Cleanfax, August 2019

Th e more objects and activities we have in a space the more complexity and disorder we have and therefore the more cleaning we need Th e amount of unwanted matter that builds up in an environment is mainly a function of an activity level and the size of the compartment Th e more objects and activities we have at work in a space the more unwanted matter we generate and the more cleaning and maintenance we need Eff ective cleaning of a defi ned space with a known activity level and an intended use requires a suffi cient amount of energy to move matter In cleaning suffi cient energy is indicated by money labor and technology Simply allocating cleaning resources and time as a function of space alone without considering the activity level intended use of the environment and its need for a specifi c level of sanitation will not produce eff ective cleaning The importance of time Time is a critical element of diff erent cleaning methods In cleaning We locate and identify the pollutant We capture it by breaking it down chemically or mechanically We contain it on a surface or suspend it in an air or liquid fl uid We remove the surface or fl uid Finally we dispose of the pollutant Obviously so many steps take time Less obviously each step takes time If adequate time is not allocated to any one of these steps cleaning will not be as eff ective as it could be As an example we might apply a solvent to break down grease If we simply apply the solvent and then wipe it off there will not have been ample time for a chemical reaction to take place and the grease to break down We sometimes refer to this as adequate dwell time Connected compartments Cleaning is applied to environmental compartments or subcompartments A compartment or subcompartment is simply a space that contains matter and energy All objects in the built environment are subcompartments of that environment as well as the natural environment Major subcompartments of the indoor environment include fl ooring the indoor atmosphere elevated surfaces such as walls shelves furniture and ceilings and heating ventilation and air conditioning HVAC systems Any object or place found within these subcompartments is also a subcompartment Understanding an environment allows us to know the natural tendencies so that we can be most eff ective at removing or repositioning matter Depending on how eff ectively each of these compartments is cleaned they either achieve their intended purpose or create unintended environmental conditions or hazards Because matter and energy are constantly in motion 14 CLEANFAX AUG 2019 compartments are connected and influence each other in terms of transferring matter Depending on the compartmental matter load and environmental conditions such as convection and natural ventilation unwanted matter is continuously transferred from one compartment to another Open and closed systems Pollution constantly builds up and interferes with every human endeavor Cleaning is always necessary to keep matter at a sanitary level in these closed built environments In an open environmental system matter or energy may be lost or gained often through movement between the insides and outsides of the system or due to processes of creation or destruction within the system Carpet is an open system and matter and energy are always crossing its boundaries In a closed environmental system matter is kept within the system matter moves between the compartments of the system In order to conserve energy modern buildings tend to be closed systems Matter tends to build up and reaches a steady state condition when it is in a closed compartment Th e quantity of matter in a system depends on surrounding emitting sources and human activity levels Feedback Positive feedback causes the matter and energy change in a system to escalate Negative feedback causes the change in a system to bring about the original state When a system reaches equilibrium the amount of matter in each compartment stabilizes ceasing to change in time Th e reason is that the rate in equals the rate out For steady state the rate of matter in plus the rate of creation of matter inside the compartment equals the rate out plus the rate of destruction inside the compartment Scheduled cleaning will produce a steady state condition indoors e full list of resources is available at cleanfax com science concepts Dr Michael A Berry is recognized internationally as an expert in the subject of indoor environmental quality He retired from the United States EPA in 1998 For over 20 years he taught a broad range of environmental science and management courses at the University of North Carolina Now retired he maintains a professional interest in environmental science and public health