by Marc Ward
Clay Times Jan. 2003
Guess what’s the number one recurring question I receive. It always goes something like this; “Do I really need to put a safety system on my burners?” That may be the question, but what I hear is a statement. The statement is; “I don’t have or don’t want to spend the money.” And what that statement lacks is one critical piece of analysis. That missing item is the concept of risk management. I know, I know…. you’re thinking you’re going to read an article that’s starting to sound like a bunch of parental scolding. I prefer to think of it as friendly advice.
You notice in the above paragraph, I used the term risk management. Risk management is NOT risk avoidance, NOR is it risk taking for the simple act of taking a risk. In a free society, fortune flows to those that can manage the most risk. Those that take the most unmanaged risk will burn out in a great failure, while those that avoid risk will go nowhere. In simple terms, this boils down to a simple idea. Place as many bets as you can, but never make bets you can’t afford to lose. So, how does this apply to burner safety systems?
There are many folks out there that have been firing kilns for decades without any kind of safety system. To them the idea seems silly that they need this stuff. After all, nothing has ever happened to them. They just don’t have the same filter that I do. I talk to people who have lost houses and studios, I talk to people that have lost kilns and been hurt. I have even talked to one person that decided after the second trip to the burn-unit that maybe they needed to rethink how they were doing things. These are the people that were taking risks… not managing them. People that avoid the risks don’t have gas kilns, so I usually don’t speak with them in the course of my business. The problem that many of the risk takers have is that they are unaware of the specific risk they are taking and this makes managing those risks impossible. How do you know what the risks are then?
Here’s the biggest risk with firing a gas kiln. LP (propane) is heavier than air. Natural gas is lighter than air so it is not as dangerous, but it can still easily produce the same catastrophic results as LP when confined. Because LP is heavier than air it can “pool” inside a kiln, inside a building, in a low spot on the ground… you get the idea. The greater the pooling is, the greater the explosive potential. How does pooling happen? If a burner goes out…wind, water in the line (very rare), someone turns a valve off, then on. Somehow the flame stops, but the gas doesn’t. With a kiln on a hill in windy Kansas, fired by natural gas, nothing might happen… the gas simply is blown away before it reaches an explosive concentration and can find no other source of ignition. But, that same kiln on a still day could explode if you go out there and strike a match to light it. Take an LP fired kiln in a basement. If there is some form of outage and the gas continues and finally reaches a spark from a blower, a switch, anything…the building could well be leveled. If you think I’m trying to scare you,….well, yea…maybe a few of you out there that don’t realize the risks you are taking. Risks, that fully realized, far outweigh the relative inexpensive costs of a simple safety system. Again, this is taking the bet you can’t afford to lose. You bet X amount of dollars in savings from having no safety system against X amount of dollars for your property and maybe your health. Then you have to couple this bet with the probabilities.
A raku kiln that is always attended has a very, very low probability, hell, almost a nonexistent probability of a catastrophic event. It is too small, you can turn the gas off faster than many safety systems can, and the kiln (containment vessel) is usually not as massive as a brick kiln. You can sure get hurt, but the catastrophic risks are pretty much absent. The same is true with a glassblower’s glory hole. They are standing right there, it’s usually pretty small, and they can react fast. Here’s my short list (not the entire list) of situations that MUST have some form of safety system that can shut down the gas in case of a flameout.
Any kiln that is candled overnight without constant supervision.
Any kiln that is below grade (like a basement).
Any kiln that is inside a structure.
Any kiln that is operated by multiple operators.
I guess the best way to decide if what you’re doing is safe is to think like your insurance company. That’s their business, risk management and taking bets based on probability. If you know in your heart that a reasonable insurance company would run away real fast from covering what you are doing, then you know you’re not managing your risks properly. Have fun and be safe.