UFC 3 -430-11
14 February 2001
To avoid possible mismatch have the I/P furnished with the valve or damper instead of
separate procurement.
5-2.4
Dampers. Dampers can be operated either manually or by means of an
actuator. This paragraph covers only actuator-operated dampers. Manually operated
dampers are not included in this document.
Specify temperature, pressure, pressure drop, type of shutoff, materials,
applicable data when selecting dampers.
Provide a hand wheel or lever so that the damper can be manually operated
in case of damper actuator failure.
5-2.5
Pressure Relief Valves. Provide pressure relief valves in accordance with
the applicable codes. Refer to paragraph 3 -15 for applicable codes.
5-2.6
Rupture Disks. Use reverse buckling type rupture disks at the inlet of the
relief valve in corrosive services.
5-2.7
Level Instruments. Provide level i nstruments in accordance with applicable
codes. In general, provide separate vessel connections for each level instrument.
Provide 12.7 millimeter ( -inch) minimum vent and drain valves with plugs for all level
instruments.
5-2.7.1 Gauge Glasses. Complete coverage of total liquid range is not always
required. Consult the applicable codes for requirements. Also consider all operating
conditions and upsets. Provide gauge glasses to cover and overlap a minimum of 5.08
centimeters (2 inches) beyond the ranges of displacers and switches.
Gauge glasses should only cover the critical range zone such as high, low,
and normal levels when the range is also covered by differential pressure type level
Provide illuminators for transparent gaug e glasses.
5-2.7.2 Displacer. Displacer type level instruments can be used for level ranges up
to 1.52 meters (60 inches) of fluid height. Avoid use of internal displacers except for
open tanks and sumps. Provide carbon steel body material with stainless steel trim as a
minimum.
5-2.7.3 Differential Pressure. Use differential pressure type level instruments
instead of displacer type level instruments for ranges over 1.52 meters (60 inches) of
fluid height. They may also be used for ranges under 1.52 meters (60 inches).
5-2.7.4 Capacitance Level. Avoid the use of capacitance type level instruments in
boiler plants.
5-3
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