0. API Subcommittee SC-6 Discussions Valves and Wellhead Equipment
API 6A 21st Edition WG
API Subcommittee SC-6 Discussions
Valves and Wellhead Equipment

1. 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

2. Work Teams/Captains Documentation Specialist / Jill Bell
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

3. 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

4. Moved repair Annex J to 6AR Removed Annex H – Tools (TR needed)
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

5. Clarified Tree Cap dimensions by modifying tables in Annex
Key Items addressed
Corrected valve bore metric conversion for one set of drifts (mtric/Imperial)
Clarified Tree Cap dimensions by modifying tables in Annex

6. 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

7. Thoughts on HPHT Approach
API Subcommittee SC-6 Discussions
Valves and Wellhead Equipment

8. Scope of 6A 20th Edition Document (Current Code)
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
Let’s take a minute to review the current scope as it exists in the 20th Edition
It includes 2,000 psi to 20,000 psi working pressure equipment
There are five different Product Specification Levels. PSL 1 through 4 with increasing requirements and a PSL 3G which adds gas testing to the popular PSL 3. Over the years, PSL 3 has become the standard for critical equipment. PSL 4 is rarely used.
Currently all PSL’s are available for all pressure ratings so you can have 20,000 psi working pressure equipment with PSL 1 requirements
Sour and non-sour service classes are available for all working pressures, allowing for high pressure equipment to be rated for sweet service
Impact requirements are 20 joules or 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 2K & 3K equipment
The design requirements are self contained in Clause 4 and follow the rules of ASME Boiler & Pressure Vessel Code Section VIII Div 2:2004 with some modifications
External loading created by bending moments and axial forces are not explicitly addressed but must be considered when designing casing and tubing heads, tubing-head adapters, Other End Connectors, as well as for tools for running, retrieving, clean-out and testing
Current high temperature derating requirements contained in informative Annex G including alternate material derating factors generated by AWHEM several years ago
Use of QTC’s for material properties for production components
Design validation by means of product testing is contained in Annex F which is an informative requirement

9. Existing Supporting Technical Reports Referenced in API 6A
API TR 6AF, Technical Report on Capabilities of API Flanges Under Combinations of Load
API Spec 6A
API TR 6AF
API TR 6AF2
API TR 6AF1
API TR 6AF1, Technical Report on Temperature Derating on API Flanges Under Combination of Loading
API TR 6AF2, Technical Report on Capabilities of API Integral Flanges Under Combination of Loading —Phase II
API 6A references these three technical reports to address combinations of loading and temperature deratings for the entire family of flange sizes.
The 6AF technical report presents the results of analysis work with different load conditions: Makeup, Pressure, Tension, and Bending Moment to establish the load capacity of all flanges given in the April 1986 Editions of API 6A and API 6AB. API 6AB covered 1-13/16 through 7-1/16 30,000 psi flanges but has been withdrawn.
API TR 6AF1 adds in 350F and 650F temperature derating considerations and drops the withdrawn 6AB flanges.
API TR 6AF2 builds off API TR 6AF by adding a thermal component of 250F internal temperature and 30F external temperature and addresses all flanges sizes in API 6A 16th Edition. It also adds in the effects of lockscrews on flange loading capability.

10. API 6A 21st Edition Reorganization Proposal
Annexes
Stud Sizing
Purchasing
Heat Treat Qualification
Elevated Temperature
Unit Conversion
Flange Bolt Torque
Special Equipment
Monogramming
Validation
General Requirements
Manufacturer Design
Equipment
Legacy
As soon as the draft ballot is circulated, we will start on reorganization of the document with hopes of reducing the overall size and making things easier to find
The chart shows some current thoughts around a reorganization strategy to better accommodate HPHT while still maintaining legacy equipment.
Some of the existing Annexes will be moved to separate documents such as tooling, Repair and Remanufacture and Design validation procedures for surface safety valves and underwater safety valves

11. API 21st Edition / HPHT Alignment
Approach
6A HPHT
Materials
Design
Validation QC
With that overview in mind, let’s talk a little bit about HPHT alignment.
We see the alignment with HPHT as a four pronged approach.
The four elements we will need to address are:
Materials
Design
Validation
Quality Control

12. API 21st Edition / HPHT Alignment
Approach
6A HPHT
Materials
Design
Validation QC
Let’s start with Materials and Quality Control

13. Materials & QC Changes
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
As I stated earlier PSL 4 has been relatively unused. This is mainly due in large part to its restriction for weld repair. We have decided to target PSL 4 for HPHT Bodies and Bonnets or Pressure Containing Equipment. Some of the changes that we have made are
Remove weld repair restriction to make PSL 4 more 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 would be required
Separate quench loads not allowed with just single prolongation
BSL 3 per 20E would be a requirement for closure bolting. One key aspect is that it drives higher NDE requirements on bolting raw material.
Stud and nut hardness matching would be a requirement
20H HSL level 2 or 3 Furnace Calibration requirement is a consideration
2 = tighter calibration and survey requirements
3 = full AMS 2750 compliance which includes very detailed requirements for temperature sensors, instrumentation, furnaces, system accuracy tests, surveys, records, and quality assurance. 6 Furnace classes and 5 instrumentation types. Different requirements based on furnace class and instrumentation type
AWHEM material derating factors will be normative in the absence of actual test data
High strength nickel alloy requirements will be in conformance with API 6A-CRA
Sour service compliance per NACE MR0175 will be mandatory to eliminate fouling situations where a “sweet” service well sours beyond NACE limits due to higher operating pressures

14. API 21st Edition / HPHT Alignment
Approach
6A HPHT
Materials
Design
Validation QC
Let’s talk a little bit about our approach to design

15. Design (≤ 15K Per Current 17TR8)
ASME Section VIII Div2 with API allowable stresses
ASME Section VIII Div2 with API material properties
Prior to work on the 6A 21st Edition, SC-6 moved forward with a joint task group from SC 6, SC 16, and SC 17 to create a Standard based on ASME Boiler and Pressure Vessel Code, Section VIII, Division 2, Appendix 4 (2004 edition with 2005 and 2006 addenda). It includes further limits established for oil and gas products as determined by API standardization committees. This is API Std 6X.
Like the ASME code, it allows for three methods of analysis
(Click)A linear elastic analysis
(Click)A non-linear elastic perfectly plastic analysis method
(Click)A true-stress true – true strain For select failure mode only (unusual) to address serviceability or functional problems caused by high strain – eg. Threads, sealing mechanisms
17TR8 was created and given to the various subcommittees to determine how best to incorporate the principles of 17TR8 into the various product specs
This slide walks through the logic of 17TR8 for equipment less than or equal to 15K and as you can see it follows a path through API Standard 6X.
For select failure mode only (unusual)

16. Design (>15K ≤20K Per Current 17TR8)
If we follow 17TR8 for equipment greater than 15K and less than 20K, it takes us through the ASME Section VIII, Div 2 and would drive us to either linear elastic analysis with strain based limits on the amount of yielding through the thick wall sections or true-stress-true-strain analysis.
This in fact eliminates a very valuable method of elastically-perfectly plastic analysis. 6X has a subset of this method called limit load analysis which incorporates small strain theory to predict collapse and has proven to be a reliable method for 6A components.
Next Slide

17. Assess legacy 20K Flanges with newer methods
Design
Assess legacy 20K Flanges with newer methods
Add Wall Thickness
Caveat Statement
to 6A/6X. Cannot
Average Stresses in
Thick Wall
A path we would propose and is something we are working on in concert with the 17TR8 design and analysis committee as well as the authors of 6X.
It would enable a single design method for 6A equipment
It would also incorporate the fatigue screening methodology currently in 17TR8
We would also propose an assessment of the legacy 20K flanges with the newer design methods
We would also propose some validation but we will talk about that in the next section
PR2/PR3
PR4

18. 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
“Provisions of paragraph , 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.
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
“Provisions of paragraph , 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.

19. API 21st Edition / HPHT Alignment
Approach
6A HPHT
Materials
Design
Validation QC
Let’s talk about validation

20. Validation
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
As I stated earlier, currently validation via prototype testing is not a normative requirement (Annex F is Informative) and will most likely remain that way
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 (see next slide)

21. expansion coefficient that may result in excessive relative movement);
PR2
As described in API 6A Annex F
PR3
The 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
PR4
The 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
The recommendation here would be to follow a program based on analysis to provide for functionality in light of HPHT conditions for the equipment
For non-fatigue sensitive equipment one would follow the PR2 or PR3 path depending on functional requirements of the equipment or life expectations
If you were to take the fatigue sensitive path in the design diagram than the more rigorous testing per PR4 would be required
The challenge will be to ensure that analysis is thorough enough to consider all effects of the HPHT exposure
additional performance validation testing at elevated operating temperature in an operating environment;
2) validation of interaction between mating parts that may have varying thermal properties (e.g. different thermal
expansion coefficient that may result in excessive relative movement);
3) additional thermal cycles beyond a governing product specification;
4) validation of the equipment plastic shakedown behavior;
5) modification of the defined validation program that cites endurance cycling tests (such as opening or closing at
rated working pressure of valves/chokes/actuators) could be conducted in three (3) groups at defined
temperature parameters (e.g. elevated, room, and minimum).

22. API 21st Edition / HPHT Alignment
Approach
6A HPHT
Materials
Design
Validation QC

23. Global Plastic Collapse per API STD 6X
Workgroup Proposal
Analysis approach to 20K - Elastic Perfectly Plastic w/Large Strain
Potential 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? OR
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)
Proposal Per 5/11/15 meeting with Paul Bunch, John Fowler, Nigel McKie, David Zollo
HPHT Design Flow-Chart From 17TR8
Figure 1