Control Valve Packing Considerations for LDAR and Enhanced LDAR Programs

1. Control Valve Packing Considerations for LDAR and Enhanced LDAR Programs Blake Coleman Sales Engineer Meet Low-E requirements without compromising control valve performance

2. Control Valve Packing Needs Industry Fugitive Emission Standards Packing Technology Packing Principles Applying Principles Agenda

3. Control Valve Considerations What drives control valve packing selection? High cycle demand of control valve applications Low emissions for compliance with LDAR and Enhanced LDAR requirements Minimal maintenance between turnarounds Maintaining dynamic performance for loop control

4. Control Valve Fugitive Emission Standards • Address high cycle and low emission requirements through leakage and cycle classes • ISO 15848-1 • Isolation Valves (on-off) • 500-2500 cycles required • Control Valves • 20,000-100,000 cycles • Valve specific type testing (e.g. ENVIRO-SEAL packing in a Fisher valve) • ANSI/FCI 91-1 • Exclusively written for control valve packing • High Cycle • Valve specific type testing (e.g. ENVIRO-SEAL packing in a Fisher valve) A direct comparison of FCI 91-1 and ISO 15848-1 requirements is not possible.

5. Historical Perspective Traditional packing approach at the time “the more packing rings, the better” “just tighten the packing if it begins to leak…if the valve can still stroke it’s okay” leakage vs. friction

6. Control Valve Packing Design • In light of 1990 Clean Air Act, LDAR, and lower control valve emission requirements: • Fisher initiated a packing development and testing program to address these challenges • Testing revealed several important observations • Traditional approach of trying various materials and arrangements would not stand up to new leakage criteria • Development • Through empirical laboratory studies and research, Fisher identified 5 control valve packing design principles used today

7. Identified 5 packing design principles Controlled packing stress Minimized packing arrangement Packing ring containment and support Stem guiding and alignment Stem surface finish Slide 7 Emerson Confidential

8. Design Principle 1 – Controlled Packing Stress Creating a seal Resilient packing material placed between stem and bonnet Deformed (stressed) to fill any voids Limitations Stationary follower relies solely on resiliency of packing itself to establish and maintain stress Volume loss due to compression and filling voids causes stress to decrease Must re-tighten packing nuts to re-establish stress Maintenance intensive Difficult to ensure correct stress is applied initially or at later maintenance stage Insufficient stress = weak seal Too tight = overstress and increase in excessive packing loss by extrusion or wear Torque packing nuts to load packing flange Creates axial load on follower and stress in packing Packing stress transmits into radial load, creating seal between stem and packing box Traditional Packing Approach Slide 8 Emerson Confidential

9. Design Principle 1 – Controlled Packing Stress Spring stack between packing flange and follower to establish and maintain a controlled load and stress on packing (live-load) Benefits Packing stress is maintained via Bellevilles even as packing volume and height is lost through friction, extrusion, or consolidation, Slight reduction in spring force as packing consolidates, but will not compromise seal integrity because springs and packing are properly paired Reduces effects of thermal cycling Less maintenance (re-tightening) Additional considerations Must be used in conjunction with anti-extrusion system to prevent loss by extrusion via constant stress Stem alignment control is crucial Torque packing nuts to load packing flange Compresses Belleville springs which live-load follower axially and create constant stress in packing Packing stress transmits into radial load, creating seal between stem and packing box Solution: Live-Loading Slide 9 Emerson Confidential

10. Design Principle 2 – Minimized Packing Arrangement Quality and position of the seal depends on Ability of packing to deform under compressive load Friction between the packing and stem Understanding where sealing occurs Slide 10 Emerson Confidential

11. Consolidation Packing consists of stacked rings Air is trapped between the rings when first installed As packing is stressed, the air is compressed and forced out of the packing As air leaves, the effective volume of packing decreases, e.g. “consolidates” Stationary follower: consolidation reduces stress and radial deformation (seal) Must be re-tightened Live-loading: consolidation minimally reduces packing stress Springs take up lost height from consolidation Consolidation further minimized by Minimizing number of packing rings needed to create a seal Packing ring design that minimizes voids Slide 11 Emerson Confidential

12. Friction The greater the area of contact between packing and stem (more rings), the greater the friction Graphite packing has high friction Additional rings only increase friction Requires larger actuator Slow stem movement Poor control Slide 12 Emerson Confidential

13. Where Sealing Occurs Key takeaway: one ring seals Additional packing rings provide no improvement in sealing force Consider packing material behavior under axial pressure… If packing acted as a fluid: Uniform radial pressure and seal If packing acted as a solid: Little or no axial load transmitted to radial pressure to deform packing and create seal Solution: Utilize minimum number of packing rings Actual PTFE packing behavior Non-uniform radial load with maximum stress near the middle of the packing set -Design Principle 2 Actual Graphite packing behavior Non-uniform radial load with maximum stress near the top due to high friction between the packing and stem countering the downward load Slide 13 Emerson Confidential

14. Design Principle 3: Packing Ring Containment and Support PTFE has 2 deficiencies Coefficient of thermal expansion is 10x that of steel Tends to cold flow when stressed As PTFE packing heats, it tries to expand Increases stress in packing Flow (extrude) past retaining rings and out of the packing box More PTFE packing = more expansion force = more difficult to retain As PTFE cools, the amount lost to extrusion will reduce the sealing stress Requires re-tightening and maintenance program As a result, thermal cycling is a major cause of packing loss, leakage, and short service life Extrusion of PTFE Slide 14 Emerson Confidential

15. Packing Retention and Anti-Extrusion Packing lost via 2 mechanisms Wear caused by friction (Graphite) Extrusion (PTFE) Live-loading can moderate stress reductions from packing loss, but it cannot prevent extrusion altogether Solution: anti-extrusion rings Less pliable material than packing “seals” the packing, not the leakage Efficient load transfer from follower to packing Tight fit to stem to prevent extrusion without scratching stem surface Design Principle 3: Packing Ring Containment and Support Slide 15 Emerson Confidential

16. Design Principle 4: Stem Guiding and Alignment Valve stems and shafts experience radial movement Bending stress Imperfect alignment of actuator High packing loads Leads to non-uniform packing stress around the stem Guiding and alignment controls Solution: Close fitting follower to serve as guide bushing PTFE lined for tight clearance and reduced friction when temperature allows Hard carbon bushing rings for graphite packing systems Belleville springs centered around the stem or shaft reduce alignment issues as opposed to being installed under each packing stud where differences in packing nut torque have greater influence Slide 16 Emerson Confidential

17. Design Principle 5: Stem Surface Finish Solution: Smooth, polished stem finish Reduces packing erosion and friction Enhances anti-extrusion ring effectiveness

18. Applying Design Principles: ENVIRO-SEAL PTFE PTFE packing rings stressed and load maintained via live-loading with adequate spring compression remaining to compensate for expansion Optimal packing stress derived by lab testing Minimize the number of packing rings Confirmed by lab testing Employ special anti-extrusion rings to contain PTFE and protect against extrusion and consolidation V-shaped packing ring and anti-extrusion ring shapes to closely match and reduce packing ring voids Add anti-extrusion washers to further contain the anti-extrusion rings PTFE lined packing follower serves as bushing and stem alignment Polished valve stem Slide 18 Emerson Confidential

19. ENVIRO-SEAL PTFE – Sliding Stem Design Principle 4: Guiding Design Principle 1: Live-loading Packing Follower (Stainless Steel) Springs (N07718) Design Principle 3 Anti-Extrusion Ring (Filled PTFE) Design Principle 3 Anti-Extrusion Washers Lantern Rings (Stainless Steel) Packing Box Ring (Stainless Steel) Design Principle 2: Optimized Minimal Packing Packing Ring (PTFE) Design Principle 5: Polished stem finish

20. ENVIRO-SEAL Graphite ULF Design Principle 1: Live Loading Springs (N07718) Design Principle 4: Guide Bushing (Carbon) Design Principle 3: Containment Packing Ring (Composite) Design Principle 2: Optimized Minimal Packing Packing Ring (Flexible Graphite) Packing Washer Packing Box Ring (Stainless Steel) Design Principle 4: Guide Bushing (Carbon) Design Principle 5: Polished stem finish

21. Considerations for control valve packing Does packing solutions meet control valve fugitive emission standards? ANSI/FCI 91-1 ISO 15848-1 Does it use design principles to meet leakage and control valve cycle requirements with minimal maintenance? Controlled packing stress Minimized packing arrangement Packing ring containment and support Stem guiding and alignment Stem surface finish Does it meet LDAR (500ppm) and Low-E/Low-leaking (100ppm)? Does it maintain dynamic performance required of control valve applications? ENVIRO-SEAL…designed, tested, and validated to fugitive emissions standards to meet Low-E requirements Slide 21 Emerson Confidential

22. Questions?