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Electrical Heater
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Electrical heater has been part of an industry around since the early 1900s providing heating elements for residential, commercial and industrial applications. In the latest decade the electric heaters have undergone extensive changes because of the standards that have been placed upon manufacturers who make them. There are many heaters on the market today that are well-known for presenting no fire hazards, and these heaters are well tested and maintain the safety standards that all heaters must have to be manufactured. NPI offers many alternatives to electric heaters such as the presence of NEMA 4 terminal boxes which prevent moisture from penetrating terminal boxes, as well as NEMA 7 explosion proof categories that help prevent sparks from occuring within the terminal boxes, Companies can purchase efficient electric heater by searching from the many online stores that supply them.


Namdaran Petrogas Industries Co. manufactures a complete line of flange heaters, circulation heaters, tubular heaters, and immersion heating elements for a wide variety of industrial and commercial applications since 1969. With a resourceful sales team and knowledge base, NPI is able to provide customers with neater and controls with exceptional, performance and reliability - making NPI the one stop for all heating product needs.

Our electric heating products are available with digital or mechanical controls and/or thermocouples to help provide customers with accurate temperature readings. Our heating products are also available with industrial grade safety features such as high limit cut off controls to help preserve valuable heating equipment from over-heating.

  • Industries served
  • Oil & Gas
  • Processing plants
  • Chemical
  • Marine
  • Power generation
  • Medical
  • Utilities
  • Petrochemical
  • Refineries
  • Pharmaceutical
  • Food processing
  • Construction
  • General manufacture
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Type of Electrical Heater
1) Flanged Heaters

Flanged industrial immersion heaters are commonly used in many chemical, petroleum and water based applications. Consisting normally of an ANSI rated flange with several hairpin elements or bugle tubular elements extending from the face of the flange, this electric heater uses direct heat application to the liquid medium. A thermowell is often used within the bundle of elements to allow for a probe (either a thermocouple, RTD or basic mechanical thermostat) to relay temperature readings to a digital controller that cycles and maintains the desired target temperature. Often a high limit sensor is also used to help protect liquid mediums from over-heating and, offers protection to the flanged heater as well.NPI flanged immersion heaters allow the flexibility of using many different alloys to help resist corrosion and maintain life longevity of the flanged heater. Steel flanges are typically used for lubricant oils, heavy and light oils, waxes as well as mildly corrosive liquids and low flow gas heating. Process water, soap and detergent solutions as well as demineralised or deionised water applications often use steel flanges. Stainless steel flanged heating elements are used with mildly corrosive solutions as well as severe corrosive solutions. Food applications also use stainless steel for sanitary purposes. The sheath materials used can be steel, stainless steel, copper as well as exotic alloys such as inconel, hastalloy and titanium. Extremely corrosive environments such as salt water should use exotic alloys such as titanium to avoid sheath breach over excessive durations. Industries that use exotic alloys can include military, chemical and process industries.

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Typical Application:

  • Natural Gas
  • Fuel Gas
  • Crude Oil
  • KO Drums
  • Catalyst Regeneration
  • Molecular Sieve Regeneration
  • Heating Medium
  • Glycol Reboilers
  • High Temperature Applications
  • Hazardous Area ‘L’ Immersion Heaters

Protection Control:

  • Dimension inspection
  • Electrical inspection
  • Mechanical inspection
2) L Type Immersion Electrical Heater

By using our immersion heaters you will get the most efficient heating, as all the energy which is generated, will be directly obtained by the medium, you are heating. The heating element in our L  type immersion heater is replaceable, which means that the heating element can be replaced rapidly almost without use of any tools, and furthermore you do not need to empty your tank or vessel while replacing .Our immersion heaters are available in a wide selection of rates, sizes and sheath materials suitable for heating of water, oil, air and other gases. We also deliver moisture resistant immersion heaters and models for hazardous areas. All our equipment can be delivered with approval according to your requirement.

3) High Temperature Electrical Heater

To attain high process temperature in some industries for oil and gas heat operations embedding two or three and sometimes even more vessels which comprise an electrical flanged heater each, might be an optimum solution.to purchase such level of temperatures influent passes through a series of parallel tubes or vessels and move in vicinity of heater elements and as it passes through every stage it gains more temperature to desired volume.it may use more than two or three bundles depending on temperature required by taskmasters. namdaran petrogas industries company is manufacturing all sort of electrical heaters and has the ability to fabricate them into various multipleand parallel designs in accordance with design codes and standard requirments.

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Control Panel

Namdaran petrogas industries company can supply electric control panels for the regulation and control of electric heaters to satisfy all customers requests without power limit. The panels are designed and constructed to guarantee maximum reliability and safety in accordance with the current standardsControl panels are used to regulate temperature and provide safety mechanisms in place to prevent overheating your liquid and protect your heating elements. Control panels come in many different terminal boxes - standard TEMA 1 terminal boxes, dust proof boxes, waterproof boxes and explosion proof boxes for hazardous areas. Digital controllers are used to display ambient and target temperatures of your solution. They contain contactors, relays, fuses, on - off disconnect switches, and other components to help regulate your NPI heater in a safe environment. In conjuction with thermocouples or RTD sensors, control panels are the "brains" of the system and determine the heat intensity of your heaters. Control panels are typically available for heaters generating at least 30 Amps to over 200 Amperes. Special accomodations can be made for systems that are over 200 Amperes. NEMA 4 terminal boxes are typically used for outdoor applications where concerns of moisture and humidity is a factor. Flow switches can also be used for circulation heaters. All Wattco control panels come with circuit schematics as well as support documentation that might be required for configuration purposes.
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• Basic models(remote mounted controls available upon request)
• Fully-equipped models
• Contactor power switching
• Stage contactor
• Solid state switching
• Design drawings
• Replacement parts
• Operating instructions
• Component manuals


  • Thyristor control system
  • Step contactor sequence control
  • PLC programming
  • Spares and after sales service
  • Factory testing:
  • Full load/ Heat soak testing
  • Harmonic analysis
  • R F interfacing test
  • Oscilloscope photometry
Soon after the introduction of electric power into coal mines, it was discovered that lethal explosions could be initiated by electrical equipment such as lighting, signals, or motors. The hazard of fire damp or methane accumulation in mines was well known by the time electricity was introduced, along with the danger of suspended coal dust. At least two British mine explosions were attributed to an electric bell signal system. In this system, two bare wires were run along the length of a drift, and any miner desiring to signal the surface would momentarily touch the wires to each other or bridge the wires with a metal tool. The inductance of the signal bell coils, combined with breaking of contacts by exposed metal surfaces, resulted in sparks which could ignite methane, causing an explosion.

Divisions or Zones (Gases, Vapors and Dust)
    In an industrial plant such as a refinery or chemical process plant, handling of large quantities of flammable liquids and gases creates a risk of leaks. In some cases the gas, ignitable vapor or dust is present all the time or for long periods. Other areas would have a dangerous concentration of flammable substances only during process upsets, equipment deterioration between maintenance periods, or during an incident. Refineries and chemical plants are then divided into areas of risk of release of gas, vapor or dust known as divisions or zones. The process of determining the type and size of these hazardous areas is called area classification. Guidance on assessing the extent of the hazard is given in the NFPA 497 Standard, or API 500 and according to their adaptation by other areas gas zones is given in the current edition of IEC 60079.10. For hazardous dusts, the guiding standard is IEC 61421.10.Typical gas hazards are from hydrocarbon compounds.

Safe Area
  An area such as a residence or office would be classed as safe area, where the only risk of a release of explosive or flammable gas would be such things as the propellant in an aerosol spray. The only explosive or flammable liquid would be paint and brush cleaner. These are classed as very low risk of causing an explosion and are more of a fire risk (although gas explosions in residential buildings do occur). Safe area on chemical and other plant are present where the hazardous gas is diluted to a concentration below 25% of its lower flammability limit (or lower explosive limit (LEL)).

Division 2 or Zone 2 Area:
  This is a step up from the safe area. In this zone the gas, vapor or mist would only be present under abnormal conditions (most often leaks under abnormal conditions). As a general guide for Zone 2, unwanted substances should only be present under 10 hours/year or 0–0.1% of the time.
Division 1 or Zone 1 Area:
Gas, vapor or mist will be present or expected to be present for long periods of time under normal running. As a guide for Zone 1, this can be defined as 10–1000 hours/year or 0.1–10% of the time.
Zone 0 Area:
Gas or vapor is present all of the time. An example of this would be the vapor space above the liquid in the top of a tank or drum. The ANSI/NEC classification method consider this environment a Division 1 area. As a guide for Zone 0, this can be defined as over 1000 hours/year or >10% of the time.
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Zones (Dusts)

In the case of dusts there is still a chance of explosion. An old system of area classification to a British standard used a system of letters to designate the zones. This has been replaced by a European numerical system, as set out in directive 1999/92/EU implemented in the UK as the Dangerous Substances and Explosives Atmospheres Regulations 2002
The boundaries and extent of these three dimensional zones should be decided by a competent person. There must be a site plan drawn up of the factory with the zones marked on.

The zone definitions are: Zone 20
A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is present continuously, or for long periods or frequently.

Zone 21
A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is likely to occur, occasionally, in normal operation.

Zone 22 A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is not likely to occur in normal operation but, if it does occur, will persist for a short period only.

Gas Groups

Explosive gases, vapors and dusts have different chemical properties that affect the likelihood and severity of an explosion. Such properties include flame temperature, minimum ignition energy, upper and lower explosive limits, and molecular weight. Empirical testing is done to determine parameters such as the maximum experimental safe gap, minimum ignition current, explosion pressure and time to peak pressure, spontaneous ignition temperature, and maximum rate of pressure rise. Every substance has a differing combination of properties but it is found that they can be ranked into similar ranges, simplifying the selection of equipment for hazardous areas.
Flammability of combustible liquids are defined by their flash-point. The flash-point is the temperature at which the material will generate sufficient quantity of vapor to form an ignitable mixture. It is a critical data in determining whether the area needs to be classified or not. A material may have a relatively low autoignition temperature yet its flash-point is above the ambient temperature then the area may not need to be classified. Conversely if the same material is processed(heated) above ambient temperature and the handling temperature is above its flash-point, the area MUST be classified. Each chemical gas or vapour used in industry is classified into a gas group.

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Apparatus marked IIB can also be used for IIA gases. IIC marked equipment can be used for both IIA and IIB. If a piece of equipment has just II and no A, B, or C after then it is suitable for any gas group.

A list must be drawn up of every chemical gas or vapor that is on the refinery/chemical complex and included in the site plan of the classified areas. The above groups are formed in order of how volatile the gas or vapor would be if it was ignited, IIC being the most volatile and IIA being the least. The groups also indicate how much energy is required to ignite the gas by spark ignition, Group IIA requiring the most energy and IIC the least.
Equipment Protection Level (EPL)

In recent years also the Equipment Protection Level is specified for several kinds of protection. The required Protection level is linked to the intended use in the zones described below:

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Temperature Classification

Another important consideration is the temperature classification of the electrical equipment. The surface temperature or any parts of the electrical equipment that may be exposed to the hazardous atmosphere should be tested that it does not exceed 80% of the auto-ignition temperature of the specific gas or vapor in the area where the equipment is intended to be used. The temperature classification on the electrical equipment label will be one of the following (in degree Celsius):

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The above table tells us that the surface temperature of a piece of electrical equipment with a temperature classification of T3 will not rise above 200 °C.
Auto-Ignition Temperatures (Vapors & Gases)

The auto-ignition temperature of a liquid, gas or vapor is the temperature at which the substance will ignite without any external heat source. The exact temperature value determined depends on the laboratory test conditions and apparatus. Such temperatures for common substances are:

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He surface of a high pressure steam pipe may be above the autoignition temperature of some fuel/air mixtures.
Auto-Ignition Temperatures (Dust)

The auto-ignition temperature of a dust is usually higher than that of vapours & gases. Examples for common materials are:

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Type of Protection

To ensure safety in a given situation, equipment is placed into protection level categories according to manufacture method and suitability for different situations. Category 1 is the highest safety level and Category 3 the lowest. Although there are many types of protection, a few are detailed.


Ex Code







 Equipment is robust can stand an explosion  from within, without transmitting the flame to the  outside.
 Equipment has flameproof gaps (max 0.006"  propane​/ethylene, 0.004" acetylene​/hydrogen)

IEC/EN 60079-1

Zone 1 if gas group & temp. class correct

Motors, lighting, junction boxes, electronics

Increased Safety


 Equipment is very robust and components are  made to a high quality .

IEC/EN 60079-7

Zone 2 or Zone 1

Motors, lighting, junction boxes

Oil Filled


 Equipment components are completely covered  with a layer of oil.

IEC/EN 60079-6

Zone 2 or Zone 1

Heavy current equipment

 Sand​/Powder​/Quartz Filled


 Equipment components are completely covered  with a layer of Sand, powder or quartz.

IEC/EN 60079-5

Zone 2 or Zone 1

Electronics, telephones, chokes

Electronics, telephones, chokes


 Equipment components of the equipment are  usually encased in a resin type material.

IEC/EN 60079-18

Zone 1 (Ex mb) or Zone 0 (Ex ma)

Electronics (no heat)



 Equipment is pressurised with a positive  pressure; gas cannot get in for air coming out  or  equipment is purged with a diluting gas  such as  air. If air is used, it is ducted in from  outside the  hazardous area.

IEC/EN 60079-2

Zone 1 (px or py), or zone 2 (pz)

 Analysers, motors, control boxes, computers

Intrinsically safe


 Any arcs or sparks in this equipment has  insufficient energy (heat) to ignite a  vapourEquipment can be installed in ANY  housing provided to IP54.
 A 'Zener Barrier' or 'opto isol' or 'galvanic' unit  may be used to assist with certification.
 A special standard for instrumentation is  IEC/EN 60079-27, describing requirements for  Fieldbus Intrinsically Safe Concept (FISCO)  (zone 0, 1 or 2).

IEC/EN 60079-25
IEC/EN 60079-11

'ia': Zone 0 &
'ib': Zone 1
'ic: zone 2

Instrumentation, measurement, control

Non Incendive


 Equipment is non-incendive or non-sparking.
 A special standard for instrumentation is  IEC/EN 60079-27, describing requirements for  Fieldbus Non-Incendive Concept (FNICO)  (zone 2) .

IEC/EN 60079-15
IEC/EN 60079-27

Zone 2

Motors, lighting, junction boxes, electronic equipment

Special Protection


 This method, being by definition special, has  no specific rules. In effect it is any method  which can be shown to have the required  degree of safety in use. Much early equipment  having Ex s protection was designed with  encapsulation and this has now been  incorporated into IEC 60079-18 [Ex m]. Ex s is a  coding referenced in IEC 60079-0. The use of  EPL and ATEX Category  directly is an alternative  for “s” marking. The IEC standard EN 60079-33  is made public and is expected to become  effective soon, so that the normal Ex certification  will also be possible for Ex-s.

IEC/EN 60079-33

Zone depending upon Manufacturers Certification

As its certification states

The types of protection are subdivided into several sub classes, linked to EPL: ma and mb, px, py and pz, ia, ib and ic. The a subdivisions have the most stringent safety requirements, taking into account more the one independent component faults simultaneously.
Multiple Protection

Many items of EEx rated equipment will employ more than one method of protection in different components of the apparatus. These would be then labeled with each of the individual methods. For example a socket outlet labeled EEx'de' might have a case made to EEx 'e' and switches that are made to EEx 'd'.

IP Code

Solids, First Digit
The first digit indicates the level of protection that the enclosure provides against access to hazardous parts (e.g., electrical conductors, moving parts) and the ingress of solid foreign objects.

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Liquids, Second Digit
Protection of the equipment inside the enclosure against harmful ingress of water.

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Cable Gland Selection

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