Toxic Fiends

To state the obvious, detecting toxic or combustible gases—or the lack of appropriate oxygenation in an area—before an event occurs is an important part of maintaining security in commercial, institutional and industrial applications, including wastewater plants, refineries and nuclear facilities. It also is an opportunity for electrical contractors to engage in a growing market as asset protection and personnel security become increasingly mandated.

According to Frank Yesh, marketing at Rel-Tek Corp., Monroeville, Pa., the three main types of gas hazards are toxic, flammable and asphyxiate. Examples of toxic risk is poisoning by carbon dioxide, carbon monoxide, hydrogen or chlorine. Flammable gases that present the risk of fire and/or explosion include propane, methane, compressed natural gas or liquefied natural gas, and asphyxiates result in suffocation when oxygen is displaced or consumed by reaction with another gas.

Different sensors detect different gases. Electrochemical cell sensors detect toxic gases in the parts-per-million range and are used in applications like boiler and mechanical rooms, according to Kevin McKeigue, senior marketing manager, fixed gas detection for Honeywell Analytics, Lincolnshire, Ill.

“The sensors’ cells have specific electrolyte solutions inside of them to sense a specific gas. When present, the gas charges the sensor, which takes a reading and signals the control center or building automation system, which then sounds the alarm, or takes other appropriate, preprogrammed actions,” he said.

Catalytic sensor technologies are used to detect combustible gases and are most commonly used in places like commercial kitchens, loading docks or other industrial applications.

“Catalytic beads are wrapped around a wire, and as the combustible gas makes contact with a bead, its temperature rises, changing the resistance of the wire and displaying an output level defined as the lower explosive limit or upper explosive limit. The control center can then take appropriate action based on that information,” McKeigue said.

Asphyxiant gases are hazardous only in special circumstances, such as enclosed spaces (e.g., mines), and the Occupational Safety and Health Administration, the National Institute for Occupational Safety and Health, and the American Conference of Industrial Hygienists guide exposure limits.

In the oil and gas industry, thermal camera systems, which can weigh up to 100 pounds and are made up of network or digital recording devices, are deployed in Class I, Division I hazardous areas to maintain surveillance and help prevent major catastrophes. Smaller cameras are used to detect oil or gas leaks in other applications, such as pipelines, and can also provide the perimeter protection of a facility.

The market for gas detection systems is growing at a rate of 5 or 6 percent per year in North America.

According to Will Moore, business development manager, oil and gas, at Pelco by Schneider Electric, Clovis, Calif., there is a $500 million worldwide potential sales market for the high-definition, pan, tilt and zoom thermal cameras that customers are demanding.

Gas detection systems used to be mostly stand-alone, but as the demand for the technology grows, they are being more frequently integrated with the building’s fire alarm system.

“In commercial facilities in particular, the security and life safety staff would not necessarily know what safe levels are or what appropriate action to take,” McKeigue said.

But when gas detection is tied into the security and life safety system, the fire department is notified, and those officials have the required expertise.

Where do contractors come in?
Yesh said the integration of gas detection system into the BAS is a growing application market that provides multiple opportunities for electrical contractors.

“These include basic relay outputs control fans and doors to provide desired ventilation to avert gas build-up and warn of increasing danger levels prior to an explosion, poisoning or suffocation by asphyxiates,” Yesh said.

Even those systems that must operate separately because of their platforms can share results with centralized integration displays.

To make the most of their opportunities in the market, contractors need to understand the building’s infrastructure, what the gas threats are and where they exist inside the building. The EC should also know how to best integrate gas detection into the fire and life safety system to provide the building owner with the requisite high level of safety.

“Contractors have an opportunity during the design phase to note where gas detection may be of benefit and can use their knowledge of codes to demonstrate what the mandated requirements are and what opportunities exist for the owner to generally improve the safety levels of the building,” McKeigue said.

In addition, gas detection systems will become a requirement as the nation’s transportation industry evaluates, and adapts to, alternative fuels, such as natural gas or methane.

“Electrical contractors could develop close relationships with gas system designers now to profit from this growing arena of low-voltage installation projects,” Yesh said.

BREMER, a freelance writer based in Solomons, Md., contributes frequently to ELECTRICAL CONTRACTOR. She can be reached at 410.394.6966 and

About the Author

Darlene Bremer

Freelance Writer

Darlene Bremer, a freelance writer based in Solomons, Md., contributed frequently to ELECTRICAL CONTRACTOR until the end of 2015.

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