Issue Date: December 29, 2017

Atmos International Limited

Atmos Portable Tightness Monitor (ATPM) - for Bulk Piping and Hydrant Fuel Systems

Software Version 1.3

Line Leak Detection Method for Airport Hydrant and Field Constructed Systems


Leak rate of 0.0021% of pipeline volume per hour at separate defined pressures of 150 and 100 psi in pipeline segment being tested with PD = >95% and PFA = <5%.

Leak Threshold

0.00105% of pipeline volume.

A pipeline system should not be declared tight if the test results indicate a loss that equals or exceeds the preset threshold.


System tests either single or double-walled fiberglass, plastic or steel piping. Diameter of piping ranged from 6 to 18 inches during the evaluation. The performance of the APTM system is a function of pipeline capacity and is expressed in terms of a percent of the pipeline volume per hour.

Pipeline Capacity

Minimum of 2,000 gallons, maximum of 201,690 gallons.

Waiting Time

No waiting time between delivery and testing.
45 to 60 minutes between dispensing and testing

Test Period

Test time durations during the evaluation averaged 30 minutes with stabilization times between 30 and 90 minutes following pressure adjustment.

System Features

Instrumentation consists of a pressure transmitter and data acquisition unit connected to a computer equipped with software. The system negates the effects of any product temperature changes that may occur during a test by comparing high and low pressure profile data from the pipeline to see if an actual leak is present in the pipeline. Its performance is defined in relation to the size of the pipeline that is used to test.


System must be calibrated in accordance with manufacturer's instruction which is recommended every two (2) years.


This method has NOT been evaluated for the regulatory leak detection requirements now required in 40 CFR 280.252 of the 2015 EPA UST regulations for airport hydrant or field constructed pipeline systems.
System designed for use on large underground bulk pipelines such as bulk piping and airport hydrant fueling systems.
This system should not be used if trapped vapor is present in the pipeline. The third-party evaluation utilized a total of 24 tests. 18 of these tests were conducted with various induced leak rates.


Atmos International Ltd.
Manchester, UK

Evaluator:  Ken Wilcox Associates

Tel: +44 161 445 8080

Tel:  (816) 443-2494

St., Pauls, 781 Windsor Road

Date of Evaluation:  07/26 /2016

Manchester M20 2RW, United Kingdom





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