90 Deg elbow to Two 45 Deg elbows

[reddy3]

Hi,

Is it allowed to cut a 90deg elbow to two 45 degree elbows to use in oil refinery plant? If yes or no, kindly please guide me to the code which states it.
(Background: A client ordered a two 45deg elbows, we have 90deg elbows sitting in the shelf which matches its nps, sch and material spec.)

Thank You.

 

[XL83NL]

Technically, if you cut a 90 deg elbow into two 45 deg elbows, the fitting is no longer a B16.9 compliant fitting and needs further analysis per 304.7.2, see 304.2. (assuming B31.3 is your code of construction).
However, me personally, I dont see much problem with such practice, although I dont see much advantage of that vs using a B16.9 elbow. If I were the owner, Id have little trouble acceptiong it under most conditions.

 

[Dhurjati Sen]

Dear reddy3,

Hope we are talking about carbon steel. Suggest an extra NDT (i.e. LPI of the cut surface to detect surface cracks, if any) to convince the client.

Else procure 45 degree elbows ASAP.

Regards.

DHURJATI SEN

https://www.nace.org/people/dhurjatisen

 

[weldstan]

It has certainly been done before; however, the cut ends may not mate well with the pipe to which it will be attached. We have done it in the past to meet scheduling requirements with acceptance of the Owner.

 

The cut ends will mate to each other (obviously not your objective), but will almost certainly not conform to the dimensions stipulated for a weld end. In addition to what XL83NL stated.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[reddy3]

I thank the valuable time of each and every person who replied, It helped in connecting the dots in my knowledge.
When the 90 degree was cut the ends were out of roundness and slightly the outside diameter was out of tolerance and finally we ordered the 45 elbows.

@Dhurjati Sen-Thank you. It is a stainless steel elbow.

@XL83NL-Thank you. I shared the information provided to our client.

Kindly could you guys share your knowledge in case if the dimensions of cut elbows are within tolerances, what NDT tests would help in supporting the elbow to justify.




Thank you.