You may have already guessed it – measuring pipework is not as simple as it sounds. This article will give you some pointers to help you get started. This article discusses the dimensions, methods, variations and reliability of the methods. By the time you’re done reading this article, you should have a general idea of how to measure pipework correctly. But before you go any further, remember to refer to our tips to make your measurements accurate and reliable.
Dimensions
For pipework that has an inside diameter of 50 mm to 100 mm, the outside diameter must be thirty to fifty millimeters smaller than the inner diameter. For smaller pipework, the distance between the outside edges of the cups must be thirty to fifty millimeters smaller than the inner diameter. The same goes for larger pipework. Similarly, pipework that is 25 to 30 mm in diameter must have a length of thirty to thirty-five millimeters greater than the outer diameter of the pipe.
Pipe dimensions are also different based on the pipe material and schedule. Pipes with the same nominal size may not be available in a different material. For example, NPS 6 pipe, Sch. STD, will be slightly bigger than the Sch. XXS. Similarly, NPS 8 pipe, Sch. LSX pipe, and other pipes with the same nominal size and wall thickness are available in different materials.
Outside diameters are also known as nominal diameters. The outside diameter of a pipe is equal to its inner diameter if the wall thickness of the pipe is thin enough. In most cases, pipe wall thickness is the limiting factor when choosing a pipe size. The size of the inner diameter of a pipe is called the internal diameter. Pipe walls are typically thinner than DN50, and the nominal diameter is the average of both.
Pipes with different nominal diameters are called nominal bores. Although this measurement is not exact, it is close to it. For instance, a pipe with a two-inch outer diameter will have a nominal bore of fifty eight millimeters. This is the most common pipe size used for plumbing and heating applications. And pipe sizes are also commonly standardized. However, the nominal bore is not the same as the actual size, so it’s important to make sure you get the right one.
Methods
The different types of measurement methods used for pipework have different benefits. They vary in the degree of accuracy they provide and their usefulness for different purposes. For example, a tangential measurement, which measures the diameter of a pipe, can help to measure the wall thickness. The common mistake that many people make when using this measurement technique is assuming that the amount of material that has been penetrated equals the thickness of the pipe. For example, a 3mm pipe has to penetrate 6mm steel to reach the inner wall thickness. This is not the case as the inner wall thickness is much higher than the outer wall thickness.
Another method for measuring pipework involves using an arbitrary coordinate system. To do this, a total station is set below a circular pipe. The pipe is scanned until the end of the string overlaps with the OD of the pipe. By calculating these coordinates, the length can be calculated. In some cases, it is also necessary to determine the elevation value of endpoint one. If these two measurements are not possible, the height accuracy of the pipe can still be determined accurately.
In addition to the angular measurement, there are other measurements that can be made for pipework. These include linear and angular measurements. Linear measurements are more accurate than angular measurements, and they can account for non-zero dimensions. In addition to linear measurements, a lateral measurement can also account for the dimensions of pipe joints. In general, lateral measurements are useful for connecting two vertical pipes. For example, a vertical pipe is connected with a horizontal pipe through selected pipe joints.
Variations
There are a number of variations in pipework and their corresponding sizing requirements. For most piping applications, these are unimportant. However, in pipelines that transport corrosive materials or other liquids, such as fuel oil, these measurements are essential. Moreover, the pipelines are often placed in remote locations, where they are subjected to high atmospheric pressures. To meet these requirements, the pipework has to be accurately sized.
The method proposed by the authors involves estimating the vibration stress of pipework by comparing the displacements at four points: A, B, and C. This is known as the root section vibration stress. Using the displacements measured by the four contactless displacement sensors, the authors can estimate the vibration stress of piping at the root section. Then, they can calculate the vibration stress at the root section directly. To do this, they first calculate the R of the pipe at four different points, A, B, and C, and then calculate the average of the four displacements.
For many pipes, the outside diameter, or OD, is the most commonly used measurement. However, even with this measurement, the pipe is never exact to its nominal value. The differences between the two measurements depend on the manufacturing process. The OD of the pipe corresponds to the outside diameter. The OD of a pipe is usually measured in inches, though sometimes a pipe’s inner diameter is smaller than the nominal size.
For most pipelines, the end of the pipe is never perfectly round. Nevertheless, the human eye cannot discern these variations. Consequently, the pipe end is measured with a special tool designed to record the wall thickness all around the pipe. This tool can match the pipe end with the next one, thus achieving a high-low measurement. This tool is available in many varieties. In addition to the end measurement, there are other variations in pipework measurements.
Reliability
When measuring pipework, accuracy and precision is vital. The latest technology can accurately record up to 1,000 measurements at one end of a pipe and create a point cloud of the pipe geometry. Once collected, this data can be processed using special software dedicated to measuring pipework. Accurate dimensional analysis of pipework is especially useful in situations where accurate pipe alignment is crucial, such as deep water pipelines. The following are some of the benefits of measuring pipework accurately and precisely.
AGT800 Laser Pipe & Pole Measuring System – The AGT800 Measuring System uses two non-contact laser sensors. Each sensor emits a Class II laser beam, which calculates the material thickness and calibrates based on the measurements. This system also saves users time and effort by reducing the need for large files of paper for record-keeping. The AGT800 is designed to quickly and accurately measure the wall thickness of pipe and pole.
The DDM Method – With DDM, the process can be easily automated and will yield better results than existing methods. It is based on the nonlinear maximum flow model, which calculates the maximum amount of water a pipeline can supply given potential link failures. The method provides symmetric designs, wherein pipe size increases are proportional to increase reliability. This method is also suited for measuring high-volume pipework.
Non-destructive Inspection – The importance of non-destructive inspection methods cannot be stressed enough. In fact, reliability evaluation is an essential step of non-destructive inspection. The reliability metric used is the probability of detection. The threshold and thickness are modeled using a cumulative log-normal distribution function. The electromagnetic acoustic transducer method is the most popular of the three non-destructive inspection techniques.
Cost
A powerful and accurate pipe-measuring tool can make a huge difference in the economics of a pipe manufacturing company. The system can pay for itself within a year of installation – or sooner, depending on the current raw material price. A powerful measurement tool helps processors run close to their required wall thickness range and achieve 100% compliance with regulations. Ultimately, this results in significant material savings and increased output. Here are three reasons why pipe manufacturers should consider investing in such a system.
Lack of standardization. Pipe dimensions differ across the world. In the US, pipe dimensions are quoted in feet, while in Europe, they are expressed in inches. In 1999, NASA lost $125 million on the Mars Climate Orbiter project when a faulty pipe measurement caused the lander to disintegrate. Standardizing dimensional terminology would help prevent misunderstandings, and ensure consistency in pipeline construction. It would also reduce the amount of pipe that needs to be installed.
The accuracy of measurement data is essential. With the help of a pipe-measuring tool, a company can guarantee accurate measurements. The cost of using a tool varies, depending on the type of pipe and its size. Some tools are inexpensive, while others can be expensive. Many of them offer guaranteed accuracy, higher repeatability, and improved precision. In addition to accuracy, these tools use new and innovative technology to provide better measurement results.
A flexible measuring tape is useful for this purpose. It measures the outside diameter of the pipe. If a pipe has no internal measurement, you can measure its outside diameter using a string. The string is stretched between two strings. The measurement is then used to determine the Nominal pipe size. Once you have the nominal pipe size, you can proceed with the rest of the pipe-laying process. The process is expensive if you are unable to identify problematic welds.