Plant Inspections

Plant inspections are an integral part of risk management process. They are necessary to ensure equipment are safe and reliable to minimize risk to people, the environment and plant production downtime.

 

Plant Inspections can be categorized as;

1) External Inspections Periodically,

2) Internal Inspections During Planned Shutdown and

3) Emergency Inspections During Breakdown.

Risk Based Inspection

Risk Based Inspection is a risk assessment and management process that is focused on the loss of containment, of pressurized equipment in processing facilities, due to material deterioration.

These risks are managed primarily through equipment inspection. The technique is used to determine inspection intervals, method of inspections and scope of inspections. For example, you may determine your pressure vessel internal inspection based on API 510 requirement or carry out the risk based inspection and determine the interval, method of inspection and scope of inspection. The API 510 allows you to choose this alternative method. API RP 580 provides the definition and general requirement for risk based inspection and API RP 581 introduces you to a specific quantitative methodology for risk based inspection implementation.

The key equipment on a plant that are inspected and their respective codes and standards applicable for in-service inspection, repair and re-rating are described below.

Pressure Vessels

The following codes and standards and recommended practices are used for pressure vessel inspection:

  • API Standard 510; Pressure Vessel Inspection Code: In-Service Inspection, Rating, Repair, and   Alteration
  • API RP 572; Inspection Practices for Pressure Vessels
  • API RP 576; Inspection of Pressure-relieving Devices
  • API RP 571; Damage Mechanism Affecting Fixed Equipment in the Refining Industry
  • ASME PCC-2; Repair of Pressure Equipment and Piping
  • National Board Inspection Code NB-23
  • ASME PCC-2, NB-23 and API 510 can be used for pressure vessel repair.

 

Piping Systems

The following codes and standards and recommended practices are used for piping inspection:

  • API Standard 570; Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems
  • API RP 574; Inspection Practices for Piping System Components
  • API RP 571; Damage Mechanism Affecting Fixed Equipment in the Refining Industry
  • ASME PCC-2; Repair of Pressure Equipment and Piping
  • ASME B16.5, Pipe Flanges and Flanged Fittings
  • ASME PCC-2, NB-23 and API 570 can be used for Piping repair.

 

Storage Tank

Following codes and standards and recommended practices are used for storage tank inspection:

  • API Standard 653; Tank Inspection, Repair, Alteration, and Reconstruction
  • API RP 575; Inspection of Atmospheric and Low-Pressure Storage Tanks
  • API RP 651; Cathodic Protection of Above ground Petroleum Storage Tanks
  • API RP 652; Lining of Above ground Petroleum Storage Tank Bottoms
  • API RP 571; Damage Mechanism Affecting Fixed Equipment in the Refining Industry

 

Steam Boiler

The following codes and standards and recommended practices are used for steam boiler inspection:

  • ASME Section VII Recommended Guideline for the Care of Power Boilers
  • API RP 573; Inspection of Fired Boilers and Heaters
  • API RP 571; Damage Mechanism Affecting Fixed Equipment in the Refining Industry

 

Process Heater

The following codes and standards and recommended practices are used for process heater inspection:

  • API RP 573; Inspection of Fired Boilers and Heaters
  • API RP 571; Damage Mechanism Affecting Fixed Equipment in the Refining Industry

 

Valves

The in-service inspection code for Pressure-relieving Devices is API RP 576. This code is used in conjunction with API STD 510. The API 510 determines the requirement for inspection interval and API RP 576 specifies the inspection practice. The in-service code for other industrial valves such as Globe Valve, Gate Vale, Check Valve and Plug Valve follows API STD 570 and API RP 574. If a major  repair is carried out, then valve testing might be needed, which can be done based on API 598.