Pipe Heating Heat Trace Technical Specification

ELECTRIC HEAT TRACKING SYSTEM SPECIFICATION

( PROCESS LINES ELECTRIC HEATING SYSTEM TECHNICAL SPECIFICATION )

1. SCOPE

2. CODE AND STANDARDS

3. ELECTRICAL FIELD CLASSIFICATION

4. DESIGN BASICS

5.DESIGN

6. APPLICATION TYPES

7.MATERIAL PROPERTIES

8.CONTROL PANEL

9. INSTALLATION

10. GROUNDING

11.ISOLATION

12.TEST AND COMMISSIONING

13.DRAWINGS AND DOCUMENTS

  1. SCOPE:

1.1. This specification covers the general conditions necessary for heating pipes and equipment by wrapping them with electrical heating cables specially produced for PROTECTION OF PROCESS TEMPERATURE, and the minimum conditions required for the selection of heating cables and accessories required for electric heating, control system design, manufacturing, assembly, testing and commissioning.

  1. CODES AND STANDARDS

2.1. The electrical heating system must have been designed, manufactured, installed and tested in accordance with the latest version of the codes and standards specified below.

-IEC 60079 Electrical Equipment Suitable for Explosive Gas Environments

– Degrees of Protection Provided by IEC 60529 Protection Boxes (IP Code)

-IEC 60800 300/500V Rated Voltage Heating Cables for Anti-Icing and Comfort Heating

-BS 6351 Electric Surface Heating

-IEEE Std.515 IEEE Recommended Practical Information for Design, Installation, Testing and Maintenance of Electrical Heat Monitoring Systems for Industrial Applications

  1. ELECTRICAL SITE CLASSIFICATION

3.1. Equipment, materials and installation must comply with the electrical classification required by the site.

3.2. Electrical materials and equipment to be used in non-explosive areas must have environmental protection and must be at least IP65 protected.

3.3. If any electrical heater cable work is required in potentially explosive areas, material temperature classes should be selected based on the minimum auto-ignition temperature as specified in NEC Standard Part 500 or EN50014; device protection boxes and electrical installation material must comply with the field class and have an internationally valid certificate ( ATEX ).

  1. DESIGN BASICS:

4.1. Minimum air temperature ……..

4.2. Maximum air temperature ………

4.3. Maximum wind speed ≤ …….. km/h

4.4. For electric heating system, 400VAC,50Hz,3Ø, N, PE or 230VAC, 50Hz, 1Ø, N, PE should be used.

4.5. Environment: Exproof / Non-Exproof

4.6. Information and documents to be provided by the BUYER:

– Pipe list to be heated

– Pipe diameter and material and length

– Pipe route (pictures of isometric and general locations).

– Pipe and Instrument diagrams (P&ID)

– Fluid name

– Fluid flash temperature (in explosive atmospheres)

– Insulation type and thickness

– Desired temperature value

If this information is not available as drawings and documents, their determination will be made on site by the contractor.

  1. DESIGN

5.1. All applications will be made according to the calculated heat loss. Calculated heat loss values will be given with the offer.

5.2. The heater cable with the closest value to the calculated heat loss should be selected. A large number of low power heaters will not be used to compensate for the heat loss.

5.4. When calculating the heat loss, a minimum of 20% safety factor should be considered.

5.5. Self-regulating heating cables should be used in the Heat Tracing system, which is required to keep pipelines or tanks at high temperature or to increase them from a certain temperature to a certain temperature.

5.6. When calculating the heater cable length, the one on the pipe; Materials and equipment such as Flange, Pump, Valve, Pipe Support / Suspension Elements, Vents and Drains, Instruments should be considered. The required cable allowances for these should be added to the total cable amount.

5.7. Each heating system will be divided into zones (zones) according to the maximum circuit length of the heater cable (taking into account 5% voltage drop). Each zone will be monitored from the main screen with a separate temperature sensor for process heating or temperature maintenance.

5.8. Each zone (zone) will form 1 circuit.

5.9. Each circuit will be fed through single-phase and combined devices with residual current protection (RCBO) at the outputs.

5.10. Minimum start-up temperature will be taken as +10°C.

5.11. Plc devices should be used for temperature control.

  1. APPLICATION TYPES:

It is applied for electric heating systems, frost protection, process heating and melting. The control panels to be designed for these applications will be sufficient to operate in the following modes.

  1. Auto Mode :

When the Selector Switch is in the “AUTO” position, the plc also works automatically.

  1. Manual Mode :

In manual operation, the system is activated by moving the selector switch to the “MAN” position. The heater system operates independently of the sensor and provides continuous heating.

6.1 PROCESS HEATING SYSTEM

The purpose of the process heating system is to raise the pipes and equipment, which are liquid inside, to high temperatures by giving sufficient heat to their outer surfaces or to maintain their current high temperatures.

Energizing and de-energizing of the electric heater should be done by the plc and the touch screen, which are set according to a certain temperature.

Surface temperature element detected by an RTD sensor placed on piping or equipment must be used with PT100 modules in the PLC.

Each process heating system control panel should contain the following equipment;

– Main circuit breaker,

– In each heater circuit; “Man – Off – Auto” Selector Switch, contactor, residual current fuse (RCBO),

– Lamp Test Button

– In the heating system, the pipe temperature should be measured using a Pt-100 type surface sensor.

– PLC and touch screen must be suitable for communication with the existing system.

– The brand in which PLC is used must be approved by the EMPLOYER firm.

– The touch panel software should provide the following information to the user;

  • Language selection should be possible on the screen. (Turkish English)
  • Circuit name, current temperature of the line, set temperature, Man-0-Auto switch position, line ready to operate, running fault information should be visible on the main screen.
  • There should be a pop-up page on the main screen to make simple temperature adjustments for each heater.
  • Set temperature, offset value, hysteresis values should be adjusted by opening a separate pop-up page for each circuit on the settings screen. The system should be able to be started and stopped manually on the page. In addition, the line-related heater is active, high temperature alarm, low temperature alarm, contactor did not pull, contactor contacts stuck, Sensor not connected information should also be monitored.
  • In the settings page, the activation times of the lines should be adjusted so that the entire system is not activated at the same time in case of power cuts.
  • On the settings page, the operating times of the line and the number of activations should be followed.
  • On the Alarms page, all system-related alarms should be monitored as active alarms and historical alarms.
  • Voltage current power information of the panel should be able to be monitored on the analyzer screen.
  • The HMI must have Modbus TCP-IP Ethernet communication. It should be in a structure suitable for remote access (with VNC etc. programs).
  • User definitions can be made on the HMI.

 

  1. ELECTRIC HEATING SYSTEM MATERIAL FEATURES

7.1. SELF-REGULATING HEATER CABLES

  1. The output power of the heater cable should vary according to the changing temperatures along the pipeline due to heat-losing parts such as pipe fittings, support elements.
  2. The heater cable must be shielded with metal braid.
  3. Self-regulating heating cables must be resistant to 225 0 C when energized and 225 0 C when de-energized. The output power of the heating cables will be zero at the maximum withstand temperature.
  4. In the case of corrosive chemicals such as acid and base, the outside of the metal mesh should be covered with a Teflon outer sheath.
  5. The cable should be cut in desired lengths and suitable for use, depending on the installation situation.

Heating cables should preferably be one of ISITMAX, HTS GLOBAL. In the use of different brands, approval must be obtained from the EMPLOYER company officials.

7.2. BOXES

Supply and sensor junction boxes to be used in the field must have the following features.

  • Must be made of glass fiber reinforced polyester
  • IP-65 protection class
  • Operating temperature: -40°C / + 70°C

7.3. TERMINATION AND CONNECTION KIT

It should be silicone-based, specially produced for this purpose. These kits should be used with liquid gaskets with suitable features. The kits must be exproof certified.

Certificate Ex II 2 GDExe IIC Gb Ex tb IIIC Db

Operating Temperature: -40°C / 250°C

7.4. WRAPPING TAPES

Polyester based tapes will be used for low temperature and antifreeze applications, and glass fiber tapes will be used for high temperatures.

7.5. EXPROOF TERMINATION KITS

Heating cables or Pt-100 sensors should come out from under the insulation and enter the junction boxes through this kit and should not be exposed. These kits must be exproof certified with features suitable for the environment.

  • Protection class:IP-54
  • Certification: Ex II 2G Ex eb IIC T3-T6 G
  • Operating Temperature: -40°C / 230°C

All junction boxes can be gathered on a platform depending on the condition of the field. Heating cables and sensors must be connected to junction boxes with suitable cable glands.

7.6. WARNING LABELS

Labels bearing the warning “CAUTION ELECTRIC HEATING EXISTS” will be affixed on the metal coating of the insulation. It will be resistant to outdoor environment, rain and snow. In addition, the writing on it will be resistant to the sun and will not fade.

7.7. PT-100 SENSORS

To measure the pipe surface temperature, it must be 3-wire. Pt-100 sensor termination kit and junction box should be used together.

7.8 SUPPLY CABLES

The cables will be 0.6/1kV pvc-xlpe insulated, multi core, copper conductor type cables.

7.9 SENSOR CABLES

The cable to be used must be LIHCH type with a cross section of 3×1.5mm2.

7.10 CABLE GLANDS

Brass cable glands must be used for the supply cables. Spiral holder glands should be used for sensor cables.

  1. CONTROL PANEL MANUFACTURING

8.1. The electric heating panel must be made of at least 2mm sheet metal.

8.2. The panel sheet should preferably be TEMPA Pano or ERDEM Pano brand. Panel switchgear materials will be Siemens or Schneider brand. Approval must be obtained from the EMPLOYER company officials for the use of different brands.

8.3. Interconnection cables inside the panel will be passed through special cable channels.

8.4. The touch screen should be placed on the cover so that it can be adjusted without opening the panel cover.

8.5. All control cabinet, electrical equipment and control devices shall be labeled in accordance with the vendor’s drawings. Remarks will be determined by buyer’s requests.

8.6. Each control panel must have a nameplate on the front surface showing the panel number and description and must be written in letters of at least 12mm height.

8.7. There will be an espagnolette lock on the panel cover.

8.8. At least 20% clearance must be left on the panel mounting plate!

  1. ASSEMBLY

The company will share the reference list and the distributor letter.

9.1. In general, heating cables are mounted on the pipes as a single line without spiraling. Where the heat loss exceeds the output power of the cable, the second heater can be used in parallel.

9.2. Self-regulating, fixed-strength cables are attached to the pipe surface with a PVC polyseter or glass fiber adhesive tape at maximum intervals of 0.3 meters.

9.3. The heating cable and the energy cable to be drawn from the control panel will be combined in minimum IP65 protected junction boxes placed on the pipe.

9.4. The PT100 sensor and the sensor cable to be pulled from the control panel will be combined in minimum IP65 protected junction boxes placed on the pipe.

9.5. The PT100 sensor to be used will be suitable for the field conditions.

9.6. The junction boxes to be used must be attached to the pipe with a termination kit and stainless clamp or on a platform.

9.7. A self-adhesive WARNING LABEL should be placed on the pipe insulation to be made after the heater cable assembly is completed, indicating that the electrical heater is present.

  1. GROUND

Each feeder cable coming from the panel to the junction boxes must contain a yellow/green ground wire. This grounding wire must be according to the standards and the heating cable must be grounded by connecting to the metal mesh screen outside the heating cable.

  1. INSULATION

Insulation type will be Rubber. Insulation thickness should be taken as a minimum of 19mm.

All thermal insulations are made of aluminum, stainless steel, etc. must be metal-clad and mounted without gaps. The metal coating thickness should be a minimum of 0.5 mm. Water must not leak into the insulation. The edges of the metal coating should be insulated with external type silicone to prevent water penetration into the insulation.

  1. TEST AND COMMISSIONING:

12.1. The specified checks and tests must be performed on each control board and on each heater cable.

12.2. The authorized representative of the MASTER COMPANY has the right to check the control panel and the electric heater cables according to the industrial standards, the manufacturer’s standards and the manufacturer’s drawings.

12.3. Each control panel should be energized at the factory and all operating and alarm functions should be tested.

12.4. In the field, all heater wires must be 500 VDC Meger tested.

12.5. Before assembly, Meger test should be performed on the heating cable.

12.6. After the cables are laid, the Meger test should be performed on the heating cables before the pipe insulation is applied.

12.7. After the heat insulation is done, Meger test should be done on the heater cable.

12.8. All Meger readings should be 20 MΏ or higher. Otherwise, the heater cable must either be repaired or replaced. Field Meger tests should be recorded and reported for each cable.

  1. DRAWING AND DOCUMENTS

13.1. The contractor should specify the following information in the information sheets to be created as a result of the design studies.

– Line number

– Line diameter

– Line material

– Fluid

– The flashing temperature of the fluid

– Line length

– Number of valves

– Number of flanges

– Number of equipment

– Number of supports

– Insulation material and thickness

– Amount of heat loss (Heat loss)

– Selected heater cable type

– Length of heater cable

– Number of turns (spiral pitch)

13.2. Layout drawings of the heating system will be prepared.

13.3. Will prepare cable layout drawings.

13.4. Circuit diagrams of the panels will be given.

13.5. User manuals of all electrical devices and materials used will be given.

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