bridge pipe crossing
bridge pipe crossing
(OP)
I have a 6,000 foot bridge that is 300 feet above grade. I have been tasked with specifying the dry pipe fire standpipe system on this bridge. An acutal fire engineering firm will do the design build of the system but I want to make sure I am specifying it correctly. Can anyone shed some insight as to what the specs should be for material, flanges, expansion joints etc? I am thinking galvanized steel, but is ductile iron used ever, I can only seem to find restrained mechanical joints with ductile iron pipe? It looks like most standpipes have restrained joints with expansion joints in the system and the pipe is supported on roller hangers. I'm probably looking at 600 psi flanges correct due to the height, length and movement of the bridge? Any help is appreciated! Thanks.





RE: bridge pipe crossing
http://www.dipra.org/pdf/bridgeCrossings.pdf
Check the DIPRA website for other information that may be helpful.
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RE: bridge pipe crossing
RE: bridge pipe crossing
Thanks much.
RE: bridge pipe crossing
RE: bridge pipe crossing
RE: bridge pipe crossing
You have both provided some good information and it is very much appreciated.
rconner - the weblink was very helpful, thank you for this link. It seems from that information and additional information that there are two main piping methodologies that can be used as you point out. For black carbon steel pipe if used, it appears that for above-ground exposure to the elements and for locations near bodies of brackish or salty water some sort of coating must be provided. Galvanized pipe could also be used with or without an exterior coating The question then is if internal protection of the piping is in order through the use of galvanized pipe or some sort of internal lining.
swoosk172 - the piping approach you provided is similar to what I have found that was used on other similar projects. As outlined to rconner above, you may want to verify if some sort of exterior coating is in order in addition to the galvanized pipe. One source offers fusion-bonded epoxy (FBE) and recommends an outer covering of a UV protective coating. But all this material does add cost. I have also found after discussing the issues of pipe vibration, expansion, water hammer, etc. that there are engineering firms that handle piping designs all the time, which includes methods like you describe. For fire protection, a good resource is NFPA 502 (2011) that I was told is a recommended standard but one not necessarily adopted by the AHJ or local codes.
RE: bridge pipe crossing
RE: bridge pipe crossing
I'm a bit late from the dates on your posts. But I wanted to share a little input.
swoosh172
In your original post, it was stated "An actual fire engineering firm will do the design build of the system but I want to make sure I am specifying it correctly". My question is, as to why would you need to specify something that someone else is carrying out as a "design-build"? In other words, you would want to carry out preliminary hydraulic calcs in order to size the pipe but that is as far as I would take it. My plans would then show an "X inch" line to be "built by others" or "by separate submittal".
Those preliminary hydraulic calculations with any applicable code would then determine the expected pressure in the pipe and thereby choosing a pipe material. Again, however I would only specify the material if I was responsible for the design. That would also include any anchorage, fittings, etc.
Now in previous fire system applications, I have seen vitaulic materials used for "indoor" applications such as piping inside a parking structure or not exposed to the elements. In fact, in one of my previous projects I spoke to a vitaulic rep and he did not recommend such materials for an outside application. In my case, it involve dry stand piping to be attached to the outer face of a hospital building.
Like rconner's recommendation, I would use steel or dip for this application, including an outer coating to protect against exposure. There are flexible expansion joints or expansion-contraction joints that you could call out to address pipe movement due to seismic or any other loading producing movement. EBBA Iron is one manufacturer but there are others. I would also check into NFPA requirements for additional guidelines.
In short, its just a heads up on taking liabilities on a pipeline that is be designed and bult by others.