SCBA and You: Is the air you’re breathing safe?
Learn about the common contaminants that affect your compressed breathing air
Sponsored by Trace Analytics, LLC
By Molly Natchipolsky, FireRescue1 BrandFocus Staff
Self-contained breathing apparatus (SCBA) is a critical piece of personal protective equipment (PPE) issued to firefighters. By wearing an SCBA filled with clean, compressed breathing air, firefighters protect their respiratory system from fire, smoke, heat and toxic gases, allowing them to do their jobs for extended periods under extreme conditions.
But it’s not just the elements or toxins within a fire or hazmat incident that can compromise the health and safety of firefighters. Contaminants from unregulated or irregularly tested compressed breathing air compressors and cylinders can cause serious illness or even death. Therefore, compliance with NFPA 1989: Standard on Breathing Air Quality for Emergency Services Respiratory Protection is critical.
“The key to reducing the risk for contamination is quarterly testing of compressed air breathing systems by an accredited laboratory, as well as testing any time contamination is suspected,” explained Ruby Ochoa, President and owner of Trace Analytics and a member of the NFPA 1989 Technical Committee.
Take a look at the four most common contaminants, how they compromise health and safety, and what can be done to mitigate these risks:
Carbon Dioxide (CO2) is a by-product of motor exhaust, human respiration, and natural decay of organic material. While CO2 is classified as a toxic gas, it can be tolerated at much higher levels than other contaminants, such as carbon monoxide. Carbon Dioxide stimulates the respiratory system, causing a person to breath faster and deeper. This accelerates the effects of CO2 and increases the intake of other toxins that may be in the breathing air. According to NFPA 1989, the limit for safe intake is 1,000 ppm.
The compressor intake is often the source of CO2 contamination. If the compressor takes in high levels of CO2, the air in the compressor’s cylinders will also contain high levels of CO2. This can occur if the intake is in a closed-off room that is used by many people at one time. Respiration in colder months can contribute to the build-up of CO2. Contamination can also occur when a compressor is placed in an area near vehicles that are running and emitting exhaust, such as in a station bay.
Carbon Monoxide (CO) is odorless, tasteless and colorless, making it one of the most dangerous contaminants because people don’t realize they’ve been exposed. When CO is inhaled, it bonds with hemoglobin, displacing oxygen and forming carboxyhemoglobin (COHb) resulting in a lack of oxygen to the body’s cells. This is especially damaging to the brain and the heart because they both require large amounts of oxygen to function properly.
The symptoms of CO poisoning are similar to the flu, which includes headaches, fatigue, nausea and dizziness. It can also cause disorientation and unconsciousness, putting firefighters who are exposed to carbon monoxide in greater danger. According to NFPA 1989, CO in compressed air should be limited to 5 ppm.
Like carbon dioxide, one common source of CO contamination in compressed air is the compressor. CO is a product of incomplete combustion and some compressors have oil-based lubricants that can produce carbon monoxide as they heat. However, the most common cause of CO contamination is the compressor’s intake air. The intake must be in a well-ventilated area, away from sources of carbon monoxide. Additionally, filters must be changed regularly to ensure they are working properly.
Although CO contamination is extremely dangerous, water vapor contamination is the most common. When ambient air is compressed, the air temperature rises, causing the compressor to squeeze the water vapor out of the air.
Excessive water can lead to corrosion, potentially exposing the user to harmful material from within the system. In cold weather, water vapor can freeze, causing an air flow blockage. High water content increases the risk of exposure to other impurities, such as corrosive particulates. Additionally, the system’s structural integrity can be compromised.
A high water vapor reading can mean that the filter is saturated. This decreases its efficiency for removing other contaminants, such as carbon monoxide. Be sure to change the filters regularly, especially in warm, humid climates.
Finally, contamination can also be the result of total volatile hydrocarbons in the compressor or air intake. A hydrocarbon is an organic compound comprising only carbon and hydrogen, such as ethanol, butane or toluene. A substance becomes “volatile” when it transitions from a liquid to a gas phase. You may see air quality specifications refer to THC (total hydrocarbons) which is the same as TVHC. Both represent the gaseous or vaporous oil found in compressed air.
Within the compressor, overheated lubricants can create fumes that slip through the filters and get into the cylinders. Likewise, intake air can capture vapors from motor exhaust or cleaning solvents in the station or nearby dry-cleaning shops, beauty salons, chemical plants, or industrial/manufacturing plants.
Regular maintenance and service, such as changing filters, will help alleviate this issue, as will positioning the intake in a well-ventilated area.
To ensure the safety and well-being of your firefighters, test your compressed breathing system quarterly by an accredited laboratory, such as Trace Analytics, a leader in compressed air laboratory testing since 1989.
“The goal of NFPA 1989 is to keep our nation’s firefighters safe. Trace Analytics wants to make the sampling and testing process as easy as possible for all departments to help achieve that goal,” said Ochoa.