Project Title
End User, Location
Job Number
ENHANCED STEAM TRACING
SPECIFICATION
Page 1 of 3
Revision: 0
Date: 20 Jul 2012
1. GENERAL
1.1.
This specification describes the minimum mandatory requirements governing the design
and installation of an enhanced steam tracing system for process piping. The system will
be used to maintain process temperature inside the piping.
1.2.
The enhanced steam tracing system will feature CSI’s HΔT® Tracing for piping & HΔT®
cast aluminum heating jackets for valves and other piping components.
2. ENHANCED STEAM TRACING FOR PIPING
2.1.
CSI’s HΔT® Tracing is intended for pipe heating applications which feature a large
temperature difference (ΔT) between the heating medium (i.e., steam) and the process.
Good process applications for HΔT® Tracing generally include liquid and vapor
processes where the ΔT exceeds 50°F. Vapor applications that may be sensitive to dewpoint condensation and subsequent corrosion are not good candidates for HΔT® Tracing.
2.2.
HΔT® Tracing features a 2-inch wide HΔT® element which significantly enhances the
heat transfer from conventional ½-inch stainless steel or copper tube tracing. Heat
transfer compound (HTC) is used to ensure good conductive heat transfer between the
tubing, HΔT® element, and piping.
2.3.
HΔT® elements are provided in straight lengths for piping and pre-formed pieces for
fittings.
2.4.
The vendor is responsible for performing heat transfer calculations to determine the
number of enhanced tracers required to achieve the thermal requirements for each line.
2.5.
Typically, tracers should be located at the 3, 6, 9, or 12 o’clock positions around the pipe
circumference. For piping which requires only 1 or 2 HΔT® tracers, the 3 and 9 o’clock
positions are best for avoiding potential interferences with pipe supports, high-point
vents, and low-point drains.
2.6.
The enhanced tracers shall be attached to the process piping with ¾” wide X 0.030”
thick stainless steel banding.
2.7.
Before attaching the enhanced tracer to the pipe, the concave surface of the enhancer
shall be coated with a thin layer (approximately 1/4”) of HTC. The type of compound
used shall be based on the maximum service temperature and the recommendations of
the vendor.
Project Title
End User, Location
Job Number
2.8.
ENHANCED STEAM TRACING
SPECIFICATION
Page 2 of 3
Revision: 0
Date: 20 Jul 2012
The placement and distance between the bands/straps shall be based on the
recommendations of the heating element supplier. In general, each 5-foot section of
enhanced tracer should feature 3 bands.
3. HEATING JACKETS FOR VALVES AND OTHER PIPING COMPONENTS
3.1.
HΔT® cast aluminum jackets shall be specially designed and manufactured to fit the
specific process component that it will heat. Within the aluminum casting, a carbon
steel pressure chamber shall be embedded which will contain the heating medium
pressure and isolate the aluminum from the heating medium.
3.2.
The jackets shall be cast of ASTM A356 copper-free aluminum. The pressure chambers
shall be fabricated of carbon steel components that meet the ASME Code, Section VIII,
Div. 1, latest addenda. Material traceability (MTRs) for all pressure chamber
components is required. Welders of the pressure chambers shall be certified to the
ASME Code, Section IX, latest addenda, for the welding procedures used.
3.3.
The jacket pressure chambers shall have a minimum design pressure rating of 150 psig
@ 400°F. This rating shall be verified in accordance with the ASME Code, Section
VIII, Div. 1, latest addenda.
3.4.
Jackets shall be attached to the valves and piping components with the hardware
supplied by the vendor.
3.5.
Immediately before attaching the jacket to the valve/component, the inside surface of the
jacket should be coated with a layer (approximately ½” thick) of hardening type HTC.
4. SYSTEM DESIGN
4.1.
The vendor shall design the enhanced steam tracing system to achieve the client’s
thermal requirements as stated in the P&ID’s, piping line lists, piping isometric
drawings, and/or data sheets.
4.2.
The heating medium shall be ___ psig saturated steam available at the outlet of the steam
manifold. The minimum steam pressure required at the inlet of the steam trap for
successful trap operation and condensate return shall be ___ psig.
4.3.
Design ambient conditions are ___°F with a 20 mph wind speed. The insulation type
and thickness for each line will be indicated on the piping line lists and/or piping
isometric drawings.
Project Title
End User, Location
Job Number
ENHANCED STEAM TRACING
SPECIFICATION
Page 3 of 3
Revision: 0
Date: 20 Jul 2012
4.4.
To accommodate thermal expansion within the tubing, expansion loops are required
when straight piping runs exceed 20 feet, and the expansion loop should be located at the
middle of the run. For straight runs exceeding 100 feet, there should be one expansion
loop per 50-foot segment, with the loops evenly spaced along the run. Additional
expansion loops can be included as needed to facilitate installation.
4.5.
Others will design and supply all utilities infrastructure including supply/return
manifolds, supply/return lines which connect the manifolds to the tracing system, and
steam traps.
4.6.
Careful consideration shall be given to the selection of steam traps (supplied by others).
A mechanical trap (inverted bucket, float, free-float) with continuous air purging
capability is the most robust choice for a bolt-on heating system. If thermodynamic
traps are preferred, the condensate return pressure must be less than half of the steam
pressure at the trap inlet for successful operation. Thermostatic traps are not
recommended since they require condensate to back up in the heating system in order to
achieve adequate subcooling to allow the trap to open.