Entering tanks and working on other potentially hazardous infrastructure is often part-and-parcel of working in a distillery—especially a small one, where a few team members wear many hats. And while there’s a strong bootstrapping, do-it-yourself ethos in the industry, there are also procedures to safeguard overzealous employees from a wide range of dangers.
Hazards that you need to consider include engulfment issues, such as being drowned or buried in grain, water, mash, spirit, or any other material, as well as the potential to be literally cooked alive in a heated vessel, or—most commonly — the danger of hypoxia and death in a high-CO2 environment.
Any vessel that includes even one of these hazards needs to be clearly marked with a sign—“Confined Space, Permit Required”—and the foundation of lock-out/tag-out procedures is eliminating those dangers so that the vessel can be reclassified as safe for entry.
Entering a vessel simply means breaking the plane of the tank, such as sticking your head through a manway door. With fermentation vessels, in particular, this can be a dangerous act if the tank hasn’t been properly vented of carbon dioxide, which can quickly overwhelm you if you’re visually inspecting the tank after emptying it. Naturally, it can also involve the process of fully entering the vessel to do repairs, or to retrieve items that may have been dropped into the tank or added intentionally—flavoring additions, for example.
Proper lock-out/tag-out procedures start with a thorough, step-by-step look at any risks associated with a piece of equipment or part of the infrastructure, identifying all associated hazards, and creating a detailed, written plan to address them. That may be as simple as locking out a specific circuit breaker when fixing a hard-wired piece of equipment, but it often requires looking at multiple systems.
Along with electrical hazards, the average distillery has some level of grain handling, water flow, heat, and other potentially dangerous systems. To develop a proper lock-out/tag-out procedure, you need to look at all of the systems connected to a particular vessel or piece of equipment. Is it connected to grain handling? Is it connected to water? Is it connected to a mash-transfer system? Is it heated? All of these latent dangers need to be eliminated before a vessel or system is considered safe to be worked on.
Properly eliminating these hazards isn’t as simple as unplugging a piece of equipment, flipping a breaker, or closing a valve. Locking out a vessel means that you need to physically apply devices that ensure someone else can’t mistakenly reconnect or turn on those hazards, a lock that ensures the devices aren’t removed, and a tag that helps to identify what is happening. A proper lock-out/tag-out kit will include components for valves of different sizes and types, electrical plugs, breakers, multiple locks, and hang tags that help communicate the “who” and “what” of the project to anyone who may want to tap into the locked-out utility.
Lock-out/tag-out procedures should include a checklist for you to work through step-by-step, initialing or signing off on each step. Besides identifying and neutralizing individual hazards, you need to inform any relevant personnel that a certain piece of equipment will be locked out.
You also need to let off any residual energy in the system, such as running out water that may be left in the line downstream of the lock. This is especially pertinent to a steam system; while a boiler may be locked out at the breaker panel, there can still be residual steam pressure in the boiler or heat in the vessel that needs to be considered. Properly locking out a boiler or other piece of equipment with so much latent energy may involve shutting it down the day before work is actually done.
Locking out a vessel can involve a single hazard, such as water, or multiple hazards, such as water, steam, and an agitator, all of which must be identified and locked. When you are locking out a vessel, you need to keep possession of the keys to the locks for all of the lockout devices you applied.
Lock-out/tag-out procedures also aren’t limited to use on confined spaces. Any work done on systems that need to be shut down to be repaired, such as boilers or electrical systems, should have a written procedure in place. Electrical breakers are a common avenue to isolate systems ranging from the obvious electrical infrastructure, to steam boilers, or even compressed air systems. (An air compressor is another place where there can be considerable residual energy; a tank of compressed air may be able to operate equipment for several minutes despite the compressor itself being powered down.)
Multiple people can even be working on the same locked-out system. One individual may be fixing a steam leak on a given vessel while someone else is fixing a mixer or motor on the same vessel, or different people may be using the same locked-out window to address different electrical issues on the same circuit. In these cases, each party should apply their own lock to the lock-out device and maintain possession of their own key or keys so that if one party finishes, they’re not able to remove the lock-out device and put the other party in danger.
Of course, all of this framework has little value without good training and communication. Any member of your distillery team who may need to lock out equipment should be fully trained and comfortable with the written SOPs and executing them. Employees who have not been trained still need to understand the meaning behind the “Confined Space” signage to ensure there are no mistakes or safety breakdowns.
Tackling repairs and improvements to equipment or infrastructure can carry inherent risks, but there are ways to mitigate those dangers. Distillers who thoughtfully and carefully apply lock-out/tag-out procedures can move forward with their planned projects carefully, but confidently.