Setting 12" Megalug Style Chilled Water Lines at UVa South Lawn

Chilled Water Lines and the Megalug system
Water serves as a great way to move thermal energies. Many large and intensive heating and cooling systems are heated and cooled more efficiently with heat exchangers built with water lines than with traditional AC cooling.

The megalug system is designed to join ductile iron pipes from 3 inches to 4 feet in diameter. Placed around the UVa underground they serve with steam tunnel pipes, water lines, and chilled water systems.

Technical Notes
Capable of handling lines with up to 350 psi the megalug system is very popular. At UVa the lines are usually carrying a load of 60 psi and are tested for 2 hours at 200 psi*. These lines were given bedding in several inches of stone dust. All bolts are tightened to 90 lbs.

Insulation
Depending on the depth of the line the lines may require insulation of some sort - I believe this is the stinky glass insulation stuff we use - watch out! it's got glass shards in it and has cut many hands, beware of it in your eyes as well.

Tools needed
Every megalug kit contains a megalug, the nuts 'n bolts, and a gasket. Armed with an 1-1/4" wrench, a chipping hammer (for banging in gasket), and a torque wrench (set to 90 lbs) you're good to go. An air wrench may be helpful on larger pipes - deep-welled 6 sided sockets work the best. In case for some reason you need to back up a broken megalug use the 5/8" socket.

Here's a video of Johnny aka "Blaze", Travis aka "T-Bone", installing a 12" line for the South Lawn project - "Happy Dawg" is the bank man, Norris operating, Rick Lane foreman.



*When it comes to testing water lines
***Many lines are going to have small pockets of air in them - it's often impossible to avoid this. Over time air may leak out, or with enough flow of water it may eventually lessen it's impact...
***Remember to consider the temperature outside when you start and finish - 4 degrees Celsius water's most dense temperature.
***Seal's often require some time to harden into place - pressurize lines over night and expect the gaskets to be in better positions - a few drops of water in a line may lower psi markedly.