ED+C Magazine

Less is More

March 2, 2012
wc1

Water mist fire protection systems have been successfully used for many years to keep people and property safe throughout the world. wcheadshot

Water mist technology was first introduced in North America in the early 1990s, and since then has proven to be highly effective at fire suppression, gaining credibility and recognition as a solid alternative to traditional sprinkler systems in commercial buildings. As both the control and suppression mechanisms have become better understood over the past decade, the use of water mist technology has expanded to a range of land-based buildings, including museums, hotels, data centers, hospitals and skyscrapers.

Water mist systems provide superior fire suppression capabilities compared to traditional sprinklers in both water usage and firefighting properties. They use less water and are more efficient at suppressing fires; the mist consists of fine droplets that absorb heat more efficiently than water drops discharged by traditional sprinklers therefore blocking radiant heat and cooling the flame. The micro-droplets also vaporize more efficiently, which reduces oxygen available at the flame source thereby enhancing fire suppression.  Less water means less damage, less clean-up time and less cost.

 

Mist Systems

There are two predominant types of water mist systems in the North American market: high pressure (>500 psi) and low pressure (175 psi or less). High pressure water mist systems use less water compared to low pressure water mist systems, and consume significantly less water than traditional sprinkler systems to effectively control and suppress fires. Fire tests with Marioff’s high pressure water mist system, HI-FOG, and traditional sprinkler systems show that HI-FOG used up to 90 percent less water to bring the same fire under control. This feature makes high pressure water mist systems more environmentally sustainable than traditional sprinkler systems.

High pressure water mist systems deliver potable water at a high velocity through specially designed and patented sprinklers targeting two main elements that fire needs to survive — heat and oxygen. The result is a mist consisting of fine droplets that have a significantly greater specific surface area (surface area per unit mass of water) and heat-absorbing capacity compared to water drops discharged from low pressure water mist systems and traditional sprinkler heads. Additionally, high pressure water mist systems typically require fewer nozzles than low pressure water mist systems.   

High pressure water mist systems also help minimize impact on natural resources. These systems eliminate the need for, and cost of, extending water mains or increasing water pressure. Water mist systems have become an important fire suppression option in areas where water is expensive, in short supply or not readily available, or where water pressure is low. The stainless steel tubes used in high pressure water mist systems do not rust and useful life can reach 100 years versus less than half which can be typical for black iron pipes that are used by traditional sprinkler systems. Furthermore the significant build-up of impurities and bacteria associated with the contents of black iron pipe is avoided, so clean-up is faster, safer and easier compared to traditional sprinkler systems. High pressure water mist systems minimize costly business interruptions and downtime, which allows organizations to recover more quickly after system activation.

 

Easy Installation

High pressure water mist systems have a distinct advantage in retrofit settings where buildings are being updated to meet new fire codes. Water mist technology is easily customizable and features small, lightweight, bendable stainless steel tubes that are more adaptable than those used in traditional sprinkler systems. This makes installation easier, especially in older buildings with tighter spaces. Water mist systems also take up less volume than traditional sprinklers as they consist of small tubing that is quick to install and easy to maneuver around unique angles, corners and architectural obstructions. The tube network is small enough to be hidden from view by using a variety of design elements, such as crown molding to preserve the building aesthetics.

 

Wider Acceptance

When water mist fire protection technology launched in North America more than a decade ago, architects, engineers, contractors and building owners began incorporating the technology into proposed building designs.

 In December 2011, water mist technology achieved a critical milestone when HI-FOG became the first water mist fire protection product to receive Underwriters Laboratory (UL) listing for Ordinary Hazard Group 1 (OH1) applications. This listing, together with HI-FOG’s Factory Mutual (FM) Light Hazard (LH) system approval, has paved the way for HI-FOG to provide a complete fire protection solution for a range of commercial buildings, including data centers, high rise buildings, hospitals, hotels and cultural heritage sites.