The Critical Equipment Series has covered design and design risk reduction. A Laboratory Test Program (LTP) is the final step in validating the equipment design after updating it with all improvements determined through design risk reduction and related activities.
The term validation is used here because it means to “prove the validity or accuracy of something”. The purpose of the LTP is to prove that the final design performs as expected and that design risk has been minimized.
With some equipment designs, there will be a high probability of passing the LTP. In other cases, the probability will be lower because of unresolved design risk, but this risk will have been discovered using DfR activities such as FMEAand simulation. In these situations, the lab test program must also assess the unresolved risks. An example would be the expected low temperature sealing limit of a TFE/P seal. This could be initially estimated using glass-transition temperature (Tg), but in practice it may be different because of seal geometry. The LTP should therefore test to observe this temperature and include contingency tests if the expected temperature is not observed.
An effective LTP will have these attributes:
- Reflect the criticality of the equipment and application TRL; lower TRL projects should have extensive LTPs while higher TRL projects may have streamlined LTPs.
- Incorporate industry product standards when possible.
- Confirm operation within specification (OWS).
- Confirm the selection of factors of safety and temperature deration factors.
- Use root cause analysis when a test failure occurs.
- Include testing with margin to quantify the difference between OWS and equipment limits established through calculation or simulation.
- Include confirmation testing to establish repeatability of results.
Also, LTPs have little efficacy without documented acceptance criteria. These must be quantifiable whenever possible and include aspects such as post-test component condition, serviceability, and system integration. TRUTH: The LTP must confirm OWS and assess unresolved design risks.
This is the 10th in a series of 10 articles on critical equipment design for offshore completions.