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A comprehensive set of questions and answers related to bomi's air handling, water treatment & plumbing systems exam. It covers key concepts such as human comfort, heat transfer methods (convection, conduction, radiation), sensible and latent heat, air properties, and pressure dynamics in air conditioning systems. The material is organized into review quizzes and key concept summaries, making it a valuable resource for exam preparation and understanding fundamental principles in hvac and plumbing. It also includes explanations of charles' and boyle's laws, and discussions on internal heat loads and ventilation strategies. Designed to help students and professionals master the essential knowledge required for building systems management and operation.
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Air Handling, Water Treatment & Plumbing System Chapter 1 Human Comfort Review Quiz 1 1 - The rate of exchange of fresh air for returned air in an air conditioning-system is based on the period of time covered and the number of building: Occupants 2 - All of the 3 following are methods of heat Radiation Convection
Conduction NOT Reduction 3 - Which heat load source is most likely to affect all zones of a building? Lighting equipment 4 - To compensate for heat gain from office equipment in modern office building, air- conditioning systems have been designed to offset how many watts per square foot? 1 to 3 Watts per square foot. 5 - The leftover heat in a building from the day before is the: Pull-down load 6 - What exists when the temperature and relative humidity of a person's environment permit the person to lose metabolic heat at the same rate he or she produces it? Thermal comfort
12 - Boyle's law states: As Pressure goes up, volume goes down. 13 - Maintaining temperature and Blank have a direct impact on maintaining human comfort. Humidity 14 - How does introducing air-conditioned and filtered air at a positive pressure into a building help building comfort? It causes the outward escape of air, limiting infiltration. Chapter 1 Key Concept 1 - What is the relationship between thermal comfort and metabolic heat? Thermal comfort exists when the temperature and relative humidity of a persons environment permit the person to lose, without conscious effort, metabolic heat at the same rate he or she produces it.
2 - What occupant activity level is chosen when engineers design an air-conditioning system? average and peak activity levels 3 - What is the rate of exchange of fresh air for return air based on in an air-conditioning system? The rate of exchange of fresh air for returned air is based on the quantity of fresh air required for each building occupant over the course of time. 4 - Define heat Heat is a form of energy which cannot be destroyed only transformed or moved. Heat is added to conditioned air in the winter and removed in the summer. No shit. 5 - What happens to the rate of heat transfer if the difference in temperature increases? the rate of heat transfer Increases if the difference in temperature increases 6 - What are three methods in which heat is transferred? Convection
9 - Define latent heat The energy that is used or released during the change in state. 10 - Define relative humidity The amount of water vapor held in the air 11 - Does moist air have more or less density than dry air? Moist air has less mass than dry air and is less dense than dry air. 12 - What is the atmospheric pressure of air at sea level? 14.7 psi 13 - Explain Charles' law: Charles law explains why gases expand when heated and contract when cooled. 14 - Explain Boyle's law
Boyle's law states that a constant temperature, as the volume increases, the pressure decreases. 15 - How does the human body regulate temperature? Sweating when overheating too cool down. 16 - What system produces the most heat in a building? Zoning HVAC system? Maybe look into this one. 17 - What are the four main categories of internal heat loads? People Heat Load Lighting Heat Load Equipment Heat Load System Heat Load 18 - How have office building HVAC systems been designed to compensate for heat gain from office equipment?
1 - Absolute pressure is equal to standard sea-level plus: Gauge pressure 2 - It is unusual for an air-conditioning system to exceed how many p.s.i.g or p.s.i.a? 0.5 psig 3 - The pressure of the air being pushed against the inside walls of a closed duct by a fan is called: Static pressure 4 - The pressure that is created when air moved is called: Velocity pressure 5 - Velocity pressure is found by subtracting: Static pressure from total pressure
6 - A pressure drop is the difference in air pressure between where air enters a device and: Where the air leaves the device 7 - When designing a duct system, it is important to remember that directional changes increase friction and Blank efficiency. Reduce 8 - The higher the airflow velocity in a duct work system is, the more Blank will be generated, and the power efficiency will increase. Noise 9 - Which material used to construct duct work is prohibited from use in hospitals and kitchens by many local codes, and has been declared a possible carcinogenic to humans by the World health Organization? Fibrous glass wool 10 - A draft exists when room air movement aka velocity is at or above how many fpm? 50 fpm
15 - What is a key aspect of a well-designed air-distribution service? Maintaining air outlet noise below an objectionable level. 16 - Anti-smudge rings will help reduce deposit on outlets, but the best solution is to: Select outlets with lower velocities 17 - Complying with codes regarding fire dampers help to: Prevent facilities from smoke inhalation 18 - All of the following are commonly used methods of alleviating noise and vibration issues with equipment: Housekeeping pads Vibration isolators Inertia bases NOT Fan cancelers Chapter 2 Key Concept
1 - Define absolute pressure The total pressure that is exerted on a gas or liquid from all sources, including the atmospheric pressure. Expressed in psia Absolute pressure (psia) is equal to the sum of the atmospheric pressure and gauge pressure. 2 - Define static pressure The pressure of the air being pushed against the inside walls of a closed duct by the fan. 3 - How is velocity pressure calculated? VP = SP - TP The total pressure is a combination of static air pressure and velocity pressure. TP = SP + VP
The supply duct is installed in a continuous, closed loop around the perimeter of the building. Ideal for single-story buildings with concrete slab floors where the ducts are sometimes cast into the slabs. 9 - What is a problem with using fibrous glass wool as duct-work material? The World Health Organization has declared fibrous glass wool as carcinogenic to humans. Cannot use it in hospitals or kitchens. This type of material is used in low-pressure and low velocity duct systems. They have high friction. 10 - Which type of duct uses fiberglass insulation? Flexible duct. 11 - How can duct leakage be eliminated? Can be eliminated through use of sealants applied to all duct joints - duct collar tap-ins, branch intersections, access doors, and air terminal connections.
12 - Generally, how long can a duct be before it needs to be insulated? You should insulate of the duct is more than 50 feet long. 13 - What determines the amount of ventilating air required in a building? The amount of ventilating air required depends generally on the number of people occupying a space, their activities, the volume of space, and the duration of the stay of the occupants in the space. 14 - According to ASHRAE Standard 62-1989, how many cubic feet per minute of air exchange should maintain an acceptable IAQ level? The air exchange rate should be 15 cubic feet per minute (cfm) to maintain acceptable indoor air quality in a reception area Office space and confrence rooms, the standard is 20 cfm 15 - What are the key elements of proper room ventilation? The object is to properly combine temperature, humidity, and air motion in the occupied zone of the room, from the floor to 6 feet above the floor. Conditioned space must be distributed so that horizontal and vertical temperature variations within the space are minimized.
Air distributing ceilings are use of the confined space above the ceiling as a supply air plenum. This supply air plenum receives the conditioned air directly from the air handling unit with a minimal supply air duct system consisting of a short main duct and no branch ducts. 19 - What are dampers? Airflow in the duct system is controlled by volume dampers. 20 - What are some characteristics of volume or balancing dampers? The dampers provide a resistance to airflow to adjust how much air flows to various areas. Dampers are installed in each branch duct to ballace the quantity of airflow in the duct system. Volume dampers are also called balancing dampers. 21 - Why are fire dampers important? Fire dampers must be installed between walls in the ducts to maintain seperation of one tenants pace from another. Fire damper prevents the spread of fire and smoke from one area to another through a duct system.
22 - What is a silencer? A silencer is a specially designed duct component that changes airflow characteristics so as to reduce the noise made in the duct. Chapter 3 Air-Handling Units, Fans, and Building Pressurization Review Quiz 3 1 - For a centrifugal fan, which type of fan blade affords a wider range of efficiencies and lower noise levels? Airfoil 2 - The amount of work a fan performs to move a specific volume of air at a specific speed is called what? AHP - Air Horse Power
