ges should have the diameter thickness and drilling in
accordance with the "manufacturer's standard" for "extra heavy" flanges.
All low pressure flanges should have diameter, thickness and drilling in
accordance with "manufacturer's standard" for "standard flanges."

The flanges on high pressure lines should be counterbored to receive
pipe and prevent the threads from shouldering. The pipe should be
screwed through the flange at least 1/16 inch, placed in machine and
after facing off the end one smooth cut should be taken over the face of
the flange to make it square with the axis of the pipe.

[Illustration: 2000 Horse-power Installation of Babcock & Wilcox Boilers
and Superheaters, Equipped with Babcock & Wilcox Chain Grate Stokers at
the Kentucky Electric Co., Louisville, Ky.]

For pressures above 160 pounds, where superheated steam is used, all
high pressure steam lines 4 inches and over should have solid rolled
steel flanges and special upset lapped joints. In the manufacture of
such joints, the ends of the pipe are heated and upset against the face
of a holding mandrel conforming to the shape of the flange, the lapped
portion of the pipe being flattened out against the face of the mandrel,
the upsetting action maintaining the desired thickness of the lap. When
cool, both sides of the lap are faced to form a uniform thickness and an
even bearing against flange and gasket. The joint, therefore, is a
strictly metal to metal joint, the flanges merely holding the lapped
ends of the pipe against the gasket.

A special grade of soft flanging pipe is selected to prevent breaking.
The bending action is a severe test of the pipe and if it withstands the
bending process and the pressure tests, the reliability of the joint is
assured. Such a joint is called a Van Stone joint, though many
modifications and improvements have been made since the joint was
originally introduced.

The diameter and thickness of such flanges should be special extra
heavy. Such flanges should be turned to diameter, their fronts faced and
the backs machined in lieu of spot facing.

In lines other than given for pressures over 150 pounds, all flanges for
wrought-iron pipe should be threaded. All threaded flanges for high
pressure superheated lines 3-1/2 inches and under should be "semi-steel"
extra heavy. Flanges for other than steam lines should be manufacturer's
standard extra heavy.

Welded flanges are frequently used in place of those descri