Download NAFA CAFS Exam Q&A: Air Filtration and Contamination Control and more Exams Chemistry in PDF only on Docsity!
What are the 3 types of media used in contaminate control - correct answer ✅Active carbon, chemically treated carbon, potassium permanganate What is residence time? - correct answer ✅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 - correct answer ✅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 - correct answer ✅The fraction of the contaminate that once in contact with the media is removed by either physical or chemical means What is Capacity - correct answer ✅The amount the media is capable of removing - this determines the life of the filter
What are two types of filter options - correct answer ✅partial bypass, total retention What is the ASHRAE standard 62.1/62.2 - correct answer ✅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? - correct answer ✅ 4 What are the IAQ testing applications - correct answer ✅Particulate contaminants, Gas phase, systems integrity, comfort parameters What are the control strategies - correct answer ✅Filtration, source removal, Dilution Min demonstrated overspray filter eff must be at least - correct answer ✅98%
In the filter industry, a manometer is used to measure what? - correct answer ✅Pressure drop across the filter Airflow through a booth must be? - correct answer ✅high enough to keep the concentration of VOC vapor below 25% of its lowest explosive limit ULPA stands for? - correct answer ✅Ultimate low penetration Air Filter Name the components of a HEPA filter - correct answer ✅Media, separators, filter pack, sealant, framing, gasketing What size particles behave like a gas, have negligible settling rates and are affected by Brownian Motion - correct answer ✅Particals less than .1 microns A 2 stage air cleaner utilizes what 2 things? - correct answer ✅An Ionizer section, a collector section
Name the types of HEPA separator styles - correct answer ✅'aluminum and mini pleat Name the different HEPA frame material - correct answer ✅Partical board, plywood, extruded alum, formed sheet metal What is media velocity - correct answer ✅the speed of the air as it moves through the filter media What are the types of HEPA filter sealants - correct answer ✅Rubber bases, urethane, epoxy, hot melt, silicone What are the styles of Dust Separation equipment - correct answer ✅cyclone, shaker, reverse pulse, jet pulse What are the different types of air cleaners - correct answer ✅media, electronic, agglomorators what is the minimum efficiency for ULPA - correct answer ✅99.999% on .1 to .2 microns
correct answer ✅carbon in the dust shorts out the electrical connections VOC - correct answer ✅Volatile organic compound MPPS - correct answer ✅Most penetrating particulate size what are the factors that affect filter life - correct answer ✅partical size, underrating/overrating What is Chemisorption - correct answer ✅the result of chemical reactions on and in the surface of the absorbent What is the optimum final pressure drop - correct answer ✅the point where the sum of power cost & filter cost is at a minimum
What is the total cost of filtration - correct answer ✅the sum of all first cost that can be depreciated..plus the sum of the annual operating cost UVGI - correct answer ✅Ultraviolet Germicidal Irradiation How does UVGI work? - correct answer ✅The DNA of the micro organisms absorb the UVGI energy - this breaks the DNA strand What are the types of PCO reactors - correct answer ✅coated wall annular design, packed bed, flat bed, box reactors Why capture aerosolized metal working fluids - correct answer ✅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 - correct answer ✅semi synthetic, synthetic, straight, soluble
What is initial resistance - correct answer ✅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? - correct answer ✅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? - correct answer ✅Source control, ventilation/dilution, removal control What is straining? - correct answer ✅occurs when the smallest dimension of dust particle is greater than the distance between adjoining media fibers What 3 factors affect mechanical filter selection? - correct answer ✅efficiency, pressure drop, capacity
What are the active charged media types? - correct answer ✅Triboelectric charging, corona charging, charging by induction Categories of impingement filters - correct answer ✅panel, washable, roll, and lint filters Having larger fibers on the air entering side and smaller fibers on the air exit side is called? - correct answer ✅Graduating density Baffle grease filters must meet the requirements of NFPA standard - correct answer ✅ 96 Minipleats have more media than most extended surface filters providing two advantages - what are they - correct answer ✅lower initial pressure drop and longer life in service Two types of gasketing for HEPA's are? - correct answer ✅closed cell neoprene and non newtonian gel seal
Two main methods for molecular contaminant removal are? - correct answer ✅Absorption and Chemisorption Particles bypass cells allow for retrofit without? - correct answer ✅large pressure increases in the system Name the three procedures for engineers to use in ASHRAE standard 62.1 - correct answer ✅Ventilation rate, indoor air quality, natural ventilation procedure Impingement filters are characterized by? - correct answer ✅Relatively high velocities and low pressure drop The four principles of air filtration are? - correct answer ✅Impingement, interception, diffusion, and straining The velocity of the air through any one square foot of media in an extended surface filter is called? - correct answer ✅Media velocity
What percent of the total cost of a filter is energy cost? - correct answer ✅81% UVGI is most effective on micro organism in what range of the light spectrum - correct answer ✅200 to 280 nanometers What are vapors? - correct answer ✅Gases formed by evaporation of materials that are normally a liquid or solid What are the principles of air flow? - correct answer ✅Quantity of Air(Q) the velocity of air (V)and the area of the filter (A) What is pressure drop? - correct answer ✅the resistance a filter adds to the system What are the principles of Particulate Air Filtration - correct answer ✅Mechanical, electrostatically charged media, electronic air cleaners
surfaces - the strength of the bond depends on the van der waal forces between the gas and the surface What is Gas? - correct answer ✅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? - correct answer ✅reaction at ambient temperatures/small addition of resistance to the HVAC system/complete destruction of a contaminant into harmless elements Humidity can hinder? - correct answer ✅Adsorption When does Interception occur? - correct answer ✅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? - correct answer ✅Dust particle size, density of the dust, depth of the filter, velocity of the airflow Impingement filters work by? - correct answer ✅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 - correct answer ✅cross draft and down draft Welding smoke is removed how? - correct answer ✅Using a source capture hood What is face velocity? - correct answer ✅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?
correct answer ✅99.97% on 0.3 microns
What is MERV - correct answer ✅Minimum Efficiency Rating Value When exhaust air exceeds intake air________must be provided to replace the difference - correct answer ✅Make up air A drawback of PCO may be the? - correct answer ✅high initial cost of equipment what should technicians do before servicing units in which UV lights have been installed? - correct answer ✅Turn off the lights prior to opening compartments where the lights are located Why should UVGI lights be installed downstream of filters? - correct answer ✅UV light can destroy certain types of filter media Running filters to their maximum pressure drop may? - correct answer ✅cost more in energy than the cost to change it sooner
Fan efficiency, drive efficiency and motor efficiency calculate into what cost? - correct answer ✅energy cost A major source of pollution in a building is? - correct answer ✅people Tuberculosis patients must be kept in rooms that are? - correct answer ✅Negative pressure to the other rooms Testing HEPA filters after installation is called? - correct answer ✅In-place leak testing or cold DOP test If static pressure goes up, velocity pressure goes? - correct answer ✅Down Metal working fluids are used to? - correct answer ✅cool, lubricate and clean production parts
