Something smells, but it is not just the screened sewage pouring into Bellingham Bay since early Saturday morning. A report at the City of Bellingham’s website says a “pipe failed” resulting in “significant flooding of the underground galleries and a shut down of the secondary treatment process”.
The report is grossly inaccurate. Pun intended. The photo clearly shows the failure of the anchors suspending the pipe. If the pipe had failed, it would have spilled its process contents, become much lighter and remained suspended.
Instead, the anchors obviously failed, causing the pipe to fall, buckle and spill its ‘goods’.
This strongly indicates a material specification problem with either the anchors or the concrete holding them. If the anchors were inadequate, there’s a claim against the designer or contractor. If the concrete is to blame, we we may have much more serious problems to worry about. And another claim.
Which is it?
Will taxpayers be tapped to fix a so-called failed pipe, or will the City Administration get to the bottom of the real problem and assign the liability where it truly belongs?
Comments by Readers
Jerry Vekved
May 12, 2017Some cleanup (pun intended) of terminology may be in order here:
The rod-and-yoke assembly formerly hanging from the ceiling is a “hanger”. These provide vertical support only; other support types are needed for lateral and axial support or restraint if such is needed.
“Anchor” has several rather weighty meanings in piping, and in the photo above. It is possible that some sort of concrete anchor was used to secure the hangers to the ceiling. Such will consist typically of a heavy steel rod, partly or fully threaded, secured somehow to the concrete. Means of securing these to the concrete consist of embedding when poured, or an expansion type or adhesive type installed in a drilled hole. In piping design terms, an “anchor” provides support or restraint in the axial (parallel to pipe run) direction; an anchor may or may not provide restraint in the vertical or lateral direction, and/or restraint against rotation. Various combinations of piping components, support devices and construction methods are used to anchor pipe. Likewise for supporting pipe vertically and laterally.
One would need to know much more than what is shown in the photo and written in press releases, in order to comment on the pictured support scheme. You assert that a “material specification problem” is indicated - that’s no more or less probable than a process design problem, an unforseen upset condition, failure of a protective system, and/or an operating error.
Bill McCallum
May 12, 2017I haven’t seen any discussion of the leak in the four-inch gas line that feeds the sludge incinerators at Post Point. According to city documents the leak presented the potential for a catastrophic failure of the line and a shut down of operations at the treatment plant. Is it a coincident that the accidents occurred two months apart or portends the future?
Tip Johnson
May 15, 2017Thanks, Jerry for the more accurate hardware terminology. However, I’ll stick with my “material specification problem” hypothesis because engineers normally specify structures to withstand anticipated process perturbations. The main point here is that if the “pipe” failed it would still be hanging. Instead, the suspension system failed causing the pipe to rupture. That’s either metal hangers, epoxy anchors as you suggest, or concrete substrate. All materials. The question is, whose design was insufficient?