Applies To
	Product:	AutoPIPE
	First Affected Version:	08.09.00
	Found in Version:	09.02.01.07
	Fixed and Released in Version:	09.03.00.08
	Area:	Calculations
	Severity:	Critical
	Backlog Issue Number:	135799 (8737)

Problem Description

Transition weld SIF uses thickness at plus side of the joint

Reason

The tapered transition weld SIF uses the pipe thickness downstream of the transition (or on the plus side of the point along the segment). If the upstream pipe thickness is smaller, the SIF value will be un-conservative.

The SIF is calculated as follows:

    SIF = 1.3 + 0.0036*Do/tn + 3.6* offset/tn  <= 1.9

Where Do and tn and the pipe outside diameter and nominal thickness respectively and offset is weld offset or mismatch.

For later ASME NC/ND code years (1992 and later)  the offset term is removed.

The following codes are affected for version 9.0 or earlier:

ASME NC/ND codes (all code years)

The following codes are affected for version 9.2.1.7 or earlier

ASME B31.1 (all code years except 1969)

ASME B31.8 and B31.8 offshore Codes

JSME Code

Swedish Code

TBK 5-6 Code

French RCC-M Code

European EN 13480 Code

Japanese MITI Code

The following considerations are provided below to assist in your evaluation of the potential impact of this defect on the results.

1. Evaluate whether this defect has affected any existing models by considering the criteria below:

a.  Is the piping code used listed above?

b.  Does the model have a transition weld (entered as Xtra Data at a point or as a joint end type on a valve)?

c.  Does the pipe wall thickness change and that the upstream thickness is smaller?

d.  Is the SIF less than 1.9

A ‘No’ to any of the above criteria means that this defect does not affect the model’s results.  No further consideration for this model is necessary.

Otherwise, some possible mitigating conditions described below should be considered when evaluating the impact of this defect on the results.

2.  Evaluate possible mitigating conditions on the impact of this defect on the results.

a. Transition weld entered as a weld connection on a flange is not affected

b.  ASME NB/NC and ND codes are not affected for versions 9.1 and 9.2 

Solution:

Use the pipe side with minimum thickness when evaluating the transition weld SIF.

Additionally, to assist in the screening of the models created in previous program versions for any potential impact by this defect, the program shall automatically examine the model database after opening the model and generate a report (model name + "_8737.TXT") listing the affected points. 

Avoidance:

Reverse the pipe segment so that lower thickness is on the plus side of the point. Alternatively delete the Xtra data and enter a zero weight flange with a transition weld connection 

Also See:

Critical and High issues released in AutoPIPE V8i v.09.03..