b31.3

Date 02-05-2006 12:19

let me ask this, in b31.3 normal cycle, the radiography requirements are listed in "other examinations" does that mean that if piping is leak and pressure tested within code specs that radiography is not necessary? is there anyway that nde can be bypassed as long as proper leak and pressure test are done? the piping is used for liquid nitrogen, argon and oxygen service. wouldnt the rapid increase and decrease of temperature classify this as severe cyclic? our engineer wasnt sure. he said that it is full penetration welds required. normal service allows 1-1/2 inches of ip in any 6 inches of weld so if hes calling for full penetration then its probable thats its severe cycle right?

By spatterbrain (*)

Date 02-05-2006 13:21

1. Radiography is still necessary prior to Leak and Pressure Testing. See paragraph 345.1.
2. NDE cannot be waived. It's the other way around.
3. If your engineer cannot tell you, who can? Look at your specifications for the piping line class. If it is classed as Normal Fluid Service, then that's what it is.
4. If there is IP in the weld and it is Normal Fluid Service, then it is accceptable by code if it does not exceed 1 1/2" in 6" of weld length. If your Engineer wants to impose a more stringent acceptance criteria, that is his option. That doesn't mean it is Severe Cyclic Service.

I think thats what you are asking.

By cryogenicshaun (**)

Date 02-05-2006 16:03

i know that xray can be performed in lieu of hydro or pnuematic test as long as 100% radiography is performed but i wasnt quite sure if it would work both ways. i didnt think it would but i wanted a second opinion. the engineer isnt imposing to exceed the requirements he said that full penetration welds are required. hes primarily just the vessel engineer. thats why hes not so certain about the piping after the flange aspect of it.

By spatterbrain (*)

Date 02-06-2006 04:12

Yes but that’s because the code addresses full penetration welds. Partial penetration welds are different. A (FJP) Full Joint Penetration Weld that is in any particular fluid service can have a discontinuity in it like LOP, for instance, as long as it does not exceed the acceptance criteria. That doesn't mean it is a partial pen weld. It is still a FJP.
But no you cannot get away from NDE. It must be performed prior to Pressure Testing. That way you will know if there are any detrimental defects in the joint that could result in a blow out during pressure testing.
Look at the definition of "Severe Cyclic Conditions" in 300.2. I believe it is on page 7 in the 2004 Edition of B31.3. If the system does not meet that definition, then it is "Normal Fluid Service".
Also look at Appendix "G".
You didn't mention a flange in your first post. Where is the flange located? Is it attached to a vessel?

By cryogenicshaun (**)

Date 02-06-2006 12:02

yes it is attached to the vessel. but the piping after the flange is what im talking about. i know that the piping from the vessel wall to the first flange all falls under asme sec viii. i agree with everything youve said. they were my thoughts exactly. but i needed to hear someone else say it. its been quite a dispute about this at the company i work for. the ownership actually had me doubting myself and my interpretation of the codes for a minute there. i appreciate you helping me out here.and with youre help i think im back on the right track again.

By spatterbrain (*)

Date 02-07-2006 05:10

Glad to be of help, but remember, either way, you must perform NDE. There is no way out of that.
But also remember if there is PWHT invloved, it is a requirement to perform NDE after all final heat treatment for P No.'s 3, 4 & 5 materials. P No. 1 doesn't matter, unless your specifications call it out.

By vonash

Date 03-03-2006 01:26

Me too Spatterbrain.

By Jim Hughes (***)

Date 03-07-2006 23:40

Cryogen,

If you look at 341.4.1 under "other examination" it says that "In process examination in accordance with para. 344.7 may be substituted for all or part of the radiographic or ultrasonic examination on a weld for weld basis if specified in the engineering design or specifically authorized by the inspector." Then if you look at 344.7 it tells you what type of in-process inspection you need to do to meet 341.4.1.

Hope that helps
Jim