NAFA Guide To Air Filtration Fifth Edition Chapter 9 Controlled Environments presented by the National Air Filtration Association It might be said that just about every environment is “controlled” when it comes to comfort engineering. This chapter is devoted to not just comfort, but specialized applications of filtered air.

Controlled Environments - Definition: Almost all industrial processes require clean air to protect a product or process of production. Clean the air required by the product or process Blanket the product/process with cleaned air Offer enough air flow to move contaminated air away from product/process Highlight 3 points.

Cleanroom Standards ISO 14644-1 defines a clean room as : “a space in which the concentration of airborne particles is controlled and which is constructed and used in a manner to minimize the introduction, generation and retention of particles inside the room, and in which the relevant parameters, e.g. temperature, humidity and pressure are controlled as necessary” Slide is self explanatory

Laminar Airflow Defined as air moving in a laminar direction from one point to another (in a perfect world). Laminar airflow is defined as air moving in a completely lamininar direction from point A to point B…..in a perfect world this might happen, but in reality, air rarely moves in this type of fashion. It is believe that airflow in the range of 90 fpm +-10% results in good laminarity without causing eddy currents.

Cleanrooms Types of Cleanrooms: “Non Unidirectional” (previously known as non-laminar flow)-were originally known as conventional cleanrooms. There are two types of cleanrooms based on air distribution – non-unidirectional where clean air is introduced and mixes with contaminated air and then the air is removed by outlets located at or near floor level. In conventional clean rooms HEPA filters are usually located at the end of the blower section (blowthrough type system) in a mechanical room.

Cleanrooms Unidirectional- which means one direction or laminar flow cleanrooms. …and unidirectional cleanrooms where the air enters and passes through the room with a piston-like effect, with as much laminar flow as possible, removing and replacing the contaminated air with clean air. Usually, unidirectional cleanrooms deliver air through the ceiling and remove it through the floor. In laminar flow cleanrooms the HEPA/ULPA filters are located in the ceiling and are the last component the air passes before entering the clean space

Filter Type & Installation Room-side replaceable ceiling module Fan Powered Module Cleanroom filters can utilize either a disposable HEPA/ULPA ceiling module which is connected to a central HVAC system by means of a duct connected to the module, or can utilize a fan powered downflow module. The fan powered downflow module usually gets its air from the interstitial space above the cleanroom where tempered air is brought from the mechanical room and mixed with return air from the cleanroom.

Cleanroom Cleanrooms are classified by the International Standards Organization (ISO) 14644-1 and have an ISO number based on the quantity of particles per cubic foot of air. For example, an ISO Class 1 room has =<10 particles 0.1 micrometer, and =<2 particles 0.2 micrometers. The ISO classes of air runs from 1 to 9 (reference page 9.4 in the text). The number and type of HEPA filters in a cleanroom dictates the class.

Clean Benches & Biological Safety Cabinets Clean benches and biological safety cabinets are examples of small, self-contained controlled environments. The will be discussed more fully in a later presentation

Other Controlled Environment: Pharmaceutical Compounding-Sterile Preparation Rooms – keeping intravenous products sterile during mixing and regulated by USP 797. Firing Ranges – lead dust Libraries, Archives and Museums – preservation of irreplaceable documents and artifacts Nuclear Energy Applications – HEPA filters on Department of Defense Qualified Products List - DOD filters must be tested at qualified DOE filter test sites. Pharmaceutical compounding rooms are a fairly new requirement and have lead to spaces being constructed in hospital pharmacies for this purpose. Firing ranges require airflow past the shooter, moving explosive powders and lead dust down range and through specially designed and installed HEPA filtered HVAC systems. Libraries, Archives and Museums offer a protected environment for irreplaceable artifacts. The nuclear power industry and other nuclear applications utilizes special HEPA filters tested to UL and DOD Standards.

Other Controlled Environment: Computer Equipment – MERV 9 to 13 to remove circuit-fouling dust particles Photographic Industry – control dust particles on developed film-i.e. particles in developing rooms can cause spots on photos Storage Tanks – breather filters control particle contaminants during fill and drain operation Large computer rooms are becoming more commonplace and ultra-clean environments and precise temperature and humidity are required. The photographic industry may be shrinking however there are still requirements for non-computer based photos that require clean developing areas. Storage tanks require HEPA breather filters to clean makeup air.

Other Controlled Environment: Control Rooms – paper mill and petrochemical plant control rooms must have air free of molecular and particulate contaminants Sewage Plant- require high efficiency MERV 14 in their compressed aeration systems. Petrochemical and paper mill plants filter to keep particulate and molecular contaminants for their computer control rooms. The process of converting sewage into sludge requires a unique process including the filtration of fine particles that could plug the aeration process.

Other Controlled Environment: Textile Plant- Most airborne particles are lint. These particles are controlled with synthetic filters. Gas Turbine – -10 micron and larger can cause erosion of turbine compressor blades -5 micron and smaller particles cause deposits on and fouling of turbine blade In systems with heavy concentrations of lint rotary “drum” self cleaning filters are used regularly. Gas turbine applications Gas Turbine Filter

Other Controlled Environment: Telecommunication Equipment Rooms- This technology driven industry requires a wide range of filtration products. Primarily MERV 12-MERV14, depending on the location and type of equipment being used. Many other applications

-All Industries- All processes require filtration which equates to sales All processes are unique and require a degree of specific knowledge The NAFA organization and its affiliated programs can provide you with that necessary knowledge NAFA associates can provide you with the necessary products and technical support for those products.

Sample Questions Name two types of cleanrooms? Non-unidirectional (conventional) and unidirectional (laminar flow) A Breather Filter protects content of? Strorage tanks – air moving both in and out of the tank Gas turbine supply air must be free of 5 micrometer particles because? They stick to and foul the turbine blades – 10 micrometer particles erode the blades

Thank you. Questions?