Field installed Ductile Iron Flange?

[llamallama]

One of our contractors has constructed an elevated slab with several pipe penetrations. The slab supports two vertical turbine pumps and a suction lift high pressure pump. The piping is all ductile iron flanged pipe.

Details: 10'x18'-10" thick elevated slab above wetwell with two mats of reinforcing; two penetrations for 8" ductile iron flanged suction and discharge line; two penetrations (17 inch) for vertical turbine pumps.

My original design was spool pieces and linkseal at all penetrations, so the detail was for a 12 inch hole (9 inch OD + 1.5 inch link). My issue is that the spool pieces were never installed. Now we have 12 inch holes with no way to install the 13.5 inch flange through the hole.

Is there a way to field install a flange, or is there some other method besides coring the holes to > 13.5 inches and grouting? I prefer not to use megaflange because it is at a 90 degree direction change in the manifold and will be transferring transverse load.

Thanks for any insights out there.

This is the PS plan view

http://files.engineering.com/getfile.aspx?folder=ce6d6127-e724-43fd-8742-22b6b66fed03&file=Plan.pdf

This is a section of the PS.

http://files.engineering.com/getfil...c00-4f83-bd87-34fa1e95c0ac&file=Section_A.pdf

 

[bimr]

Don't think there is any way to install the screwed on ductile iron flanges in the field. You should be able to delete the small spool pieces, that may allow you to install the pipe. Also don't think there will be any problem with the use of megaflanges if you go that way.

You have some other potential problems that you should address.

Note that the weight of the pipe discharge line and pipe inlet should not be borne by the pump. The pump is not structurally designed to support this weight.

Pumps should generally be arranged so there is access for maintanance. That is why the pump discharge line is typically elevated.

Note that the mass of the pump concrete foundation must be five (5) times the mass of the pump, base plate and other equipment that is being supported or vibration will occur.

Note that you may have a vortexing problem because of the location of the pump suction close to the floor and wall. Check the hydraulic institutes guidelines. This link may help you.

http://www.mcnallyinstitute.com/14-html/14-12.htm

 

[bimr]

http://www.clowwatersystems.com/attachments/submittal73_74.pdf

 

[bimr]

It is possible to put a flange on in the field, but is not recommended. It would also be more difficult to screw it on if the spool is already installed in a vertical position (through the hole in the floor).

See the upload.

http://www.ebaa.com/PDF/Brochure.1000.pdf

 

[rconner]

For further information the latest practice bimr refers to is sometimes referred to in the mostly small diameter fabrication field as a pipe end with "flange hand-tight" (meaning I think with the traditional understanding that it is to be provided with more substantial tightening, and also a good quality and application of thread sealant, in the field).

[While some folks also accomplish something that sounds like what you are talking about by passing grooved end ductile iron piping through smaller holes or sleeves than possible with flanged, and then using a special transition device like a "Vic-Flange" to in effect then transition/bolt this grooved end immediately to a standard flange (device has same bolt center etc., but utilizing a special rubber gasket end seal), the manufacturers of such devices and the pump manufacturer should probably be consulted to make sure any additional flexibility compared to more rigid flanges does not cause any problems near the pump connections.]

Everyone have a good weekend!

 

[dicksewerrat]

I would cut a 22 inch dia. hole in the top slab off to the side and install a Manhole cover. Use that hole to install your pipes and to clean out the wet well once in a while. And let the contractor who didn't follow the plans pay for the modifications. Then modifiy the rest of your pump station plans to include an access for cleaning them out. Oil, grease and other solids will build up in these wetwells because of the corners.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[llamallama]

Thanks all for the input. I have been away for a while and unable to respond. We decided to go with megalug and full length rods for the vertical runs.

The elevations worked so the pump base is directly on the concrete slab w/o any housekeeping pad, so it anchors into the cap slab with some considerable weight.

We checked with the pump mfg and the clearance should be OK.

As far as access, we worked with the space we had. I would have liked more, but in this case it is as good as it gets, understanding that major maintenance will require a crane.

Thanks All