Confined Spaces: Even in Craft Distilleries and Microbreweries

“I have a horror of being in confined spaces.”  — Hayley Mills

At a craft distillery that is not too far from Bluefield’s offices, the owner spoke about his need to climb into the pot still to clean out the stillage, especially the spent grains. He saw me wince and said, “Yeah, I know. It’s a confined space.” Yet there was no sign on the still warning “DANGER – PERMIT-REQUIRED CONFINED SPACE, DO NOT ENTER.” He conceded that he didn’t even have any kind of written permit program, as called for in OSHA’s permit-required confined spaces regulations, 29 CFR 1910.146.

His saving grace was that he didn’t have any employees working in the production area. He was the only person entering the still pot, the only one involved in making whiskey. As his business grows, there will come a time when he has production employees and he’s going to need a written program.

In the meantime, though, he must personally face the hazards of confined space entry.

The Hazards of Confined Space Entry

As much as employers hate the obligation of complying with OSHA regulations and the ever-present threat of citations and fines, the requirements spelled out in the regulations are hard to argue with if you care about safety. The permit-required confined space regulation spells out four types of hazards that would render a confined space permit-required:

1. Contains or has a potential to contain a hazardous atmosphere;
2. Contains a material that has the potential for engulfing an entrant;
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;
4. Contains any other recognized serious safety or health hazard.

Which of these may be present in a distillery or brewery? Before trying to figure out if there are permit-required confined spaces, however, the first question to answer is whether there are confined spaces in the facility?

What Is A Confined Space?

Again, using the guidance from 1910.146, there are three conditions that a space must meet to be considered a confined space:

1. It must be large enough and so configured that an employee can bodily enter and perform assigned work; and
2. It has limited or restricted means for entry or exit; and
3. It is not designed for continuous employee occupancy.

Tanks, vessels, and pits are often considered confined spaces because they have limited means for entry or exit. Equipment is not a confined space if it is too small to get into to perform work. A standard 53-gallon charred oak barrel is not a confined space. You may be able to stuff a body into one, but a worker could not enter one and perform work. A prison cell, on the other hand, is large enough to enter and may have limited or restricted means of entry or exit, but it is designed for continuous occupancy. So, it is not a confined space, either, even when used for solitary confinement.

The space under a workroom sink is not a confined space. It has limited or restricted means for entry or exit—having to get down on your hands and knees to enter qualifies as a limited or restricted means for entry or exit—and is not designed for continuous employee occupancy. However, it is not large enough to bodily enter to perform assigned work.

What spaces at a distillery or brewery might satisfy the conditions of a confined space? Cookers, fermenters, day tanks to feed bottling lines, still pots, proofing tanks, storage tanks, and electrical vaults are all examples of spaces with the potential to be confined spaces. That is, if they are big enough to enter bodily and configured for entry.  When the manufacturer of the equipment provides an entry hatch, there is an expectation of entry. The entry hatches on new equipment are typically 24” in diameter, or in some cases, 24” x 18” elliptical hatches. Some older equipment, however, has entry hatches as small as 18” in diameter. Anything smaller is not an entry hatch.

Turning Confined Spaces into Permit-Required Confined Spaces

To be a permit-required confined space, a space must be or have the potential to be hazardous. Any single hazard is enough.

Engulfment hazards:  The most common hazard is an engulfment hazard. When a tank is designed to contain a liquid or a solid, there is a potential for a worker inside the tank to be engulfed. So, any tank at a distillery or brewery that is big enough for someone to climb into is a permit-required confined space, even if all it contains is water.

Hazardous atmospheres:  It is also important to keep in mind that confined spaces may have the potential to contain hazardous atmospheres. What are hazardous atmospheres?

• The first concern should always be oxygen levels. If the oxygen level is less than 19.5% or above 23.5%, the atmosphere is hazardous. It is the very nature of fermentation to produce carbon dioxide (CO₂), which will displace air. But this can also happen if slow oxidation inside the vessel is consuming the oxygen.
• The second concern, especially where spirits are found, is an atmosphere that could contain more than the 10% of the lower flammable limit (LFL) of a flammable gas or liquid. For ethanol, the LFL is 3.3% by volume in air. That means that concentrations of 0.33% by volume in air (3,300 ppm)—a partial pressure of 0.0485 psig—are hazardous by this definition. A spirit at 80 proof exceeds this limit at a temperature of 93°F (34 C). At higher proofs, even lower temperatures can result in concentrations of 0.33% by volume in air.
• The third concern should be CO₂, not just because it dilutes air, but because CO₂ has its own hazards. The fermentation of sugars to ethanol produces 27.5 standard cubic feet of CO₂ for every proof gallon of ethanol generated. OSHA considers an atmosphere to be hazardous whenever any chemical listed in 29 CFR 1910.1000 Table Z-1 exceeds its permissible exposure limit (PEL). OSHA lists CO₂ in Table Z-1 with a PEL of 5,000 ppm. It’s important to note that air containing 5,000 ppm CO₂ instead of the usual 430 ppm CO₂ will only be diluted from 20.9% oxygen to 20.8% oxygen, so oxygen monitoring will not detect dangerous levels of CO₂.
• The fourth concern in terms of hazardous atmospheres is combustible dust. When solids like grains, whether milled or unmilled, are stored or handled, an atmosphere may contain combustible levels of suspended dust. Unlike the LFL of flammable gases or liquids, the Minimum Explosive Concentration (MEC) of combustible dusts is not reported because it is very dependent on particle size as well as composition.  As a rule of thumb, however, assume there is a risk of flash fire or explosion if the dust is thick enough to impair visibility at a distance of 5 feet.

Internal configurations:  When it comes to internal configurations that can make confined spaces into permit-required confined spaces, they include any vessel that doesn’t have a flat bottom. Both dished bottoms and conical bottoms meet the condition of “inwardly converging walls or by a floor which slopes downward and tapers to a smaller cross-section”. Other aspects of internal configurations that could trap entrants include internal coils and agitators.

What Is An Entry?

Once a confined space is identified as a permit-required confined space, entry into that space requires a written permit. Obviously, when a worker bodily enters the space, fitting their entire body into the vessel, they have entered the space. The regulations don’t require that an entire body be in the space to consider it an entry. How much of a body must enter the space? Up to the waist? A leg or arm? The head?

It’s much less than that. OSHA considers that an entry has occurred “as soon as any part of the entrant’s body breaks the plane of an opening into the space.” A finger is enough. A fingertip is enough. A fingernail is enough. Moreover, the entry doesn’t have to be through an entry way large enough for a body to pass through. Reaching into the permit-required space through an inspection port would be a confined space entry requiring a permit.

Mark Those Confined Spaces

No one wants to deal with more OSHA regulations. By the same token, no one wants to pull the body of a dead coworker out of a confined space. At any scale that a craft distillery or microbrewery is likely to be operating, there will be permit-required confined spaces. Anyone responsible for safety at one of these facilities should make sure that they have identified all of the confined spaces in their facility and determined which are permit-required confined spaces. Then, mark each confined space with a sign reading “DANGER – PERMIT-REQUIRED CONFINED SPACE, DO NOT ENTER” or other similar language.

The signs are readily available online.

Then, decide if employees will be entering the confined spaces. If so, make sure to implement a written permit-required confined space program