systems) at the time of this evaluation.
Leak Threshold A pipeline system should not be declared tight when tracer chemical or hydrocarbon greater than the background level is detected outside of the pipeline system.
Applicability Gasoline, diesel, aviation fuel, fuel oil #4, waste oil. 
Pipeline Capacity Not limited by capacity.
Waiting Time Ranges from 1 week to 4 weeks (normally 2 weeks) after tracer is added to tank. 
For very large pipeline systems, several days or weeks may be required to circulate tracer-labeled product through all parts of the pipeline. 
Waiting time begins after tracer has reached all portions of the pipeline being tested.
Tracer Dosage Tracer is added to tank manually or automatically using a metered injection pump at tank fill or tank discharge pipeline. 
Tracer-labeled product must be circulated through pipeline before test period begins. 
Pressurized pipeline must be brought up to operating pressure or operated on a daily basis. 
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 pipeline injection uses metered injection pumps to automatically inject tracer every time product flows through pipeline. 
Dosage is based on pipeline size and flow rate.
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. 
Pipeline must be accurately located to ensure that all pipeline surfaces are within the zone of influence of a sampling probe. 
Probes must be installed per manufacturer's guidelines.
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 surrounding pipeline may limit effectiveness of test method (e.g. when applied to pipelines 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 pipeline 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.


Praxair 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:  (800) 394-9929

Evaluator: Control Strategies Engineering (out of business)
E-mail: Tel: Contact Praxair Services, Inc.


Date of Evaluation:  05/92


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