In late fall of 2014, a major petrochemical customer in Midland, Michigan called Macomb in to look at an emergency situation on a 34¿ O.D. low pressure steam main (25 PSIG). Something catastrophic had happened — the kind of thing you hope you never have to deal with.
Twisted metal
The damage happened on a section of pipe that was carried over a plant entrance on a trestle (or pipe bridge). A welded pipe anchor had broken, causing welded pipe slides, guides, and their bases to twist.
Additionally, a 28¿ O.D. vertical riser had tipped over, and a portion of the horizontal main had fallen off the trestle. Fortunately, the pipe’s contents stayed inside the pipe.
The utilities maintenance division was obviously concerned about what had happened and in a big hurry to figure out what had caused the event. Even more important, they needed to fix this dangerous situation without interrupting building heat since cold weather was coming.
Experienced engineers from the petrochemical company quickly recognized the symptoms of hydraulic shock — commonly known as water hammer — a condition in which water carried by steam can generate extreme force, powerful enough to twist and bend steel or even break it.
Blowdown of the system header revealed the line was still full of condensate and at least two large inverted bucket steam traps had failed. The customer needed a plan to straighten out the steel, put the pipe back in place, and then make structural repairs.
An improved solution, collaboratively executed
Rigging and crane operators from Three Rivers Co. and Bierlein provided the estimated cost of putting everything back where it belonged. The customer asked Macomb to figure out a solution for supporting the pipe. Macomb went right to work on the design and drawings for the new pipe support system.
A key component in the improved support design is the use of modern pre-insulated pipe supports, which have several benefits over inexpensive welded pipe shoes. Many large companies that are interested in thermal efficiencies, steam quality, and safety prefer to use these innovative supports.
A welded pipe shoe radiates heat out to the support steel, which is costly as well as dangerous to the touch. Modern insulated pipe supports are mechanically bolted on the pipe, so they require no welding. The insulation, which is a combination of calcium silicate and marinite P, marries up neatly to the support insulation and actually helps to support the load.
Quick turnaround on a complex repair
Macomb works with several suppliers of pre-insulated pipe supports. For this job, we opted to work with Rilco Manufacturing in Houston, Texas, which consistently stands out as one of our best suppliers. Macomb placed an order for ten 34-inch and five 28-inch supports. Rilco set to work to deliver them in five weeks.
Meanwhile, repairs got underway. The old insulation was stripped off, the old shoes torched off, and the piping temporarily cribbed with treated 6-by-6 lumber beams. The new pipe supports arrived on Christmas Eve, and all the components were installed by early January 2015.
Macomb is proud to have worked with our trusted vendor Rilco to provide a long-term solution for our petrochemical customer.
The Macomb Group is proud to offer our customers quality products and innovative, engineered solutions. To learn more, contact us by email at info@macombgroup.com or by phone at 888-756-4110.
