API 5L - ANNEX E- Magnetic particles-acceptance criteria

[alanisphoenix]

Hello,
i have a question about the annex relative to Magnetical Particles.

According to API 5L the standards to use are ASTM E709 or ISO 10893-5
ASTM A709--> Has not acceptance criteria
ISO 10893-5 > have 3 levels, M1, M2, M3 and says specifically that the magentical particles (point 6.2) is not useful to determinate the deep of the imperfection.

API annex E.6.1.2 says:
The imperfections that have depth <12.5t...etc etc..

So my question is:
1- Has not API an acceptance criteria according to ISO 10893-5? For UT for example it specifies ISO 10893-10 U2/C or for ISO 10893-8 U2
2- How can be evaluated by Magnetic Particles if the depth is more or less that 12.5%WT? This is impossible by Magnetic Particles even ISO 10893-5 says it.

So how i can comply with the requirement (depth less that 12.5%wt) if using M.Particles is not possible determinate the depth. HOw can i evaluate it?

thank you for your help.