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How Special Hazards Fire Suppression and Traditional Sprinkler Systems Differ

Posted by AnnMarie Fauske on 09.18.18

By Mike Angstadt, President, Flagship Fire (Guest Blogger) with Dr. Ashok Dastidar, Vice President of Dust and Flammability, Fauske & Associates, LLC

Foam Deluge System
Foam Deluge System

Not all fires are created equal, and how you attack a blaze depends on both the source and the surrounding environment. Most buildings will be adequately protected by a traditional sprinkler system, but in the wrong setting, a sprinkler system can cause additional damage to inventory or equipment, or even make the fire worse.

To understand why and how to choose the right fire suppression system, it's important to first understand how traditional and special hazards fire suppression systems differ.

How traditional sprinkler systems work

Traditional fire sprinklers send a spray of water to the immediate area. Each sprinkler head is heat activated and only triggers when it detects a temperature substantially above the norm. In a traditional setup, the sprinkler heads will not all turn on at once — each activates on its own.

The main goal of a traditional sprinkler system is to extinguish a traditional fire — the type that might be encountered if a stack of paper in an office or warehouse were to be ignited. This is accomplished by initiating a sprinkler head that disperses water over a predetermined area. Depending on the design of the system, this water might be dispersed as large droplets, a fine mist, or something in between.

Where traditional sprinkler systems fall short

The biggest downside to traditional sprinkler systems is the risk of additional property damage. This is especially true in a business setting with computers, other electronics, or paper documents that might be caught in the spray. While fire would also obviously be damaging, this doesn't mean that accepting water damage is the only other alternative.

The other area where traditional sprinkler systems are ineffective is in certain types of fires. Just like you shouldn't dump water on a kitchen grease fire, water can make electrical or industrial fires worse. In addition to spreading the flames, it could cause electrical shocks or other injuries to occupants who either haven't yet evacuated or are trying to extinguish the blaze.

Special hazards

There are numerous potential hazards that must be taken into account when designing a fire suppression system. Flammable liquids or bulk materials could be spread around by a liquid spray. Chemicals, gases, or other industrial materials may require a specific type of suppressant. In other cases, the fuel for the fire may allow it to burn too hot or too fast for traditional suppression methods.

Vapor ImageEach application requires its own special design to contain and control the flames. This may include using multiple types of fire suppression systems within the same building if different areas within the buildings have different needs. While this may involve a higher construction or refitting cost than a traditional sprinkler system, not using the right fire suppression system presents tremendous risk to life and property and may carry an increased insurance cost.

“Using a one-size-fits-all fire suppression system in locations of flammable/combustible pools or where deposited dusts could be present is very risky, states Dr. Ashok Dastidar, Vice President of Dust and Flammability, Fauske & Associates, LLC.  "The pressure or flow from the suppression system can loft the deposited dust or pool of flammable/combustible liquid creating a large flash-fire or even an explosion. Care and detailed engineering considerations should be taken when devising a fire suppression strategy. There is even a greater concern when metal fines and filings are present. Water suppression systems can react with the hot burning metal to create explosive hydrogen gas!”

How special hazards fire suppression systems help

Unlike traditional sprinkler systems, which often take a one size fits all approach, special hazard fire suppression systems are designed specifically to quickly and safely extinguish a particular type of fire in a particular environment.

There are several different types of these systems depending on the environment that needs to be protected.

Deluge systems

A deluge system dumps massive amounts of a mixture of water and foam all at once, rather than a slow and steady spray or mist. With a deluge system, the goal is instant extinguishment rather than containment.

Water deluge systems are used in high risk areas where there is extreme danger from a quickly spreading fire, but no chemicals or equipment that would make water ineffective or dangerous. Where water can't be used, a foam deluge provides an effective alternative.

Chemical systems

Chemical and CO2 suppression systems

Chemical systems provide a dry fire suppression alternative, using CO2 or other chemicals to starve the fire of the oxygen it requires to burn.

Chemical systems are commonly used in server rooms and other places with expensive electronics. The chemicals leave no trace and provide the possibility that the equipment can be used again in the future or can protect data for recovery. Chemical systems provide a dry fire suppression alternative, using CO2 or other chemicals to starve the fire of the oxygen it requires to burn.

There is little risk to life when these systems are used. They work quickly enough that the fire is suppressed and oxygen is restored from surrounding areas that most occupants will feel minimal, if any, effects.

Special hazards fire suppression agents

In order to be effective, a special hazards fire protection system must include both fire detection and control. Some of the common fire suppression agents used in special hazard fire suppression systems could include:

● Clean agents

● Inert gases

● CO2

● Water mist

● Foam

● Hybrid systems

● Dry chemicals

Know which system to use

Both traditional fire sprinklers and special hazard fire suppression systems have their place, and choosing the right system, or a combination of systems is essential to protecting property, equipment and personnel.

“I would also caution people occupying or repurposing a previously existing structure," adds Dr. Dastidar.  "The old fire suppression system was not designed for your specific process and the new inherent hazards that it brings. For example, a facility that was designed for general storage that now houses a metal working operation was not designed with a fire suppression system that can handle metal filings or fines. Re-engineering the suppression system is warranted. The same review is necessary if accidents involving flammable/combustible liquid spills are now possible in the repurposed storage location.”

For more information regarding fire suppression and traditional sprinkler systems, contact Mike Angstadt at Flagship Fire (866) 242‑3307.

For more information regarding a flammability test of liquids, gases, vapors and hazardous or combustible dust lab testing and related on-site safety services, please contact Dr. Ashok Dastidar at Fauske & Associates, LLC, info@fauske.com or 630-323-8750.

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