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Total Equivalent Length

iPhone / iPad
  • Utilities
  • Productivity
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Total Equivalent Length (TEL) is for engineers and piping designers alike to be able to take an isometric drawing, or walk down a pipe in the field, and easily input the number of fittings you see and translate them to an equivalent length of straight pipe. I've made it extremely easy to use while either walking down the line or checking an iso drawing. You can enter the full length of pipe using the key pad--or much easier--you can hit the "+" or "-" button to increase or decrease the value by 1. This goes for the piping or the fittings. For version 1, I simply have straight pipe (of course, L/D ratio is = 1), and several normal fittings, like tees, 90 degree elbows (ells), 45 degree bends, a gate valve, pipe entrance (e.g. from a vessel entering the pipe), and an "other" category where you can input any other "L/D" ratio you want.

In version 2, I updated it to have 8 different fittings (as before) but each line of fittings can be changed to a choice of other fittings (see screen shots for examples)--so hit the arrow next to a fitting, and it'll toggle between a list of fittings built into the app, each with their own L/D ratio built it. What's more, you can overwrite any of the L/D ratios to your own custom value (but not, if you toggle between L/D ratios, any custom entries you make will be switched back to the default values).

This app makes it easier for the piping designers and engineers to talk equivalent length. Say, for example, an engineer tells you that you cannot exceed 55 feet of equivalent length of piping, else, you'll have to increase one line size in diameter. Well, anyone can count the straight feet of pipe, but using this app, now anyone can translate the fittings from the piping design (or field design) into a final equivalent length of straight pipe. This can reduce the cycle time between piping designers and engineers by empowering the piping designer to check the design before giving it back to the engineer. Also makes field walks easier, and decreases lost time due to rework on piping designs.

As you hit the '+' or '-' signs for changing the number of fittings, the total equivalent length at bottom automatically updates (no need to hit a separate "calculate" button each time).

You can enter up to 3 individual pipe sizes and their fittings at once. You can also copy the fittings counts from the column for 'pipe 1' to the second column of data, and also from the second to the third one. This allows for easy comparison of pipe diameters versus total equivalent length. This is especially handy for determining whether increasing pipe diameter will necessarily save you pressure drop in a line if there's a lot of fittings (e.g. for PSV inlet line applications where pressure drop is tight).

Lastly, if you don't like one of the "L/D" values I have in there now, well, you can always change it. One drawback--it won't save your change, so you'll have to manipulate it each time you come back to it after a shutdown.

I do plan on multiple updates to this software, including, but not limited to: selection of different styles of block valves; links to online references regarding total equivalent length articles.

Version 2.1: iPhone version now available, but only with one column for diameter (iPad version has three different possible diameters that can be manipulated).