HVAC Engineering Precautions – It's Better Safe Than Sorry
Make sure you take the correct precautions when it comes to your system’s energy source.
Heating and air conditioning is something we all take for granted. We probably don’t remember that each type of heating and air conditioning system comes with a “user beware” awareness. Why user beware? Well, the energy source, whether it be fuel oil, natural gas, propane gas, refrigerant, or ammonia that generates the heating or cooling, each requires precautions when used as part of an engineered system.
I thought I’d highlight how each of these systems can be hazardous but want to note that all these heating and cooling sources are safe to use when engineered, operated, and maintained correctly.
Fuel oil heating — Oil leaks are not good for the environment and can occur in one’s home or in the building he or she works in. Pipe leaks primarily occur at fittings, valves, or on pieces of equipment. Leaks can occur around oil filters if the filter removal caps are not put back on correctly. Oil tanks, whether above or below ground, can experience leak(s) over time in the tank due to corrosion from within. The handling of oil in tanks must be done with care to prevent spills. Carbon monoxide is an odorless, colorless gas that results from burning oil, which can be lethal, so it’s important to make sure the equipment room has adequate ventilation maintained as equal or positive pressure within the room.
Gas heating and cooling — Unlike oil leaks, gas leaks can be deadly because gas is primarily made up of methane, which is highly flammable. Whether a heating or cooling unit, gas-burning equipment is similar to oil-burning equipment in that it produces carbon monoxide. Maintaining a positive pressure within the equipment room is needed to assure proper combustion and reduce the risk of carbon monoxide poison. Another safety concern with gas-fired equipment is the gas pressure safety relief valve that relieves the gas pressure when an excessively high-pressure setting is reached. These safety relief valves must be vented to the outdoors to prevent the gas from being released into the equipment room, where an explosion can occur from a spark or a flame in the vicinity.
Solutions to potential fossil fuel and gas hazards include routine maintenance inspections, leak detection systems, pressure-relief piping to the outdoors, heat detectors, carbon monoxide detectors, and preventing an equipment room from being under a negative pressure. Also, keeping the oil burner clean and in good working order is essential.
Refrigerant cooling and heat recovery — There is a wide range of refrigerants, and, for the most part, they are odorless. These gases can be harmful to one’s health and, occasionally, may be deadly. If deeply inhaled, they can cut off vital oxygen to a human’s cells and lungs. The major concern with the use of refrigerants is with large chiller equipment where hundreds of pounds of refrigerant are contained in a single refrigeration unit. A refrigerant leak will displace the oxygen in the room. For that reason, equipment rooms should have refrigerant monitoring and an exhaust evacuation system. Because of the large volume of refrigerant contained in a large chiller, these units have pressure relief valves that must be vented to the outdoors to protect any workers in the equipment room.
The solutions to these potential hazards are routine maintenance inspections, pressure-relief piping to the outdoors, refrigerant monitoring, and exhaust air system to the outdoors.
Ammonia refrigeration — This type of mechanical cooling is more common in the industrial sector of the refrigeration business versus mechanical cooling in the commercial and institutional sectors. This colorless gas compound is classified as a high health hazard, and exposure can be life-threatening with immediate burning sensations to the eyes, nose, throat, and respiratory tract. High airborne concentrations can be ignited and pose a significant fire and explosion hazard, especially in a confined space.
The solutions to these potential hazards are too numerous to list here, but there are guidelines (OSHA requirements, etc.) that explain how this gas can be safely used. In addition to its performance to provide low-temperature cooling, it does not have a greenhouse gas impact on the environment that chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) have. These refrigerants are being banned and phased out around the world.