Complex Piping Design Guide
This design guide addresses the heat tracing requirements of
complex piping. Whether the application is a small project or a
complete network of piping and equipment, designing an electric
heat tracing system for complex piping is simplified by using
Thermon self-regulating cables. The information contained
in this design guide will take the reader through a step-by-step
procedure to make proper heating cable selections based on:
| • Pipe size | • Minimum ambient temperature |
| • Thermal insulation type
and thickness | • Heating cable start-up temperature |
| • Desired maintenance temperature | • Available power supply |
| • Maximum exposure temperature | • Electrical area classification |
After following the prescribed steps in this design guide, the
reader will be able to design, select and/or specify or establish
a bill of materials for a heat tracing system.
Typically, complex piping is located inside a process unit and
consists of relatively short runs of pipe with frequent tees, as
well as in-line valves, pumps and related process equipment
that also requires heat tracing. Circuit lengths can range from
several feet (less than one meter) to several hundred feet (meters)
in length; however, the average is usually 100 feet (30
meters) or less.
For applications ranging from freeze protecting water lines to
maintaining elevated process temperatures as high as 300°F
(149°C), Thermon self-regulating, cut-to-length, parallel resistance
heating cables are recommended. Variations in the heat
loss of the insulated pipe (due to equipment, supports and/or
insulation) are compensated for by the heating cable’s PTC
(Positive Temperature Coefficient) characteristic. Thermon offers
heating cables specifically designed, manufactured and
approved to cover a wide range of applications.
BSX ™ . . . Designed for freeze protection and temperature
maintenance at or below 150°F (65°C), BSX is well-suited for
both metallic and nonmetallic piping and equipment.
RSX ™ 15-2 . . . Designed for applications where the watt density
requirements preclude the use of the standard range of BSX cables.
HTSX ™ . . . Designed for process temperature maintenance or
freeze protection applications up to 250°F (121°C) and withstand
intermittent exposure temperatures (power-on) up to
420°F (215°C), intermittent exposure temperatures (power-off)
up to 482°F (250°C) and continuous exposure (power-off) to
400°F (204°C). The cable is capable of withstanding the exposure
temperatures associated with steam purging.
VSX ™ . . . Designed for process temperature maintenance or
freeze protection applications up to 300°F (149°C) and withstand
intermittent exposure temperatures (power-on) up to
450°F (232°C), intermittent exposure temperatures (power-off)
up to 482°F (250°C) and continuous exposure (power-off) to
400°F (204°C).
Computer Aided Design Program . . .
Thermon has developed a sophisticated yet easy-to-use computer
program, CompuTrace®, that provides detailed design
and performance information. Users of CompuTrace are able
to input application-specific information into the program and
obtain detailed electrical and thermal performance information.
Calculations made within the program are based on the formulas
prescribed in IEEE Standard 515-2004.
The information input to and/or generated from Compu-
Trace can be printed and summary reports, including “load
chart” information, exported for use in other programs. While
CompuTrace is a valuable asset to use in designing a heat tracing
system, the design steps detailed in this guide will still form
the basis for identifying the design process necessary to establish
a properly functioning heat tracing system.
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