In this second of a two-part series, one of the nation’s foremost experts in forensic examination of concrete and related building materials, Geoffrey
In this second of a two-part series, one of the nation’s foremost experts in forensic examination of concrete and related building materials, Geoffrey Hichborn, illustrates how vapor emission and moisture dome tests increase pressure on defendants in the battle against frivolous concrete defect claims tied to alleged sulfate attack. In the first part of the article, Hichborn discussed the historical origins of the moisture dome testing and the potential sources of water vapor that might show up during such tests.
SULFATE ATTACK CLAIMS
All sulfate claims require demonstration that there are sulfates in the local environment and that the compounds can migrate through the concrete when exposed to its surface. Water is the obvious medium bringing sulfates from the soil into the concrete.
Plaintiffs argue that the two consequences of water and sulfate are: (1) that sulfates will ultimately turn the concrete to mush; and, (2) water that courses through the (increasingly) porous and permeable concrete leads to water damage inside a house. Never mind that a mature concrete slab is nearly impermeable to water; and, water vapor (Brewer) and dome tests provide inaccurate and misleading results (Hichborn and Bondy).
NONSULFATE ATTACK CLAIMS, OR SULFATE LITE
If sulfate is taken out of the case, plaintiffs still can argue water damage inside the house. This is what Hichborn calls the sulfate lite case. Even without the sulfates, the plaintiff has an appealing argument: water made it through the concrete, damaged the concrete, flooring, wall structures, caused mold, and damaged the contents of the house. Finally, in some cases, personal injury to the occupants is asserted.
In the 2006 Castron, et al. v. Fieldstone, et al. trial, the defendants believed the plaintiffs would have used this argument Û water damage to the flooring and contents of the house Û if the dome tests had not been excluded as junk science.
Hichborn comments: What we’re finding in case after case, whether it’s a sulfate claim or not, is that plaintiffs are using the dome tests to demonstrate that the concrete is porous and permeable, that water is coursing through the concrete, and that there is damage to the flooring materials. So, when they are making those claims, and the presence of sulfates is not asserted or demonstrated, I call it sulfate lite, because it’s the same general proof, but excludes sulfates. Thus, the vapor emission (Dome) test can give them two barrels from the same shotgun, or in this case, a water pistol.
It’s far more expensive to play the sulfate card, so a lot of plaintiffs don’t do it, or will do it but won’t mean it, because they don’t need to retain and pay as many experts, don’t spend as much money, and yet they still have a significant cost of repair. They push the cost of the investigation and repair so high that the opposing guy is going to settle for defense costs.
Excerpts from Moisture dome tests: What Do They Measure? by Kenneth B. Bondy and Geoffrey D. Hichborn, Sr., March 23, 2000:
Calcium chloride moisture dome tests are used by some consultants in construction defect litigation as a measure of concrete slab permeability and as a measure of vapor migration from below the slab into residential spaces above.
The authors conducted an extensive 16-month test of the tests to determine what this test actually measured. They concluded that this use of the test is inappropriate Û junk science Û because no generally accepted standards exist, nor could they possibly exist, which relate the results of a dome test/moisture dome test to either concrete permeability or to acceptable levels of vapor entering an existing residential space.
The test, typically in a kit form, consists of a rectangular clear plastic dome, a sealed container of calcium chloride crystals, and a gasket. The crystals are placed under the dome, which is sealed to the concrete floor for 60 to 72 hours. The crystals are then removed and weighed to determine how much water vapor was absorbed.
Hichborn’s examination of moisture dome testing led to the following conclusions:
The dome test is not reproducible. Test results have been shown to vary by more than 100 percent under identical test conditions. There are many reasons for this. The nonreproducibility of the test can be attributed largely to the lack of a standard for particle size distribution of the calcium chloride crystals and the impossibility of identical finishing and grinding of the test surface. Also, small variations in relative humidity, temperature, and moisture conditions have a relatively large effect on the results.
The primary source of water vapor measured in a moisture dome test on a mature slab, and virtually all of the vapor measured beyond 3 lb./1,000 sq.ft./24 hours, is from water that was in equilibrium in the concrete pores and is activated by the test itself.
The maximum amount of water vapor that can be transmitted through a typical residential concrete slab, from the soil below up into the room above, is 2 lb./1,000 sq.ft./24 hours. That amount of water vapor emitted in a 24-hour period can be removed by a 3-ton air conditioning unit in an average-sized production home in 13 minutes.
Moisture dome tests will vary by up to 30 percent within the range of temperatures and relative humidities recommended by ASTM specifications. The most influential measurable variable affecting the results of the test is the soil/concrete temperature. Differential vapor pressures do not seem to be related in any consistent way to test results.
Moisture dome test results cannot be related to any concrete property, including porosity or permeability. No standards exist that relate the results of the moisture dome test to concrete properties, and most of the water measured in the test is activated by the test itself, or influenced greatly by ambient environmental conditions having nothing to do with concrete properties.
Moisture dome test results cannot be used as a measure of acceptable levels of vapor transmission into an existing residential space. No such standards of acceptability exist, and most of the moisture measured in the test is not transmitted through the slab.
Hichborn concludes with several observations. More and more is being written about the tests, but much of it tends to be anecdotal. Little, if any, systematic work is being done to support the plaintiffs’ experts’ errant notion that moisture dome tests can somehow evaluate concrete installations or materials.
It is strange that many of the test kits in wide use do not satisfy the ASTM requirements for them. It seems unfortunate that the ASTM committees in charge of the moisture dome test come from the general building-materials and construction community, rather than the specialized community of cement and concrete performance and materials professionals. There also is an increased use of the concurrent pH tests of concrete, which is similarly invalid, as there are no standardized methods to perform or interpret them.
We have seen flooring failures with low moisture dome test values and great flooring performance with high ones. In a similar vein, some witnesses have attempted to infer water-to-cement ratios using moisture dome test values, another baseless activity.
It is particularly astonishing that some concrete investigators and flooring investigators actually manufacture and profit from the sale of moisture dome test kits. One judicial test of junk science in California is whether the one offering the method stands to profit from its general use and acceptance. If so, for the court, the profit motive well may trump the argument to accept such results as valid evidence.
There remains no generally accepted, objective, and standardized protocol for verifying or evaluating the degree and significance of water damage in projects where moisture transmission, flooring damage, and defective concrete and slab construction are asserted. There are ways to verify the acceptability of concrete materials and construction, though these could be expanded.
For more information, contact Hichborn Consulting Group at 714/637-7400; [email protected]; www.hichborn.com.
FOOTSTEPS OF HIS FOREFATHERS
Cement is in Geoffrey Hichborn’s blood. His grandfather, Donald Hichborn, and great-grandfather, Stanley Hichborn, owned and operated a concrete and engineering company in the early 1900s, during which time they worked with Fred Harvey Co. and the Atchison, Topeka & Santa Fe Railway to build tourist destinations in the Southwest. Their most noted structure is the Indian Watchtower at Desert View, designed by architect Mary Colter and built in 1932 at the Grand Canyon.
Although the affinity for engineering and concrete construction skipped a generation Û Hichborn’s father, Hal, worked for IBM in the then-fledgling computer industry Û today Hichborn is one of the nation’s foremost experts in the forensic examination of concrete and related building products. A certified engineer, he is president and CEO of Hichborn Consulting Group in Orange, Calif., and regularly serves as an expert witness for both defendants and plaintiffs in high-profile construction liability cases. Professionally, he is a Fellow of the American Concrete Institute, serves on several committees and subcommittees of the American Society for Testing and Materials, and is the 2007 president of the Forensic Expert Witness Association, Orange County Chapter. Joining him in his office are his two daughters, Marni Woods, the firm’s general manager, and Kristen Hichborn, executive administrator.
In some circles, Hichborn is better known as the Concrete Detective for his investigative analysis of concrete defects and their causes, and for devising methods of debunking junk science in the courtroom. In one instance, he devised a procedure that demonstrated that plaintiffs’ expert witnesses were unable to tell the difference between a Tums tablet and piece of concrete when presented with scanning electron microscope images of each of these substances. And, he helped devise a study that found the moisture dome test had no validity in providing evidence of sulfate attack on concrete. He also has designed and directed specialized tests and evaluations for the research and development of new products and for solving complex field problems.
While Hichborn is a graduate of the University of California and a licensed professional engineer, he especially admires people like his great-grandfather and those who preceded him Û people who had no formal degrees or licenses, but possessed a great deal of engineering and materials knowledge and built bridges, mines, dams and other complex structures.
They were smart people that knew how to apply logic, wisdom, rationality and planning to a problem, Hichborn says. And, the problem was either the alignment of a railroad or a truss, or the excavation or shoring of a mine, or doing something through planning and analysis to devise a rational plan that would benefit mankind.
He pays homage to his predecessors through an extensive collection of historic photos, drawings, maps and equipment that have turned his office into a virtual museum. It includes 19th century photos of bridges, mines and trusses Û any work that engineers are famous for. His most prized possession is a 200-year-old map of Capt. James Cook’s voyages. I think those guys were brilliant, really special. They had skills we don’t have today in our specialized world, Hichborn says. I have built a collection that honors them. I also honor them by striving to emulate their principles of logic and planning while going about the work I do each and every day.