Global X-Ray Customized NDT Reporting
Reports are customized to meet the needs of the customer. Reports include design pressures, isometric piping drawings, tank and vessel drawings, a listing of the required thickness, thickness measurements, the resulting MAOP, and recommendations. They may include photographs, copies of U-1A's, visual notes, a glossary, operating pressures, relief pressures, total metal loss, metal loss rates, or a next inspection schedule. Reports will typically include a summary, action and caution items, corrosion allowances, and remaining life.
The design pressure of a pressure vessel will be shown on the vessel's nameplate. It is also shown on the manufacturer's U-1A document if it is a coded vessel. The operating pressure is the maximum pressure that the vessel or piping circuit may be exposed to. Safety devices such as a PSV or pressure switches are used to limit the pressure in a vessel or piping circuit. The setting for the safety relief device is referred to as the relief pressure.
When the technician is at a facility for an erosion/corrosion survey, he makes an isometric hand sketch of the piping system as he takes readings. This sketch is not drawn to scale, but it does show the piping, elbows, tees, etc. in the correct spatial orientation and the locations of the thickness measurements. It is recommended that the sketch be redrawn in AutoCAD by our draftsmen and that the thickness readings be captured in the UltraPIPE program. An AutoCAD drawing will display the lowest thickness measurement taken at each location and this will automatically update when new readings are collected in the future.
Tank and Vessel Drawings
Tank and vessel drawings are not drawn to scale, but show the overall dimensions, nozzle locations, and thickness reading locations. It is recommended that the field sketch be redrawn in AutoCAD by our draftsmen and that the thickness readings be captured in the UltraPIPE program. AutoCAD drawings will display the lowest thickness measurements taken at each location and these will automatically update when new readings are taken in the future.
Wall thickness for a tank or pressure vessel is measured using ultrasonic technology. Wall thickness for piping may be measured with ultrasonic technology or radiographic technology. A pit gauge is used to subtract the depth of a pit from the measured wall thickness.
At the customer's request, the technician can photograph the equipment being surveyed with a digital camera. Photographs of visually problematic areas, or photographs of the setup for radiography are common requests.
ASME coded pressure vessels have a manufacturer's U-1A data report form when they are built. The customer may provide a copy of this form, or we can obtain one from the manufacturer on behalf of the customer for pressure vessel calculations. A copy of the U-1A can be included as part of the report.
Visual inspections are used to supplement radiographic and ultrasonic examinations. Systems are inspected for surface rust, paint condition, pitting, leaks and other signs of damage or problems.
Reports based on the UltraPIPE program include a glossary of specialized definitions used by UltraPIPE.
Total Metal Loss
The difference in wall thickness between the first thickness measurement and the last thickness measurement is the total metal loss. For the special case where there appears to be metal growth, the total metal loss is zero.
Metal Loss Rate
The total metal loss divided by the time it took to lose the metal, is the metal loss rate.
The recommended schedule for next inspection is based on the calculated remaining life and API codes.
The summary is a table that displays critical information for each circuit, vessel or tank included in a survey. Typical information to include would be design pressure, operating pressure, relief pressure setting, MAOP, corrosion allowance, corrosion rates, and remaining life. The information displayed is customized to the customer's requirements.
An action item is a condition that needs immediate attention such as a calculated maximum allowable operating pressure (MAOP) that is less than the design pressure. A caution item is a condition that indicates a potential problem but doesn't require immediate attention, such as high corrosion rate. Both action items and caution items are based on conditions defined by the customer.
The difference between the current thickness and the required thickness is the corrosion allowance. The required thickness may be due to a calculation for design pressure, or it may be a minimum requirement for structural integrity, or it may a minimum thickness as defined by the customer.
The remaining life for each data point is calculated based on the required thickness, last thickness measurement, corrosion rates, and code requirements.