LEFT: ❶ Honeywell Analytics’ XNX is a universal transmitter that transmits gas readings from an open-path infrared gas detector for monitoring hydrocarbons in perimeters, duct runs, etc. and a point infrared gas detector for monitoring hydrocarbons around process machinery. PHOTO COURTESY OF HONEYWELL ANALYTICS ❷ Some explosion-proof devices, such as this pull station from Hochiki America Corp., can be used in haz- ardous areas. PHOTO COURTESY OF HOCHIKI AMERICA CORPORATION ❸ This Explosion Proof Vane Type Waterflow Switch signals a fire system any time water is flowing through the system. It is important to know if water is flowing, especially in a hazardous area which may have faster fire spread potential or limited runoff holding capabilities. PHOTO COURTESY OF POTTER ELECTRIC SIGNAL ❹ This Explosion Proof Post Indicator Valve Switch mounts to post indicator valves and some butterfly valves to provide a signal if the valve is closed more than two turns. A majority of fire suppression failures occur from a valve closed. Monitoring these valves, especially in explosion-proof environments is critical to ensuring system readiness. PHOTO COURTESY OF POT- TER ELECTRIC SIGNAL ❺ FAAST aspirating fire detector is designed to provide very early warning detection of fires before they become apparent. The detector is designed to be intrinsically safe (explosion-proof, safe operation in combustible areas) while contributing to rapid, reliable detection of flames at their earliest origin of development. PHOTO COURTESY OF HONEYWELL ANALYTICS ❻ This Explosion Proof Outside Screw & Yoke Valve Supervisory Switch monitors the closing of a valve from the full open position. This switch helps keep suppression systems from accidentally being closed when an emergency occurs in a hazardous area. PHOTO COURTESY OF POTTER ELECTRIC SIGNAL ❼ FD Series Flame detectors by Honeywell Analytics detect in ultraviolet, ultraviolet/infrared and triple infrared spectral ranges. These capabilities increase reliability while preventing false alarms. The detectors are designed to be intrinsically safe (explosion-proof, safe operation in combustible areas) while contributing to rapid, reliable detection of flames at their earliest origin of development. PHOTO COURTESY OF HONEYWELL ANALYTICS
there is not even a single widely recognized defini- tion of the term “hazardous.”
NO BOILER PLATE SOLUTIONS As Patrick Hogan, vice president of marketing for Lincolnshire, Ill.-based Honeywell Analytics explains, fire systems for hazardous areas typically are designed by an engineer who specializes in those systems, often for a particular industry. “The engineers responsible for the design use best prac- tices,” Hogan explains. “They create these based on an amalgam of national codes with their own standards. Bid specifications are very much best of breed. In heavy industrial operations, there’s not a lot of boiler-plated solutions.” Planning a fire system for a hazardous area is
likely to involve a range of processes, including risk assessment and mitigation. Engineers do a lot of modeling as well as engineering studies, explains Hogan. “They build a risk assessment model and create a mitigation or shut-down phi- losophy based on the likelihood of all of those things happening simultaneously,” he says. Corporations develop their own minimum stan- dards based on this kind of data, Hogan explains. “What is the acceptable level of risk, the frequency of an event, and how likely is it to go undetected. That combination gives them a math equation.” Using this information, Hogan describes, “They
may add more sensors and checks and balances in their systems: Before we turn this on, we must turn that on. That makes it unlikely we will open a valve without venting. They create very complex business models.”
Such tightly designed systems can cost tens of millions of dollars for a large installation such as a
Standards Bodies
Never was the saying, “The customer knows best,” truer than in the area of fire systems for hazardous areas. For example, no one is likely to be more familiar with the hazards and requirements of the chemical industry than a chemical company. Consulting with customers about the requirements of their industry is critical to devising the optimum fire system to meet their needs.
Here are just a few of the organizations with which you may need to consult:
• Compressed Gas Association (CGA);
www.cganet.com • Factory Mutual;
www.fmapprovals.com
• International Code Council (ICC);
www.iccsafe.org
• National Electrical Manufacturers Association (NEMA);
www.nema.org
• National Fire Protection Association (NFPA);
www.nfpa.org
• Occupational Safety and Health Administration (OSHA);
www.osha.gov
• Underwriters Laboratories;
www.ul.com November 2010 61
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