chapter piping spool

8/10/2019 chapter piping spool

1/21

Chapter 9


2/21

A spool or isometric spool drawing :

An assembly of pipe and fittings

The last in a series of drawings made of pipe & fittings before physicalassembly (welding, threadingetc) begins

Contains a bill of materials required to assemble the spool.

simple drawing

Spools are often done by the contractor, in cases where your companydoes construction for outside companies, this means YOU will be doingthe spools for assembly on-site or in a shop and then transported to theplant location.


3/21

There are two basic methods used to illustrate pipe spools:

Double line

Single line

Easiest to interpret because theyclosely resemble the actual appearanceof the pipe

Basically double line piping drawings

Notice the orthographic layout at rightused for double line spools

Notice the use of centerlines andhidden lines


4/21

Require some visualization skills

Centerline becomes the pipe & isdrawn as a thick line

Centerline extensions are shown atelbows & flanges

Elbows can be shown as eitherradius (upper drawing) or square (seelower right). This will be dependent oncompany standards.

As in Double Line, use only numberof views needed to fully describe theassembly.

Elbow usingradius

Squared elbow


5/21

There is a third type of spool drawings that some companies use:

Pipe is drawn single line

Fittings are shown double line


6/21

There are a couple of ways to dimensionspools and no matter which method is used,

its ALWAYS important to know the exactlengths of pipe and the locations of anybranches on that pipe

THESE ARE CRITICAL!

Guidelines for Dimensioning Spools:

Provide overall lengths of the spool

Dimension to each branch fitting inthe spool

Dimension each straight run of pipe Two or more fittings that are welded

or joined are termed fitting -to- fitting(FTF) and their overall length shouldbe dimensioned if no straight length ofpipe is involved

The shortest dimensions should beplaced closest to the pipe and overalldimensions should be farthest fromthe pipe


7/21

Used by many companies to illustrate the entire spool in a singleisometric view.

Easier for pipefitters and welders to understand than orthographicdrawings or the flat spools.

Represents clearer picture of the actual assembly of pipe and fittings

Isometric Drawing is not drawn to scale

Fully dimensioned and contains complete bill of materials

Some companies use a specialized software to create isometric spoolsand require only data entry. This software can generate a notated isometricdrawing, a bill of materials and a travelers list.

FYI: Travelers list: history of each weld and who made it.

In this class, we will use isometric spools for detailingpipe and fittings.


8/21

Type of three-dimensional drawing

Developed using the three primarydimensions of an object: height,width and depth

Combines the three dimensionsinto a single view to provide a

pictorial representation Must be drawn on axes that

measure 30 from the horizontalplane


9/21

Notice how ALL views of the pipe are used in determining theisometric drawing.


10/21

Its the primary source for materialtake-off

It provides a detailed description ofthe pipes routing and configuration,

from beginning to endThis is done byusing the drawing symbols, callouts,coordinates & elevations provided onthe piping arrangement drawing

Most companies prefer to drawpiping isometrics with the north arrowpointing up and to the right. NEVER show the north arrow pointing down!

Plan View

Isometric View


11/21

Length dimensions and informational notesor callouts are used on isometrics to definethe pipes exact routing through the facility.

The placement of dimensions on thedrawing establishes precise lengthsbetween fitting, valves, equipmentconnectionsetc.

Information such as coordinates,elevations, nozzle projection, pipe size andpound ratings are used to calculate lengthsof a run of pipe.

Dimensions are placed on isometrics thatindicate center-to-center, center-to-faceand face-to-face measurements


12/21

Dimensions cant provide all the information required to describe a

piping isometric. Any information thats pertinent to a piece of pipeMUST BE conveyed on the isometric.

Notes and callouts are used to add significant information:

Notes:

Denote pipe size and pound rating of fittings, flanges and valves

Specify insulation type and thickness, locations for pipe guides,anchors or supports

Also used to specify information on offset angles

Callouts:

stipulate instrumentation locations

stipulate size

stipulate specification breaks

stipulate fabrication details


13/21

At times the amount or size of the pipe that will be shown on a spool isdependent on how big a piece of pipe the contractor can move suchas, is it going to be moved to the site via a train boxcar or is it going inthe back of a truck?

If you know the size of the truck or railcar, you can calculate the spoolsize from the isometric drawing

Things to keep in mind when drawing spools:

Valves are often not shown in spooldrawings check your companystandards in this class you willinclude valves in spool drawings.

Spools end at a flange or field weld

Show NORTH on a spool drawingunless otherwise specified by yourcompany

Draw an orthographic spool with asingle view that shows all straightlengths of pipe and all fittings

If a straight run of pipe in anorthographic spool drawing doesntshow in your principal view, show it in apartial orthographic viewand alwaysproject this view 90 from the main one

When making an isometric spool,choose the view that shows the leastnumber of line crossings


14/21

1. Spools are often drawn not -to- scale

2. All straight lengths of pipe are shown in proportion to one another

3. Some companies prefer NOT using scale on spools and rely totally on

written dimensions (that means those written dimensions need to be correct& accurate!), other companies want spools drawn at a certain scale

4. Whether NO SCALE or TO SCALE, the written dimensions are the MOSTimportant part of the spool and they MUST be accurate.

In instances where installation is not on -site, spools MUST be tagged.

This means that each individual spool piece is given an identification numberor MARK.

The marking or tagging method is determined by the company standards.

Typically this mark or tag is the pipe specification (like A15) plus a numberor letter to identify the spool.

The marks or tag numbers usually show up first on the isometric drawing.


15/21

B.O.M.

Material list of the spool drawing

Contains vital statistics of all components needed to construct thespool

On some CAD systems, all of the pipe and fittings are automaticallytabulated as you draw and the BOM is generated by the computer withoutyou having to do any of the calculations.


16/21

serve to identify a piece of

pipe or a fitting on the spooldrawing and associate it to adescription in the B.O.M.

Item number is foundinside a circle on the drawing

with a leader line pointing tothe part

The same number appearsin the bill of materials thatalso contains a detaileddescription of the part

Item numbers should be aligned when possible to create use a guidelinewhen possible to locate all the item symbols on


17/21

In fo rm ation g rou p ing : an ordered arrangement or aligning of any type oftext or symbols on a drawing

Main thing to remember when making ANYdrawing is that it has to be interpreted by otherpeople.

In the case of spools, a pipefitter will be following yourgraphic and written instructions to build the pipeassembly.

The assembly of pipe and fittings will be easier IFyour graphic and written instructions are easy to read

and convenient to find on the drawing.


18/21

technical description of the pipe or fitting containing any codes,ratings and specifications required for the accurate identificationof the component

information in a material description may be used by pipefitters,

purchasing agents and cost estimatorsCommon method is to show pipe (lowest schedule number and

smallest diameter first), then common fitting, followed by flangesand finally, odd fittings

Make sure the information in the bill of materials iscompletefollow the guidelines set forth by your company


19/21

Spool drawings are some of the least complex in process pipe drafting

Spool drawings can be the MOST important as far as accurateinterpretation is concerned.

Never measure spool drawings as they are seldom drawn to scale ALWAYS read the dimensions shown on spool drawingssome spools

arent always drawn proportionally so may be deceptive in theirrepresentationREAD the DIMENSIONS, dont rely on just the drawing!

ALWAYS check the squaring-in lines and planes for correctinterpretation of the direction of odd-angle bends.

Read ad check the items in the bill of materials especially quantitiesand material descriptions

Check the pipe dimensions on the drawing with corresponding pipelengths in the bill of materials


20/21

Thanks for viewing this Tutorial.

Any questions, comments or complaints can be registered at the nextclass meeting, via email or drop by my office.

Email: [email protected]


21/21

Parisher, Roy A. & Robert A. Rhea. 2002. Pipe Drafting and Design. 2 nd Ed. Gulf Professional Publishing_Butterworth-Heinermann.

Shumaker, Terence M. 2004. Process Pipe Drafting. The Goodheart-Willcox Company, Inc. Tinley Park, Illinois.

chapter piping spool

Documents

Transcript of chapter piping spool