( PROCESS LINES ELECTRIC HEATING SYSTEM TECHNICAL SPECIFICATION )
2. CODE AND STANDARDS
3. ELECTRICAL FIELD CLASSIFICATION
4. DESIGN BASICS
6. APPLICATION TYPES
12.TEST AND COMMISSIONING
13.DRAWINGS AND DOCUMENTS
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.
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
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 ).
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.
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.
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.
When the Selector Switch is in the “AUTO” position, the plc also works automatically.
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;
7.1. SELF-REGULATING HEATER CABLES
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.
Supply and sensor junction boxes to be used in the field must have the following features.
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.
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.
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!
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.
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.
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.
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.
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
– 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.