Intrinsic Safety vs. Explosion-Proof Containment: How to Choose the Right Architecture for Hazardous Area Control Systems

In our third article on intrinsic safety, we build on the concept of explosion-proof containment and how it differs from intrinsic safety. Even with industrial automation in place, many skilled employees still work in hazardous areas, making safety a top concern for most industries.

Choosing the right architecture for control systems in hazardous areas is vital. When explosions happen, you want to know that you have systems in place to protect your workers, your assets, and prevent fire and contaminants from spreading. Yet having an intrinsic security and safety system in place to prevent explosions from happening in the first place is safer and more proactive. In this article, we’ll look at the key differences between intrinsic safety and explosion-proof containment, and explore which is preferable when creating industrial control systems.

A Brief Overview of Intrinsic Safety

As we’ve explored in our previous articles, intrinsic safety, or IS, is a globally recognized term that means electronics have been adapted for use within hazardous areas. Specifically, intrinsically safe devices are incapable of producing the electrical or thermal energy required to create a spark or otherwise ignite combustible substances.
This is critical for a range of industries including:

  • The food manufacturing industry, which creates dust and flammable vapors
  • Waste recycling, which deals with any number of combustible materials
  • Waste-water filtration, which utilizes flammable chemicals and creates flammable and explosive gases
  • Pharmaceuticals and other industries dealing with large amounts of volatile chemicals

IS can save lives in any industry that requires devices powered by electricity and involves flammable materials.

The Benefits of Intrinsic Safety

Intrinsic safety ensures the architecture of control systems prevents fire and explosions by reducing the voltage and current that passes through wiring and electric circuits. The primary benefits of this are:

  • Protecting the lives and wellbeing of employees
  • Cutting costs on expensive countermeasures and reactive solutions to dealing with fire and explosion
  • Allowing continuous production by preventing accidents and allowing for more on-site maintenance
  • Future-proofs industries by allowing them to be more connected and utilize more electronic devices and equipment

Of course, intrinsic safety isn’t the only industrial safety measure in use. For industries where fire and explosion are a risk, explosion-proof containment may be deployed. Explosion-proof devices have casings constructed from tough materials such as cast iron. If the device creates a spark in a hazardous area and explodes, the casing prevents the parts from flying out into the area and also contains flames and other sources of ignition. Explosion-proof does not, however, mean that the equipment or casing would survive an explosion that occurred outside the containment.

Key Ways that Intrinsic Safety and Explosion-Proof Containment Differ

1. Containment versus Prevention

Containing an explosion is critical. In 2008, the horrific Georgia sugar refinery explosion killed 14 and injured 40 more in an incident the U.S. Chemical Safety Board labeled as “entirely preventable.” The explosion, like many in the food industry, was caused by dust hanging in the air. This dust makes its way into electronic devices, so when sparks occur, the dust ignites. Fire travels so quickly through the dust that it acts like a pressure wave, causing devastating explosions. Containing explosions within the source device minimizes the impact and saves lives.
Conversely, devices that cannot produce a spark are intrinsically safe. They give workers and management peace of mind, as long as the power levels are controlled through the entire system.

2. Destruction of Equipment

While containing explosions is necessary, once the explosion-proof containment has done its job, the equipment will either need costly repairs or need to be replaced entirely. This is in direct contrast to intrinsically safe apparatuses that can be used indefinitely until they experience the usual wear and tear of their particular industry use.
In a packaging plant, industrial scales should last many years with regular maintenance. If the scales are not intrinsically safe, they could cause a spark and therefore an explosion. Explosions at packaging plants aren’t as uncommon as you might think. In 2020, chemicals at a Georgia packaging plant exploded and injured several people. One of the major concerns was contaminants escaping and harming the local residents. Thankfully, emergency responders prevented this from happening. Intrinsically safe equipment could, in many cases, prevent incidents like this from happening at all, protecting lives and saving costs on replacing equipment and other assets.

3. Maintenance of Equipment

Most industrial equipment needs regular maintenance to continue working at maximum efficiency. Explosion-proof devices are difficult to access, and the power must be switched off in the entire area once a contained device is exposed.
Many intrinsically safe devices can be worked on individually while the rest of the equipment in the area continues working as normal. Exposing the wires and circuitry on IS apparatus doesn’t pose a risk of explosion, helping to avoid downtime.

4. Upgrades or Rewiring Challenges

Similarly, when equipment needs to be upgraded, augmented, or rewired, explosion-proof devices must come offline. This makes it difficult to future-proof your plant, as you have to plan extensive upgrades around production schedules and demand. There may never be a time where you can upgrade explosion-proof equipment without reducing productivity.

5. Cost and Installation

Intrinsic safety technology is less expensive than explosion-proof containment. It is also less cumbersome to install in an existing setting. Many explosion-proof devices are bulky and take up large amounts of space, which could disrupt the equipment layout in a hazardous area. Intrinsic safety doesn’t take up any extra space unless additional devices need to be added to legacy systems to ensure correct power regulation.
Choosing the right architecture for your industrial control systems depends largely on your requirements as an industry. High-power equipment that won’t function with an energy reduction needs explosion-proof containment. For most other devices, intrinsic safety ensures electrical devices in hazardous areas are extremely unlikely to cause a fire or explosion. Contact ICA for more information on intrinsic safety and incorporating it in your industrial setting.

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