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Information Bulletin: Temporary Engineered Pressure Enclosures Guidelines and Requirements

Information Bulletin

Information Bulletin: Temporary Engineered Pressure Enclosures Guidelines and Requirements

January 18, 2022

Information Bulletin
Boiler, PV and Refrigeration

Reference Number:

IB-DA 2022-01



Effective June 1, 2022

This information bulletin provides guidelines and requirements for temporary Engineered Pressure Enclosures and details the responsibilities for owners of pressure equipment in BC.

Engineered Pressure Enclosures (EPE) are mechanical components designed by Professional Engineers to temporarily seal leaks on compromised pressure equipment when it is impracticable to shut down for immediate repair. An EPE temporarily provides a pressure equipment owner with a method to stop a leak or reinforce a compromised area pending permanent repair.

Under the Safety Standards Act, Section 69 (3) states that a person must not use a regulated product in a manner that is unsafe or that creates risk of personal injury or damage to the property. Accordingly, a regulated product owner is responsible for the equipment and ensuring its safe installation, operation, and removal at end of life.

Technical Safety BC is aware that some owners have been applying EPEs as permanent installations without any timeline for replacement. Technical Safety BC is providing this information to clarify the requirements for design registration and provide guidelines on the responsibilities for owners of pressure equipment in British Columbia.

Basis for Engineered Pressure Enclosures

EPEs that meet regulations are registered as CSA B51 Category H pressure fittings. They can be applied as part of pressure piping alterations or unfired pressure vessel alterations and are assessed and captured under new pressure fitting registrations on the following basis:

  • Power Engineers, Boiler, Pressure Vessel and Refrigeration Safety Regulation (PEBPVRSR), Section 84(2) requires design registration of pressure equipment.
  • CSA B51 Clause 4.1.1 requires registration and acceptance to the regulatory authority of the pressure equipment.
  • CSA B51 Clause 4.1.4 requires registrations to be revised when there is a change in the pressure-retaining ability of the equipment.
  • PEBPVRSR, Section 87(1) and CSA B51 Clause 11.5 requires design registration of an alteration to registered pressure equipment which deviate from the original design intent.

EPEs are pressure equipment and will have a Canadian Registration Number (CRN) as they may experience the same operating conditions as the pressure equipment they are protecting. EPEs should be designed by a Professional Engineer following a Recognized and Generally Accepted Good Engineering Practice (RAGAGEP). Design registration ensures that a Professional Engineer was involved in the design and fabrication of the fitting and has assessed the design risks.

Requirements for Registering Engineered Pressure Enclosures

In addition to the registration requirements for a pressure fitting, EPEs have specific registration requirements as detailed below.

All fittings:

  • Calculations and general arrangement drawing that demonstrates design to CSA B51 and ASME PCC-2
  • Manufacturer QMS Certificate
  • Engineering scope of work for the intended end-use of this fitting
  • Statutory Declaration Form for Pressure Fittings
  • A design package for CRN registration if the EPE is not registered (EPE shall be designed as per CSA B51)

EPE specific:

  • Reasonable form of preliminary design and operating hazard assessment
  • Justification to describe why an EPE is required
  • The description of the operating equipment it will be applied to and its current condition
  • A risk assessment evaluating the risk with and without the addition of an EPE
  • A maintenance and monitoring procedure including removal confirmation date
  • Site location

As per CSA B51, registration of fittings shall be resubmitted for validation no more than ten years after the date of acceptance. As EPEs are a unique applications of pressure fittings and are intended to be installed temporarily, the design registration does not serve as a reflection of the acceptable operating duration of an EPE. The pressure equipment owner, in conjunction with the Safety Officer, will determine the safe operating duration of the EPE and its removal after a permanent repair to the original pressure retaining equipment.

Best Practices for Engineered Pressure Enclosures

Several publications standardize design conditions for EPEs, which Professional Engineers can use as a best practice references:

  • ASME PCC-2, Repair of Pressure Equipment and Piping, Part 2 – Article 2.4
  • EPRI (USA) NP-6523-D – On-Line Leak Sealing
  • Health and Safety Executive (UK) – Leak Sealing Repair Clamps advisory
  • Health and Safety Executive (UK) – Weldless repair of safety critical piping systems
  • NRC Inspection Manual, Part 9900, On-Line Leak Sealing Guidelines.
  • EEMUA (UK)-Category Mechanical, Ref. No.199 – On-Line Leak Sealing of Piping - Guide to Safety Considerations
  • API-579-1/ASME FFS-1 – Fitness-For-Service

Under operation, the fitting is temporarily used on pressure equipment until the next reasonable opportunity to complete repairs or alterations to the original equipment.  Although the fitting is fit-for-purpose for the immediate operating conditions, factors such as material degradation, installation defects, changes to service or operating conditions, or upset conditions will reduce the reliability of the fitting over time. Owners of these installed fittings must be made aware of the risks of these temporary enclosures and assess a reasonable maintenance, replacement, or removal strategy with the Safety Officer.

Operation Risk Assessment Guidelines

Owners of these installed fittings shall be aware of the risks of these temporary enclosures and assess a reasonable maintenance, replacement, and removal strategy. Some hazards to consider include but are not limited to:

  • The process to install these may require personnel to work in high hazardous work environments, requiring the system to be in operation while the EPE is installed.
  • EPEs are mechanical devices protecting damaged equipment or components, therefore there is a high likelihood of repetitive failure if root cause analysis and corrective actions are not developed.
  • The mechanism to seal the component may require an injection sealant or high-pressure integrity gasketing, which will require constant maintenance.

Since it is understood that an EPE has unique operating requirements that are site-specific, the owner shall conduct a site-based risk assessment and present to the Safety Officer upon request. Risk assessment shall demonstrate, at a minimum, the following requirements:

  • scope of work and basis to install an EPE;
  • duration of installation and repair or replacement interval;
  • inspection and replacement interval; and
  • design and operation risks that were considered at a site and maintenance level.

Upon the complete submission and successful review of submittals, a temporary approval of installation and operation of the EPE may be issued. As EPEs are a unique application of pressure fittings, even if the pressure fitting is already registered as per requirements of CSA B51, the application of the EPE must still be submitted for review and registration.