Galavnized Pipe Sleeves

[lilrascal]

I have a project that I've been asked to help on involving a waste water pump station (not my forte). The contractor has submitted Cast-in-place Galvanized Steel Pipe Sleeves. The project specs read only that the sleeves should be made of or coated in a corrosion resistant material. I'm bothered by the possibel affect of Hydrogen sulfide gas on the Galvanization. I'd prefer HDPE or Coated DIP. Please comment and TIA.

 

[bimr]

Where are these sleeves used?

Embedded into a concrete wall in a wetwell?

Diameter of the sleveve.

Municipal wastewater?

 

[lilrascal]

The sleeves penetrate the concrete wet well for the influent and effluent piping. It is a regional waste water pump station with residential, commercial ,and indusrial flows. Sleeves are for 10", 12" and 24" pipes.

 

[cvg]

I think you could make a case that galvanized steel is not very corrosion resistant against hydrogen sulfide (sulfuric acid). It does not meet the requirements of the spec. Plastic, epoxy, fiberglass, rubber or stainless materials and coatings might be better suited.

 

[jgailla]

We usually spec SS 318 for piping in wetwells.
I also agree that galvanized steel should not be used. Lined ductile iron should be acceptable as a cheaper alternative to SS 318 if the spec is unclear.

 

[bimr]

The amount of hydrogen sulfide will depend on the climate and the wastewater characteristics. In the southern US, the effects of corrosion are more severe than in the north. You might check into what your client is normally using in this application.

Pipe sleeves are used when small piping passes through concrete walls. Wall pipe may be used for larger piping. Wall pipes are normally used in this application. Wall pipes are made of ductile iron pressure pipe with plain ends and integral water stop

Sometimes steel is used for sleeves as in this example:
"Where the cast iron suction and discharge lines pass through the station wall, they shall be reinforced with one-fourth-inch thick steel sleeves, welded inside and out, to the station walls. The space between the cast iron pipes and the steel sleeves shall be packed tight with expanding cement grout to prevent leakage."

Steel (with a coating) is also frequentyly used for construction of lift station wet wells.

You may use a coating over galvanized steel to protect the sleeves:

http://www.henry.com/fileadmin/pdf/literature/sf_sleeves_collars_fax_version.pdf

You may use also use flexible seal on the sleeve end:

http://www.fernco.com/plumbing/flexible-couplings/pipe-sleeve-seals

Not familiar with the use of plastics for wall sleeves.

 

[cvg]

BIMR
by plastic, I meant polyethylene. A piece of HDPE solid wall pipe could be used for a sleeve and would be very resistant to corrosion. I saw a photo (just yesterday) of ductile iron pipe which was used in a wet well in Florida. After just 18 months it was removed and was completely corroded through the pipe.

note that your reference above to steel sleeves refers to sleeves passing through the "station wall" - not in the wet well. I believe there is little chance of corrosion within the "station" as compared to the highly corrosive atmosphere within the "wet well".