mariolucas75
Civil/Environmental
Dear All,
API 510 code says for pitting assessment that pits even if they go beyond corrosion allowance might be acceptable if they do not penetrant into half of required thickness and not "that much wide" :
"During the current inspection, widely scattered pits may be ignored as long as all of the following are true:
a) the remaining thickness below the pit is greater than one-half the required thickness (½ t
required), and greater than 1.6 mm (0.062 in.);
b) the total area of the pitting deeper than the corrosion allowance does not exceed 45 cm2 (7 in.2) within any
20 cm (8 in.) diameter circle;
c) the sum of the pit diameters whose depths exceed the corrosion allowance along any straight 20 cm (8 in.)
line does not exceed 5 cm (2 in.)"
My question is - the deeper pit might be acceptable rather than shallow but wide - intuitively does it relates to for example if i have a membrane and make a needle hole in it - its vibration properties will not change much .... but if I excavate some portion of its thickness on wide area it's overall mechanical properties will change / vibration for example ?
Thank you
API 510 code says for pitting assessment that pits even if they go beyond corrosion allowance might be acceptable if they do not penetrant into half of required thickness and not "that much wide" :
"During the current inspection, widely scattered pits may be ignored as long as all of the following are true:
a) the remaining thickness below the pit is greater than one-half the required thickness (½ t
required), and greater than 1.6 mm (0.062 in.);
b) the total area of the pitting deeper than the corrosion allowance does not exceed 45 cm2 (7 in.2) within any
20 cm (8 in.) diameter circle;
c) the sum of the pit diameters whose depths exceed the corrosion allowance along any straight 20 cm (8 in.)
line does not exceed 5 cm (2 in.)"
My question is - the deeper pit might be acceptable rather than shallow but wide - intuitively does it relates to for example if i have a membrane and make a needle hole in it - its vibration properties will not change much .... but if I excavate some portion of its thickness on wide area it's overall mechanical properties will change / vibration for example ?
Thank you
