NAFA CAFS /Exam Questions With Correct Solutions

NAFA CAFS /Exam What are the 3 types of media used in contaminate control - ANS Active carbon, chemically treated carbon, potassium permanganate What is residence time? - ANS the time it takes air to cross a distance equal to the thickness of the filter without accounting for the resistance of the media through which it travels What are the variations of the contamination control principle - ANS clean the air required by the process, blanket the product with cleaned air, offer enough air flow to move contaminated air away from the product What is removal efficiency - ANS The fraction of the contaminate that once in contact with the media is removed by either physical or chemical means What is Capacity - ANS The amount the media is capable of removing - this determines the life of the filter What are two types of filter options - ANS partial bypass, total retention What is the ASHRAE standard 62.1/62.2 - ANS Ventilation for acceptable indoor air quality to specific minimum ventilation rates IAQ which will be acceptable to humans and are intended to avoid adverse health effects How many classifications of air is there? - ANS 4 What are the IAQ testing applications - ANS Particulate contaminants, Gas phase, systems integrity, comfort parameters What are the control strategies - ANS Filtration, source removal, Dilution Min demonstrated overspray filter eff must be at least - ANS 98% What is the min eff for a Super ULPA - ANS 99.9999% on MPPS What are the factors affecting ESP design and efficiency - ANS partical size, velocity through filter, voltage on ionizer and collector, collector plate spacing, collector plate loading, ionizer spacing and ozone What are the types of Microorganisms - ANS Virus, Bacteria, Fungi A baghouse is composed of - ANS house, hoppers, tubesheet and plenum A typical oil mist electrostatic presipitator has what sections (inlet to outlet) - ANS Baffle, ionizer, collecting, fan and optional after filter PCO has how many types of reactor configurations - ANS 4 In the filter industry, a manometer is used to measure what? - ANS Pressure drop across the filter Airflow through a booth must be? - ANS high enough to keep the concentration of VOC vapor below 25% of its lowest explosive limit ULPA stands for? - ANS Ultimate low penetration Air Filter Name the components of a HEPA filter - ANS Media, separators, filter pack, sealant, framing, gasketing What size particles behave like a gas, have negligible settling rates and are affected by Brownian Motion - ANS Particals less than .1 microns A 2 stage air cleaner utilizes what 2 things? - ANS An Ionizer section, a collector section Name the types of HEPA separator styles - ANS 'aluminum and mini pleat Name the different HEPA frame material - ANS Partical board, plywood, extruded alum, formed sheet metal What is media velocity - ANS the speed of the air as it moves through the filter media What are the types of HEPA filter sealants - ANS Rubber bases, urethane, epoxy, hot melt, silicone What are the styles of Dust Separation equipment - ANS cyclone, shaker, reverse pulse, jet pulse What are the different types of air cleaners - ANS media, electronic, agglomorators what is the minimum efficiency for ULPA - ANS 99.999% on .1 to .2 microns What are the two types of cleanroom filters - ANS roomoside replaceable ceiling module, fan powered module Removal of dust on an elctronic air cleaner is done how - ANS washed off, if it has agglomerated it can be blown off Lofted glass media can be found most often in what style filter - ANS Pocket or rigid What is final resistance - ANS pressure at which the filter would be considered fully loaded how do mechanical filters remove dust - ANS capturing on media Why can't electronic air cleaners be tested for loading using the ASHRAE 52.2 test - ANS carbon in the dust shorts out the electrical connections VOC - ANS Volatile organic compound MPPS - ANS Most penetrating particulate size what are the factors that affect filter life - ANS partical size, underrating/overrating What is Chemisorption - ANS the result of chemical reactions on and in the surface of the absorbent What is the optimum final pressure drop - ANS the point where the sum of power cost & filter cost is at a minimum What is the total cost of filtration - ANS the sum of all first cost that can be depreciated..plus the sum of the annual operating cost UVGI - ANS Ultraviolet Germicidal Irradiation How does UVGI work? - ANS The DNA of the micro organisms absorb the UVGI energy - this breaks the DNA strand What are the types of PCO reactors - ANS coated wall annular design, packed bed, flat bed, box reactors Why capture aerosolized metal working fluids - ANS hazardous to people, may damage equip and facility, may be illegal to exhaust outside, can be reused What are the types of metal working fluids - ANS semi synthetic, synthetic, straight, soluble mist and smoke removal is done with what type of filters - ANS media, centrifugal, electrostatic What are the Merv rating/color coded of lofted microglass media - ANS yellow=14, Pink=13, orange=11, tan 50=9 what is the function of ceiling diffusion media - ANS clean the air of particles 5 micron and larger, diffuse he air evenly across the booth Why do HVAC testing - ANS Determine efficiency of the particle size removal, amount of contaminate removed, and pressure drop What is the ANSI/ASHRAE 52.2 - 2012? - ANS A design qualification test, destructive test to measure merv, the test aerosol is Potassium Chloride .3 to 10 micron, dust loading aerosol to final pressure drop is the Ashrae standard dust test What is initial resistance - ANS Pressure required to move air through the filter at a certain air flow it written in inches, water or pascals HEPA filter testing consists of? - ANS Penetration converted to overall efficiency including gaskets, sealing and framing, initial resistance and 2 flow testing (leak test) What are the three ways to control molecular contaminants? - ANS Source control, ventilation/dilution, removal control What is straining? - ANS occurs when the smallest dimension of dust particle is greater than the distance between adjoining media fibers What 3 factors affect mechanical filter selection? - ANS efficiency, pressure drop, capacity What are the active charged media types? - ANS Triboelectric charging, corona charging, charging by induction Categories of impingement filters - ANS panel, washable, roll, and lint filters Having larger fibers on the air entering side and smaller fibers on the air exit side is called? - ANS Graduating density Baffle grease filters must meet the requirements of NFPA standard - ANS 96 Minipleats have more media than most extended surface filters providing two advantages - what are they - ANS lower initial pressure drop and longer life in service Two types of gasketing for HEPA's are? - ANS closed cell neoprene and non newtonian gel seal ANSI/ASHREA 52.2 averages particles sized in how many broad composite categories - ANS (3) E1, E2 and E3 ANSI/ASHREA 52.2 what are the ranges of these averages - ANS E1=.3 to 1.0 E2=1.0 to 3 E3= 3 to 10 microns What is the name of the current European Air Filter Standard? - ANS EN779:2002 Name two types of cleanrooms - ANS non- unidirectional (conventional) and unindirectional (laminar flow) A breather filter protects content of? - ANS storage tanks - air moving in and out of the tank Gas turbine supply air must be free of 5 micrometer particles because? - ANS they stick to and hurt the turbine blades - 10 micron particles erode the blades Two main methods for molecular contaminant removal are? - ANS Absorption and Chemisorption Particles bypass cells allow for retrofit without? - ANS large pressure increases in the system Name the three procedures for engineers to use in ASHRAE standard 62.1 - ANS Ventilation rate, indoor air quality, natural ventilation procedure Impingement filters are characterized by? - ANS Relatively high velocities and low pressure drop The four principles of air filtration are? - ANS Impingement, interception, diffusion, and straining The velocity of the air through any one square foot of media in an extended surface filter is called? - ANS Media velocity What percent of the total cost of a filter is energy cost? - ANS 81% UVGI is most effective on micro organism in what range of the light spectrum - ANS 200 to 280 nanometers What are vapors? - ANS Gases formed by evaporation of materials that are normally a liquid or solid What are the principles of air flow? - ANS Quantity of Air(Q) the velocity of air (V)and the area of the filter (A) What is pressure drop? - ANS the resistance a filter adds to the system What are the principles of Particulate Air Filtration - ANS Mechanical, electrostatically charged media, electronic air cleaners What is Diffusion? - ANS explains the capture of very small particles (Brownian Motion - the erratic path taken by very small particles because they are bombarded by other particles) This erratic path ncreases the probability that the particles will come into contact with the fibers Dust separation is used for two objectives? - ANS Recover valuable product from plant processes that generate dust 2. Clean air to stay in compliance with OSHA and EPA requirements What is Aerosol? - ANS An assemblage of small particles, solid or liquid suspended in air What is Absorption? - ANS the process by which a liquid or a gas is taken into the interstices of a porous substance and held there What is Adsorption - ANS the process by which gas molecules adhere to surfaces - the strength of the bond depends on the van der waal forces between the gas and the surface What is Gas? - ANS Any material that has the tendency to expand indefinitely and which completely and uniformly fills the container it occupies A PCO advantage is it's? - ANS reaction at ambient temperatures/small addition of resistance to the HVAC system/complete destruction of a contaminant into harmless elements Humidity can hinder? - ANS Adsorption When does Interception occur? - ANS When a dust particle follows air streams but still comes into contact with the fiber as it passes around it. It is fiber size dependent and is enhanced when fiber and particles are close in size What does the effectiveness of impingements filters depend on? - ANS Dust particle size, density of the dust, depth of the filter, velocity of the airflow Impingement filters work by? - ANS larger particles do not move around the fiber with the airstream and are carried into the fiber due to their speed, weight and size What are the categories of enclosed finishing booths - ANS cross draft and down draft Welding smoke is removed how? - ANS Using a source capture hood What is face velocity? - ANS the speed of the air as it approaches the filter face in order to be classified a HEPA filter the efficiency must be at least? - ANS 99.97% on 0.3 microns What is the difference between hot DOP and cold DOP - ANS Size of particle challenge Underrating a filter may have the unintended consequence of - ANS Changing the efficiency curve What are the four characteristics that can make an overspray filter hazardous? - ANS Corrosivity, ignitability, reactivity and toxicity Why is industrial finishing used? - ANS enhance the life of the product, make it pretty Natural ventilation procedure allows what? - ANS Outdoor in - windows What is PCO? - ANS Photocatalytic Oxidization What is ASHRAE? - ANS American Society of Heating, Refrigerating and Air conditioning Engineers What is MERV - ANS Minimum Efficiency Rating Value When exhaust air exceeds intake air________must be provided to replace the difference - ANS Make up air A drawback of PCO may be the? - ANS high initial cost of equipment what should technicians do before servicing units in which UV lights have been installed? - ANS Turn off the lights prior to opening compartments where the lights are located Why should UVGI lights be installed downstream of filters? - ANS UV light can destroy certain types of filter media Running filters to their maximum pressure drop may? - ANS cost more in energy than the cost to change it sooner Fan efficiency, drive efficiency and motor efficiency calculate into what cost? - ANS energy cost A major source of pollution in a building is? - ANS people Tuberculosis patients must be kept in rooms that are? - ANS Negative pressure to the other rooms Testing HEPA filters after installation is called? - ANS In-place leak testing or cold DOP test If static pressure goes up, velocity pressure goes? - ANS Down Metal working fluids are used to? - ANS cool, lubricate and clean production parts What are the two general categories of Enclosed Finish Booths? - ANS cross draft and down draft Name for issue when a person comes into a building and experiences flu-like symptoms? - ANS sick building syndrome Healthcare facilities follow filter guidelines of? - ANS American Institute of Architects (AIA) Bacteria reproduce by - ANS cell division Even though smaller than 0.3 microns HEPA filters can remove? - ANS viruses Filter efficiency is best determined by a (n) - ANS Independant laboratory ANSI/ASHRA 52.2 test An electronic air cleaner collects particles by? - ANS Electrostatically charging them and collecting them on oppositely charges plates 1 millionth of a meter call a? - ANS Micron The air we breath is composed mainly of? - ANS Nitrogen The size of the particles in outdoor air are mainly what size? - ANS 1 micrometer Rated flow of air through a filter at specifies pressure drop is called its? - ANS Capacity