Compliance Testing Of Pressure Vessels To New Jersey Defined Ultrasonic Testing Standard SNT-TC-1A

All steel tanks and pressure vessels will corrode over time depending upon various factors including service, material of composition, internal lining, its content, chemical treatment if any, construction, operating conditions, service and maintenance, as well as external conditions.  Traditionally, tanks containing water and having a varying water line are under the greatest corrosion threat.

While most tanks will provide decades of reliable service, unknown influences can advance their deterioration.  Of all forms of tanks, pressurized vessels present the greatest danger should failure occur.  Our Tank Corrosion Photo Gallery presents just some of the threats we have investigated over past decades at tanks of all types.

In most cases, one or more indications are provided in advance of a greater tank or pressure vessel failure.  Thread leaks, outer surface corrosion, inlet or outlet piping leaks, pinholes, failures at weld seams – all such events offer clear indication to a potentially far more serious problem, and for any responsibly run maintenance department, will prompt an immediate response in terms of further investigation, repair, or replacement.

For virtually all building properties today, and especially for any manufacturing facility, compressed air storage supplies a critical service; operating all pneumatic based control services from air conditioning, to fire sprinkler, to manufacturing equipment operation.  Its failure raises the potential for both serious personal injury as well as extended service interruption.

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Well Maintained Replacement Required

CorrView International, LLC offers testing services for tanks and pressure vessels in accordance with SNT-TC-1A, which is the “Recommended Practice No. SNT-TC-1A: Personnel Qualification and Certification in Nondestructive Testing.” Physical tank testing follows the American Society of Mechanical Engineers (ASTM) published guidelines under Pressure Vessels, Section 5, Article 23 Standard Practice for Ultrasonic Examination.

The results of each investigation are presented in multiple formats and include the following:

Full Identification

All relevant and definable information about the tank or pressure vessel is recorded such as physical size, original wall thickness, operating conditions, manufacturer, construction, installation date, ASTM stamp or code, physical accessibility, and service, etc.

Testing Grid

A standard grid is assigned to the tank along its X and Y axis.  The shell and heads are tested and evaluated individually since they are typically constructed to different wall thickness standards.  Ultrasonic wall thickness measurements are taken at approximately 12 measurements per 1 sq. ft. in order to best define tank conditions and to identify isolated pitting.

Visual Inspection

A visual inspection of the tank is performed and all areas of concern are noted.  Evidence of leaks, repairs, or other deficiency are documented by photograph for inclusion into the final report.  Exterior rust, pitting, surrounding water infiltration, and other environmental factors are noted.  Any concerns at inlet or outlet piping to the tank or pressure vessel will also be noted into the report.

Ultrasonic Thickness Results

Individual results are provided for the tank shell, and both its top and bottom, or left and right side heads.  Three individual sets of statistics are calculated volume, surface area, and density of thickness measurements taken.  Wall thickness data is provided showing the number of thickness measurements recorded, average and minimum thickness values, minimum allowable wall thickness, and percentage of wall loss.

Graphical 3D View

A three-dimensional graph is provided of the shell and both heads displaying all wall thickness measurements and illustrating the condition of the tank or pressure vessel.  Separate visualizations are provided for the shell and heads given that wall thickness varies, and different conditions are common.

Raw Thickness Data

All wall thickness data is provided in standard spreadsheet format in order to document for further investigation or clarification the detail upon which the report has been compiled.  This information is made available in Microsoft Excel, Quattro Pro, or any required computer format.

Report Background

A review of our ultrasonic field testing and reporting procedures is provided, and includes an explanation of calculations made, terminology, and theory, etc.

Report Summary

A narrative summary of the report is provided, and provides recommendations if appropriate.

Appendix

All additional information relative to the condition of the tank is provided.  This may include additional photographic evidence to a problem or other concerns raised during the inspection procedure.

Please contact CorrView International, LLC for further explanation and pricing.  We provide further information on this Internet site related to our ultrasonic pipe and tank testing services.  A full interactive report is also provided documenting our inspection of larger domestic cold water and fire sprinkler water storage tanks.

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