PIPING SPOOLS

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PIPING SPOOLS
Layout Construction
ISOMETRIC SPOOLS
Bill of Materials
Chapter 9
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• A spool or isometric spool drawing
• An assembly of pipe and fittings
• The last in a series of drawings made of pipe
  fittings before physical assembly (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 company does construction for outside
companies, this means YOU will be doing the
spools for assembly on-site or in a shop and then
transported to the plant location.
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Layout and Construction

• There are two basic methods used to illustrate
  pipe spools
• Double line
• Single line

Double Line Spools

• Easiest to interpret because they closely
  resemble the actual appearance of the pipe
• Basically double line piping drawings
• Notice the orthographic layout at right used for
  double line spools
• Notice the use of centerlines and hidden lines

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Single Line Spools

• Require some visualization skills
• Centerline becomes the pipe is drawn as a
  thick line
• Centerline extensions are shown at elbows
  flanges
• Elbows can be shown as either radius (upper
  drawing) or square (see lower right). This will
  be dependent on company standards.
• As in Double Line, use only number of views
  needed to fully describe the assembly.

Elbow using radius
Squared elbow
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There is a third type of spool drawings that
some companies use
Single-Double Spools

• Pipe is drawn single line
• Fittings are shown double line

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Dimensioning Spools
There are a couple of ways to dimension spools
and no matter which method is used, its ALWAYS
important to know the exact lengths of pipe and
the locations of any branches on that pipe THESE
ARE CRITICAL!
Guidelines for Dimensioning Spools

• Provide overall lengths of the spool
• Dimension to each branch fitting in the 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 should be dimensioned if no
  straight length of pipe is involved

• The shortest dimensions should be placed closest
  to the pipe and overall dimensions should be
  farthest from the pipe

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In this class, we will use isometric spools for
detailing pipe and fittings.
ISOMETRIC SPOOLS

• Used by many companies to illustrate the entire
  spool in a single isometric view.
• Easier for pipefitters and welders to understand
  than orthographic drawings 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 spools and require only data
  entry. This software can generate a notated
  isometric drawing, a bill of materials and a
  travelers list.

FYI Travelers list history of each weld and
who made it.
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WHAT is an ISOMETRIC SPOOL?

• Type of three-dimensional drawing
• Developed using the three primary dimensions of
  an object height, width and depth
• Combines the three dimensions into a single view
  to provide a pictorial representation
• Must be drawn on axes that measure 30 from the
  horizontal plane

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Notice how ALL views of the pipe are used in
determining the isometric drawing.
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WHAT is an ISOMETRIC SPOOL?

• Its the primary source for material take-off
• It provides a detailed description of the pipes
  routing and configuration, from beginning to
  endThis is done by using the drawing symbols,
  callouts, coordinates elevations provided on
  the piping arrangement drawing
• Most companies prefer to draw piping isometrics
  with the north arrow pointing up and to the
  right. NEVER show the north arrow pointing down!

Plan View
Isometric View
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ISOMETRIC SPOOL Dimensioning
Length dimensions and informational notes or
callouts are used on isometrics to define the
pipes exact routing through the facility. The
placement of dimensions on the drawing
establishes precise lengths between fitting,
valves, equipment connectionsetc. Information
such as coordinates, elevations, nozzle
projection, pipe size and pound ratings are used
to calculate lengths of a run of pipe. Dimensions
are placed on isometrics that indicate
center-to-center, center-to-face and face-to-face
measurements
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ISOMETRIC Notes and Callouts

• Dimensions cant provide all the information
  required to describe a piping isometric. Any
  information thats pertinent to a piece of pipe
  MUST 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

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Scales and size
At times the amount or size of the pipe that will
be shown on a spool is dependent on how big a
piece of pipe the contractor can move such as,
is it going to be moved to the site via a train
boxcar or is it going in the back of a truck? If
you know the size of the truck or railcar, you
can calculate the spool size from the isometric
drawing
Things to keep in mind when drawing spools

• Valves are often not shown in spool drawings
  check your company standards in this class you
  will include valves in spool drawings.
• Spools end at a flange or field weld
• Show NORTH on a spool drawing unless otherwise
  specified by your company
• Draw an orthographic spool with a single view
  that shows all straight lengths of pipe and all
  fittings

• If a straight run of pipe in an orthographic
  spool drawing doesnt show in your principal
  view, show it in a partial orthographic viewand
  always project this view 90 from the main one
• When making an isometric spool, choose the view
  that shows the least number of line crossings

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• Spools are often drawn not-to-scale
• All straight lengths of pipe are shown in
  proportion to one another
• 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
• Whether NO SCALE or TO SCALE, the written
  dimensions are the MOST important part of the
  spool and they MUST be accurate.

"Tagging" "Marking" Spools

• In instances where installation is not on-site,
  spools MUST be tagged.
• This means that each individual spool piece is
  given an identification number or 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 number or letter
  to identify the spool.
• The marks or tag numbers usually show up first on
  the isometric drawing.

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Bill of Materials

• B.O.M.
• Material list of the spool drawing
• Contains vital statistics of all components
  needed to construct the spool

On some CAD systems, all of the pipe and fittings
are automatically tabulated as you draw and the
BOM is generated by the computer without you
having to do any of the calculations.
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Item Numbers

• serve to identify a piece of pipe or a fitting
  on the spool drawing and associate it to a
  description in the B.O.M.
• Item number is found inside a circle on the
  drawing with a leader line pointing to the part
• The same number appears in the bill of materials
  that also contains a detailed description of the
  part

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

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Information grouping an ordered arrangement or
aligning of any type of text or symbols on a
drawing
Main thing to remember when making ANY drawing is
that it has to be interpreted by other people. In
the case of spools, a pipefitter will be
following your graphic and written instructions
to build the pipe assembly. The assembly of pipe
and fittings will be easier IF your graphic and
written instructions are easy to read and
convenient to find on the drawing.
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Material Description

• technical description of the pipe or fitting
  containing any codes, ratings and specifications
  required for the accurate identification of the
  component
• information in a material description may be
  used by pipefitters, purchasing agents and cost
  estimators
• Common method is to show pipe (lowest schedule
  number and smallest diameter first), then common
  fitting, followed by flanges and finally, odd
  fittings
• Make sure the information in the bill of
  materials is completefollow the guidelines set
  forth by your company

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Print Reading Techniques

• Spool drawings are some of the least complex in
  process pipe drafting
• Spool drawings can be the MOST important as far
  as accurate interpretation is concerned.

Points to remember when Reading a Spool

• 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 their
  representationREAD the DIMENSIONS, dont rely on
  just the drawing!
• ALWAYS check the squaring-in lines and planes
  for correct interpretation of the direction of
  odd-angle bends.
• Read ad check the items in the bill of
  materials especially quantities and material
  descriptions
• Check the pipe dimensions on the drawing with
  corresponding pipe lengths in the bill of
  materials

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Thanks for viewing this Tutorial. Any questions,
comments or complaints can be registered at the
next class meeting, via email or drop by my
office.
Email rstrube_at_mail.accd.edu
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REFERENCES
Parisher, Roy A. Robert A. Rhea. 2002. Pipe
Drafting and Design. 2nd Ed. Gulf Professional
Publishing_Butterworth-Heinermann.
Shumaker, Terence M. 2004. Process Pipe Drafting.
The Goodheart-Willcox Company, Inc. Tinley Park,
Illinois.