|MN471000, Pressure Safety Manual
Sponsor: Michael W. Hazen, 4000
|Revision Date: October 8, 2007
Replaces Document Dated: August 29, 2007
This document is no longer a CPR. This document implements the requirements of Corporate Procedure ESH100.2.PS.1, Control Pressure Safety Hazards.
IMPORTANT NOTICE: A printed copy of this document may not be the document currently in effect. The official version is the online version located on the Sandia Restricted Network (SRN).
Pressure Safety Manual
4. PROCURING PRESSURE VESSELS AND SPECIAL SYSTEM COMPONENTS
Subject Matter Experts: Shane Page, and David Paoletta
Contributor: Pressure Safety Committee
MN471000, Issue R (Q not used)
Revision Date: October 8, 2007; Replaces Document
Dated: August 29, 2007
Administrative Change: November 21, 2007, January 28, 2008, June 8, 2010, and May 26, 2011, and January 19, 2012
This chapter describes the requirements for the design, fabrication, testing, and documentation of pressure vessels and special components. Special components are one-of-a-kind components for special applications that are not available as stock items from commercial suppliers. These components must meet the same requirements as vessels to assure an adequate margin of safety. The term "vessels" as used in this chapter shall include these special components.
When procuring pressure vessels and special system components, Members of the Workforce shall ensure that they:
- Meet or exceed the requirements of this manual.
- An adequate factor of safety.
- Proper materials and processes.
- An adequate overpressure test.
Members of the Workforce should:
- Secure approvals at an early stage from representatives of the following functions:
- Materials Application Engineering and Design Support contact.
- Experimental Mechanics Department (1522) or the Mechanics of Materials Department (8776 ).
- Establish early liaison with an SNL buyer to expedite procurement of hardware or services.
- Use appropriate portions of the following checklist for procurement of pressure vessels, special system components, and services not available through the Just-in-Time (JIT) contract (see next topic).
Members of the Workforce shall provide appropriate information from the following checklist to the contractor who needs a minimal package of technical information to provide acceptable pressure vessels, special system components, or services:
- Specify and define these operating conditions:
Select the design procedure.
- Maximum Allowable Working Pressure (MAWP).
- Normal operating temperatures, and temperature extremes.
- Cyclic nature of pressure loading.
- Presence of hostile environments.
Select or specify the materials and processes
- Select an appropriate design, preferably based on the use of Section VIII, Division 1, ASME Code, if applicable.
- Specify an adequate factor of safety as part of the design. (See Ch. 3, Selecting the Factor of Safety, for the process necessary prior to justifying a factor of safety of less than 3.5.)
Specify an overpressure test and include these items:
- Consult the materials organizations as to the adequacy of the contractor's proposals, and specify the materials and processes to be used.
Specify all documentation. This includes supplementary notes and any required certifications for fabrication and procurement that are specified in this chapter.
- Test level, which is usually 1.3 X MAWP (see Ch. 6).
- Holding time at test pressure
- Temperature during test
- Instrumentation, measurements, and methodology desired
- Whether a Sandia representative is needed to witness the test
- Any special requirements.
Members of the Workforce shall procure vessels and special components by one of the following methods:
- Designed and built by SNL.
- Designed by SNL and built by outside contractor or by another DOE agency
- Designed and built for SNL by outside contractor or by another DOE agency
- Bought from a supplier's commercial stock
- Obtained "used" from surplus or previous owner.
Members of the Workforce shall:
Members of the Workforce should consider the following items when their vessel is designed either in-house or by an outside agency:
Members of the Workforce shall, when building a vessel in-house or having an outside agency build a vessel, ensure that the following items are considered:
- Specify that an outside contractor must furnish these certifications to document the pressure vessel work:
- Material properties (e.g., yield stress, ultimate stress, elongation, fracture toughness properties, etc.)
- Process specifications followed (e.g., weld, heat treat, stress relief)
- Inspection techniques and results (specify complete set of NDT evaluations required)
- Details of overpressure test and results (specify overpressure test procedures). Overpressure test may also be done in-house and is required before any vessel is used at SNL (see Ch. 6).
- Vessels designed and fabricated to the ASME Code by a Certified Code Shop are code-stamped and registered with the National Board of Boiler and Pressure Vessel Inspectors.
Members of the Workforce shall:
Members of the Workforce shall ensure that "used" pressure vessels or special systems meet the requirements of this manual with regard to:
- Adequate factor of safety
- Proper material and fabrication process
- Adequate overpressure test
Members of the Workforce shall observe these principles when obtaining used vessels:
- If ASME Code-stamped, require documentation of history of use and validation of Code stamp. The Code stamp on components may be invalidated by:
- Modifications made by a non-Code shop
- Operations beyond the design limits of pressure or temperature
- Corrosion beyond allowable amounts.
- If non-Code-stamped: Require documentation to show that the design standards were met originally and are still valid.
Note: The requirements for an adequate data package still must be met (see Ch. 9). Some used equipment that does not have sufficient, or any, documentation may require extensive testing to reestablish its adequacy. Lack of this effort or the costs associated with its accomplishment, may preclude the use of these items in a manned area. It may be less expensive, in some cases, to purchase a new item.
Note: This section discusses the advantages and disadvantages of procuring pressure vessels designed and built according to ASME Code from outside contractors, and outlines the general procurement process. This discussion applies only to vessels carrying "U" or "UM" stamps.
Members of the Workforce should:
Members of the Workforce should be aware of the following advantages of procuring pressure vessels designed and built according to ASME Code from outside contractors:
- Code shop assumes limited responsibility for vessel failure
- Make use of industry-accepted standards.
- Design and drafting costs are less
- Fabrication costs may be less
- Preparing a PSAR is simplified, if one is required.
- Design is conservative
- Assures that the design meets the PSM requirements.
Members of the Workforce should be aware of the following disadvantages of procuring pressure vessels designed and built according to ASME Code from outside contractors:
- Fabrication costs may be more.
- The design is conservative and may cause problems if size and weight are important
- Does not normally cover size of less than 6 in. inside diameter, or an operating pressure of less than 15 psi, although in some instances a Code Stamp may be obtained
- Provides for only these shapes:
- Certain defined shells of revolution, or flat plates for the heads of cylindrical vessels.
- Only the vessel is coded, not the bolted closures, piping, etc.
- Modifications or repairs must be done by ASME Code shops.
- Limited to those listed in the ASME Code, Section VIII, Division 1
- Information may not be state of the art
- Not all the materials listed in Section VIII, Division 1, are acceptable to SNL in certain applications. The designer should therefore verify with the Materials Application Engineering (6219) that his preliminary selection from the list is satisfactory for intended use.
Members of the Workforce shall follow this process for procuring pressure vessels designed and built according to ASME Code from outside contractors.
||Define design parameters in accordance with "Checklists: Requirements for Pressure Vessels Fabricated to the ASME Code by Certified Code Shops," this chapter.
||SNL requester and Purchasing representative
||Define contract requirements in accordance with "Checklists: Requirements for Pressure Vessels Fabricated to the ASME Code by Certified Code Shops," this chapter.
||Send Request for Quotation to ASME Code shops only.
||Review bid information from the contractor for the following:
- Negotiate as necessary on design
- Check the material with the Materials Organization
- Ensure overpressure test of 1.3x MAWP (see Ch. 3, "Conducting Adequate Overpressure Tests," and Ch. 6.)
Caution: When using ASME Code-approved carbon and low-alloy steels, ensure that overpressure test is done at the lowest operating temperature.
- Review fabrication drawings for acceptance
- Receive the pressure vessel only after confirmation of testing and documentation.
Note: Certain requirements must be met to obtain a pressure vessel fabricated to ASME Code, Section VIII, Division 1, from an outside contractor.
Members of the Workforce shall use this checklist of design parameters when preparing contracts for pressure vessels fabricated to the ASME Code by certified code shops:
- Maximum allowable working pressure.
- Operating temperature range.
- Working fluid
- Use cycle (e.g., 2 per hour, 6 per year).
- Corrosion allowance.
- Overpressure-test requirement. Reminder: Test level=1.3 x MAWP.
- Special requirements (e.g., special closures, pressure relief devices, access doors, supports, inspections, environmental considerations for temperature and corrosion, additive finish).
Members of the Workforce shall use this checklist of contract requirements for pressure vessels fabricated to the ASME Code by certified code shops:
- Design and fabricate in accordance with Section VIII, Division 1, of ASME Code
Materials Note: SNL may request minimum charpy V-notch impact energies for parent material and weld material (fusion zone and heat-affected zone) at specific temperatures. (See ASME Code, Section VIII, Division 1, Table UG-84.)
- Vessel shall be Code-stamped and registered with the National Board
- Requester shall obtain fabrication drawings for approval before fabrication
- Requester shall obtain two copies each of the material certification, manufacturer's data sheets, and the inspection report before acceptance
- Address shipping and handling
- Vendor furnishes all hardware (e.g., bolts, nuts, gaskets, seals)
- Date(s) required.
Members of the Workforce should follow this procedure to procure cryogenic systems:
||Contact the Facilities Customer Representative to discuss requirements for cryogenic systems.
||Initiate a Request for Facilities Support (RFS)
- Assemble specifications for the cryogenic system and delivery systems
- Give the specification to the requesting line organization along with required signoffs.
||Proceed with site work and the delivery system.
The purchasing organization is responsible for procuring cryogenic storage vessels and liquid cryogens.
Members of the Workforce shall ensure that:
- Pressure vessels and other system components are labeled to identify them with the associated data package.
- Labels shall be affixed so that they do not detract from the vessel's strength or function.
Members of the Workforce shall ensure that labels are appropriate for the type of component and the method of procurement.
- All Systems/Vessels
- An identification name to reference it to the "Data Package".
- For ASME Code Vessels
- Manufacturer's name and the year built
- Manufacturer's serial number
- MAWP and maximum operating temperature
- Date and pressure level of overpressure test
- Supplementary data as appropriate
- For Relief Valves
- Serial number
- Set pressure (verified by pressure test)
- Date tested
- Identification of the tester (PRV Test Station ID).
Members of the Workforce shall complete the documentation required to make up the Data Package that is created for all pressure systems regardless of procurement means.
Members of the Workforce should document the pressure ratings of the types of components in systems consisting of commercially available components.
Note: For those components that do not have this information stamped on the items themselves, a copy of the appropriate page/section from the supplier's catalog with the item description and rating highlighted adequately documents this category of components.
Members of the Workforce should document system that contain components that have been custom designed and fabricated. These components are not listed in commercial suppliers' catalogs and the information to document the integrity of the vessel and component is generally more extensive. Optional information includes:
- Specifications and ratings.
- Design and as-built drawings.
- Calculations to support design factor of safety.
- Materials callout and any supplementary notes.
- Certification information, generally for Code vessels.
- Processing information such as welding, manufacturing techniques, or special materials treatments.
- Overpressure test accomplishment and results.
Note: See Chapter 9 for documentation information.
Shane Page, firstname.lastname@example.org
Al Bendure, email@example.com
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