Instrument Installation . This section provides guidance for the installation of field
instrumentation, its associated tubing and location, and specific details about commonly
used pressure, level, flow, and temperature instruments.
General. Impulse tubing and valve material may differ from piping of the process
system they serve, but generally they equal or exceed the parameters of the
process system with respect to material, temperature, and pressure ratings.
Consider the use of expansion loop or flexible metal hoses on impulse
and sample lines where thermal or seismic movement is a concern.
Provide sensing lines with continuous slope to promote their being either
full or free of liquid as appropriate. The recommended slope is 1 inch per
foot. For instruments sensing steam up to 20 psia, the recommended
minimum slope is 2 inches per foot.
Prevent instrument tubing from coming in contact with structural steel and
concrete (painted or unpainted) surfaces of building members, except for
penetrations requiring closure. For tubing below 200 EF, grout may be
used for penetrations.
Tubing installed in exposed locations subject to accidental crushing or
damage should be protected by structural channels or tube track. This
type of protection should not render the tubing and fittings inaccessible.
Capillary tubing sealed to the instrument by the manufacturer should not
be cut during or after installation unless specifically required by the
installation drawing or manufacturer' instruction (e.g., capillary system
through a penetration).
Instrument Location . When locating instruments consider the following:
routing of sensing lines from the process tap to the instrument;
sensing line penetration through walls and floors;