Telltale hole: when to use it

[lpfaustini]

thread809-255764

Dear fellows,

According to API-650,

5.7.2.10 Reinforcing plates for shell openings, or each segment of the plates if they are not made in one piece, shall be provided
with a 6 mm (1/4 in.) diameter telltale hole. Such holes shall be located on the horizontal centerline and shall be open to the
atmosphere.

5.8.11.4 All non-circular miscellaneous pads shall have rounded corners with a minimum radius of 50 mm (2 in.). Pads that
must cover shell seams shall be provided with a 6 mm (1/4 in.) telltale hole (see 5.7.3.4).

Is that a reccomended practice?

 

[lpfaustini]

I'm in a big problem, the pads are already welded. How can we proceed with the leak test?

 

[IFRs]

You need holes to do the test and you are not supposed to post the same question in more than one forum.

 

[lpfaustini]

I'm sorry. I was in the heat of the moment. Please ignore my last post. My first post prevails.

API-650 says:
"Pads that must cover shell seams shall be provided with a 6 mm (1/4 in.) telltale hole (see 5.7.3.4)."

I'm confused. All pads must have telltale holes, isn't that right?

 

[IFRs]

Where are you reading this? In the current version, 5.7.3.4 does not contain this language. In any case, all repads need holes to test the welds and provide a path for leak detection. Leave them open perhaps with a plug of grease to keep moisture from getting between the pad and the shell.

 

[lpfaustini]

I saw in 5.8.11.4

About leave them open,

Our assembly supervisor wants to close the holes. I told him not to close them (API is crystal clear). But he insists, saying he is an experienced 70 years old engineer and did that in more than 10 sites here in Brazil with sucess. He called me nuts when I told him to put grease in the holes.

 

[IFRs]

I believe that this reference is for repads on the tank bottom.

 

[jeevesme]

You should never insert a plug or weld the hole shut. It's called a telltale hole for a reason. The grease is to help deter crevace corrosion.