What is Building Science? Why are we hearing this term used in today's design and construction organizations? More importantly, how does H.A.M. apply to this subject?
In simple terms, Building Science is the application of physics and construction technology used to develop solutions that limit risk associated with Heat, Air, and Moisture (H.A.M.), as they relate to a building's operational efficiencies and overall lifespan. The harsh reality is that many building professionals are unaware of the conditions that increase the propensity for reduced building performance and increased liabilities that relate to uncontrolled Heat, Air, and Moisture. Not knowing how to minimize risk can be like walking through a minefield; the outcome can be unpredictable and disastrous. Many of the issues we face today, from past and current practice, are the results of improper application of building science principles; more specifically, thermal protection from Heat gains and losses, uncontrolled Airflow, and overall Moisture management (H.A.M.).
• Let's carve our first slice of H.A.M.. •
Controlling heat is vital to controlling temperature. Ultimately, we want to make sure our building occupants remain comfortable, healthy, and productive. Many undesired effects can result from a lack of heat control. For example, extreme differences in outdoor/indoor temperature can cause moisture to form in wall cavities and ceiling assemblies. This unseen phenomenon is a result of humid air releasing moisture due to low performing insulation and moisture barriers. Thermal dynamics tell us that heat is always seeking cold in order to achieve equilibrium. No matter what the desired temperature is, heat is either trying to enter or exit the building. To address the issue of controlling heat, one must know its mode of travel via radiation, conduction, and convection. Insight on how heat moves, and how to prevent unwanted heat transfer, can greatly reduce liabilities and yield substantial energy savings through the reduction of heating/cooling loads.
• Still hungry? Let's have a second helping of H.A.M.. •
Controlling air movement is just as important as heat control. In fact, you can relate uncontrolled heat migration to simple air movement. Heat rises, right? Actually, hot air rises. This is an important principle to remember since hotter air has the ability to hold a greater percentage of moisture. Introducing uncontrolled hot, humid air into a conditioned space is an occurrence we want to control. As previously stated, humidity inside of a wall or ceiling assembly can lead to condensation. Condensation, in turn, promotes rotting, reduced insulation value, mold, bacteria growth, and odor. By studying the dynamics of airflow, we understand its nature and how pressure differences within the structure can cause unwanted heat and moisture movement. Airflow is another essential puzzle piece to achieving energy efficiency and good indoor air quality.
• Got room for more? Let's squeeze in one more slice. •
Just as "Location, Location, Location" is a primary concern when dealing with real estate, "Moisture, Moisture, Moisture" should be our primary concern when designing and constructing buildings. Plain and simple, moisture is THE number one problem! Uncontrolled moisture is the kryptonite to our super structure. As building professionals we must take into consideration that moisture travels in more ways than just its liquid form. Capillary action, vapor diffusion, and convection are all methods of moisture migration that must be addressed if we hope to build a healthy, comfortable, and efficient building. With this knowledge we can begin to understand how moisture moves within, and ultimately impacts, the building envelope and its materials.
• Somebody call for a stretcher, that third slice did me in. •
Finally, Heat, Air, and Moisture are the key elements we must control in order to maximize building performance and overall life span. Utilizing a holistic perspective and sound building science principles are the keys to our future success. Many buildings fail due to misapplication and lack of attention to the three basic elements: Heat, Air, Moisture (H.A.M.). It is not uncommon that the concept of going green is often centered on products that claim to be the ultimate solution to an issue. The reality is that any issue requires a systematic approach incorporating a variety of details to address that particular issue. Through continued education in building science, and implementation of the principles we have discussed, we can learn to control H.A.M.. Utilizing these principles enables us to design efficient buildings that meet the needs of our clients, reduce liability, increase marketability, and contribute to society a product that will increase the quality of life for generations to come.