Intrinsic Safety vs. Containment Methods: What Are the Pros and Cons for Your Industrial Setting?

Welcome to the first in our exclusive five-part series exploring the benefits of intrinsic safety technology in industrial facilities, vapors anywhere there are toxic chemicals, or even dust from garments in clothing factories. There are many ways to prevent or contain fires and explosions, but which should you use?

ICA takes a look at the various industrial safety methods that protect workers and equipment from fire or explosion, including containment, purging, and intrinsic safety.

 

Risks of Ignition and Combustion in Industrial Settings

Depending upon the nature of your industry, you’ll have several different industrial hazards that can lead to either a fire or an explosion. Some of the most common include, equipment that generates heat, or sparks generated within electrical devices or wiring connections. Manual equipment can also sometimes create sparks, which can ignite chemical vapor, dust, or any combustible material.

Part of your health and safety protocols should include a list of potential industrial hazards and hazardous areas.

Identifying Hazardous Areas

Hazardous areas are, by definition, any location where the level of danger to team members or assets is increased. Do you have areas where the temperature is frequently raised, such as exothermic reactors, or where food is cooked, or clay is fired? These could pose a fire risk, especially when combined with accidental fuels like flour dust. Inconstant pressure can be another hazard as it can move gasses and dust around into areas where it can catch fire. 

Anywhere your organization stores chemicals or fuel could potentially be classed as a hazardous area, but areas that use these products or that you have to transport these products through should also be included in the evaluation. That’s especially true for areas containing electrical devices, particularly if you don’t have measures in place to prevent sparks, such as intrinsic safety technology.

To understand if an area is potentially hazardous, you need to understand exactly what causes fires.

The Ignition Triangle

The ignition triangle is a straightforward method for assessing fire hazards. Every fire needs all three of the following: Oxygen, fuel, and an ignition source.

Oxygen can come from the air, but it may also occur when chemicals mix and produce levels of oxygen that are sufficient to initiate or sustain combustion. Ignition means a source of heat or a spark. Fuel is anything combustible. Industrial safety is, in part, assessing areas within your facility to discover where all three points of the ignition triangle exist. It also includes choosing suitable fire prevention methods to keep your site as safe as possible.

Choosing a Safety Method

How do you choose what industrial safety precautions to employ within your plant or factory? The first step is to understand the basics of each method and how it works to prevent fires and explosions caused by industrial hazards.

Containment

Containment is currently the most popular form of industrial fire and explosion safety method in the United States. 80% of industrial sites use some form of containment method, although many may also combine this with other safety techniques. It’s important to note that containment is not a form of prevention. Containment protects surrounding workers and assets from an explosion that has occurred. Anything within the containment area becomes damaged or destroyed, so there is always a constant cost factor when considering explosion containment methods.

Containment uses a system of enclosures to isolate an explosion or fire from the rest of the industrial setting.

Pros

  • Stops fires from spreading
  • Contains the force of explosions, protecting lives and assets outside the enclosures

Cons

  • Takes a segmented rather than holistic approach
  • Damage and destruction caused even by contained explosions can create further hazards
  • Intense staff training is required to ensure containment devices are being used or deployed correctly
  • Complex mountings and fasteners can lead to cutting corners, compromising the safety of employees and assets

Segregation

It’s possible to segregate a fire from the rest of the plant using different purging methods. This might include injecting nitrogen in the space to render the atmosphere inert and prevent combustion. Air pressure can also be used to prevent the movement of either dust or vapors, keeping the fuel source of combustion carefully contained. Insufficient purging can lead to devastating consequences, however, like the PETROLAB tanker ship that suffered an explosion due to accumulating gasoline vapors back in the 1990s. Several people were killed, and the entire ship and a wharf were destroyed. It took 63 hours to get the blaze under control. It’s important to realize that risks like this still exist in every setting that deals with chemicals or any material that produces dust or vapor. 

Pros

  • Purging can be used as a regular way to ensure piping systems or vessels are kept free of combustible materials
  • Purging can be effective with rigorous procedural control

Cons

  • Purging can be very expensive, particularly in terms of the equipment necessary to maintain specific pressure levels
  • Nitrogen poses an asphyxiation risk if not handled correctly

Protection and Prevention via Intrinsic Safety

Containment waits for an explosion to occur and then blocks it from spreading. Purging aims to remove fuel sources. Intrinsic safety goes one step beyond by removing the ignition source. As we saw above, with no ignition spark or heat source, combustion cannot exist. Intrinsically safe equipment has components and wiring methods that prevent sparks and hot surfaces from forming. This effectively removes one corner of the ignition triangle.

Pros

  • Prevents explosions and fires regardless of the environment
  • Can be implemented on a system-wide basis
  • Authorized for use in all classes and zones, including Zone 0 in the EU – this currently does not have a comparable designation in the United States, but that could change as education on industrial safety improves

Cons

  • Requires experienced electrical engineers to implement the system throughout an industrial setting
  • Limited to low voltage and DC applications

Short Term Savings vs. Long Term Safety

Why do so many industries rely on containment when intrinsic safety is often the better, safer option? It could be that cost is a concern, as it’s less expensive in the short term for some settings to deploy containment devices. However, those short-term costs are nearly always misleading. When fires or explosions do occur, the containment devices often have to be replaced, as do any components or pieces of equipment inside the enclosures. Intrinsic safety might cost more in the short term, but it creates a holistically safe environment, preventing fires and explosions. This organically provides long-term savings, protection of your assets, and, more importantly, a safer workplace for your teams.

Work with an expert team like ICA to ensure your organization takes advantage of the highest level of safety protocols. Get in touch for a comparative assessment and to find out more. In our next article, we’ll take a look at the origins and progression of intrinsic safety technology – where it all started and where we are now. Bookmark our blog to ensure you don’t miss it

If you want to view more videos

Intrinsic Safety with ICA Engineering – YouTube


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