Shop Drawing

Er, if it can be assembled in the shop, weld it in the shop. Otherwise it's a field joint.

"Simples!ξ"

"Is there any standard that explain when we must shop of field a joint?"

In addition to PW's good common sense answer, the project specifications (if applicable) should call out any restrictions or limitations regarding shop vs field fabrication.

thank you for your respond what is PWS ?

The "PW's" in the comment "In addition to PW's good common sense answer..." is a shorthand version of the name of poster #1, PWSlack.

What indeed.

jafary64,

You have two questions:

1. I want to joint numbering or shop drawing an isometric. I am not sure what you are asking here. Could you please explain this in more detail?

2. Is there any standard that explains when we must shop weld or field weld a joint?

There is no a "Standard" that explains when we must shop weld or field weld a joint. However there are "reasons" commonly accepted for doing one or the other. Below is a question on the same subject I received on another forum along with my answer.

Shop versus Field Fabrication

The Question:

In piping isometrics, in general practice, what is the size boundary for shop material and field material? Shop fabrication as. Field fabrication?

My answer:

Over the past fifty or more years the most common answer to this has been:

· 3" and larger (Butt Weld) piping is Shop Fabricated

· 2 1/2" and smaller (Socket-welded & Screwed) piping is Field Fabricated

· All assembly material (valves, bolts, gaskets, etc.) is Field material

However, this is not an answer that fits all situations. These situations might include:

· There have been projects where considerations such as exotic material and the required special welding process force the shop fabrication of all sizes.

· There have been projects where all piping was shop fabricated because there is no space available at the job site to receive, store or fabricate piping of any size.

· There have been projects where local Union agreements forced different size breaks for Shop versus Field

· There have been projects where the plant location (Arctic or desert) will cause different decisions for shop versus field

· There have been projects where the location and local economy has provided the availability of vast number of high quality trainable labor resources to be able to receive bulk piping material and Field fabricate all piping at the job site

The bottom line on this subject is there is the Rule and then there are the Exceptions. Each project needs to carefully consider all the issues for their project and make the right choice for that specific project.

If you are assembling it in the shop (in house) to be sent as completed its a standard weld. If you are shipping parts separately to be welded on site then it is a field weld regardless if your company or another is doing the welding on the job site. If you do only drawings then you have to know if the company you are sending the drawings to will be making and assembling the parts will be doing all the welding (standard weld symbols) or if they will send some parts separately to be welded in the field (field weld symbols).

Do you mean you want to catalog or assign a number to the drawings, including isometrics?

Drawings would/should state whether the joint is done in the field or at the shop.

buy an "asic" manuel from amazon.com. about $75.00. it should give you the the information you need and much more.

i mis-understood the question. disreguard my comment.

Hi

have not came across any such standard, usually my company follow the below mention procedure.

1. The very first is dwg. the joint numbers on the isometric starting from the very first joint and leaving the very last joint on an isometric dwg. to avoid the repetition of the joint no's.

2. We have three different symbols;

a. a rectangular box 6mmx20mm = for spool pieces.

b. a circle of 10 mm dia divided in two equal halfs or 14 mm dia.

b.1. upper half contains the joint abbreviation like FW-Field weld, FFW-Free field weld, SW- Shop weld, BW-Butt weld, SOC-Socket weld, BR-Branch weld, RP-Reinforcement pad weld or THD-Threaded joint.

b.2. The lower half contains the joint no. like 1,2,3,4.......

3. For spool no. you need to know your pipe lengths ( get it from purchasing dept. - 6 mtrs or 12 mtrs length per pc from the supplier).

4. Your weld map is then submitted to QA/QC Dept. for feeding all the info. in to their WELD SUMMARY SHEET.

5. Weld summary sheet contains different sections like : Pipe dia, thk., material, heat no. WPS no. , Process (GTAW,SMAW, ETC.),Fit up inspection date, Weld (root/cap), visual inspection, NDT Record, and so on. for troubleshooting the problem if caused in future. All the details relating to one single joint is maintained, even the welder name and his/her ID no.

Note: for pipe size 2" and below : all shop fitted.

2" to 4" : length of the pipe must be 100 mm more for site

adjustment.

6" to 12" : length of the pipe must be 150 mm more for site

adjustment.

Hope this will give you an idea...

When I was in training to be a piping designer in the 70's, We were instructed that our shop spools (isometrics) were to be design to fit the shipping container. Each job had a designed method for shipping to site. Wheather a truck bed, rail car, barge, etc. We were given the max dimensions in a project book. When drawing our spools, and reached the maximum shipping constraints, we would add the field weld (FW) symbol to the nearest welding location, within the box. Second spool would continue from that FW. Each spool would get a piece mark number, with line number and a numeric value starting at one, for identifying spools for erection in field. This was our basic method.

Experienced designers would also add FWs at spec changes, line number changes, and change of construction types. With experience, (welders yelling, field notices, etc...) a designer would learn to look at the field weld and the assemblies to make sure a field weld was convienent.

Welders yelling? That never happens what do you mean you can't make that weld on a piece of 24" that sets off the wall 4".

I have two uncles who are fitters. Maybe they just yell cause there uncles.

I am not a welder, but, I have had them call me out to the field and asked how I would do the field weld. It would look sooooo good on the computer. You gotta learn some how.

Amen, I am also a pipe welder who later became a pipe detailer and I also, at times lose prospective on field weld locations.

In can make a big difference in weld time, if your not having to contort, use a mirror, monkey hood or bend rods.

One of the best designers I have work with was an ex-fitter from Califorina who worked on the oil platforms. He had great insite, when it came to layouts.