Stock orifice
flanges are manufactured for use with
1/16' thick gaskets. The centers of
the pressure tap holes are required
to be 1" from the inlet (upstream)
and 1" from the outlet (downstream)
faces of the orifice plate. Therefore,
stock flanges have the centers of
the pressure tap holes 0.94"
from the face of the flange. If thicker
gaskets are to be used, it is necessary
that a special location be specified
for the pressure tap holes. This Is
especially true if a high beta ratio
is to be used. Refer to A.G.A. Report
No. 3, Figure 5 for allowable variations
in pressure tap hole locations.
