Mississippi HVAC Practice Exam

Piping 4 items

Our study plan for this topic: Gas piping materials, specifications, and approved pipe types (steel, copper, CSST, PE, polyamide); Gas piping sizing methods — longest length, branch length, and hybrid pressure approaches; Allowable pressure drop and maximum operating pressure for gas piping systems; Pipe joint types and connection methods (threaded, brazed, welded, press-connect, flared); Hydronic piping materials, fittings, and joint standards (IMC Chapter 12); LP-Gas piping service limitations, pressure ratings, and installation requirements (NFPA 58); Piping support, protection, and spacing requirements; Fuel oil piping materials, joints, and system installation requirements (IMC Chapter 13).

Insulation 1 item

Our study plan for this topic: R-values of common building materials (batt, board, loose fill, spray-on insulation types); Duct wall insulation R-value requirements and correction factors (R-2 through R-8); Effect of insulation R-value on heating and sensible cooling duct loads; Opaque panel U-values and HTM calculation for walls, ceilings, roofs, and floors; Vapor retarders for externally insulated ducts in humid climates; Duct insulation fire and smoke ratings (flame spread and smoke-developed index requirements per IMC Section 604); Double-wall duct insulation construction and liner installation standards; Compression correction factors for batt and blanket insulation.

Hangers and Supports 3 items

Our study plan for this topic: Hanger spacing requirements for horizontal ducts (maximum intervals and proximity to elbows and branch intersections); Minimum hanger sizes for rectangular duct by half-perimeter and support spacing; Minimum hanger sizes for round duct by diameter and support spacing; Upper attachment methods and allowable load limits (safety factor of 4 relative to failure load); Lower attachment methods for connecting hangers to duct; Trapeze hanger selection and load calculation; Riser support methods and spacing intervals for vertical ducts; Effects of flexible duct sag and compression on pressure drop and equivalent length.

Sound, Vibration and Seismic Control 1 item

Our study plan for this topic: Noise sources in HVAC systems (blower, fittings, dampers, outlets); Air velocity limits for noise control in duct runs and outlets; Duct geometry design to acoustically decouple noise sources from occupied spaces; Vibration isolation methods for equipment and ductwork; Crosstalk prevention through duct layout and line-of-sight avoidance; Noise attenuation using duct liner, duct board, and sound traps; Noise Criteria (NC) values for residential and multi-family occupancies; Vibration isolation connectors and flexible duct connections per IMC Chapter 6.

Heating and Cooling Principles 3 items

Our study plan for this topic: Heat transfer mechanisms (conduction, convection, radiation); Sensible heat and latent heat distinctions; Compression refrigeration cycle components and operation; Thermal resistance values (K-value, C-value, R-value, U-value); Indoor and outdoor design temperatures for load calculations; Manual J residential and Manual N commercial load calculation methods; Heat pump heating and cooling modes and efficiency ratings; Refrigerant classification, environmental impact, and pressure-temperature relationships.

Refrigerants and Refrigeration 6 items

Our study plan for this topic: Refrigerant classification by chemical type (CFC, HCFC, HFC, HFO, HC); Environmental regulations and refrigerant phasedown (Montreal Protocol, Clean Air Act, AIM Act, Kigali Amendment); Refrigerant identification, numbering system, and safety classifications (ASHRAE 34, ODP, GWP); Refrigerant cylinders: types, color coding, DOT regulations, and safe handling; Refrigerant recovery, recycling, and reclamation procedures and equipment; System evacuation procedures and vacuum measurement; Checking refrigerant charge by superheat and subcooling methods; IMC Chapter 11 refrigeration system classification, occupancy requirements, and machinery room provisions.

Load Calculations 10 items

Our study plan for this topic: Heating and cooling design temperature selection (indoor and outdoor design conditions); Thermal resistance and transmittance values (R-value, U-value, K-value, C-value) for building components; Fenestration heating and cooling load calculations using HTM values; Opaque panel heating and cooling load calculations (walls, ceilings, floors, doors); Infiltration load estimation methods (ACH method, component leakage area method); Duct system load calculations (heat loss, sensible and latent gain factors, leakage and insulation effects); Internal loads (occupants, appliances, lighting) for cooling load estimates; Engineered ventilation sensible and latent load calculations.

Testing, Adjusting and Balancing 1 item

Our study plan for this topic: Air-side balancing procedures and damper adjustment; Airflow measurement instruments and methods (flow hood, anemometer, pitot tube, velometer); Blower door testing for building envelope airtightness and duct leakage; Duct leakage testing using duct blaster pressurization; System operating point determination using blower curves and system resistance curves; Available static pressure calculation and friction rate design values; Air velocity limits for ducts, grilles, registers, and diffusers; Duct system noise problems and draft identification and correction.

Controls 3 items

Our study plan for this topic: Thermostat types, sensing elements, and operational principles; Motor starting relays (current, potential, PTC, and solid-state); Pressure motor controls (high-pressure, low-pressure, oil pressure, and safety controls); Control system fundamentals (range adjustment, differential adjustment, cut-in and cut-out settings); Direct digital control (DDC) systems and building automation systems (BAS); Zoned system controls (dampers, zone control panels, bypass dampers, and freezestats); Heat pump controls (reversing valve operation, defrost controls, and thermostat wiring terminals); Electronic expansion valves (EEVs) and solenoid valve control applications.

A/C and Heat Pump Equipment 4 items

Our study plan for this topic: Split system configurations (central, mini-split, multi-split, VRF); Heat pump operating principles and reversing valve operation; Compressor types and protection devices (reciprocating, rotary, scroll); Metering device types and selection (capillary tube, fixed orifice, TXV, biflow valves); Packaged and self-contained equipment types (room AC, PTAC, PTHP, rooftop units); Geothermal and water-source heat pump system types and components; Heat pump efficiency ratings and defrost controls (SEER2, HSPF2, reverse cycle defrost, auxiliary heat); Commercial system types (chillers, VRF, cooling towers, compressor capacity control).

Furnaces and Heaters 4 items

Our study plan for this topic: Gas furnace sequence of operation and heat exchanger types (primary vs. secondary, condensing vs. noncondensing); Gas burner types and ignition systems (atmospheric, power, standing-pilot, intermittent-pilot, DSI, HSI); Gas furnace safety and operational controls (high-limit switch, rollout switch, pressure switch, ignition control module lockout functions); Combustion principles and efficiency testing (CO2, O2, CO content, stack temperature, gas pressure measurement); Oil furnace components and operation (gun burner, fuel unit, primary control unit, cad cell relay, stack relay); Electric heating systems and controls (resistance elements, sequencers, duct heaters, baseboard units, safety cutoffs); Heat pump heating operation, defrost controls, and auxiliary heat; Venting categories, vent types, and installation requirements for gas-fired appliances (Type B, direct-vent, Category I–IV, chimney sizing).

Chimneys, Flues and Vents 3 items

Our study plan for this topic: Vent system types and appliance matching (Type B, BW, L, single-wall metal pipe, special gas vent); Chimney and vent termination height and location requirements; Sizing of Category I venting systems using code tables (single and multiple appliances); Vent connector installation requirements (slope, length, clearances, materials, joints); Masonry chimney requirements (lining, cleanouts, inspection, reuse with gas appliances); Factory-built chimney listing, installation, and support requirements; Draft hoods, draft controls, and mechanical draft systems; Direct-vent and Category II/III/IV appliance venting requirements.

Combustion Air 2 items

Our study plan for this topic: Indoor combustion air requirements and volume calculations; Outdoor combustion air methods and opening sizing; Combustion air duct requirements and installation; Primary air, secondary air, and excess air in gas burners; Makeup air units and negative pressure prevention; Dampered openings and motorized louver interlocks; Mechanical combustion air supply systems and appliance interlocks; Protection from corrosive or flammable fumes in combustion air supply.

Fuel Gas Systems 9 items

Our study plan for this topic: Gas piping materials, fittings, and allowable pipe types (steel, copper, CSST, PE); Gas pipe sizing methods and capacity tables (longest length, branch length, hybrid pressure); Gas piping pressure requirements and maximum operating pressure limits; Gas piping installation requirements (support, identification, testing, purging, and leak detection); Venting system types and appliance category matching (Type B, BW, L, direct-vent, single-wall metal); Chimney and vent sizing, termination heights, and clearance requirements; LP-Gas container types, installation, separation distances, and location requirements (NFPA 58); Combustion air requirements for gas-fired appliances (indoor, outdoor, and combined methods).

LP Gas Systems 5 items

Our study plan for this topic: Container location and separation distance requirements; Pressure regulator types, selection, and installation; LP-Gas piping materials, joints, and installation requirements; Piping system sizing methods and tables for undiluted propane; Container appurtenances including pressure relief valves, excess-flow valves, and liquid level gauges; LP-Gas transfer operations and safety procedures; Cylinder storage requirements inside and outside buildings; Corrosion protection for underground and aboveground LP-Gas systems.

Ducts 10 items

Our study plan for this topic: Duct sizing calculations using ACCA Manual D (friction rate, available static pressure, total effective length); Rectangular duct construction standards (gauge selection, reinforcement schedules, pressure classification); Round, oval, and flexible duct construction standards (gauge, seams, joints, negative pressure requirements); Duct leakage, sealing requirements, and testing methods; Duct insulation requirements and efficiency (R-values, conduction losses, vapor retarders); Duct system types and layout (radial, extended plenum, reducing trunk, trunk-and-branch); Duct hangers, supports, and installation requirements; Fitting equivalent lengths and their effect on duct system design.

Boilers and Hydronics 4 items

Our study plan for this topic: Boiler types and classifications (conventional vs. condensing, cast-iron vs. steel vs. copper-tube, wet-base vs. dry-base); Boiler safety devices and controls (pressure-relief valves, low-water cutoff, aquastat, high-limit control, flow switch); Hydronic system piping configurations (series loop, one-pipe, two-pipe direct return, two-pipe reverse return, zoned systems); Expansion tanks and air-removal components (bladder/diaphragm tanks, air scoops, air separators, air vents); Hydronic system valves (mixing valves, balancing valves, pressure-reducing valves, backflow preventers, flow-control valves, zone valves); Hydronic piping materials, joints, and installation requirements per IMC Chapter 12; Radiant hydronic systems (wet and dry underfloor installation methods, PEX tubing, manifolds, embedded piping code requirements); Boiler water treatment, system start-up, balancing, and troubleshooting (water quality, glycol, cavitation, circulation problems).

Machine Room 1 item

Our study plan for this topic: Machinery room design and construction requirements (IMC Section 1105); Machinery room ventilation requirements: normal and emergency rates; Refrigerant detectors and emergency pressure control systems; Fuel-burning appliances and open flame restrictions in machinery rooms; Means of egress requirements for machinery rooms; Special requirements for flammable refrigerant machinery rooms (Groups A2, A3, B2, B3); Remote control and emergency shutoff systems for machinery room equipment; LP-Gas facility construction, ventilation, and heating requirements (NFPA 58 Chapter 10).

Evaporative Cooling 2 items

Our study plan for this topic: Basic principles of evaporative cooling and psychrometrics (dry-bulb, wet-bulb, relative humidity relationships); Direct evaporative cooler components and operation (wetted media/excelsior pads, blower, water supply, pump); Wet roof cooling methods (roof ponds and roof mist cooling systems); Indoor/greenhouse evaporative cooling applications; IMC Section 928 installation requirements for evaporative cooling equipment (level platform, water supply, wall/roof flashing, air intake location); Cooling towers and evaporative condensers installation requirements (location, drift eliminators, drainage, water supply per IMC Section 908); Climate suitability and limitations of evaporative cooling (hot, dry vs. humid climates); Absorption and Evaporative Cooling Systems.

Safety 4 items

Our study plan for this topic: Lockout/tagout (LOTO) procedures and requirements; Personal protective equipment (PPE) selection and use; Electrical hazards and GFCI protection on construction sites; Fire hazards, fire extinguisher classes, and PASS technique; Fall protection systems (guardrails, personal fall arrest, safety nets); Ladder and stairway safety requirements; Refrigerant and pressure vessel hazards; Hazard communication and Safety Data Sheets (SDS).