Pipe Fitters MATH

Pipefitters Primer Chapter 6 Pipefitter Trade Math Section 3 Geometric Calculations

Geometry involves the study of shapes, it is used for calculating the lengths, surface area, and volume. In some cases Geometry is used for calculating the measure of angles but some angle calculations require the use of Trigonometry. Trigonometry will be covered separately from Geometry. Due to the fact that I am not a true mathematician I may mistakenly list aspects of Trigonometry as Geometry or vice versa. In my perception Trigonometry is the area of mathematics that deals with Trigonometric ratios. A review of some basic Geometric Formulas and Terminology Squares

Pipefitters do not make much use of squares but it is very common in some other areas of construction work especially cost & material estimations. It is also helpful for Pipefitters to remember that if you divide a square in half from one upper corner to the opposite lower corner, you will have two 45,45.90 triangles. Knowing this gives us some methods of verifing a true 90° angle. Such methods will be covered in future chapters. Circles

An example of an arc length calculation in Pipefitting

Suppose that you are assigned to install a nozzle on a tank. The center point for one nozzle has been located already but you must locate the center point for the other. We begin by calculating the circumference of the tank. Circumference = diameter * π Note: The exact value of PI can not be calculated it is a decimal value with no known end. The more decimal places you use the greater the accuracy. To the 10th decimal place π = 3.1415926536 (this is rounded up from 3.0141592653586...) Our diameter = 15' so the circumference = 15' * 3.1415926536 = 47.123889804 Using my feet, inches & fraction calculator I get 47' 1 1/2" (47 feet 11/2inches) But let's verify this in order to assure that you know how if needed Converting 47.123889804 feet to inches and fraction 47.123889804 is already in terms of feet so, we begin by subtracting the 47 leaving us with 47 feet plus 0.123889804. Next we convert the decimal into terms of inches, to do this we multiply 0.123889804 by 12, giving us 1.486677648 or 1.486677648 inches, Our tape measures are not laid out for decimal numbers so we must convert 1.486677648 into a fraction with a denominator of 16, 8, 4, or 2. To do this we convert 0.486677648 into 16ths by multiplying 0.486677648 by 16, giving us 7.786...we round this off to 8 sixteenths. 8/16 = 1/2 if needed see the section on reducing fractions in section 2 of this chapter Back to the problem at hand The next step is to multiply our circumference by the ratio of the degree measure of our arc divided by 360 (the total number of degrees in our circumference). We have 27 degrees in our arch and 27 divided by 360 is 0.075 47' 11/2" * 0.075 = 3' 67/16" If we do this with a calculator that does not do fractions we get 47.12289 * 0.0755 = 3.53429 feet 0.53429 * 12 = 6.411501 inches and 0.411501 * 16 = 6.584013 16ths which rounds of to7/16 So the second nozzle will be 3' 67/16" from the first one. This Section is under construction