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API 6A-21st Edition HPHTMay 2015
API 6A 21st Edition WG
API Subcommittee SC-6 DiscussionsValves and Wellhead Equipment
API 6A 21st Edition - HPHTMay 2015 2
Progress Since January Meeting
• Several TG meetings with focus on comment ballot release
• Worked to clarify document approach to HPHT for BSEE HPHT presentation
• A draft document including ordered PDF (90 pages) changes has been generated and circulated for a “comment-only” ballot. The draft contains only proposed technical & editorial changes but no reorganization of content
API 6A 21st Edition - HPHTMay 2015 3
Work Teams/Captains
– Design / Jean Brunjes– Materials, Welding and Cladding / Sterling Lewis– Organization / Eric Wehner– Qualification / Tom Lambert– Quality / Mike Briggs
– Documentation Specialist / Jill Bell– Co-Chairs / Eric Wehner & David Zollo
API 6A 21st Edition - HPHTMay 2015
Key Items addressed
• Definition of a manufacturer requirements added• Tied pressure / NACE limitations to PSL’s• Annex M reworked to move requirements to main
body of the document. Annex M is normative.• PSL 4 requirements changed to align with potential
HPHT requirements (no welding requirement removed)
• PSL 3 – heat lot traceability requirement added• Welding hardness survey requirements removed to
default to NACE• Minimum clad thickness requirement added• Better definition of design criteria when referring to
clad thickness
API 6A 21st Edition - HPHTMay 2015
Key Items addressed
• Moved repair Annex J to 6AR• Removed Annex H – Tools (TR needed)• Design rules moved to 6X• Defined performance and product testing for
bleeder plugs• Revised Annex L and added 4” HPVR• Added language to reference 20 series
specification requirements (castings, bolting-BSL-1 minimum requirement)
• Eliminated PR1 in Annex F • Annex C stud length replaced by AWHEM TR
API 6A 21st Edition - HPHTMay 2015
Key Items addressed
• Corrected valve bore metric conversion for one set of drifts (mtric/Imperial)
• Clarified Tree Cap dimensions by modifying tables in Annex
API 6A 21st Edition - HPHTMay 2015
Plan forward
• Send current draft out as comment only ballot• Start reorganization work / Annex Work
– Annex J replace by 6AR (Circulate Draft Prepared by Ed)– Annex H replace with TR (Tools)– Annex I & O - Eliminated
• Resolve comments• Reorganize the entire document per Eric’s plan
– General– Defined Equipment (Design excluded)– Manufacturer designed equipment
• Address HPHT• Have final document ready for ballot by June 2016
API 6A 21st Edition - HPHTMay 2015
Thoughts on HPHT Approach
API Subcommittee SC-6 DiscussionsValves and Wellhead Equipment
API 6A 21st Edition - HPHTMay 2015 9
Includes 2,000 to 20,000 psi working pressure equipment PSL 1,2,3,3G & 4 All PSL’s available for all pressure ratings Sour and non-sour service classes for all pressure ratings Charpy V-notch impact requirements 20 joules (15 ft-lbf) for all PSL
Levels Hydrostatic testing to 1.5 times working pressure for 5KSI thru 20KSI
equipment & 2 times working pressure for 2&3K Design requirements – self contained: Per ASME BPVC Section VIII Div
2:2004 with some modifications External loading (bending/axial) not explicitly addressed but must be
considered when designing casing/tubing heads, tubing-head adapters,OEC’s, tools for running,retrieving, clean-out and testing
Current high temperature derating requirements contained in informative Annex G
Use of QTC’s for material properties for production components Design validation by means of product testing is an informative
requirement
Scope of 6A 20th Edition Document(Current Code)
API 6A 21st Edition - HPHTMay 2015 10
API Spec 6A
API TR 6AF
API TR 6AF2
API TR 6AF1
Existing Supporting Technical Reports Referenced in API 6A
API TR 6AF1, Technical Report on Temperature Derating on API Flanges
Under Combination of Loading
API TR 6AF, Technical Report on Capabilities of
API Flanges Under Combinations of Load
API TR 6AF2, Technical Report on Capabilities of API Integral Flanges
Under Combination of Loading —Phase II
API 6A 21st Edition - HPHTMay 2015 11
Annexes
Stud Sizing
Purchasing
Heat Treat Qualification
Elevated Temperatu
reUnit Conversion
Flange Bolt
Torque
Special Equipment
Monogramming
Validation General
Requirements
Manufacturer DesignEquipmen
t
Legacy
Equipment
API 6A 21st Edition Reorganization Proposal
API 6A 21st Edition - HPHTMay 2015 12
6A HPHTApproach
Materials
Design Validation
QC
API 21st Edition / HPHT Alignment
API 6A 21st Edition - HPHTMay 2015 13
6A HPHTApproach
Materials
Design Validation
QC
API 21st Edition / HPHT Alignment
API 6A 21st Edition - HPHTMay 2015 14
• Target PSL 4 for HPHT - Bodies and Bonnets (Pressure Containing Equipment)– Remove weld repair restriction to make PSL 4 usable– Require prolongation or sacrificial part for material property tests– Test location shall be at T/4 of prolongation or thickest section of sacrificial
part – Testing per heat treat batch– Separate quench loads not allowed with just single prolongation
• BSL 3 per 20E bolting requirement (Closure Bolting)• Stud/nut hardness matching• 20H HSL level 2 or 3 Furnace Calibration requirement
– 2 = tighter calibration and survey requirements– 3 = full AMS 2750 compliance
• AWHEM material derating factors normative in the absence of actual test data
• High strength nickel alloy requirements in conformance with API 6A-CRA
• Sour service compliance per NACE MR0175 mandatory to eliminate fouling situations where a “sweet” service well sours beyond NACE limits
Materials & QC Changes
API 6A 21st Edition - HPHTMay 2015 15
6A HPHTApproach
Materials
Design Validation
QC
API 21st Edition / HPHT Alignment
API 6A 21st Edition - HPHTMay 2015 16
Design (≤ 15K Per Current 17TR8)
API 6XASME
SECTION VIII, DIV 2
Elastic-Perfectly
Plastic
≤ 15K17TR8
Assess 17TR8 Logic
True Stress-True StrainLinear-Elastic
> 15K≤20K17TR8
For select failure mode only (unusual)
ASME Section VIII Div2 with API allowable
stressesASME Section VIII Div2 with API material properties
API 6A 21st Edition - HPHTMay 2015 17
Design (>15K ≤20K Per Current 17TR8)
API 6A 21st Edition - HPHTMay 2015 18
API 6X
ASME SECTION VIII,
DIV 2
Elastic-Perfectly Plastic
> 15K≤20KPROPOSED 6A
≤ 15K17TR8
Assess 17TR8 Logic
True Stress-True Strain
Linear-Elastic
FatigueSensitive
S-N ScreeningYes
ValidationNo Validation
Design
PR4PR2/PR3
Add Wall ThicknessCaveat Statement to 6A/6X. Cannot
Average Stresses inThick Wall
Assess legacy 20K
Flanges with newer
methods
API 6A 21st Edition - HPHTMay 2015
Fatigue screening requirements per 17TR8?
• For fatigue screening, we have legacy designs that are justified based on documented field history and successful performance. This is permitted under ASME BPVC Section 8, Div. 2 Paragraph 5.5.2.
• “Provisions of paragraph 5.5.2.2, Experience with comparable equipment operating under similar conditions.”
• For designs where equivalency to a legacy design cannot be
established, a fatigue screening analysis would have to be performed for each application to determine the necessity as well as the method to be used for fatigue analysis. Using the SN method, a screening can be conducted on high stress concentration areas to assess fatigue life and necessity to do a more exhaustive fatigue analysis.
API 6A 21st Edition - HPHTMay 2015 20
6A HPHTApproach
Materials
Design Validation
QC
API 21st Edition / HPHT Alignment
API 6A 21st Edition - HPHTMay 2015 21
• Currently validation via prototype testing is not a normative requirement (Annex F is Informative)
• 17TR8 dictates that a FMEA (failure modes and effects analysis) be conducted in order to develop an appropriate validation program
• Guidance for PR3 & PR4 testing are included in 17TR8
Validation
API 6A 21st Edition - HPHTMay 2015 22
PR2As described in API 6A Annex F
PR3The validation testing requirements of PR2 plus the addition of the appropriate tests below:
Elevated Temperature Performance Testing
Mating component validation
Additional thermal cycling
Endurance cycling testing
PR4The validation testing requirements of PR3 plus the additional procedures associated with validating the design verification process of with respect to fatigue sensitive components through one of the following methods:
strain-gauging program of a representative specimen or component comparison (FEA) results
Component fatigue testing
API 6A 21st Edition - HPHTMay 2015 23
6A HPHTApproach
Materials
Design Validation
QC
API 21st Edition / HPHT Alignment
API 6A 21st Edition - HPHTMay 2015 24
Workgroup Proposal
Per 6X Limit Analysis
Global Plastic Collapse per API STD 6X
Tri-axial Stress
(Div 2:5.3.2)
Ratcheting(Div 2: 5.5.7)
OR
Analysis approach to 20K - Elastic Perfectly Plastic w/Large StrainPotential API TR “6AF3” This is (Limit analysis in 6X with large displacement) (Ref. API Std 6X Clause 6.2 We would take a different approach from the ASME methods and support our approach via some comparative analysis of existing 20K API flanges • Leakage Criteria
• Separation threshold
• Flange Stresses• 1.5 x Working Pressure
• Bolting Stresses
• 83% of yield w/temperature derating?
HPHT Design Flow-Chart From 17TR8Figure 1
Proposal Per 5/11/15 meeting with Paul Bunch, John Fowler, Nigel McKie, David Zollo