Formula for an Unequal 45-Degree Lateral

Page 114

Formula for an Unequal

45-Degree Lateral

Information Required: ODI of both sizes of

insulation

Step 1: Draw a horizontal line with a 45-

degree line intersecting that line.

Step 2: Draw a 90-degree lines down from

each end of the horizontal lines. Also draw a

90-dgree line to the end of the 45-degree

line.

Step 3: Using half the ODI of the large

insulation, draw a half circle at each end of

the horizontal line.

Step 4: Using half the ODI of the smaller

insulation draw a semi-circle at the end of

the 45-degree line

Step 5: Trisect the small semi-circle into

equal parts and draw parallel lines from all

trisected points to pints below the

horizontal line. Label as in figure 1.

Step 6: Using half the smaller ODI, draw

half-circles inside the larger ODI circles of

both ends of the drawing.

Step 7: Trisect the half-circles into equal

parts and draw lines at 90-degree vertically

to points on the large arcs and draw

horizontal lines.

Step 8: Draw the lines from the stem

portion of the fitting to corresponding

numbered lines of the body portion of the

fitting and mark the points where they

intersect. Connect all of those points.

Step 9: Draw a 90-degree line closer to the

body portion of the fitting to establish a

measuring line.

Step 10: Divide the circumference by 2 and

using the number of divisions of the small

semi-circle (in this case 4) do the stretch-

out for the stem of the fitting and label as

shown in figure 2.

Step 11: Take measurements from the

measuring line, to the intersecting points of

both body and stem lines and transfer to

the corresponding numbered lines on the

stretch-out. Connect all these points to

obtain half the fitting. Fro the other half

add for a lap allowance.

Step 12: For the hole cut-out take half the

circumference of the large insulation and

draw a measuring line as shown in figure 3.

Step 13: Take the distance between 1-2 on

the right side of figure 1 and transfer that

distance from the top horizontal line down.

Do the same for 2-3 & 3-4.

Step 14: Draw lines to connect

corresponding numbered points and label

as shown in figure 3.

Step 15: From the measuring line in figure 1

transfer both points 1 to the stretch-out. Do

the same for points 2, 3, and 4. Connect all

the points to obtain half the body portion of

the fitting. For the other half add for laps.