Exhibition & Conference

13-16 September 2021

Singapore EXPO, Singapore

Technical Programme

Maitha Almazroeui

Inspection Engineer


16:00 - 16:30

Wednesday, 18 September 2019

T3.6 Non-Intrusive Inspection (NII)

Technical themes:  Pipeline Maintenance & Integrity Management

Abstract Summary :

Oil and gas operating facilities need more state of the art inspection techniques and tools to ensure process safety and integrity throughout the design life of the assets. Legal internal inspection requires pressure equipment shutdown and HSE clearance for safe man entry. However, the associated costs for internal inspection are frequently higher than the actual cost of the inspection itself. Furthermore, mechanical damages could be caused during inspection preparation.

To adopt an industry’s new methodology, ADNOC Gas Processing introduced Non-Intrusive Inspection (NII) as a practical and value adding inspection tool for its operating sites.

Non-Intrusive Inspection (NII) is the examination of a pressure vessel without any personnel entry, which can be applied whilst the equipment is in service. NII is a stringent engineering process in which inspection tasks are designed with the aim of replacement or deferment of a conventional internal visual inspection (IVI), where comprehensive planning and evaluation are carried out to ensure the inspection meets a specified criteria under an equivalent or higher level of confidence than IVI. NII technology has an extensive advantage if inspection is performed from the outside of the vessel without opening i.e. non-intrusively.

The primary objectives of NII are:

  1. To develop & implement new inspection method that will assist our operational plants with reduction of S/D scopes.
  2. To avoid confined space entry which can be hazardous to human.
  3. To minimize environmental damage from releasing of toxic chemicals, waste disposal while cleaning and preparing for entry of process equipment.
  4. To shorten the turnaround/ shutdown by carrying out most or all of the inspection work in advance of the shutdown.
  5. To minimize disturbances to the vessel (blinding/spading, boxing-up risks), which could create new problems.
  6. To allow the inspection to be carried out when a potential problem is identified, without interfering with other operations and shutdown.

Methods / Process:

  1. Screening of Pressure Vessels: Selecting pressure vessel to see if the vessel is suitable for NII or not based on the surface temperature and area accessibility.
  2. NII Assessment: Based on the Feasibility and the set the key inspection requirement.
  3. NII Work Scope: Where we developing the work instruction to perform the inspection.
  4. On-site Inspection: Which mean performing of the inspection.
  5. Evaluation: The evaluation of the inspection carried out is consists of two aspects that are conformance level and data analysis.
  6. Justification: To justify replacement or deferment of IVI with NII.
  7. Integration of NII and RBI: Updating RBI Parameters.


The aim of this activity is to assess the conformance of the inspection achieved to the work scope. The NII sets out to meet all the objectives of the IVI and delivers equivalent (or better) information to the Risk Based Inspection (RBI) system to allow re-grading and adjustment of the subsequent interval where appropriate.