Mississippi Mechanical Contractor Practice Exam

Boilers and Hydronics 6 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); Safety and relief valve requirements and discharge piping installation; Boiler controls (aquastat, low-water cutoff, high-limit control, flow switch, pressure-reducing valve); Hydronic system piping configurations (series loop, one-pipe, two-pipe direct/reverse return, zoned systems); Expansion tank types, sizing, and installation requirements; Hydronic piping materials, joints, and connection methods per IMC Chapter 12; Air removal components and procedures (air vents, air scoops, air separators, bleeding and purging); Radiant hydronic systems (wet and dry underfloor installation methods, embedded piping requirements, insulation and thermal break).

Gas Systems 10 items

Our study plan for this topic: Gas piping materials, fittings, and allowable pipe types (metallic pipe, copper tubing, CSST); Gas piping sizing methods and capacity tables (longest length, branch length, hybrid pressure methods); Gas piping pressure requirements and pressure testing; LP-Gas container types, installation, and separation distances (NFPA 58); LP-Gas pressure relief devices and container appurtenances; Venting system types and appliance categories (Type B, B-W, single-wall, direct-vent, Category I–IV); Chimney and vent sizing, termination requirements, and clearances; Combustion air requirements for gas appliances.

Cleanouts 3 items

Our study plan for this topic: Cleanout placement intervals for horizontal drains, building drains, and building sewers; Cleanout requirements at changes of horizontal direction greater than 45 degrees; Cleanout requirement at the building drain and building sewer junction; Cleanout sizing relative to pipe size served; Cleanout installation arrangement and direction of flow requirement; Required clearance distances at cleanout openings; Cleanout access requirements and prohibition against concealed locations; Cleanout plugs: approved materials, head types, and trim cover provisions.

Plumbing Fixtures and Equipment 5 items

Our study plan for this topic: Minimum number and type of plumbing fixtures by occupancy classification; Fixture installation requirements (clearances, spacing, and setting); Fixture materials, standards, and product approvals; Flushing devices for water closets and urinals; Shower and bathtub valves, temperature limits, and anti-scald requirements; Water heater safety devices, relief valves, and installation requirements; Accessible plumbing fixtures and facilities (ICC A117.1 dimensional requirements); Grease interceptors, oil separators, and trap requirements.

Water Heaters 2 items

Our study plan for this topic: Temperature and pressure relief valve requirements and discharge piping specifications; Water heater installation requirements including access, clearances, and attic installations; Safety devices including antisiphon devices, vacuum relief valves, and shutdown provisions; Cold water supply valve and drain valve requirements; Water heater labeling, certification, and pressure marking of storage tanks; Combination potable water heating and space heating systems with temperature limiting; Drain pan requirements including materials, dimensions, and drain termination; Unfired hot water storage tank insulation requirements.

Piping, valves, controls 5 items

Our study plan for this topic: Pipe and tubing materials selection and standards (steel, copper, plastic, brass, stainless steel); Pipe joining methods (threaded, welded, grooved, brazed, soldered, solvent-cemented, press-connect); Pipe sizing and gas piping capacity tables (longest length, branch length, and hybrid pressure methods); Pipe support, hanger spacing, and hanger rod sizing requirements; Valve types and functions (isolation, pressure-reducing, backflow prevention, expansion, solenoid, pressure-relief); Refrigerant metering devices and expansion valves (TXV, AXV, EEV, float controls); Hydronic piping system components (fittings, flexible connectors, expansion compensators); Protection of piping against freezing, corrosion, and mechanical damage.

Sheet Metal and Ducts 6 items

Our study plan for this topic: Rectangular duct gauge selection and reinforcement schedules based on static pressure class; Transverse joint types and longitudinal seam options for rectangular duct; Round and oval duct wall thickness and seam types for positive and negative pressure; Duct sealing requirements and seal classes by pressure classification; Hanger and support systems for rectangular, round, and flat oval ducts; Flexible duct installation, support, and connection requirements; Duct fittings, elbows, transitions, and branch connections; Duct accessories including volume dampers, access doors, and duct liner installation.

Water Supply 5 items

Our study plan for this topic: Potable water protection and cross-connection control (backflow prevention devices, air gaps, vacuum breakers); Water service pipe materials, standards, and joint types; Water distribution system design criteria (flow rates, pressures, and fixture supply sizing); Water piping system sizing methods (segmented loss method, fixture unit loads, pressure calculations); Water pressure regulation and booster systems (pressure-reducing valves, booster pumps, tanks); Individual water supply sources (wells, pumps, disinfection requirements); Fire suppression water supply requirements (NFPA 13 water supply types, flow/pressure/duration demands); Underground private fire service main installation (pipe materials, burial depth, restraint, hydrostatic testing).

Hangers and Supports 4 items

Our study plan for this topic: Maximum hanger spacing by pipe type and material; Hanger rod sizing requirements by pipe diameter; Fastener types and installation requirements for concrete, steel, and wood; Trapeze hanger design and section modulus selection; Support of risers and riser clamp requirements; HVAC duct hanger sizing and upper attachment methods for rectangular and round duct; Pipe support spacing for water, gas, steam, and plastic pipe lines; Seismic bracing and earthquake protection requirements for hangers.

Drain, Waste, and Vent 5 items

Our study plan for this topic: Drainage fixture unit (DFU) values and system sizing; Slope and installation requirements for horizontal drainage piping; Cleanout placement, sizing, and access requirements; Trap requirements, prohibited traps, and trap seal protection; Vent types, sizing, and maximum developed length; Grease interceptors, oil separators, and other interceptor requirements; Indirect waste connections, air gaps, and air breaks; Pipe materials, fittings, and joint methods for DWV systems.

Backflow 2 items

Our study plan for this topic: Types of backflow (backsiphonage vs. backpressure) and hazard levels (high vs. low); Backflow preventer device selection per Table 608.1 (air gap, reduced pressure principle assembly, double check assembly, vacuum breakers, dual check valve); Specific application requirements for backflow protection (boilers, sprinkler systems, lawn irrigation, carbonated beverage dispensers, hose connections, humidifiers); Minimum air gap dimensions per Table 608.16.1; Cross-connection control and prohibition of cross connections without approved protection; Location, access, and installation requirements for backflow prevention assemblies; Inspection and testing of backflow prevention assemblies (annual inspections, test standards per Section 312.10); Water Supply and Distribution.

Traps and Interceptors 4 items

Our study plan for this topic: Fixture trap requirements: dimensions, seal depth, and prohibited trap types; Trap seal protection methods: primer valves, barrier devices, and fixture drain connections; Grease interceptor requirements: where required, sizing, and installation; Automatic grease removal devices and hydromechanical grease interceptors; Oil separators: where required, design requirements, and capacity calculations; Sand, solids, and specialty interceptors: clothes washers, bottling plants, and slaughterhouses; Venting, access, and maintenance of interceptors and separators; Trap sizing relative to fixture drain size and drainage fixture unit values.

Developed length 3 items

Our study plan for this topic: Calculating total effective length of duct runs using fitting equivalent lengths; Equivalent length values for duct fittings by group (elbows, tees, takeoffs, transitions); Determining available static pressure and design friction rate for duct sizing; Equivalent length of pipe fittings and valves for gas piping systems; Developed length calculations for pipe bends including setback and arc length; Equivalent length allowances for fittings in water supply piping systems; Longest length method for gas piping system sizing using developed pipe length; Full Text.

Isometric Analysis 8 items

Our study plan for this topic: Reading and interpreting pipe isometric drawings; Calculating offset dimensions including travel, run, and offset relationships; Determining setback and arc length for standard bend angles; Rolling offset calculations using the Pythagorean theorem; Pipe fitting allowances and laying lengths in isometric layouts; Locating bend starting and ending points along pipe runs; Multi-bend layouts including double offsets and 90-degree turns; Full Text.

Safety 4 items

Our study plan for this topic: Lockout/tagout (LOTO) procedures and requirements; Personal protective equipment (PPE) selection and use; Fall protection systems (guardrails, safety nets, personal fall arrest); Fire protection, prevention, and extinguisher selection; Electrical safety and ground-fault circuit interrupter (GFCI) requirements; Confined space entry requirements and permit procedures; Hazard communication, safety data sheets (SDS), and toxic/hazardous substance exposure limits; Ladder and stairway safety requirements.

Joints and Connections 3 items

Our study plan for this topic: Soldered and brazed joint procedures for copper tubing and pipe; Threaded pipe joints and connection requirements; Mechanical and grooved coupling connections; Solvent-cement joints for plastic pipe (ABS, PVC, CPVC); Flared and swaged tubing connections; Push-fit, press-connect, and compression-type fittings; Heat-fusion joints for polyethylene and polypropylene pipe; Duct seams, joints, and connection requirements for metallic and nonmetallic duct systems.

General Plumbing Regulations 3 items

Our study plan for this topic: Permit requirements and code administration; Required inspections and testing procedures; Pipe support, protection, and installation requirements; Trenching, excavation, and backfill requirements; Materials identification, approval, and third-party certification; Prohibited materials and connections to drainage and water supply systems; Flood hazard resistance requirements for plumbing systems; Minimum plumbing fixture counts by occupancy type.

Fire Sprinklers 4 items

Our study plan for this topic: Sprinkler system types (wet pipe, dry pipe, preaction, deluge); Sprinkler location requirements and allowable omissions; Sprinkler spacing, coverage areas, and deflector positioning by sprinkler type; Piping installation requirements (materials, schedules, fittings, and joining methods); Pipe hangers, support spacing, and seismic bracing requirements; Hydraulic calculations and working plan submittal requirements; Storage occupancy protection (commodity classification, CMDA, CMSA, ESFR, and in-rack sprinklers); System acceptance testing (hydrostatic tests, operational tests, and contractor certification).

Refrigerants and Refrigeration 4 items

Our study plan for this topic: Refrigerant classification (CFCs, HCFCs, HFCs, HFOs, HCs) and environmental impact (ODP, GWP); EPA regulations, Clean Air Act Section 608, and refrigerant handling certification requirements; Refrigerant cylinders: storage, disposable, and recovery cylinder types, DOT regulations, and safe handling; Refrigerant recovery, recycling, and reclaiming procedures and equipment; Leak detection methods and equipment (electronic, ultrasonic, fluorescent dye, halide torch); System evacuation procedures, vacuum pumps, and micron gauge use; Refrigerant charging methods: checking charge by superheat and subcooling; Pressure-temperature relationships and gauge manifold use in refrigeration service.

Heating and Cooling Principles 4 items

Our study plan for this topic: Heat transfer mechanisms (conduction, convection, radiation); Sensible heat and latent heat calculations; Thermal resistance and insulation values (R-value, U-value, K-value, C-value); Heating and cooling load calculation methods (Manual J, Manual N); Compression refrigeration cycle operation (evaporation, condensation, compression, metering); Heat pump heating and cooling modes and efficiency ratings (COP, SEER, HSPF); Design temperatures and indoor/outdoor temperature differentials; Gas laws and pressure-temperature relationships in refrigerant systems.

Load Calculations 5 items

Our study plan for this topic: Heat transfer principles and thermal properties (K-value, C-value, R-value, U-value); Outdoor and indoor design temperatures and conditions (Manual N Table 1A); Fenestration heating and cooling loads (HTM calculations, U-value, SHGC, PSF, CLF); Opaque panel heating and cooling loads (walls, roofs, ceilings, floors, CLTD method); Infiltration load calculations (air change method, tightness categories, door traffic); Internal loads (lighting, occupants, equipment heat gains); Duct system loads (conduction, leakage, insulation R-value, supply and return systems); Ventilation loads (engineered ventilation, sensible and latent heat equations, altitude correction).

Testing, Adjusting and Balancing 1 item

Our study plan for this topic: Airflow measurement instruments and methods (flow hood, anemometer, pitot tube, manometer); System air balancing procedures and damper adjustment; Duct leakage testing (blower door and duct blaster methods); Available static pressure and device pressure loss calculations; Friction rate and total effective length determination; Air velocity limits for ducts and supply outlets; Blower performance data interpretation and operating point; Filter inspection and pressure drop measurement.

HVAC Equipment 4 items

Our study plan for this topic: Compression refrigeration cycle components (compressor, condenser, metering device, evaporator); Compressor types and classifications (reciprocating, rotary, scroll, screw, centrifugal; hermetic vs. semi-hermetic vs. open-drive); Gas-fired heating systems (furnace types, heat exchangers, combustion, burners, ignition systems, AFUE ratings); Air-source heat pumps (reversing valve operation, heating/cooling modes, efficiency ratings, defrost controls); Split and self-contained air-conditioning systems (central, ductless mini-split, VRF, PTAC, packaged units); Electric heating systems (resistance elements, electric furnaces, duct heaters, baseboard units); Hydronic heating systems (boilers, circulating pumps, expansion tanks, terminal units, hydronic controls); Oil-fired heating systems (fuel oil properties, oil burner components, combustion efficiency testing).