Ductile Iron fittings (connecting to existing DI pipe)

I would not use a coupling on an ductile to ductile connection. I would use one when I had no other alternative such as connecting ductile (or C 900) to an over or undersized pipe, or when making a repair from a main break. Instead I specify that a solid sleeve be used if not using another type of MJ fitting to connect to an existing main. The solid sleeve is normaly between 8 and 12" long versus the 6 inches normally availible with a coupling. This give much more pipe gap availible to get a group of fittings into place. This fitting should be in the online EJP catalog, I have the paper (page B-4) one in my office.

When I do need to use a coupling, instead of the "dresser" syle coupling I use one like the Romac Macro

I never liked tightening the dresser style couplings to the point that the bolts are starting to bow. Also I have been around main breaks where the bolts rusted away after a few decades causing a leak.

I would question a pipe laying crew putting MJ fittings in the ground (and conecting to existing mains) if there was no torque wrench on site since most (there may be an exception) MJ glands now manufactured have instructions that require specific tourquing. Also they should have an outside diameter or pi tape on hand to measure and verify the outside diameter of any pipe.

The book I prefer to have on hand is the Clow (McWane) "Pipe Economy" it has great detail on pipe installation and availible fittings that the McWane corporation produces with all of its subcompanies.

I am both the engineer and owner on my projects, so I have a vested interest that the work goes well. If not, I do hear it from my coworkers.

Good Luck!

Jefferson

s0eebuch,I would not use a coupling on an ductile to ductile connection. I would use one when I had no other alternative such as connecting ductile (or C 900) to an over or undersized pipe, or when making a repair from a main break. Instead I specify that a solid sleeve be used if not using another type of MJ fitting to connect to an existing main. The solid sleeve is normaly between 8 and 12" long versus the 6 inches normally availible with a coupling. This give much more pipe gap availible to get a group of fittings into place. This fitting should be in the online EJP catalog, I have the paper (page B-4) one in my office.When I do need to use a coupling, instead of the "dresser" syle coupling I use one like the Romac MacroAs sold by EJ Prescott rather than the Romac 501 from the catalog cut sheet. These couplings (and the Viking-Johnson equivelent) do not have to be disasembled to slide onto the pipe, have a torque spec for the bolts, only two bolts no to tighten, the gaskets can be (and need to be) field modifided to fit a wide range of pipe outside diameters without having a variety of gaskets and endrings on hand.I never liked tightening the dresser style couplings to the point that the bolts are starting to bow. Also I have been around main breaks where the bolts rusted away after a few decades causing a leak.I would question a pipe laying crew putting MJ fittings in the ground (and conecting to existing mains) if there was no torque wrench on site since most (there may be an exception) MJ glands now manufactured have instructions that require specific tourquing. Also they should have an outside diameter or pi tape on hand to measure and verify the outside diameter of any pipe.The book I prefer to have on hand is the Clow (McWane) "Pipe Economy" it has great detail on pipe installation and availible fittings that the McWane corporation produces with all of its subcompanies.I am both the engineer and owner on my projects, so I have a vested interest that the work goes well. If not, I do hear it from my coworkers.Good Luck!Jefferson

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Jul 24,

The connection of ductile iron pipes is flexible. The inner and outer diameters of pipes or fittings can be connected to each other regardless of their size, as long as their nominal diameters are the same, and the joints are interchangeable. For example, the steel pipe connection method, the joint of the steel pipe mostly presents the threaded joint, welding, in addition to the Lap Joint Flange and various flexible joint types,such us Flexible Flange Adaptor. In urban water supply projects, small-diameter indoor feedwater galvanized steel pipes generally use a threaded joint.

Cast iron pipes generally use a rigid joint and a flexible joint.

1. Rigid joint: linoleum asbestos cement joint, rubber ring expansion cement joint.

2, Flexible joint: apron asbestos cement joint.

If you are looking for more details, kindly visit MIDAS.

3, Semi-rigid semi-flexible joint: hemp-lead joint.

Plastic pipe connection method for ductile iron pipe. The rigid PVC water supply pipe can be of rubber ring joint, bonding joint, flange connection and the like. The most commonly used rubber ring and adhesive connection, the bonding joint is only suitable for the connection of pipes with an outer diameter of less than 160mm; the flange connection is generally used for the connection of other PVC valve parts such as hard polyvinyl chloride pipe and cast iron pipe. The high density polyethylene plastic pipe can be connected by hot melt. The polyethylene pipe is connected to the metal pipe and connected by a steel-plastic transition joint.

The main components of ductile iron pipes are carbon, silicon, manganese, sulfur, phosphorus and magnesium. A certain amount of spheroidal graphite is distributed on the ferrite and pearlite matrix. The proportion of ferrite and pearlite in the matrix is different according to the nominal diameter and the elongation requirement. The proportion of pearlite in small diameter is small. Generally not more than 20%, the general control of large diameter is about 25%. Minimum tensile strength: 420/Mpa, minimum yield strength 300/Mpa, minimum elongation 7%.

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