IPE-TM-600 Instruments
Nozzle Spacing for Float Actuated Level Switches
IPE-TM-600-01
1. Purpose
This procedure provides design guidelines for the placement of vessel nozzles associated with float actuated level switches.
2. General
Design Engineering shall use this procedure to maintain a consistency of design practice in the placement of vessel nozzles for float actuated level switch applications.
3. Procedure
4. Special Considerations
4.1 Level switch dimensions are based upon the Magnetrol Series 3 design (ANSI B31.3 construction).
4.2 Minimum specific gravity data is based on the following materials of construction: carbon steel chamber, 316L stainless steel float, 316 stainless steel sleeve.
4.3 Process connections are available in 1, 1-1/2 and 2 inches with 1 inch being the Inflection Point Engineering standard.
4.4 Set trip point elevations for alarm and shutdown functions that do not duplicate the process alarm points of the level transmitter as follows:
a. High Trip - Set the trip point at the 100% elevation of the level transmitter range.
b. Low Trip - Set the trip point at the 0% elevation of the level transmitter range.
4.5 Consideration must be given to the position of the lower vessel nozzle relative to the vessel weld line for a low level function. The process level COF may need to be raised to accommodate the level switch trip point and nozzle spacing. Consult the skill center for Process Control for recommendations.
4.6 For a flange class and/or specific gravity not listed in the above table, consult the skill center for Process Control for recommendations.
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© 2026 Inflection Point Engineering, LLC. All rights reserved.