Restriction and suspension of activity due to banking restrictions
and international sanctions.
We hereby inform our respected customers in Iran that all direct
and official activities of Heat Trace England have been
temporarily suspended and limited due to the restrictions imposed
brought about by international sanctions on the banking system,
but all measures related to warranty and services ,after sales
supports, and engineering, etc., it is still provided trough the
exclusive and official representative of HeatTrace in Iran
(IODEC). Therefore, in order to avoid any kind of possible misuse
or abuse by profit-seeking entities in claiming to provide genuine
products branded as Heat Trace of England, be sure to inform and
inquire about this to the exclusive and official representative in
Iran (IODEC). We are looking forward to the lifting of
international banking restrictions and sanctions to start
re-presenting Heat Trace UK products by its exclusive and official
representative (IODEC) in Iran.
1. Heat Trace Ltd. - Who
are we:
Established in 1974, Heat Trace Limited is now
one of the world's leading suppliers of electric heat tracing
equipment for both process temperature maintenance and freeze
protection applications. With offices, distributors or
representation in over 50 countries, we can provide a variety of
associated products and services to complement our heat tracing
product range.
Worldwide Specialist in Heat Tracing &
Surface Heating Systems for Over 40 Years
Leading Manufacturer of Heat Tracing Cables, Controls and Ancillary
Equipment
Heat Trace Limited is committed to provide you Technically Advanced,
Highly Reliable Product meeting to your requirement, specification
& standards which can give you long term maintenance free
operation.
Our exclusive agent M/s Ista has got experienced team of engineers and installers. Strong local presence ensures that all queries at any stage of project addressed / attended promptly. We are proud to have technically strong local partner / exclusive agent in Iran.
2. Trace heating What is
it? Why have it?
Electrical heating system is used in various
industries to protect the freezing of pipes (such as gas) or to
maintain fluid temperature inside the pipes or reservoirs.
Due to varying ambient temperatures process
conditions are upset
Water based solutions may freeze in Winter
Oil / Hydrocarbon based fluids will become
viscous
Chemicals may solidify
Foodstuffs may separate
Aromatics may not produce correct aromas
Inks and dyestuffs lose consistency
Product quality and yield suffers
When HEAT TRACING is needed
When it is needed that the temperature of the fluid (process) is greater than the ambient temperature, based on the rules of thermodynamics, fluid, as a heat source, begins to lose thermal energy, and when it is cooled to ambient temperature, the amount of lost energy per unit length / surface as HEAT LOSS will be calculated in this case to compensate HEAT LOSS, heating systems and especially electrical heating systems are used.
Heat Tracing Advantage
Most industrial facilities will have
electrical power available.
A variety of types and methods of electric
tracing may be used to maintain a broad range of temperatures for
process pipes and associated equipment.
Short lengths of pipe or long pipelines in
the range of 60 kilometres in length may be heated by the use of
various types of heating cables
Electrical tracing is recommended for
non-metal and lined piping and process equipment because of the
ability to provide very low heat output.
Electric tracing is often recommended for
use with temperature sensitive products that must be maintained
within a narrow temperature range.
Simplified installation and reduced operation
and maintenance costs.
Over its history, electric tracing has
proven to be a safe choice for process pipe and equipment
heating.
POWER ON:
The maximum temperature can be tolerated by
the heating cable when it’s on. Therefore, if the surface
temperature reaches this temperature, it’s needed to be cut off
the circuit by the temperature controller and heating cable exit
from the circuit.
POWER OFF:
The maximum temperature at which the
heating cable can stand in no charge (off) condition. Therefore,
installing the cable on a surface that may have a temperature
higher than the POWER OFF temperature is totally unauthorized.
HEAT-TRACE heating cables have this feature, which has the same two parameters, thus increasing the life of the cable and reducing the cost of the project due to no need for the thermostat to cut off the current at POWER ON temperature.
ELECTRICAL HEAT TRACE VS
STEAM TRACE
Steam Tracing Historically, steam tracing
has been used more often than any other type of pipeline heating,
for freeze protection and for process heating. Steam typically has
an advantage of having a high heat capacity combined with a
suitable heat transfer coefficient. This high heat input has been
advantageous in the past because thermal insulation systems on
pipelines were often left for years without maintenance. When
energy costs were negligible, this was an acceptable method of
operation, since steam was perceived as being “free of costs”.
When flowing through a tube, the steam will dissipate its latent
heat to the process pipe to compensate for the loss in heat. During
this process the steam temperature remains constant.
However when all steam condenses, the tube
will then be filled with condensate which has a significantly lower
heat capacity and a worse heat transfer coefficient. This process
occurs gradually and along the entire length of the heating tube.
Therefore it is necessary to install a steam trap at the end of the
heating circuit to "trap the steam" and discharge the condensate
with a minimum loss of fresh steam. Because the condensate in the
heating tube has to be "pushed" to the steam trap (often upwards),
the steam system must have sufficient pressure, which limits the
maximum length of the heating circuits. Circuits which are too long
will "drown" in condensate and the heat transfer will become very
unpredictable and unstable, which adds complexity to the steam
tracing system. The inherent result of the short heat tracing
circuits is that valuable space in the process area is used for the
steam distribution and condensate collection infrastructure. Steam
traps are the most critical and at the same time most sensitive
component of the steam tracing system. Due to the mechanical nature
of the steam system with constantly moving parts often resulting in
abrasion by the steam and blockage because of poor steam quality;
steam traps are subject to frequent inspections (at least once
annually) to ensure continued operation of which a significant
number of the traps (roughly 6%) must be replaced each year. Energy
waste is often high on steam-tracing systems. Steam being a
constant temperature source, any non-flowing pipeline is elevated
to the temperature of the steam-tracing circuit over a period of
time. On flowing pipelines the steam will continually transfer
energy to the fluid at a higher rate because the temperature
differential between the steam and the fluid essentially stays
constant. Both conditions provide more heat energy to the system
than is required to maintain design conditions. To date, there is
no reliable method for controlling the pipeline temperature and
energy usage. Depending on the type of steam trap used; even under
perfect working conditions, there will always be some loss of
steam. If the traps fail-open, there will be a significant amount
of steam loss especially because these systems are in operation
24/7. A brief technical differentiation between steam and electric
heat tracing (mineral insulated) is provided in the table below.
Comparing Steam tracing to
electric Heat tracing
Typically, an electric heat tracing system is
approximately 75% of the total installed cost of a steam tracing
system, when taking into account the tracing system, the control &
monitoring, and the power distribution system.
The total installed cost will vary according to
location and specific heat-input requirements, but remain constant
as an industry average. Heat Tracing Solutions can perform a
complete technical and economic analysis on a customer’s heat
tracing system to determine the best value for that specific
application.
From a safety perspective, there is a much
higher probability of the potential for maintenance personnel to be
susceptible to burns while working on and around steam-traced
systems due to the exposed valves and traps. Electric heat tracing
on the other hand, is intrinsically safe since it has no exposed
circuits and also has ground fault protection.
Electrical heating systems can include a wide
variety of control and monitoring products, from simple mechanical
thermostats and signal lights to sophisticated multi-circuit digital
controllers. These control products vary the output of the heating
source to keep pipes from freezing or to maintain process piping at
elevated temperatures. From a maintenance perspective, with the
electric heating system, most maintenance can be based on results
from control and monitoring incorporated into the design of the
system itself.
Steam-tracing systems, on the other hand, do not
offer any reasonable form of control and monitoring. The largest
maintenance items in a steam tracing system are the steam traps, as
they are typically the items which are most likely to fail during
operation. The documented service life of a typical steam trap is
three years, with a minimum replacement cost of approximately $95.
As a result, it is also recognized that the maintenance of the
condensate return is always higher than that of the steam supply, as
the liquid and steam cause erosion of the elbows in the system.
This is why many condensate return systems are constructed of
stainless steel.
The chart shown below provides an example of
where the maintenance costs of the electrical heat-tracing and
steam-tracing systems are compared for a process maintenance
heating application.
3. Applications
a. INDUSTRIAL
vii. Rail & Points
Heating
vi. Instrumentation
v. Buried Pipelines
iv. Long Pipelines
iii.Tank & Vessel
Heating
ii. Process Temp
Maintenance
i. Freeze Protection
b. COMMERCIAL
vi. Heating of Fuel
Tanks
v. Hot Water Heating
iv. Under Floor Heating
iii. Snow & Ice Melting
ii. Roof & Gutter
Heating
i. Freeze Protection
c. TRACE HEATING PROCESS APPLICATION
TYPES
Freeze Protection:
The application of heating cable to pipe work/plant carrying
water or aqueous based solutions to prevent freezing
Temperature maintenance:
The application of heating cables to pipework and plant to
maintain their contents at a specific temperature above the
lowest expected ambient conditions
Raise and Maintain Temperature :
The application of heating cables to pipe work and plant to raise
the pipe and contents from a low start-up temperature to a
specific maintain temperature above the lowest expected ambient
conditions within an agreed period of time. This may also
include a change of state of product or may be required under
flow conditions.
4. Heat Tracing
System - Components
The components of the electrical heating system
include Heath tracing cable with installation, control and
monitoring equipment and implementation of an appropriate insulation
coating is essential to maintain the temperature and proper system
operation.
System Component:
A. Heat Trace Cable
B. Termination and Installation
Components
C. Control and Monitoring
D. Insulation
A. Heat Trace Cable
The heating system cables in terms of energy
production are in 2 types of self-regulation and constant power,
which are selected regarding to design and use.
A.1. Parallel Self-Regulating Heaters
Semi conductive parallel resistance heating
cables mainly for use in freeze protection or temperature
maintenance applications. Approved for use in both safe and
hazardous areas. For use up to 300°C (572°F).We can produce
self-regulating heating cables within the following ranges:
12 - 1000 Volts
Up to 300°C (572°F) withstand temperature
Up to 120 W/m of output
Very High Temperature
High Temperature
Low Temperature
A.2. Parallel Constant Power Heaters
to 500 °C
Constant Wattage heating cables (zonal heating
cables) can be conveniently cut-to-length, but are less popular
than self-regulating heating cables, because they often require
thermostatic control to ensure temperature safety.Suitable for use
in both safe and hazardous areas. We can produce constant wattage
heating cables within the following ranges:
12 - 1000 Volts
Up to 425°C (797°F) withstand temperature
Up to 200 W/m of output
High Temperature
Low and Medium Temperature
A.3. Series Resistance Heaters
(LONGLINE ) to 230°C
Series Resistance heating cables have to be
individually designed into particular length and load
configurations and so are not as versatile as parallel cables.
Suitable for use in both safe and hazardous areas. We can produce
series resistance heating cables within the following ranges:
Up to 6.6 kV 3 phase
Up to 230°C (446°F) withstand temperature
Up to 60 W/m of output
Up to 100 km of maximum circuit length
Low Temperature
Medium Temperature
Medium Temperature
High Voltage
B. Termination and
Installation Components
B.1. Terminations -
power end
Direct Entry Sealed Termination
Unit (DESTU)
This is an improved method, where
the j unction box is connected to the DESTU, which is mounted
onto the pipe surface. The tracer passes through the DESTU
into the junction box, avoiding the possibility of damage to the
tracer where it exits the thermal insulation.
Strip Free Unit (SF/T or SF/P)
The Strip Free connection box has been specially developed by
Heat Trace to reduce installation time and component costs.
Tracers can be terminated without the need to strip the ends of
self-regulating tracers. Strip Free units are available for
connection to the power supply and also for series and tee
connections. Strip Free boxes are particularly useful for small
diameter instrument lines which cannot support large junction
boxes.
Standard Method
This uses tracer termination gland components and a junction
box. To avoid the possibility of damage to the tracer where it
exits from the thermal insulation, a separate lagging entry kit
is required.
B.2. Terminations -
remote end
Moulden end seal
The silicone rubber end seal is fixed with an adhesive. It is a
simple and low cost form of sealing.
Strip Free End seal (SF/E)
The silicone rubber end seal is fixed with an adhesive. It is a
simple and low cost form of sealing.
Heat Shrink seal
The silicone rubber end seal is fixed with an adhesive. It is a
simple and low cost form of sealing.
A range of
miscellaneous components for use when installing Heat Trace
products:
B.4. Cable
Fixing Accessories
A range of
adhesive and non-adhesive fixing methods for securing heating
cable in position:
C. Temperature Control
Selection Guide
Type I process control -
maintaining above a minimum temperature level
is very energy wasteful. Not recommended-upgrade
to Type II process control.
Type II process
control - maintaining within a broad temperature band
can be achieved by air-sensing Power Match control
to provide good energy efficiency from the fewest number of
heating circuits i.e. least capital cost
Type III process
control - maintaining within a narrow temperature band
can be achieved by air-sensing Power Match control
plus fine-tune line control to provide good energy efficiency
from the fewest number of heating circuits.
D. Insulation
Precautions must be taken to
protect tracers from mechanical damage and moisture intrusion after
they have been installed and prior to the application of thermal
insulation. The installation supervisor shall coordinate with the
thermal insulation contractor, so that the thermal insulation is
applied as soon as possible after the installation and testing of
heat tracers.
It should be confirmed that the
thermal insulation to be installed is of the size, specification and
thickness used for the design of the heat tracing system. When a
tracer is installed onto the surface of a pipe, it’s effective
diameter is increased. The thermal insulation is usually provided in
pre-formed sections. Thus a small gap may occur due to the addition
of the tracer. In this case, ‘filler’ segments should be installed
to ensure full insulation.
Note that, if over-sized insulation
is used (i.e. the next pipe size up), then heat loss calculations
must be based on the over-sized pipe value.
Visual inspection
Carry out a visual
inspection of the thermally insulated system to ensure that:
moisture cannot penetrate the
insulation
screws used for fastening cladding
are short enough to preclude any possibility of damage to tracers
or temperature sensors.
entry cut-outs in the cladding for
heat tracers, temperature sensors, etc.., are dimensioned so as to
render contact impossible.
cladding joints and thermal
insulation entries are properly sealed with an elastic,
non-hardening sealant resistant to chemical attack.
5. Standards &
Approvals
Heat Trace takes and active part in
the development and implementation of electric heat tracing
industry standards.
Heat Trace’s products conform to
several International Standards, some of which are shown below:
6. DESIGN
(ORDER LINK)
Establish Design Parameters
Determine Heat Losses
Select the Proper Heating Cable
Determine Heat Tracing Circuit
Lengths
Control Selection
Choose Options/Accessories
Step1. Establish Design
Parameters
Piping / Equipment
Pipe size
Pipe length
Pipe material
Type and Number of Equipm
Type and number of support
Temperature
Min Ambient Temperature
Start-up Temperature
Maintain Temperature
Maximum exposure Temp
High Temperature – Limits
Electrical
Electrical area classification
Circuit Breaker capacity
Operating Voltage
Insulation
Type
Thickness
Step2. Determine Heat Losses
Safety Factor Considerations
Thermal insulation degradation
Supply voltage variations
Branch wiring voltage drop
Heating device voltage drop (if
applicable)
Increased radiation and convection on
higher temperature applications
Quality of installation of thermal
insulation
Calculating
the Heat Loss of Vessel & Tank
Step3. Select the Proper
Heating Cable
In order to determine the correct
heating tape or cable according to the application the following
information will be necessary
Maintenance temperature
Max. exposure temperature
Pipe or surface material
Supply voltage
Chemical environment
Area classification
Heat requirement
Step 3.1: Select Heating Cable
Family
Step 3.2: Select Heating Cable
Construction Options
Step 3.3: Select Thermal Output
Rating
Step 3.4: Check T-Ratings
Step 3.5: Select Voltage Rating
and Adjust for Alternate Voltages
Step 3.6: Determine Heat-Trace
Part Number
Step 3.1: Select Heating Cable
Family
Step 3.2: Select Heating Cable
Construction Options
C option cable is constructed with a
tinned copper grounding braid only.
CT/S option cable is constructed with
a tinned copper braid and Thermoplastic/Silicon Rubber over
jacket.
CF option cable is constructed with a
tinned copper braid and Fluoro polymer over jacket.
Step 3.3: Select Thermal Output
Rating
Example:
In the step above, we have chosen
the FS+ cable family and our piping is metallic. Therefore,
refer to cable data sheet, Calculated heat loss, Q, is (28.3
W/m). Find this point on the Y-axis. Maintenance temperature is
(60ºC). Find this point on the X-axis. Choose the cable that lies
above this point on the graph.
Step 3.4: Check
T-Ratings
Step 3.5: Select
Voltage Rating and Adjust for Alternate Voltages
Step 3.6: Determine
Heat-Trace Part Number
Step 4 Determine Heat
Tracing Circuit Lengths
Circuit Breaker Selection
To select the circuit
breaker size, determine the following information:
Maintenance Temperature
Heat Loss per Meter of Pipe, QT
Pipe or Tubing Size
Pipe Length
Type and Number of Valves
Type and Number Supports
Heating Cable Catalog Number
Minimum Start-Up Temperature
Heating Cable Out put
Step 4.1: Determine the Total Cable
Length
Pipe length of 50 m single pass
application
2 Butterfly Valves, additional
cable 0.6 m each valve
10 Pipe Shoe Supports, additional
cable per support is 0.6 m
= 50m 45FS+2-CF
=1.2m 45FS+2-CF
= 6m 45FS+2-CF
Total Cable
length required = 57.2 m 45FS+2-CF
Step 4.2: Determine the Total
Cable Length
Finding the heating cable type
Minimum expected start-up temperature
From Heating cable Data Sheet select
the circuit breaker trip rating
Compare the maximum circuit length for
each breaker rating to the total cable length required for each
pipe.
Select the breaker rating whose maximum
circuit length just exceeds the total cable required for the
pipe.
Number of
Circuits = Total Cable Length / Maximum Circuit Length
