The mechanical rooms in large multi-building industrial facilities are the hub of process temperature and climate control. Areas such as central utility plants, boiler and chiller rooms, mechanical and electrical rooms, and fuel rooms house myriad process cooling and heating equipment as well as systems for comfort heating, ventilation and air conditioning equipment and systems.
While modern heating and cooling systems are intelligent and efficient, their operation requires routine maintenance and response to the occasional unexpected event. The equipment within these rooms also has the potential to leak toxic gases.
When technicians enter any mechanical room, they need to be alerted to potential toxic or combustible gas leaks. The danger to workers who unexpectedly encounter refrigerant and natural gas leaks is real, with potential consequences causing symptoms and injuries that range from breathing difficulties to disorientation, falls, concussions or loss of life.
Monitoring Refrigerant Gas
You might be surprised to know it, but refrigerant gas is also considered a toxic gas. Although refrigerants are considered to have low toxicity, at high concentrations in crowded equipment areas, they can displace oxygen and lead to severe breathing difficulties. Oxygen deficiency causes too many worker injuries and deaths every year. It is considered a major worker health issue and monitored closely by the Occupational Health and Safety Administration (OSHA).
Failing to equip, train and protect technicians working in mechanical rooms from the potential hazard of oxygen deficiency and combustible gas leaks is a serious matter that can result in severe consequences for plant managers and building operators. There are mandatory reporting requirements when serious accidents occur. If releases exceed certain thresholds, the resulting investigations can lead to civil or criminal penalties.
When technicians enter any mechanical room, they need to be alerted to potential toxic or combustible gas leaks.
Furthermore, refrigerant chemicals are controlled substances regulated by the Environmental Protection Agency (EPA), which means not only are they dangerous to worker health and safety, but they are harmful to the environment. Many of these refrigerants are categorized as ozone-depleting substances and are highly monitored to protect the environment.
Gas monitors satisfy the requirements for equipment-room emissions control included in the EPA’s regulations on the use of refrigerants. In addition to the EPA, there are specific gas safety requirements outlined under Standard 15 developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), as well as local building codes.
In addressing gas safety, ASHRAE Standard 15 requires that each machinery room contains a detector — located where a refrigerant leak would concentrate — and that the detector triggers audible and visual alarms — both inside and outside the mechanical room — and activates mechanical ventilation. While professional organization standards do not have the full force of law, they have been found to be de facto regulations in terms of their authority and enforcement.
In addition to health, safety and environmental concerns, there is another major issue to consider when dealing with refrigerant gases. They are expensive when leakage occurs. From older refrigerants to the new, low global-warming-potential refrigerants, they average $40 to $60 per pound (0.5 kg).
Early, reliable refrigerant-gas leak detection and repair keeps money in your pocket by reducing plant operating costs. For instance, according to the EPA, the average leak rate for commercial chillers is 35 percent per year, which can add up fast.
Choosing the right location for fixed-gas monitors and properly mounting them is extremely important.
Boiler Room Monitoring
In addition to monitoring for refrigerant leaks, it is important to monitor mechanical-room boiler equipment to ensure an adequate supply of air and to help reduce the buildup of combustible or flammable gas concentrations. The natural gas energy cost of an inefficient boiler’s burner air-to-fuel mixture also can be a significant source of lost revenue.
In addition to process systems, large building mechanical rooms with older boiler systems can be poorly maintained or controlled with inefficient legacy equipment. These situations can lead to natural gas leaks, which can result in oxygen-deficient working environments or can cause serious gas explosions and fires. Again, there is a health and safety responsibility to protect maintenance technicians from both the effects of toxic gas leaks and the effects of methane exposure (natural gas), which, even though odorized, can quickly overcome unsuspecting workers in crowded equipment areas.
Gas Monitor Installation Best Practices
No matter whether the concern is refrigerant or boiler gas, good industry practices call for installing fixed gas-monitoring equipment in mechanical rooms and training technicians in their safe use. Modern fixed-gas monitoring systems are highly responsive, reliable, intelligent and flexible to accommodate many mechanical-room designs and equipment configurations within those rooms.
Choosing the right location for fixed-gas monitors and properly mounting them is important. Even the best, most full-featured gas monitor — when placed in the wrong location or installed without a thorough understanding of the manufacturer’s requirements — can lead to poor performance and the failure to detect a significant gas leak.
Refrigerant gas monitors typically are installed or mounted vertically. Monitors should not be mounted to anything that is subject to vibration and shock such as piping. Vibration and shock are the enemies of refrigerant- and combustible-gas sensors designed for mechanical rooms. Their electromechanical designs can be compromised over time by vibration or shock, which could lead to false alarms.
Refrigerant gas monitors require proper ambient air cooling to operate properly. Be sure to allow at least 3” clearance around all surfaces except the mounting surface. Improper cooling can result in readings that are inconsistent, unreliable and require the premature replacement of gas sensors.
Refrigerant leak monitors such as this one meet ASHRAE Standard 15 and other safety, environmental and building code requirements for HVAC mechanical rooms.
Close attention must be paid to installing the refrigerant gas monitor’s air-sample points. Depending on the gas monitor selected, a sample point may be remotely located up to 150’ (46 m) from the monitor in an area where refrigerant vapors are most likely to leak or accumulate.
It is a widely accepted best practice to locate the sample point near the barrel of the chiller and on adjacent corners to enhance the ability to monitor leaks. Because refrigerants are heavier than air, be sure to monitor for refrigerant leaks in locations such as pits, stairwells and trenches. If possible, monitor the vent line of the chiller. Also, do not forget to monitor the cylinder storage area if it is inside or near the chiller room in case of cylinder leakage.
In conclusion, when protecting technicians and mechanical rooms, it is important to work with suppliers experienced in refrigerant and combustible gas detection. In choosing a gas monitor safety partner, consider the expertise, reputation, the product quality/reliability and service capabilities of the supplier. Do not be reluctant to discuss problems or seek solutions because many times you will find that your problem has come up before and been solved satisfactorily based on the manufacturer’s years of service and number of installations. PC