1. Current Industry Assessment
API 17TR8: High-Pressure High-Temperature
Design Guidelines
API 6X/6A/17D
Linear-Elastic (L-E)
Screening
Equipment Rating
ASME Div. 2
Linear-Elastic or
Elastic-Plastic (E-P)
ASME Div. 3
Elastic-Plastic (E-P)
ASME BPVC Section VIII, Div. 2
Table Load Combinations and Load Factors for E-P Analysis
ASME BPVC Section VIII, Div. 3
Table KD Load Combinations and Load Factors for E-P Analysis

2. Current Industry Documentation
GLOBAL PLASTIC COLLAPSE
Conditions
Linear-Elastic
API 6A/6X/17D/17G
Elastic-Plastic (LRFD)
ASME Section VIII, Div. 2
ASME Section VIII, Div. 3
Normal
0.67 x Sy
2.4
1.8
Extreme
0.80 x Sy
2.0
1.5
Survival
1.00 x Sy
1.6
1.2
LOCAL PLASTIC COLLAPSE
Conditions
Linear-Elastic
API 6A/6X/17D/17G
Elastic-Plastic (LRFD)
ASME Section VIII, Div. 2
ASME Section VIII, Div. 3
Normal
N/A
1.70
1.28
Extreme
1.42
1.07
Survival
1.13
1.00

3. Source: API 16A 4th Edition (Draft) Figure 8
Path Forward
Source: API 16A 4th Edition (Draft) Figure 8
Impact to validation testing
Qualification of design margins
Similar approach in API 16A 4th Ed
Methodology is expandable beyond subsea wellheads & trees

4. Path Forward API 17TR8 Verification Task Group
Define design factors for extreme & survival events
Define the probability of occurrence or ‘buckets’ for extreme and survival conditions
Define function and/or performance post extreme and survival scenarios
Define potential impact on fatigue life for these events
Probabilistic events convert to “cumulative damage” on equipment
Engagement with API 17D, 17G, and API 16A members