API 1104 21st edition, Essential Variables

[joerg12]

Hello i have two questions concerning essential variables within API 1104, 21st edition Sep 2013:

1st question:
As per 5.4.2.1 a change in the welding process or method of application has to be considered
as an essential variable.

What does method of application mean?
Only a change from manual to automatic or semiautomatic,
or as well the type of beads e.g. stringer, weaver?



2nd question:
As per 5.4.2.3 a major change in joint design has to be considered as an essential variable.
Further, minor changes in the angle of bevel or the land of the welding groove are not essential variables.

A PQR indicates a butt weld with a landing/root face of 2mm.
Now, I want to establish a WPS indicating a butt joint without a landing/root face, has this to
be considered as a major change in the joint design?


Thank you for your help

Joerg

 

[SectionIX]

Joerg,

PRCI publishes the "Guidelines for Interpretation and Application of API 1104 – Twenty-first Edition" (Catalog No. PR-186-124502-R01)from which responses follow:

1st question:
As per 5.4.2.1 a change in the welding process or method of application has to be considered as an essential variable. What does method of application mean?

Reply:
Eight possible welding processes are listed in Section 1 (of API 1104) . Welding methods (or methods of application) include manual, semiautomatic, mechanized, or automatic, and combinations of these methods. Not all welding methods are applicable to all welding processes.
Two PQRs written for tests on welds made using different welding processes cannot be used to support a new WPS that includes the use of multiple welding processes. Qualification of two different welds made using different processes does not demonstrate that the combination of processes will produce welds having acceptable properties.

2nd question
As per 5.4.2.3 a major change in joint design has to be considered as an essential variable. What is considered a major change?

Reply:

API 1104 does not define what constitutes a minor change in joint design. It would seem reasonable to
allow changes to the bevel angle of up to +20%/-5% of the nominal value and changes to the root
opening or land of up to +/- 50% of the nominal value without the need for requalification.


In your case, removing the land face would be considered to be a major change using the above criteria.

 

[joerg12]

Thank's SectionIX

All Questions have been answered.

Thank you a lot!

No i have some grammar question, since i am German, i have some difficulties
in the easy english grammar.

Typing up a General Welding Procedure.

I say:
The company shall supply data to the contractor, about the standard and area what welding code
shall be applicable.

Would you understand?
(cross country/process piping/location class, API 1104 or ASME IX).

P.s. forgot the standard where i can find the location classes.
If you can give me a hand?
I left Northern Africa 5 years ago, was never in touch with American standards since that.
Now time is changing, and opportunities comming up again.

The percentages you are talking about, i am quite sure i read similar data in a ASME or AWS standard.
A quick refernce would help me in the saddle again.


Greetings
Joerg

 

[SectionIX]

Hi Joerg,

I personally always reference the relevant code so there is no misunderstanding. Also, as a point of information, the 21st Edition of API 1104 has not been incorporated by reference by the U.S. regulator; the 20th Edition is still relevant in the United States.


As far as Class Locations is concerned, several ASME codes, such as Table 841.3.2-1 in ASME B31.8 make such reference, but class locations, for purposes of definition can be found in 49CFR Part 192. The link and excerpt are shown below.



[URL unfurl="true"]https://www.ecfr.gov/cgi-bin/text-idx?SID=d2122275c64ef04e3458fb7a76a8637e&mc=true&node=se49.3.192_15&rgn=div8[/url]

§192.5 Class locations.

(a) This section classifies pipeline locations for purposes of this part. The following criteria apply to classifications under this section.

(1) A “class location unit” is an onshore area that extends 220 yards (200 meters) on either side of the centerline of any continuous 1- mile (1.6 kilometers) length of pipeline.

(2) Each separate dwelling unit in a multiple dwelling unit building is counted as a separate building intended for human occupancy.

(b) Except as provided in paragraph (c) of this section, pipeline locations are classified as follows:

(1) A Class 1 location is:

(i) An offshore area; or

(ii) Any class location unit that has 10 or fewer buildings intended for human occupancy.

(2) A Class 2 location is any class location unit that has more than 10 but fewer than 46 buildings intended for human occupancy.

(3) A Class 3 location is:

(i) Any class location unit that has 46 or more buildings intended for human occupancy; or

(ii) An area where the pipeline lies within 100 yards (91 meters) of either a building or a small, well-defined outside area (such as a playground, recreation area, outdoor theater, or other place of public assembly) that is occupied by 20 or more persons on at least 5 days a week for 10 weeks in any 12-month period. (The days and weeks need not be consecutive.)

(4) A Class 4 location is any class location unit where buildings with four or more stories above ground are prevalent.

(c) The length of Class locations 2, 3, and 4 may be adjusted as follows:

(1) A Class 4 location ends 220 yards (200 meters) from the nearest building with four or more stories above ground.

(2) When a cluster of buildings intended for human occupancy requires a Class 2 or 3 location, the class location ends 220 yards (200 meters) from the nearest building in the cluster.

 

[SectionIX]

To add to the above, with respect to NDE, the following is also relevant:

[URL unfurl="true"]https://www.ecfr.gov/cgi-bin/text-idx?SID=d2122275c64ef04e3458fb7a76a8637e&mc=true&node=se49.3.192_1243&rgn=div8[/url]

192.243 Nondestructive testing.

(a) Nondestructive testing of welds must be performed by any process, other than trepanning, that will clearly indicate defects that may affect the integrity of the weld.

(b) Nondestructive testing of welds must be performed:

(1) In accordance with written procedures; and

(2) By persons who have been trained and qualified in the established procedures and with the equipment employed in testing.

(c) Procedures must be established for the proper interpretation of each nondestructive test of a weld to ensure the acceptability of the weld under §192.241(c).

(d) When nondestructive testing is required under §192.241(b), the following percentages of each day's field butt welds, selected at random by the operator, must be nondestructively tested over their entire circumference:

(1) In Class 1 locations, except offshore, at least 10 percent.

(2) In Class 2 locations, at least 15 percent.

(3) In Class 3 and Class 4 locations, at crossings of major or navigable rivers, offshore, and within railroad or public highway rights-of-way, including tunnels, bridges, and overhead road crossings, 100 percent unless impracticable, in which case at least 90 percent. Nondestructive testing must be impracticable for each girth weld not tested.

(4) At pipeline tie-ins, including tie-ins of replacement sections, 100 percent.

(e) Except for a welder or welding operator whose work is isolated from the principal welding activity, a sample of each welder or welding operator's work for each day must be nondestructively tested, when nondestructive testing is required under §192.241(b).

(f) When nondestructive testing is required under §192.241(b), each operator must retain, for the life of the pipeline, a record showing by milepost, engineering station, or by geographic feature, the number of girth welds made, the number nondestructively tested, the number rejected, and the disposition of the rejects.