“Beware of false knowledge; it is more dangerous than ignorance.” — George Bernard Shaw
Because of the work we do, we often hear about OSHA requirements that don’t actually exist. Something akin to, “Well, OSHA says you have to…” Occasionally, they are right. More often though, the requirement fulfills someone’s agenda and OSHA is the boogeyman used to compel agreement.
Recently, we got a call asking about the OSHA requirement for oxygen monitoring in a boiler room. “I guess the concern is that there might be a leak of natural gas that lowers the oxygen concentration in the room.”
News of the OSHA requirement for oxygen monitoring in a boiler room came as a surprise to us.
What exactly are OSHA’s requirements for oxygen monitoring?
“OSHA Says”
A lot of the “OSHA says…” comments come from the marketers of oxygen monitoring systems. “…OSHA regulations require the use of an oxygen monitor anywhere that compressed gases or cryogenic liquids are used or stored indoors…”; “The Occupational Health and Safety Administration (known as OSHA) regulations thus require the fitting of oxygen deficiency monitors in any room where compressed gases are used or stored.” ; and “Employers are required to monitor and test atmosphere in workspaces where employee may be exposed to oxygen-deficient or oxygen-enriched conditions.” Are examples of assertions by marketers. What they have in common is that they do not cite the OSHA regulation or letter of interpretation that is the source of their assertion.
OSHA is clear that an oxygen deficient atmosphere is one with an oxygen content less than 19.5% by volume (in the Respiratory protection standard, 29 CFR 1910.134(b), and in the Permit-required confined spaces standard, 29 CFR 1910.146(b) ). The Respiratory protection standard mentions gas monitoring—in regard to carbon monoxide! Specifically, in 1910.134(i)(7), the Respiratory protection standard requires that when employers use air compressors to supply breathing air, that they monitor carbon monoxide levels. The standard could have required oxygen monitoring, but it didn’t.
OSHA does require oxygen monitoring as part of an entry into a permit-required confined space. Specifically, the Permit-required confined space standard requires that the atmosphere of a permit-required confined space be tested for oxygen content, as well as other hazardous conditions, before entry. The standard goes on to require additional oxygen monitoring during the entry under certain conditions.
So, there is an OSHA requirement for oxygen monitoring: before and during a permit-required confined space entry.
(What Is a Permit-Required Confined Space?)
To be clear, laboratories, boiler rooms, and workspaces are not permit-confined spaces. To be a permit-required confined space, a space must first meet OSHA’s definition of a confined space:
(1) Is large enough and so configured that an employee can bodily enter and perform assigned work; and
(2) Has limited or restricted means for entry or exit (for example, tanks, vessels, silos, storage bins, hoppers, vaults, and pits are spaces that may have limited means of entry.); and
(3) Is not designed for continuous employee occupancy.
Then it must contain a hazard, which OSHA defines as
(1) Contains or has a potential to contain a hazardous atmosphere; or
(2) Contains a material that has the potential for engulfing an entrant; or
(3) Has an internal configuration such that an entrant could be trapped or asphyxiated by inwardly converging walls or by a floor which slopes downward and tapers to a smaller cross-section; or
(4) Contains any other recognized serious safety or health hazard.
Laboratories, boiler rooms, and workspaces don’t meet the first criteria. They are not confined spaces. So, they cannot be permit-required confined spaces.
The NIH Weighs In
The marketers of oxygen monitoring devices are very fond of quoting the National Institutes of Health’s Protocol for Use and Maintenance of Oxygen Monitoring Devices: “An oxygen monitoring device shall be installed in any indoor location where compressed gases and/or cryogenic liquids are stored and/or dispensed in [a] manner that could create the potential for the displacement of oxygen.” What they don’t say is that the Protocol applies to NIH laboratories and research personnel in Maryland, Montana, and Arizona. There is nothing about the protocol to suggest that the NIH intended it to be applied to natural gas supplies to boilers, furnaces, and other fired equipment, or that they intended it to be applied to industrial settings.
What About Boiler Rooms?
When OSHA doesn’t have a specific regulation in place, it can turn to the general duty clause to cite employers for failing to provide a place of employment “free from recognized hazards.” Unless OSHA has specifically incorporated a third-party standard into a regulation, it cannot enforce that standard. It can, however, use that standard to show that a hazard is recognized.
So, what do the standards that apply to natural gas-fired boilers have to say about oxygen monitoring?
NFPA 54, National Fuel Gas Code (ANSI Z223.1), 2024 Edition, makes no mention of oxygen monitors.
NFPA 85, Boiler and Combustion Systems Hazards Code, 2023 Edition, makes no mention of oxygen monitors.
29 CFR 1910.101, OSHA’s Compressed Gases Standard, incorporates the Compressed Gas Association pamphlet, P-1-1965, by reference. CGA P-1-1965 makes no mention of oxygen monitors.
CGA P-1-2022, Standard for Safe Handling of Compressed Gases in Containers, the most current version of the standard that OSHA incorporates by reference, makes no mention of oxygen monitors either. (This standard doesn’t apply to natural gas-fired boilers in any case.)
But Natural Gas Piping Could Leak
By now, it should be clear that OSHA does not require oxygen monitoring in boiler rooms, sales literature to the contrary notwithstanding. But isn’t it possible for natural gas piping to leak? What should be done about that?
First, it is imperative that natural gas supplies to boilers (and all gas-fired appliances) be constructed in accordance with NFPA 54. Boilers should be equipped with burner management systems in accordance with NFPA 85. That should be sufficient to provide a workplace free from recognized hazards.
If a concern about a natural gas leak remains, however, keep in mind that natural gas is dosed with an odorant, typically one of the mercaptan. Mercaptans stink. When someone smells their distinctive “rotten cabbage” smell, take it seriously and call the gas supply company.
As For Monitoring
Oxygen monitoring in a boiler room is not necessary. It’s not even helpful. The lower explosive limit (LEL) of natural gas (methane) is 5%. Natural gas leaking into a space enough to reach the LEL would consequently lower the oxygen content of that space to 19.86%. An oxygen concentration of 19.86% is within the safe limits for oxygen.
The flammability hazard of natural gas is worse than the asphyxiation hazard. If a monitor must be installed, an LEL monitor will do better than an oxygen monitor. But neither is necessary.
Check the Regulations Yourself
When marketing literature tells you that you must do something or that you are prohibited from doing something because “OSHA says,” be ready to ask, “Where does OSHA say that?” OSHA regulations are readily available at www.OSHA.gov and you can check them yourself. If something doesn’t make sense, check it.
That said, it makes a lot of sense to monitor oxygen levels in any small or poorly ventilated room where compressed gases or cryogenic liquids such as nitrogen, helium, carbon dioxide, and argon are used. Not because it is a regulatory requirement of OSHA (it’s not), but because it is a good idea.
Boiler rooms are not one of those spaces.
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