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Technical Discussions
rt
rt
03:29 Nov-14-2008
2.5' x sch.80

i am new in NDT and was given a task to shoot a 2.5" x sch.80 pipe. Can someone give me an idea on how to shoot this? Does a DWSI with the snout in contact w/ the pipe suitable or do i have to shoot it in a distance and do i have to use a number tape or just a simple A B and C?

Thank you for your comments.


    
 
 Reply 
 
tj
tj
03:54 Nov-14-2008
Re: 2.5' x sch.80
----------- Start Original Message -----------
: i am new in NDT and was given a task to shoot a 2.5" x sch.80 pipe. Can someone give me an idea on how to shoot this? Does a DWSI with the snout in contact w/ the pipe suitable or do i have to shoot it in a distance and do i have to use a number tape or just a simple A B and C?
: Thank you for your comments.
------------ End Original Message ------------

Are you looking at the pipe or a weld? If it is weld you can come in contact with the pipe for single wall viewing. You can back the source off and superimpose the walls. You can also elipse the weld with the proper source angle at a distance instead of superimposing. This is, of course, if the applicable code allows this. Number belts are useful but not required for most applications. As for letters or numbers, an agreement should be reached with your customer if not specified.


    
 
 Reply 
 
rt
rt
04:00 Nov-14-2008
Re: 2.5' x sch.80
i am looking at a weld. your first suggestion to me looks easier but there is one question in my mind concerning the UG. which thew max. allowed is 0.02 and i am not good at calculations just yet since like i said this will be my first time shooting and actually doing it for real.

thank you for your reply by the way, it helped me a lot
----------- Start Original Message -----------
: : i am new in NDT and was given a task to shoot a 2.5" x sch.80 pipe. Can someone give me an idea on how to shoot this? Does a DWSI with the snout in contact w/ the pipe suitable or do i have to shoot it in a distance and do i have to use a number tape or just a simple A B and C?
: : Thank you for your comments.
: Are you looking at the pipe or a weld? If it is weld you can come in contact with the pipe for single wall viewing. You can back the source off and superimpose the walls. You can also elipse the weld with the proper source angle at a distance instead of superimposing. This is, of course, if the applicable code allows this. Number belts are useful but not required for most applications. As for letters or numbers, an agreement should be reached with your customer if not specified.
------------ End Original Message ------------




    
 
 Reply 
 
tj
tj
04:21 Nov-14-2008
Re: 2.5' x sch.80
----------- Start Original Message -----------
: i am looking at a weld. your first suggestion to me looks easier but there is one question in my mind concerning the UG. which thew max. allowed is 0.02 and i am not good at calculations just yet since like i said this will be my first time shooting and actually doing it for real.
: thank you for your reply by the way, it helped me a lot
: : : i am new in NDT and was given a task to shoot a 2.5" x sch.80 pipe. Can someone give me an idea on how to shoot this? Does a DWSI with the snout in contact w/ the pipe suitable or do i have to shoot it in a distance and do i have to use a number tape or just a simple A B and C?
: : : Thank you for your comments.
: : Are you looking at the pipe or a weld? If it is weld you can come in contact with the pipe for single wall viewing. You can back the source off and superimpose the walls. You can also elipse the weld with the proper source angle at a distance instead of superimposing. This is, of course, if the applicable code allows this. Number belts are useful but not required for most applications. As for letters or numbers, an agreement should be reached with your customer if not specified.
------------ End Original Message ---------

Okay, Try this.......

Determine your source size.(should be included in everyday paperwork)

Multiply that and the distance from the source side crown of the weld to the film.

Finally divide that by the distance from the source to the object being radiographed (If single wall viewing, it would be the root of the weld in contact with the film.)

Ug = Fd/D

where
Ug= geometric unsharpness
F= source size
D= distance from source to object being radiopgraphed
d= distance from source side of object to the film


    
 
 Reply 
 
tj
tj
04:25 Nov-14-2008
Re: 2.5' x sch.80
----------- Start Original Message -----------
: : i am looking at a weld. your first suggestion to me looks easier but there is one question in my mind concerning the UG. which thew max. allowed is 0.02 and i am not good at calculations just yet since like i said this will be my first time shooting and actually doing it for real.
: : thank you for your reply by the way, it helped me a lot
: : : : i am new in NDT and was given a task to shoot a 2.5" x sch.80 pipe. Can someone give me an idea on how to shoot this? Does a DWSI with the snout in contact w/ the pipe suitable or do i have to shoot it in a distance and do i have to use a number tape or just a simple A B and C?
: : : : Thank you for your comments.
: : : Are you looking at the pipe or a weld? If it is weld you can come in contact with the pipe for single wall viewing. You can back the source off and superimpose the walls. You can also elipse the weld with the proper source angle at a distance instead of superimposing. This is, of course, if the applicable code allows this. Number belts are useful but not required for most applications. As for letters or numbers, an agreement should be reached with your customer if not specified.
: ------------ End Original Message ---------
: Okay, Try this.......
: Determine your source size.(should be included in everyday paperwork)
: Multiply that and the distance from the source side crown of the weld to the film.
: Finally divide that by the distance from the source to the object being radiographed (If single wall viewing, it would be the root of the weld in contact with the film.)
: Ug = Fd/D
: where
: Ug= geometric unsharpness
: F= source size
: D= distance from source to object being radiopgraphed
: d= distance from source side of object to the film
------------ End Original Message ------------

EDIT: I have D and d explantions flipped. Sorry about that.


    
 
 Reply 
 
Nigel Armstrong
Engineering, - Specialist services
United Kingdom, Joined Oct 2000, 1096

Nigel Armstrong

Engineering, - Specialist services
United Kingdom,
Joined Oct 2000
1096
04:58 Nov-14-2008
Re: 2.5' x sch.80
----------- Start Original Message -----------

Hi rt (coincidental or on-purpose initials?)

Welcome to the forum. How new is new (to NDT)? I assume the person who assigned you the task is your supervisor and knows just how new you are. In which (any) case it is their responsibility to provide you a full radiographic technique sheet providing you and successors with all the detail you ask forum members whose only knowledge of the requirements is what you choose to tell us.

As you are new to NDT, please accept one important word which if you accept it and apply will help you to become a capable and respected technician- quality. You are a link in the chain of quality whose total strength depends on the strength of its individual links.

Many prerequisites will be dictated by the applicable Code or standard and you should ensure you know what these are (according to the Code) and apply them, but these will be general minimum requirements. You should aim to exceed these which most probably can be achieved with just a bit of thought and care.

Good luck

Nigel

: i am new in NDT and was given a task to shoot a 2.5" x sch.80 pipe. Can someone give me an idea on how to shoot this? Does a DWSI with the snout in contact w/ the pipe suitable or do i have to shoot it in a distance and do i have to use a number tape or just a simple A B and C?
: Thank you for your comments.
------------ End Original Message ------------




    
 
 Reply 
 
Juan Amado
Engineering, Inspection
Arco Industrial, S.A., Panama, Joined Nov 2001, 44

Juan Amado

Engineering, Inspection
Arco Industrial, S.A.,
Panama,
Joined Nov 2001
44
05:49 Nov-14-2008
Re: 2.5' x sch.80
----------- Start Original Message -----------
: : i am new in NDT and was given a task to shoot a 2.5" x sch.80 pipe. Can someone give me an idea on how to shoot this? Does a DWSI with the snout in contact w/ the pipe suitable or do i have to shoot it in a distance and do i have to use a number tape or just a simple A B and C?
: : Thank you for your comments.
: Are you looking at the pipe or a weld? If it is weld you can come in contact with the pipe for single wall viewing. You can back the source off and superimpose the walls. You can also elipse the weld with the proper source angle at a distance instead of superimposing. This is, of course, if the applicable code allows this. Number belts are useful but not required for most applications. As for letters or numbers, an agreement should be reached with your customer if not specified.
------------ End Original Message ------------


Here’s an example: for 2 ½” sch 80 pie, with a thickness = 0.276”, and an O.D. = 2.875”, A source with a focal spot of 0.111”, using the general requirements of ASME BPV code and a bunch of other assumptions…

You could go either of two ways (in general):

For Double Wall Single Exposure and complying with a Geometric Unsharpness (Ug) = 0.02” a Source to Object distance of D=(0.111)(.276)/0.02=1.53” would be required. Since the O.D of the pipe is larger than this (e.g. 2.875”), you could rest the source against the pipe and would have more than enough distance for a good shot.

For Double Wall Double Exposure and complying with a Geometric Unsharpness (Ug) = 0.02” a Source to Object distance of D=(0.111)(2.875)/0.02=15.95” would be required. This is so because you need to have both sides of the weld (the one closest to the film and the one farthest from the film to comply with the Ug), so the Ug calculation has to take into account the size of the whole object (pipe).

Hope this works for you.




    
 
 Reply 
 
Michel Couture
NDT Inspector,
consultant, Canada, Joined Sep 2006, 835

Michel Couture

NDT Inspector,
consultant,
Canada,
Joined Sep 2006
835
08:02 Nov-14-2008
Re: 2.5' x sch.80
Hi Nigel,

Yes my friend, I totally agree with you. Our work is an important one with some serious consequenses if we don't follow the rules (codes). Unfortunately, there are companies out there who's ethics are not to the highest standard. They like to wing it or very often will send a young tech out regardeless of results. The technician on the other hand is stuck between a rock an a hard place. You're new to the trade and it gives them carte blanche to abuse you. It does take a while to find a good company that is willing to invest in its tech and care about its client. Some people don't understand that NDT is such a vast field, that no one can know it all. Tehcnicians and management needs to keep up to date regularly. And this forum is in my opinion a very good place to do so.

Cheerio's

Michel


----------- Start Original Message -----------
: Hi rt (coincidental or on-purpose initials?)
: Welcome to the forum. How new is new (to NDT)? I assume the person who assigned you the task is your supervisor and knows just how new you are. In which (any) case it is their responsibility to provide you a full radiographic technique sheet providing you and successors with all the detail you ask forum members whose only knowledge of the requirements is what you choose to tell us.
: As you are new to NDT, please accept one important word which if you accept it and apply will help you to become a capable and respected technician- quality. You are a link in the chain of quality whose total strength depends on the strength of its individual links.
: Many prerequisites will be dictated by the applicable Code or standard and you should ensure you know what these are (according to the Code) and apply them, but these will be general minimum requirements. You should aim to exceed these which most probably can be achieved with just a bit of thought and care.
: Good luck
: Nigel
: : i am new in NDT and was given a task to shoot a 2.5" x sch.80 pipe. Can someone give me an idea on how to shoot this? Does a DWSI with the snout in contact w/ the pipe suitable or do i have to shoot it in a distance and do i have to use a number tape or just a simple A B and C?
: : Thank you for your comments.
------------ End Original Message ------------




    
 
 Reply 
 

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