CONSTRUCTION BLUEPRINT READING
ALPHABET OF LINES
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CONSTRUCTION BLUEPRINT READING
Drawings contain many types of drafting lines.
The basic straight line as seen in this slide can be
emphasized by the weight of the line, these lines are
called object lines.
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CONSTRUCTION BLUEPRINT READING
Object lines are used to show the shape of an object and all
visible edges are represented with object lines.
To specify the meaning of each type of line, contrasting lines
can be made by varying the width of the lines or breaking the
lines in a uniform way.
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CONSTRUCTION BLUEPRINT READING
Unfortunately there
is still a lot of
variation on how
lines are used.
You will need to
check the legend
for an explanation
on how the object
lines are used.
THIS BIRD’S EYE VIEW IS DRAWN
WITH MOSTLY OBJECT LINES
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CONSTRUCTION BLUEPRINT READING
The light full line is used for section lines and
building backgrounds.
The medium full line is used for lettering, symbols
and circuit lines.
The heavy full line is used for borders around title
blocks, schedules and some symbols.
The extra heavy full line is used for the border line to
establish the drawing area.
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CONSTRUCTION BLUEPRINT READING
The importance of recognizing how lines are used,
especially solid lines is the difference between block
walls and sheet rock walls or a fire wall as opposed
to a regular wall.
As a technician determining cable pathways you will
need to know what type of wall you will be
penetrating and what additional material and tools it
will require.
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CONSTRUCTION BLUEPRINT READING
The lines below are fairly consistent from one
architectural firm to another, obviously the solid lines
are also used by all architects however the way they
weight them and how they’re applied on the
drawings may vary slightly.
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CONSTRUCTION BLUEPRINT READING
The long break line is used for long breaks.
The hidden line shows the edges of objects that are
not visible in a particular view.
The match line is used to show the position of the
cutting pane, it is used on drawings of large
structures to show where one drawing stops and the
next drawing starts.
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CONSTRUCTION BLUEPRINT READING
Dimension lines vary considerably from one set of
blue prints to another, however all dimension lines
will have a number associated with them to indicate
footages.
DIMENSION LINES
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CONSTRUCTION BLUEPRINT READING
Three more lines that are regularly used are the
center line, the property line and the secondary line.
The property line is very similar to the match line
however the property line is usually a lighter weight
line.
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CONSTRUCTION BLUEPRINT READING
The center line indicates the center of objects such as
holes, pillars or fixtures.
The property line indicates land boundaries on the
site plan.
The secondary line is used to outline pieces of
equipment or to indicate reference points that are
secondary to the drawing’s purpose.
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CONSTRUCTION BLUEPRINT READING
In this drawing the blue dashed line is the hidden line
indicating the concrete footing, dimensions are shown and are
displayed on the outside of the drawing and center lines are
used in conjunction with the symbol
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CONSTRUCTION BLUEPRINT READING
In this floor plan the right side is missing and a break
line is present.
LONG BREAK LINE
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CONSTRUCTION BLUEPRINT READING
Some others lines that are used but haven’t been
noted are the extension line and the leader line.
EXTENSION LINES ARE
USED WITH DIMENSION
LINES.
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LEADER LINES TIE A
GENERAL NOTE TO A
SPECIFIC AREA ON THE
PRINT OR MAY BE USED
TO SHOW WHERE A
DIMENSION BEGINS.
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CONSTRUCTION BLUEPRINT READING
Along with all of the different lines there are
blueprint symbols that you need to be familiar with.
These symbols are call outs;
Section cuts/details
General notes
Clouds
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CONSTRUCTION BLUEPRINT READING
The section cuts or details are noted on the prints to
direct you to another set of drawings.
One of two symbols are used (they both mean the
same thing), in this case the one with the triangle
indicates a detail drawing on page E-11, drawing
number 5.
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CONSTRUCTION BLUEPRINT READING
Grounding busbar details;
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CONSTRUCTION BLUEPRINT READING
Here is an example of a stair detail;
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CONSTRUCTION BLUEPRINT READING
Detail drawings may show you how to set up the TC with the
specific placement of the plywood and racks,.
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CONSTRUCTION BLUEPRINT READING
General notes are
present on the drawings
your working with and
there can be as many as
twelve or more notes on
one page.
THE CLOUD IS PREFACED WITH A 1 IN
A TRIANGLE AND THE KEYED NOTES
ARE CIRCLES WITH NUMBERS
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CONSTRUCTION BLUEPRINT READING
General notes provide additional information that can
not be represented on the drawings.
Some examples are conduit sizes, pull box sizes,
mounting heights etc., sometimes they will use the
abbreviation typ (typical) which means do the same
thing you’ve been doing throughout the project.
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CONSTRUCTION BLUEPRINT READING
Pay close attention to the clouds as they are a
change or special condition that is not typical,
there will usually be a general note associated
with the cloud.
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