A two-minute phone call could save you thousands—and save your autoclave
Roughly 85 percent of the United States has hard water. That’s perfectly safe for cooking and washing up—recent studies have even hinted at lowered rates of heart disease and increased healthy bone density among hard-water drinkers. But that same hard water is destroying your autoclave.
Autoclave buyers rarely consider their local water quality, and few sterilizer venders bother to ask about it, despite the terrible amount of strain hard-water operation puts on any steam autoclave. A quick phone call today will save you thousands of dollars this year, and might just save your autoclave.
Hard Water is Hard on Autoclaves
Water isn’t just water. Even treated city water straight from the tap is full of minerals, especially calcium carbonate and magnesium. When this water has especially high mineral content, we call it “hard water.”
Calcium carbonate naturally precipitates out of hard water, and will build up inside pipes and appliances—much the same way it builds up to form an oyster’s shell. This will occur more quickly in harder water—which has a higher concentration of calcium carbonate—and hot water systems. The resulting rock-hard build-up (called “scale” or “limescale”) damages valves and gaskets, and impedes flow. Over time valves get jammed and pipes become so full of lime that flow is significantly restricted. In order to address this before it becomes a problem, buildings owners install a “water softener” to capture some of the minerals in the water supply as it enters the building. This lowers the water’s overall “hardness,” significantly reducing the accumulation of scale and keeping everything flowing.
But scale accumulation isn’t just about clogged pipes. A New Mexico State University study found that scale build-up in heating devices acts as a heat-sink, absorbing energy that would otherwise be directly transferred to the vessel. According to NMSU, residential water heaters hooked directly to hard water supplies accumulated four to ten times as much scale as those protected by a water softener. Because of this increased scale, those water heaters operating on untreated hard water steadily grow less efficient, and ultimately required 20 to 30 percent more energy to do the same work.
An autoclave is a significantly more complicated device than a household water heater, but it is just as susceptible to limescale. Given time, scale build-up on your autoclave is going to drive up operating costs while straining the device. In under a year that unit is going to break down.
Trapped in an Autoclave Service Cycle
When that autoclave inevitably seizes up the lab manager calls the vender, who sends out a technician—at up to $1500 per day, just for labor. That technician will then spend a day or longer replacing valves and gaskets, and chipping lime out of the chamber, boiler, and drain condenser. But even the best technician will never get out all of the lime. The lingering scale will continue to degrade the autoclave’s performance while accelerating the accumulation of new scale—until the unit seizes up again, and the lab manager places another call to that service tech. This cycle repeats every six to 12 months for the lifetime of the unit (which will end up being a lot shorter than one might expect, due to the strain placed on the unit).
After the third or fourth tech call, most labs decide the solution is to buy one of the manufacturer’s extended service contracts. This turns the maintenance headache into a fixed, recurring cost. Such parts-and-labor service contracts often cost around $3000 per year—which seems like a bargain if you’ve been paying a technician $2000 every 8 months to chip out the scale building up in your sterilizer’s pressure vessel.
But that service contract amounts to a roughly $30,000 bump to the total lifetime cost of a unit that was not cheap to begin with—and it’s a needless expense. Even in a worst-case scenario, where your water supply is as hard as a rock, you can adequately address the problem with a standard-grade water softener. These sell at big-box hardware stores for under $1000—that’s less than half the cost of a single service call, and a $29,000 savings over that long-term service contract. And that savings doesn’t take into account the energy savings inherent in keeping your autoclave in top shape.
Make a Call, Save Your Autoclave
If you are planning on installing a steam autoclave—or have one already—now is the time to check your water hardness. Fortunately, this is cheap and easy. The vast majority of labs are on a city water system. A two-minute phone call to the water company is all it takes to determine if you need to get a water softener installed. Generally speaking, water is “soft” when it has below 17 ppm (parts per million) of calcium carbonate, “moderately hard” above 60 ppm, and “hard” when it exceeds 120 ppm. (These numbers may also be given in “grains per gallon,” abbreviated “gpg.” Anything below 3.5 gpg is “soft” and anything above 7 gpg is “hard.”)
If your water company can’t answer this question, you can test the water hardness yourself. Easy-to-use water hardness test strips are sold at any pet store that caters to aquarium owners; a whole box will cost around $6.
If you do have hard water, installing a standard water softener today will pay for itself in the first six months: You’ll avoid that first $2000 service call, save about $30,000 over the next decade, and avoid all the headaches of unexpected downtime, dealing with service techs, and having to explain missed deadlines because your autoclave was offline again.
For more cost-saving examples, read through our other case studies.
- “Hard Water—To Soften or Not to Soften” (University of Kentucky)
- “Water Softeners as Energy Conserving Investments” (New Mexico State University)
- “Potential Health Impacts of Hard Water” (Pallav Sengupta, International Journal of Preventative Medicine, August 2013)