TMLs Selection for High Pressure Piping

Materials Science, Metallurgy, Welding, NDTs, Reliability Assessment, Failure Analysis, etc.
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Dlew
Posts: 51
Joined: 03 Aug 2025, 12:51
Area of interest: Mechanical Engineering

TMLs Selection for High Pressure Piping

Post by Dlew »

What are the general guidelines available to define TMLs for high pressure piping?
Please provide references from American & EU codes & standards.
mechcolor
Posts: 307
Joined: 17 May 2010, 18:05
Area of interest: Manufacturing Engineering

Re: TMLs Selection for High Pressure Piping

Post by mechcolor »

API 570 does not specifically talks about high pressure piping.
In most plants, inspectors usually classify high-pressure piping under critical service or Class 1 piping or high consequence piping circuits.
That classification then drives shorter intervals, more TMLs, stricter repair approvals, tighter corrosion allowances, and more advanced NDT coverage.
novice123
Posts: 140
Joined: 24 Jul 2010, 18:32
Area of interest: Petroleum Engineering

Re: TMLs Selection for High Pressure Piping

Post by novice123 »

ASME does have a separate section K on high pressure piping however such exclusivity is not available in API 570 when it comes to inspection.
I am not very well familiar with EU codes on this.
All we may need to consider is the areas where there is more turbulence, erosion-corrosion. Elbows, bends, reducers, and injection points should be considered points of concerns when defining TMLs on high pressure piping however understanding with ASME B31.3 about defining rules of design for high pressure piping does not necessarily correlate with API 570 service based /class defined inspection code.
octane
Posts: 171
Joined: 08 Oct 2010, 15:38
Area of interest: Mechanical Engineering

Re: TMLs Selection for High Pressure Piping

Post by octane »

In my opinion, there should not be any special focus to be provided to high pressure piping while performing inspection.
Once classified appropriately, and CMLs are assigned accordingly based upon the rules provided in API 570, I believe we are all covered.
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