Table 3-2.Computations and Measurement for a Y Connection.
Figure 3-55.True Y.
LAYOUT OF A TRUE Y
In laying out pipe for the fabrication of a true Y
without the use of templates or tables, a full-sized
drawing of the intersection (fig. 3-55) should be made.
he intersection of the center lines of the three pipes
will locate point B, and lines from B to the
intersections of the pipe walls will locate points A, C,
and D. From these points the pipe maybe marked for
cutting. Miter cutting, followed by suitable beveling,
is necessary in preparing the pipe for welding.
TEMPLATE LAYOUT FOR
TRUE Y BRANCHES
AND MAIN LINES
Inlaying out a template for a true Y, a drawing of
the intersection should be made, as shown in figure
3-56, view A. After drawing the lines of intersection,
the same essential methods as for other templates
are followed. Note that here it is suggested the
equally divided semicircumferences are more
conveniently placed directly on the base line. The
distances from the base line to the line of
intersection plotted on the unwrapped base line
determine the template.
ORANGE PEEL HEAD
A number of different types of heads are used in
welded pipe construction. Here, we are interested in
one general type, the ORANGE PEEL, since it will
often concern you in your work. A main advantage of
the orange peel is that it has high strength in resisting
If templates or tables are not available for making
an orange peel head, a reasonably accurate marking
can be secured by the following procedure for laying
out a template.
The number of arms to make an orange peel head
should be the minimum number which can be easily
bent over to form the head. Five arms and welds are
the recommended minimum for any pipe; this
number should be increased for larger sizes of pipe.
Dividing the circumference by 5 is a good method
for deciding the number of arms, provided, there are
at least 5.
To lay out the template, draw the side and end
views (fig. 3-57). Divide the pipe circumference in
view B into the same number of equal parts as it is
planned to have welds, and draw the radial lines o-a,
o-b, and so on. Project the points a, b, and so on, in