This talk is part of the Fountain Fundamentals Conference, July 10-11, 2013, Kansas City, MO.
Water Chemistry Guidelines for Art Fountains by Martin Burke
Martin: I am going to try and speak loud enough to get away from the microphone. The one element that has linked all of our presentations over the last two days is water. Water is the essential element of this functional object. The general expectation is that the water be clean, clear, odorless, luminous, crystalline, reflective, if the water is moving suddenly we have an infinite range of art forms and sounds, truly kinetic art. Water has an allure and the general expectation is that the water be cool, refreshing, and even thirst quenching.
So with the art and these expectations we approach the issue of fountain water quality. We all know that there are many challenges to water quality. These are just a few pictures from Washington DC. I probably spend more time thinking about algae than anything else but we heard from Jocelyn yesterday. She was very kind not to show us some of the things that she’s found in the Kansas City fountains, but I like this one particularly. This is a dead rat. Now this was not a staged photograph. A dead rat right next to this Hardee’s cup and I was just wondering whether they had fallen in after this big gulp and drowned or from partying the night before.
There are some very interesting things, we have the water fowl. Many of the fountains that I work on are in urban areas. You see this, probably, mulch that is up on the edge of the fountain here. We’ve got our ducks, we’ve got the exhaust from all of the cars in the area, trash receptacles, and then there is always the human element here. The expectation is that for many, the water quality from where we start is actually good for both indoor and outdoor fountains. I work on both and it really begins to change your perspective even though in an outdoor environment we see a lot of trees, vegetation, but I found that when you move into the museum, the exhibitions and the special events people will always put flowers around the basins and it’s a great source for things to get into the water source.
So when we start thinking about our water quality, we have to begin, what we’re going to do, my presentation is actually build a water quality that I’ve found that will work for us. So to build these requirements for acceptable water quality, we have to get by what we have been trained to do as conservators. We think of purified water and we usually think of it in terms of use in laboratory treatments. We’re taught to control the minerals and the contaminants so not to introduce them into our treatments of objects. The example is using buffered water for the treatment of washing paint. We polish it up, we run it through an RO unit or distilled unit and the first thing we do is we buffer it to make sure that we’re not leaching the materials out of the paper. If you do stone conservation, you’re usually buffering water again. So remember that the purification methods that we’re used to in a laboratory situation are removing all of the minerals and in many cases all of the ions from the water, which can be both a good and bad thing, so we usually think in terms of distilled water, de-ionized, reverse osmosis, which is polishing this water up so it’s very, very clean. So the first question is, is this the kind of water we should be using in fountains? Have you ever recommended using this kind of water in a fountain? And the answer as far as I’m concerned is it is just too chemically reactive. DI, RO, distilled water are all ready to combine with the gases in the air, metals in the piping system, mixed with the dirt on the surface of the water, combined with the acidic rain that’s in the environment, urine, spores in the air, you name it, the list goes on.
So in fact, I was working on a Carl Milles fountain, an indoor fountain for a museum up in Massachusetts and I had all of these conservation reports that went way back into the seventies and they had a constant problem with a bio-slime. They would drain this very small indoor fountain that had about maybe fifty gallons of water in it and they were very proud of the fact that they were using RO water directly out of their lab, pouring it in and this bio-slime would appear in a matter of a couple weeks and it was just sludge. So they had to throw it all out again and again and from what I could tell from the analysis, they had a copper and an iron plumbing system that went with this and was all buried in the concrete of the building. They had created a giant corrosion cell using purified water so they were about to put this back on display. They didn’t want to repeat the system. So if we’re not going to use purified water, what can we use? So we’re going to go to potable water or drinking water.
In general, the potable water or drinking water is a great place to start for fountains. We’ve heard this morning that the EPA standards usually consider contaminants for public health. That’s what the EPA’s primary standard looks at. When David delivers the water at the tap at your home, you’re assured that it is pure and you’re not going to get sick. But probably a more important list for conservators and for the operation of fountains is the secondary standard. That’s where we start seeing the smells and the scale that we’re going to see building up on the piping systems, the iron and the copper that is floating around in there that is not necessarily a concern of the public water systems. But remember even our potable water is still ready to combine with the gases in the air, and the metals in the pipe. When I looked at the Kansas City water analysis before I came, I’m going, “Ew, ew, look at this really hard water,” I’m anticipating that if I’m running a fountain in the town, that I’m going to have a scaling problem that I’m going to have to address in some way, so even potable water is prepared to combine in the environment.
So now with our potable and drinking water as our foundation, are we ready to fill the fountain? No. The next step is to really understand this water source that David is providing. Remember that the water analysis can change. David said that twice in the spring, we get the sludge coming down from the river and it will begin to change the characteristics of the water that you’re going to fill your fountain with. So you really have to understand and we did want to ask about the piping system. I’ve seen a lot of areas where they’ll have older metal iron pipes that can contribute to higher iron levels. When you turn on the tap, what’s reported at the various locations around the city is not necessarily what you’re going to get at your source or your tap or your piping. So you have to characterize your particular water source right before you’re going to fill the fountain.
Here’s two examples. This is a fountain I worked on in Washington DC. This is before treatment and this is the Washington National Cathedral. This is municipal water, relatively hard, high calcium and magnesium carbonates in the local water. The fountain is well maintained. This had been in operation for almost forty years before it was actually treated. Most of the area, you do see some staining, the bronze fountain is very well maintained. They added chlorine to control algae but they did have scaling water. I have a later picture I’ll show you. Some of the buildup of calcium and magnesium carbonates on the inside.
This is a current project in Potomac, Maryland. This site is supplied by deep wells on the estate. These are two Carrera marble pools. There is no circulation system, these are reflective pools. You see a heavily maintained vegetation around it that. This is an algae growing system right here. They added very low hardness water. I live only about 60 miles from this and we have two completely different water sources. I have very hard water with a lot of magnesium calcium carbonate. This is very low pH coming out of the ground maybe at 6.5, but there are no or very few minerals in it. These pools heavily and aggressively were pressure washed using 3500 PSI water. They did a great job in eroding the surface and they did very little algae control other than replacing the water.
The next thing you have to remember as you evaluate your local source is to be aware of your public heath requirements in your state. When I tested the water heater, I could detect the chlorine that was coming out of the tap and even here in the museum. Now I mentioning this because there are state regulations that cover water features and this is the one from Texas. I got this off the internet. This is a regulation from the health department in Texas saying that public interactive water features and fountains must comply with the water that you get out of a swimming pool. So they’re going to have a residual required. The only other state that I could find real quick was Oregon. There is a requirement for Oregon fountains… Robert?
Robert: Not according to the Water Bureau who maintains the public fountains. They say if you put a sign up indicating that they’re not meant to be publicly played with, that they do not have to keep it to swimming pool standards but then they tell me but “we do anyway.”
Martin: Yeah, this is one of those questions where will posting the sign relieve you of the responsibility if someone gets sick from drinking the water or gets contact dermatitis that sends them off to…so this is one of those areas you just have to be aware of. Safety is a …you know if chlorine is floating around in there, how much of a problem is that going to be. So now what we’re going to do is we’re going to actually build our chart for our water and our fountain.
So bacteria are one of these things David says he’s going to deliver the water to your fountain and it’s going to be bacteria free. But that doesn’t mean that it’s not going to start growing when you’ve got other things going on. When you can’t control the entire situation are you going to have to do something about bacteria control in your fountain? Are you going to have put a UV to sterilize it and there are a lot of options to get the bacteria out of there. You can have a sanitizer residual in the water. You can use an UV sterilizer. So when are the bacteria small organisms in the water harmful to humans causing infections, stomach tract, intestinal problems and skin irritations? I was interested last night on our tour, there was a young woman interacting in the downtown fountain walking through it, getting out as we were on our tour.
The next situation is whether a sanitizer is required. That’s why I’ve got a question mark up on it. Is it required under the local code that you have a residual sanitizer free chlorine that can combine with bacteria irrespective of other systems. David talked about systems, the ozonator systems and the UV systems assume that all of the waters run back through there. It will handle the load if designed correctly but you have to entrain all the water to make sure you get it out of there. So you’re sanitizers aka disinfectants usually will destroy microorganisms that carry the disease and sanitizers can, but not always, control algae. Remember that it doesn’t always take care of it.
Next we’re going to look at pH. Notice here that the pH is running just to alkaline. We’re going to get to the saturation index as a way of predicting whether you’ve got corrosive or scaling water. Usually when you get above 8.2, you’re just asking for trouble because you’re getting accelerated growth of algae. So these are sort of the ideal ranges. Again what is pH, it is that measure of alkalinity above and below seven as your median point and we’re going to talk in terms of corrosion and scaling of your water or it’s potential.
The next thing we get to is total alkalinity. Now alkalinity is part of the carbonate system, and usually again, conservators talk in terms of buffering capacity and this is what it does. Your alkalinity is going to tamp down wild swings in your pH. You can actually correct very easily added alkalinity within a fountain just by adding sodium bicarbonate, which will also raise your pH. Alkalinity, you want some in the water to be able to control pH balance so it helps prevent those drastic changes in pH by having some alkalinity in the water in a measure of concentration basis to neutralize and it’s usually measured in parts per million. So having a certain amount of alkalinity is important in the water.
The next thing we’re going to look at is calcium hardness. When we talk about hard or soft water and really once you start getting at these very high amounts, this is where you start seeing scaling appearing as white spots on the side or actually we saw some dramatic pictures yesterday of scale buildup on sculptural elements. These again are these areas that are secondary considerations in public water systems, the secondary standard. This is also an area where temperature becomes an issue. You’ll see particularly hot summer temperatures in the southwest, you’ll get calcium or scaling where you don’t see it during the color spring and fall times and it has to do with temperature having a dramatic effect on the potential for scaling.
Again hardness is referring to dissolved minerals, chiefly calcium and magnesium but remember the scale has a lot of other stuff in it. It isn’t purely, it’s just reached its saturation level and it’s coming out of the water. I know that in talking to Kate, that she runs a softener in her own home here to reduce the hardness, usually to protect fixtures and keep it out of your coffee maker or something. This is that fountain I showed you. Notice below the water line how everything is almost clear and everything above where you have this water spraying out and condensing on the upper parts of the bronze, you have a rather healthy buildup of scale on it.
Next we’re going to look at dissolved solids. This is usually not an issue in public water systems but you should be aware. So what is it? Technically it’s what’s left over if you evaporated everything, if you evaporated the water. Two thousand parts per million, anything above that you start getting galvanic corrosion so normally I think I measured the water here and I was getting in the tap down in the lab, I was getting around two hundred and twenty-five parts of total dissolved solids. So it’s the residue that’s left if you evaporate the water and it’s expressed as a mass of the volume and it’s usually typically measured as electrical conductance. You’re measuring the iconic capacity of the water. Conservators normally are reading conductance anyway but there’s a calculation that can flip you over to total dissolved solids.
Next we’re going to look at copper. This is really added for stain purposes and you’ll see that the, you know you’d like to have none in it but I was noticing in Ricardo’s project yesterday that you’ve replaced a lot of copper in the piping systems of that fountain. But you’re using pretty low levels here. If you have a low pH water, you can get copper staining pretty fast and particularly with stone elements. This is where it becomes an issue where you don’t want it to turn that gorgeous blue color. So try and keep your copper out of there. Keep it at very low manageable levels. The source for it is it can be in the water source but piping, copper based algaecides, so be aware.
Next we look at iron. Again we saw some dramatic pictures yesterday of iron staining and really you want to keep it…but again .3 parts per million, that’s where your staining is going to start. These are pretty low levels.
Next we’re going to look at temperature. You know you can’t really control it unless you want to cool your water but high temperatures just increase, it’s not a chemical but a physical factor, high water temperatures can certainly increase the tendency for scaling.
And the last is algaecides. Now if you’re going to use an algaecide, we talked about the use of polyquats yesterday. There was a handout that I gave out just to give you an idea of some of the algaecides that are lurking out there. If you’re going to use them you may want to measure the quantities to understand how they react in your situation. So basically they work by disrupting the food source. Remember the algaecides can kill directly and the algaestats are basically a preventative measure. So this is a list and you go, “oh, that’s all I have to control, I’m doing great, this is wonderful, and it’s a merciful short list of things that I have to worry about for my fountain parameters.” But then you’re going to say, “Well wait a minute, what about all that other stuff? David had 85 different parameters and all this other stuff. What about all those other things are they going to cause a problem?” Maybe. So what am I supposed to do? So what about all these other things, the nitrates, the heavy metals and chloramines, the phosphates, the orthophosphates that are sometimes put in public water systems to protect the pipes from corrosion. Particularly in older systems that have lead piping, there are a lot of other things that are floating around in there that you have to…so it isn’t that you don’t test for these things, it’s that you have to be specific about your specific situation. If you know you have a phosphate problem, you better test for it. But it doesn’t necessarily mean it’s all going to come out and cause a big problem.
So these basically five parameters can be fed into what’s called a saturation index. This is a prediction. It is a mathematical calculation based on these five parameters, temperature, calcium, hardness, alkalinity, pH, total dissolved solids and gives you a predictive method of whether or not you’re going to have a scaling or corrosion problem within your fountain. So the LSI which is the measured pH and basically subtracts out the pH at which magnesium carbonates will start coming out of the water. The zero point is what we’re looking for, it’s needed for scaling or dissolving or corrosive and this is going to be the basis of this afternoon’s water testing.
There is a handout which is the specific calculation method used by the chemical companies and this is the interpretation of the values that you see and again we’re going to be playing with these calculations. This is not rocket science. If you can mix a few chemicals together you can actually get this pretty fast. This is how you should approach all the water sources you see out in the public because there all of our samples will look clear and bright and reflective but they’re all a little different. Questions?
Striegel: Questions for Martin?
Martin: Stunned silence.
Unknown: The final decision is going to be from the end user as in me.
Martin: Yes and I will…
Unknown: I don’t want you to put chemicals in my water because you can’t tell me how it’s going to affect that piece of art that’s on the top of my fountain. If you could tell me that I make a decision to say yes, I want to do this or no, I don’t. So how do you address the questions that your end user’s going to have when he’s looking at a piece that he may have paid a lot of money for?
Martin: What I’ve found is that you have to think of each one of the fountains separately. Certainly if Jocelyn’s forty-seven fountains you know, great place to start but the she’s got more geese down at Main and Nichols Street than she does up on … so every one of them has to be…
Unknown: Yeah, each one is different.
Martin: Each one is different. You can make some general assumptions about your makeup water and you can…David had a great way of…if I know that I have hard water to start with and I would like to bring down that hardness level into a less potential for scaling. The idea of using RO water to mix with the water that I’ve got out of the tap just to provide…remember what we’re trying to do here is to reduce the maintenance time and we’re trying to extend the life expectancy of the artwork in that fountain. So the goal is that I don’t have to …let’s see John was out there twelve hours a week on that Calder fountain. If I can cut that to six hours a week by changing the water parameters, the flow rates, I thought that was a wonderful situation of filling in that pond. I mean what a great way of reducing the problem by taking from twenty four thousand gallons down to eight thousand gallons. You simplify the maintenance problems that you had to address so tailoring the situation for the trees that you have around there. I thought that was just a great solution to the problem.
Unknown: One last question?
Martin: Yes.
Water Chemistry Guidelines for Art Fountains by Martin Burke
This presentation proposes a set of guidelines for art fountain water chemistry. The most commonly applied water standards for fountains are adapted from or required by state and local health codes for water used in public pools, spas, and fountains. Often state and local codes and regulations require a residual sanitizer that accelerates corrosion and deteriorates fountain materials. The presentation will also encourage the use of the Langelier Saturation Index as an indicator of water’s tendency to corrode or scale fountain surfaces. Conservators must be aware of local water chemistry, state codes and regulations, and have a variety of water treatment strategies for indoor and outdoor fountains and pools. Conservators should be able to specify water chemistry parameters as part of a plan for maintenance and long-term preservation.
Speaker Bio
Martin Burke is an objects conservator and proprietor of Terrapin Neck Conservation, LLC in Shepherdstown, WV. He holds degrees from University of Michigan, Shepherd University, and pursued graduate studies at George Washington University. For seventeen years he was an objects conservator at the National Museum of American History, Smithsonian Institution and for thirteen years Head Conservator at Harpers Ferry Center, National Park Service. He is a Fellow of the American Institute for Conservation of Historic and Artistic Works (AIC). Martin specializes in treatment of metals, outdoor sculpture, and fountains and interested in controlling water chemistry to reduce and minimize deterioration of fountain construction materials and maintenance.