We Don t Measure Moisture... We Calculate Risk

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1 We Don t Measure Moisture... We Calculate Risk Qualitative versus Quantitative Inquiry Why point testing for insitu %RH as the sole criterion for assessing risk of flooring failure is fraught with danger. Benny Dickens Founder/CEO Formulators 1790 S Boyd St Santa Ana, CA The true logic of this world is the calculus of probabilities. - James Clerk Maxwell Risk can be defined many ways specific to the application and situation. The definition for risk has traditionally been confused with a potential for hazard to the point that hazard and risk are used interchangeably. Hazard anticipates the happening of an negative event where risk is defined by probabilities. Risk is concerned with the expectation of one or more results, of one or more future events. Technically, the value of those results may be either positive or negative. However, general usage tends to focus only on the potential harm that may arise from the anticipated future event. This harm may accrue either from incurring a cost ("downside risk") or by failing to attain some benefit ("upside risk"). Risk simply put is the probability of something happening. Mathematically, Risk = (probability of an event occurring) x (impact of the event occurring) One way to look at risk is to view it as a fork in the road. A decision to either avoid the potential or to mitigate against it. Either way an option black or white is necessitated. The option to choose not to choose is unavailable. More formally (and quantitatively) in a negative light, risk is proportional to both the likelihood of the hazardous occurrence and the severity of injury that can be caused by the occurrence. Risk vs Uncertainty A certain level of ambiguity results in comparing Risk vs Uncertainty. In Risk, Uncertainty, and Profit, Frank Knight (1921) established the distinction between risk and uncertainty. The term risk, as loosely used in everyday speech, really covers two things which, functionally at least, are categorically different.... The essential fact is that "risk" means in some cases a quantity both dependent and independent of measurement... It would appear that a measurable uncertainty as we shall use the term, is so far different from an unmeasurable one that it is not an uncertainty at all. We... accordingly should restrict the term "uncertainty" to cases of the nonquantitive type... Uncertainty must be taken in a sense radically distinct from the familiar notion of risk. A solution to this ambiguity is proposed in How to Measure Anything: Finding the Value of Intangibles in Business and The Failure of Risk Management: Why It's Broken and How to Fix It by Doug Hubbard. Who gives the following definitions: Uncertainty: The lack of complete certainty, that is, the existence of more than one possibility. The "true" outcome/state/result/value is not known. Measurement of Uncertainty: A set of probabilities assigned to a set of possibilities. Example: "There is a 60% chance this market will double in five years". Risk: A state of uncertainty where some of the possibilities involve a loss, catastrophe, or other

2 undesirable outcome. Measurement of Risk: A set of possibilities each with quantified probabilities and quantified losses. Example: "There is a 40% chance the proposed oil well will be dry with a loss of $12 million in exploratory drilling costs". In this sense, Hubbard uses the terms so that one may have uncertainty without risk but not risk without uncertainty. We can be uncertain about the winner of a horse race, but unless we have some personal stake or money down we have no risk. If we bet our money on a winner, then we create risk. In both cases there exists more than one outcome. The measure of uncertainty refers only to the probabilities assigned to outcomes, while the measure of risk requires both probabilities for outcomes and losses quantified for outcomes. Heady stuff, huh. Types of Risk Where risk is low, it s normally considered to be "Broadly Acceptable". A higher level of risk has to be justified against the costs of reducing it or mitigating against it and the possible benefits that make it feasible. Risks beyond this level are classified as "Intolerable". Because planned actions are subject to large cost and benefit risks, proper risk assessment and risk management for such actions are crucial to making them successful. Insurance is a risk-reducing investment in which the buyer pays a small fixed amount to be protected from a potential large loss. Gambling is a risk-increasing investment, wherein money on hand is risked for a possible large return, but with the possibility of losing it all. Risks in personal health may be reduced by primary prevention actions that decrease early causes of illness like exercise. Using a moisture resistant or waterproof flooring adhesive system over the manufacturers provided solution is risk-reducing. Means of assessing risk vary widely between professions. Indeed, they may define these professions; for example, a doctor manages medical risk, while a civil engineer manages risk of structural failure. Some industries manage risk in a highly quantified and numerate way. These include the nuclear power and aircraft industries, where the possible failure of a complex series of engineered systems could result in highly undesirable outcomes. Fault Tree Analysis Fault Tree Analysis (FTA) was originally developed in 1962 at Bell Laboratories to evaluate the Minuteman I Intercontinental Ballistic Missile (ICBM) Launch Control System. FTA is defined as another part, or technique, of reliability engineering and is a top-down, deductive analytical method. In FTA, initiating primary events such as component failures, human errors, and external events are traced through Boolean logic gates to an undesired top event such as an aircraft crash or nuclear reactor core melt or flooring failure :) The intent is to identify ways to make top events (worst case scenarios) less probable, and verify that safety goals have been achieved. An undesired effect is taken as the root ('top event') of a tree of logic. There should be only

3 one Top Event and all concerns must tree down from it. Then, each situation that could cause that effect is added to the tree as a series of logic expressions. The Tree is usually written out using conventional logic gate symbols. The route through a tree between an event and an initiator in the tree is called a Cut Set. The shortest credible way through the tree from fault to initiating event is called a Minimal Cut Set. When failure and event probabilities are unknown, qualitative fault trees may be analyzed for minimal cut sets. For example, if any minimal cut set contains multiple base events (see diagram), then the top event may be caused by a combination of failures. Many different approaches can be used to model a FTA, but the most common and popular way can be summarized in a few steps. FTA analysis involves five steps: 1. Define the undesired Top Event to study Definition of the undesired top event can be very hard to catch, although some of the events are very easy and obvious to observe such is the case with flooring failures. An engineer with a wide knowledge of the design of an installation system or a consultant with an engineering background is the best person who can help define and number the undesired events. Top events are used then to make the FTA, one event for one FTA. 2. Obtain an understanding of the system Once the top event is selected, all causes with probabilities of affecting the undesired event are studied and analyzed. Here lies the essential argument against point testing for failures related to MVER. ASTM F1869, even though fraught with possible error, attempts to measure dynamic moisture where as ASTM F2170 attempts to quantitate static moisture vapor measured as insitu %RH. These tests are asking different questions and result in values related to the top event but are derived from a differing cut set according to FTA theory. One cannot be eliminated without reducing the overall understanding of the system. Even though the top event or flooring failure is identified, the FTA must be constructed with all possible cut sets for validity. For the selected top event all causes (cut sets) must be identified, numbered and sequenced in the order of occurrence and are used for the next step which is drawing or constructing the fault tree. 3. Construct the fault tree After selecting the undesired event and having analyzed the system so that we know all the causing effects we can now construct the fault tree. 4. Evaluate the fault tree After the fault tree has been assembled, it is evaluated and analyzed for any possible improvement or in other words given a probabilistic risk assessment. This step is as an introduction for the final step which will be to control the hazards identified.

4 5. Control the hazards identified The control of potential hazards is very specific and differs largely from one system to another, but the main point will always be that after identifying the hazards all possible methods are pursued to decrease the probability of the negative top event occurrence (i.e., flooring failure). Probabilistic Risk Assessment (PRA) PRA usually answers three basic questions: 1. What can go wrong with the studied technological entity (system), or what are the initiators or initiating events (undesirable starting or base events) that lead to adverse consequence(s)? 2. What and how severe are the potential detriments (hazards), or the adverse consequences that the technological entity may be eventually subjected to as a result of the occurrence of the initiator (base set)? 3. How likely to occur are these undesirable consequences (top events), or what are their probabilities or frequencies? In a PRA, risk is characterized by two quantities: 1. The magnitude (severity) of the possible adverse consequence(s), and 2. The likelihood (probability) of occurrence of each consequence. PRA is a game of Blackjack Roulette vs Blackjack- better stated the independent trial vs the dependent trial Two distinctly different types of game. The first type of game falls under the category of independent trial. Each result is entirely independent of any other and is hence unaffected by previous results. Roulette is like flipping a coin, if it comes up heads, the next time the coin is flipped it is just as likely to come up heads. The previous occurrence has no effect what-so-ever on future results. There is no possible way to predict the future outcome based on past results. In testing for elevated moisture as it pertains to flooring failure, when we limit or methods by collecting only one form of moisture analysis we eliminate perspective. Blackjack differs from Roulette in one very important aspect when a round of blackjack has been dealt, issued cards are put in a discard pile essentially they can then be considered out of play. This type of game is termed as a dependent trial. What happened in the previous rounds does effect what will happen in the next round. For example, if I m playing in a single deck game and 4 Aces are dealt in the first round, this means that when the second round comes to be dealt, as all 4 Aces are now in the discard pile, there is no possibility of being dealt an Ace and the game just got worse for me. By collecting varied forms of moisture data relative to the propensity for failure then we develop a cohesive framework for risk assessment. Qualitative vs Quantitative We are all applying qualitative analytic techniques whether we know it or not. It s like walking into a haunted house at the park. We create an inductive data analysis based upon our chances of survivability. The argument is not for or against ASTM 1869 but in how we code or weight the value of the test

5 in our overall PRA. Philosophically, the idea or perception that moisture analysis is quantitative is false. If you can accept that all tested concrete has inherent variability then the quantitative measurement requires a qualitative explanation. Quantitative comparative studies are impossible. Each set of data collected is specific to the substrate tested. In fact within the scope of testing the time at which the tests are conducted can induce variability pertaining to cure and seasonality. To limit the type of tests taken is to limit the information gained, albeit some tests may provide more significance to the overall mitigation recommendation. Limiting the possible information will remove possible cut sets that could impact the FTA. Data collection must involve non-empirical or anecdotal information such as the history of the previous flooring installation, construction techniques, age of the slab, etc. By its very definition the qualitative treatment begs for an explanation based on the attributes of the source data, an analysis which is more holistic and contextual rather than reductionist in theory. Moisture in concrete is complex and cannot be reduced to the sum of its parts. An excellent example of the qualitative approach is given by Lee Eliseian, IFTI. By taking the individual datum and plotting a thermal-type image to the blue print of the floor, Lee grids the area and develops a discussion of risk based upon the hot spots for elevated moisture. Risk can now be qualitatively assessed on the probability of failure. Quantitative research in the lab is useful in testing performance and hypothesis. But explaining the often puzzling data collected in the field requires establishing content validity. We have to be vigilant in asking, Do our measures measure what we think they measure? Do I know what I need to know in order to risk the liability of loss? Moisture mitigation deserves a Grounded Theory approach defined as inductive research based or grounded in the observations and data, using a variety of data sources to develop a compact summary, a distillation or recommendation for a reliable mitigation protocol. Reductionist Theory Reductionism is a philosophical position that a complex system is nothing but the sum of its parts, and that an account of it can be reduced to accounts of individual constituents. In 1637 Descartes argued that the world was like a machine, its pieces like a clockwork mechanism. The machine could be understood by taking the pieces apart and placing them back together. Methodological reductionism is the position that all theories can be reduced to a single super theory. In the flooring industry the attempt is similar. To reduce all quantitative technique down to one test, one explanation for determination of risk. A contrast to the reductionist approach is holism or emergentism. Holism is the idea that things can have properties as a whole that are not explainable from the sum of their parts (emergent properties). The principle of holism was concisely summarized by Aristotle in the Metaphysics: "The whole is more than the sum of its parts".

6 Scientific holism holds that the behavior of a system cannot be perfectly predicted, no matter how much data is available. Natural systems can produce surprisingly unexpected behavior, and it is suspected that behavior of such systems might be computationally irreducible, which means it would not be possible to even approximate the system state without a full simulation of all the events occurring in the system. When we subject reductionist theory to flooring failures we subject a natural dynamic system to point testing that logic dictates extrapolative reasoning will fail. Only a holistic approach to include all data through fault tree analysis or other qualitative means can produce the proper limitation to risk. The idea that ASTM F2170 alone provides sufficient information to determine risk of failure related to the complex movement of moisture, concrete cure, efflorescent migration of salts through concrete micro-channels, turbid flow properties induced by variable aggregate size and more, seems a bit simplistic. Conclusion Life can not be controlled...life finds a way. - Dr. Ian Malcolm, Jurassic Park, 1993 Complex natural systems deserve a detailed analysis subject to historical reference and grounded in varied quantitative evaluation. The summation and qualitative treatment of this information provides the only real logical answer to proper mitigation against flooring failure subject to elevated moisture. As in life so to moisture is near impossible to control... moisture will find a way.