Understanding Explosion Proof Fan: Exd VS Exe

Identifying the omnipresent risk of flammable gases, vapours, or dust in a hazardous atmosphere is essential to ensure the safe operation of these crucial plants. A Hazardous Area Classification in the risk areas is assessed, and the substances posing the hazard must be defined to select the appropriate type of Explosion-Proof Fan required.

The level of risk is represented by classifying the hazardous area as Zone 0, Zone 1 or Zone 2 (for gas, vapour and mist atmospheres) or Zone 21 or Zone 22 for dust atmospheres. The Explosion Gas Group and Ignition Temperature of flammable substances are also clearly defined.

An Explosion-Proof Fan installed in a hazardous area must be qualified with the appropriate classification and protection. Designed to avert potential ignition sources, such as sparks or extreme temperatures, they prevent volatile atmospheres from igniting. Their pivotal role extends beyond safeguarding infrastructure, as they are also essential in protecting lives.

This article will discuss how the ignition source control is classified with the various Methods of Protection in an Explosion-Proof Fan. Two common designations of these protective devices are Exd and Exe. Delving deeper into these classifications will provide a clearer understanding of their significance and applications.

Exd: Explosion Proof Fan

Labelled ‘Exd’ or ‘flameproof’, these spark resistance fans have an Exd motor and a flameproof casing. This protection type contains any explosion produced inside the motor casing to propagate outside. They’re not about preventing an internal explosion; instead, they focus on containing it, ensuring no escalation to an external calamity. Especially in regions where explosive atmospheres are common, Exd fans come into play, assuring that potential equipment malfunctions leading to sparks remain isolated and preventing them from igniting the surrounding hazardous area.

The Exd motor of our Explosion-Proof Fan is of ATEX category II 2G, and it is suitable for ATEX Zones 1 and 2. Installation is easy because the user only needs to connect the power cables inside the connection box using flameproof cable glands, and standard motor protections are necessary outside the hazardous area. When this Explosion-Proof Fan is used with a frequency converter, the motor must be supplied with a PTC thermistor for overcurrent protection.

Exd protection is commonly used in areas with a high risk of explosive gas or vapour presence, such as chemical plants, refineries, and offshore oil platforms.

Exe: Increased Safety Fan

The Exe designation symbolises ‘increased safety’. As the name suggests, the motor of this Explosion-Proof Fan has an increased safety construction. This Exe protection type prevents any spark during the motor’s starting, operation or malfunction to avoid explosion sources in the motor.

The Exe motor is ATEX category II 2G, suitable for ATEX zones 1 and 2. Installation is more complicated as the user must connect power cables inside the connection box using increased safety cable glands, and a specially certified protection switch needs to be installed outside the hazardous area.

Their foremost defence line involves eradicating all probable ignition sources. They function below the ignition temperature of the surrounding explosive atmosphere, ensuring explosion conditions aren’t met. Their design elements include exceptional insulation to prevent electrical issues, firm connections to diminish spark risks, and, often, spark-resistant materials to mitigate ignition chances further.

Exe protection is often used in areas where the risk of explosive atmospheres is present. Still, the likelihood of internal explosions is low. It is suitable for many general-purpose electrical installations in hazardous areas.

Exd vs. Exe: A Comparative Deep Dive

Exd and Exe fans, critical components in the Explosion-Proof Fan lineup, are engineered with safety as their primary objective. However, their methodologies are different. It’s not a simple matter of picking one over the other. This choice is intricately influenced by various factors determining the potential for explosive incidents.

Here are the factors to consider:

1. Nature of the Risk: The type of explosive material is crucial when choosing an Explosion-Proof Fan for your facility.

• Gas: Environments with gaseous compounds demand vigilant monitoring. Certain gases, with low ignition temperatures, are easily combustible from minor sparks or overheating. Here, Exe fans, focusing on preventing ignition, might be more appropriate.
• Vapour: Vapours emanating often from volatile liquids can be explosive when exposed to open flames or sparks. Depending on the liquid’s volatility, the choice of fan can differ.
• Dust: Locations like grain silos or woodworking facilities present combustible dust threats. Combustible dusts don’t just pose ignition risks; their dispersion is a concern, too. In these scenarios, an Exd Explosion Proof Fan could be more suitable with its capability to contain internal blasts.

2. Frequency of Risk: Considering how regularly an environment is exposed to potential explosions is vital.

• Continuous: If risks are persistent, Exd fans, designed for maximum containment, may be crucial.
• Intermittent: A combination of Exe and Exd fans might benefit most in fluctuating risk environments.
• Rare: For infrequent risk settings, Exe fans, with their spark-resistant and preventive features, may suffice.

3. Surrounding Equipment: Considering the neighbouring infrastructure is imperative.

• Ignition Sources: Nearby machinery or systems can intensify the need for a robust Explosion Proof Fan if they are potential ignition sources.
• Cooling and Ventilation Systems: An existing ventilation system can influence the fan choice. A potent ventilation setup could enhance the preventive capabilities of an Exe fan.

In many scenarios, there’s no singular answer. Both Exd and Exe fans bring unique strengths to the table. Situations might necessitate an integrated strategy, capitalising on the preventive strengths of Exe fans and the containment strengths of Exd fans. This holistic approach ensures a comprehensive safety net for regular operations and unforeseen challenges.

Choosing the Right Explosion Proof Fan

The science and technology driving an Explosion Proof Fan stems from extensive research, development, and field application. This commitment to design and efficacy is born from an overarching objective of ensuring unmatched safety in hazardous locales.

Exd fans, with their robust design, prioritise containment, ensuring that internal threats don’t evolve into larger external ones. They’re indispensable in places with regular explosive atmospheres.

On the other hand, Exe fans focus on a proactive approach, not just responding to threats but also preventing them from materialising. Their designs prioritise preventive methods, from top-notch insulation to well-optimised electrical connections, showcasing an evolved approach to safety.

Understanding these fans’ nuanced differences is crucial for industry experts. This understanding shapes equipment choices and ensures the workforce’s and infrastructure’s safety.

As industries evolve, the requirement for a trustworthy, efficient, and secure Explosion Proof Fan remains unwavering. Beyond operational efficiency, they symbolise a dedication to safeguarding assets and lives now and into the foreseeable future.

For more reliable HVAC products and solutions like an Explosion-Proof Fan, Spark-Resistant Fan, Exhaust Fan, and more, you can always trust JA Redden. We offer only the highest quality ventilation products from Sodeca Spain with ATEX certification. Visit our website at www.jaredden.com.sg

Our assortment of ventilation products has been reinforced with a new series of inline mixed-flow fans in plastic casing Vents BOOST and Vents BOOST EC. The new product line is a logical follow-up to existing Vents ТТ PRO (EC) series.

Vents’ new product has embodied in itself all advantages of axial and centrifugal fans and received some serious additional improvements. One of its primary advantages is its high air flow efficiency reaching up to 5700 m3/h, which is almost three times more than models of ТТ PRO (EC) series can offer. Due to its high air flow capacity, Vents BOOST (EC) fans are an optimal solution for application in supply and exhaust ventilation systems of various commercial and industrial premises requiring powerful air flow.

These fans are made in polymer casing, which is perfect for premises with high humidity levels. The casing is reinforced with a metal housing adding it more reliability. Due to the conically-shaped polymer impeller with specially profiled blades, the air flow circular velocity is increased ensuring higher pressure and efficiency when compared with axial fans. Diffuser, impeller and airflow rectifier at the fan outlet provide smooth air flow distribution and enable the best combination of high air flow rate, increased pressure and low noise. Fan casing has external airtight terminal box for connection to power mains.

Vents BOOST fans are equipped with three-speed four-pole asynchronous motors and Vents BOOST EC line features energy-efficient ЕС motors. Fans are controlled by either a P3-5.0 three-stage or a smooth thyristor speed controllers, connected to the maximum speed terminal. EC models are regulated by a smooth 0-10 V controller.

The new fans are compatible with Ø 355 and 400 mm air ducts and may be installed in the beginning, in the middle or at the end of an air duct system. In order to achieve even greater air flow capacity, it is possible to install several fans in parallel. Moreover, it is also possible to install these fans in consecutive series with the purpose of increasing air pressure within the system.

For more product information, please our website at JA Redden.

There are various reasons why coils can fail prematurely. Sometimes, the coil was selected incorrectly, which made the coil significantly underperform. Most of the time, there is substantial corrosion or something else in the airstream that causes the coil to fail. However, most coils, when selected correctly with proper maintenance, can usually last from 10 to 20 years. Nevertheless, there are many factors that can affect the coil’s lifespan.

Reasons why coils fail prematurely:

• 70% of all coil performance is performed by the finned area on a coil, while the rest will be from the coil’s tubes. The fin/tube bond, which is the most important manufacturing process of any coil, becomes less efficient with thermal expansion and contraction over time. This naturally weakens a coil’s life and it became less efficient over time after operating for some years.
• During the routine cleaning of the coils, the dirt are often pushed into the center of the coil, especially on wet washing. This increases the air pressure drop across the coil. The cooling capacity of each coil is directly proportional to the amount of air going through the coil. If the air quantity going through each coil is reduced by 30%, it will mean that your coil capacity will also be reduced by 30%!
• Cleaning agents also corrode the cooling fins and it is detrimental to the coil’s performance, since each area of the fin surface matters in the overall cooling capacity.
• Coils usually fail because of leaks, due to erosion over time. The brazing on the coil construction will be failing from time to time, since the fluid travels through the coil at 0.6 to 1.5 m/s. Therefore, erosion is a major cause of coil failure, regardless of how well the coils are maintained.
• Corrosive air in the environment can also be another cause of coil failure. As such, you need to have a reliable and experienced manufacturer for replacing coils in your HVAC equipments.

What does plant operators usually do?

There are so many factors that contribute to a coil’s life. It is not unusual for operators to choose the easiest way out to try to get the failed coil working again, due to the replacement cost of involved on a new coil or the downtime required to get the coil replaced. In the end, operators are probably spending numerous attempts to try to repair the coil, hoping that it will last as long as possible. Unfortunately, the attempts do not work well and the most likely outcome is that they will need a new coil anyway, so why waste the time and money on a temporary solution?

New Replacement Coil is the Best Solution!

The true fact that coils need to be replaced rather than repaired is mainly due to energy costs. If your coil is not performing to the desired levels, you will need to increase the energy to make it work at its peak performance. Energy increases might be slight at first, but they are guaranteed to continue to rise over time. Whatever adjustment you made to your system, it is going to reduce its energy efficiency and cost you money!

If you have ever experienced repairing a coil, then you know it is labour intensive and typically not a permanent solution. Instead of going through such non-productive attempts, JA Redden will be glad to provide you our Coil Replacement solution anytime.