Mechanical Joints for Drainage


The requirment for flexible, easy-to-install fittings for carbon steel drainage piping has led to the widespread replacement of screw-type joints with mechanical joints for drainage (Named MD).

Besides, demand for large-bore piping has increased as buildings are built higher and higher, as well as for more pressure-resistant piping that can meet Japan's earthquake-resistant construction standards and cope with high-pressure drainage.

To meet these demands, Hitachi Metals has developed lightweight mechanical joints made of nodular graphite cast iron (Ductile) instead of the conventional joints made of gray cast iron.

Not only is the lightweight MD joint approximately 30% lighter than Hitachi Metals' conventional MD joints, but it is also tough enough to overcome gray cast iron's problem of brittleness.


1.Strong and durable
Substantially improved shock resistance and tensility, due to the use of nodular graphite cast iron (Ductile) as a body material instead of gray cast iron

2.Substantial weight reduction
MD joints 4"in size or over take a long time to install because of their heavy weight. The new lightweight MD joint is approximately 30% lighter than our conventional products, making it much easier to work with.

3.Same functionality as MD and CD joints
Use of a superior material does not mean that the benefits of MD and CD joints are lost. In addition, because its size is the same as that of MD and CD joints, the new lightweight MD joint can be installed in the same way as before.

Major uses

1.The MD joints can be used in:
・Sewage piping, various types of wastewater piping ・If water pressure from pressure pump lines or other lines rises over 0.08MPa, it should be used in combination with an, supporting part, MD grip.

2.Fluid temperature
・Up to 60°C ( 140°F )

3.Applicable fields:
・Kitchen, bath, sink, toilet and other household wastewater, and rainwater

4.The MD joints can be used with the following pipe types: JIS G 3452 - Carbon steel pipes for piping systems JIS G 3442 - Galvanized steel pipe for water supply JIS G 3443 - Coated steel pipe for water supply, all kinds of steel pipe with internaly resin coated JIS K 6741 - Hard polyvinyl chloride pipes JIS K 6742 - Polyvinyl chloride pipe for water supply WSP 032 - Coal tar epoxy coated steel pipe for wastewater WSP 042 - Hard polyvinyl chloride-lined steel pipe for wastewater

Chart 1: Product categories

Polyethylene piping for ga


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