Exam Cheat Sheet · Quick Reference
Idaho - HVAC JOURNEYMAN EXAM
Idaho · PSI Services Contractor
Verified, not estimated. Every figure below is drawn from the official exam structure we maintain — question counts, passing standard and topic weighting. Practice questions are grounded in the source law with statute citations. We omit any figure we can't verify rather than guess at it.
Total questions
100
Passing score
70%
Exam time
240 min
Administered by
PSI Services Contractor
Format
Reference materials allowed
Idaho State Portion 100 questions
2018 International Mechanical Code (IMC) - Chapter 1
4 Q · 4%
Scope and applicability of the IMC to mechanical systemsPermit requirements, application process, and exemptions from permitsDuties and powers of the code officialRequired inspections and inspection sequence (underground, rough-in, final)Permit validity, expiration, extensions, and revocationViolations, stop work orders, and penaltiesApplicability to existing systems, alterations, and repairsAlternative materials, modifications, and approval processes
2018 International Mechanical Code (IMC) - Chapter 2
7 Q · 7%
Definitions of air types (supply, return, exhaust, makeup, outdoor, transfer, recirculated)Definitions of mechanical system components (ducts, plenums, dampers, air-handling units)Appliance type classifications by flue gas temperature (low-heat, medium-heat, high-heat)Refrigeration system terminology (refrigerant, evaporator, condenser, compressor, high-side/low-side pressure)Combustion-related definitions (combustion air, theoretical air, excess air, draft, flue, vent)Refrigerant safety classifications (flammability classes 1/2/3, toxicity classes A/B)Commercial cooking appliance and hood type definitions (light/medium/heavy/extra-heavy duty, Type I/II hoods)Boiler and pressure vessel definitions (low-pressure, high-pressure, steam, hot water, safety valves)
2018 International Mechanical Code (IMC) - Chapter 3
9 Q · 9%
Equipment and appliance location restrictions and prohibited locationsAccess and service space requirements for appliances in rooms, attics, and underfloor spacesClearances to combustible construction and clearance reduction methodsCondensate disposal systems, drain sizing, and auxiliary drain requirementsInstallation requirements including ignition source elevation and garage clearancesPiping support intervals, materials, and protection from physical damageStructural protection during mechanical system installation including cutting, notching, and boring limitsHeating and cooling load calculations and minimum space-heating temperature requirements
2018 International Mechanical Code (IMC) - Chapter 4
5 Q · 5%
Minimum outdoor airflow rates and Table 403.3.1.1 ventilation rate requirements by occupancyNatural ventilation requirements including minimum openable area percentagesAir intake opening location and protection requirementsMechanical ventilation for Group R-2, R-3, and R-4 occupancies (Equation 4-9 and local exhaust rates)Recirculation of air restrictions and transfer air provisionsZone and system outdoor airflow calculations including breathing zone and air distribution effectivenessEnclosed parking garage ventilation requirements including CO/NO2 detectors and airflow ratesVentilation system controls, balancing, and variable air volume system requirements
2018 International Mechanical Code (IMC) - Chapter 5
9 Q · 9%
Exhaust discharge location and minimum separation distancesClothes dryer exhaust duct installation requirements and maximum duct lengthCommercial kitchen Type I hood systems: materials, grease duct construction, and clearancesCommercial kitchen Type II hood systems: materials, termination requirements, and exhaust ratesCommercial kitchen makeup air requirements and air balanceHazardous exhaust systems: design requirements, duct construction, and fire/smoke damper prohibitionsDomestic cooking exhaust equipment and duct requirementsSmoke control system design methods and equipment requirements
2018 International Mechanical Code (IMC) - Chapter 6
4 Q · 4%
Fire and smoke damper installation requirements and locationsDuct construction materials, classifications, and minimum thickness standardsJoints, seams, and connections sealing requirementsPlenum construction materials and flame/smoke spread index requirementsSmoke detection system controls for air distribution systemsReturn air opening restrictions and prohibited locationsFlexible duct and flexible air connector installation limitationsUnderground duct installation and insulation requirements
2018 International Mechanical Code (IMC) - Chapter 8
4 Q · 4%
Vent system types and appliance compatibility (Type L, pellet vents, and chimney types)Chimney and vent termination height and clearance requirementsConnector installation requirements (size, pitch, length, clearances to combustibles)Factory-built chimney listing, labeling, and installation standardsDirect-vent, integral vent, and mechanical draft system termination requirementsMasonry chimney flue lining, cleanouts, and existing chimney complianceConnector pass-through systems and clearances to combustible wall materialsPositive pressure venting systems and power exhauster requirements
2018 International Mechanical Code (IMC) - Chapter 9
3 Q · 3%
Listing, labeling, and testing standards for specific appliances (UL standards by appliance type)Factory-built and masonry fireplace installation requirements and restrictionsCooling towers, evaporative condensers, and fluid coolers: location, drainage, drift eliminators, and water supplyFloor furnace and vented wall furnace installation clearances and placement restrictionsSolid fuel-burning appliances: pellet fuel, fireplace stoves, room heaters, and hearth extension requirementsForced-air warm-air furnaces, heat pumps, and duct furnace installation requirementsEvaporative cooling equipment installation requirementsRadiant heating system installation in wood framing, concrete, and masonry
2018 International Mechanical Code (IMC) - Chapter 10
3 Q · 3%
Boiler installation standards, clearances, and working space requirementsSafety and pressure relief valve requirements and discharge piping rulesBoiler low-water cutoff controls and operational safety devicesHot water boiler expansion tank types, sizing, and installationWater heater installation, listing standards, and combination space-heating applicationsPressure vessel construction, welding, and ASME certification requirementsBoiler gauges, water-gauge glass, and instrumentation requirementsAcceptance testing procedures and documentation for boilers and pressure vessels
2018 International Mechanical Code (IMC) - Chapter 11
5 Q · 5%
Refrigerant classification and safety groups per ASHRAE 34 (Table 1103.1)Machinery room general and special requirements (Sections 1105 and 1106)System classification as low-probability or high-probabilityMaximum allowable refrigerant quantities by occupancy typeRefrigerant piping materials, installation, and location restrictionsField pressure testing requirements and test gas specificationsRefrigerant purity standards for new, recovered, and reclaimed refrigerantsEmergency ventilation, refrigerant detection, and emergency shutoff controls
2018 International Mechanical Code (IMC) - Chapter 12
5 Q · 5%
Approved piping materials and standards for hydronic systems (Table 1202.4)Joint types and installation requirements by pipe material (brazed, soldered, solvent-cemented, threaded, mechanical)Shutoff valve placement requirements in hydronic and ground-source loop systemsHydrostatic testing requirements and pressure test specificationsEmbedded piping installation, pressure testing, and joint requirements for radiant heating panelsGround-source heat pump loop system materials, fittings, joints, and installation requirementsPipe insulation characteristics and required thickness standardsPiping installation requirements including clearance to combustibles, pipe penetrations, water hammer, and steam piping pitch
2018 International Mechanical Code (IMC) - Chapter 13
4 Q · 4%
Fuel oil piping materials and applicable standards (Table 1302.3)Joints and connections for fuel oil piping systemsFuel oil system installation requirements (supply, return, fill, and vent piping)Fuel oil valves (building shutoff, appliance shutoff, and relief valves)Fuel oil gauging devices and level indication requirementsPiping protection, support, and flood hazard requirementsAbandoned or removed tank requirements and antisiphon devicesFuel oil piping testing requirements per NFPA 31
2018 International Mechanical Code (IMC) - Chapter 14
1 Q · 1%
Scope and approved applications of solar thermal systemsPressure and temperature relief device requirementsFreeze protection methods including drain-back systems and freeze-protection valvesPotable water protection and cross-connection control in direct and indirect systemsHeat exchanger requirements including single-wall and double-wall constructionHeat transfer fluid requirements including flash point, toxicity, and flammable fluid restrictionsLabeling requirements for collectors, storage tanks, heat exchangers, and fluid safetyRooftop collector installation including structural loads, materials, and penetration sealing
2018 International Fuel Gas Code (IFGC) - Chapter 1
3 Q · 3%
Scope of code applicability: piping systems, appliances, and pressure limitsSystems and installations outside the scope of the IFGCPermit requirements, application process, and exemptionsDuties and powers of the code officialRequired inspections: underground, rough-in, and finalViolations, stop work orders, and unsafe installation authorityApplicability to existing installations, alterations, and repairsPermit expiration, extension, suspension, and revocation
2018 International Fuel Gas Code (IFGC) - Chapter 2
3 Q · 3%
Definitions of appliance types and classifications (vented, unvented, automatically controlled, fan-assisted)Vented appliance categories (Category I, II, III, IV) and venting system typesGas piping terminology (piping system, point of delivery, gas riser, concealed piping, drip)Combustion-related terms (combustion air, combustion chamber, combustion products, draft, draft hood, flue gases)Pressure regulator types and definitions (service pressure, line gas pressure, MP regulator, monitoring, series)Valve types and definitions (appliance shutoff, automatic, manual reset, service shutoff, main burner control)Chimney and vent component definitions (vent types B, BW, L, special gas vent, vent connector, flue liner)Fuel gas and measurement definitions (fuel gas, LPG, BTU, cubic foot, specific gravity, atmospheric pressure)
2018 International Fuel Gas Code (IFGC) - Chapter 3
6 Q · 6%
Combustion air requirements: indoor, outdoor, and combination methodsAppliance location restrictions and prohibited locationsClearances to combustible construction and clearance reduction methodsAccess and service space requirements for appliances in attics, under floors, and on roofsElectrical bonding requirements for gas piping and CSSTCondensate disposal systems, materials, and drain requirementsAppliance installation requirements including ignition source elevation in garagesListed and labeled appliance requirements and label information
2018 International Fuel Gas Code (IFGC) - Chapter 4
7 Q · 7%
Gas pipe sizing methods and sizing tables for natural gas and propaneAllowable piping materials and standards for metallic and plastic pipe and tubingPiping system installation requirements including prohibited locations and underground installationPressure testing, inspection, and purging proceduresShutoff valve requirements and locationsPipe support intervals and piping support requirementsOverpressure protection devices and maximum operating pressure limitsAppliance connections and connector installation requirements
2018 International Fuel Gas Code (IFGC) - Chapter 5
8 Q · 8%
Venting system type selection based on appliance category (Category I, II, III, IV)Chimney and vent termination height and location requirementsSizing of Category I appliance venting systems using Tables 504.2 and 504.3Vent connector materials, clearances, slope, and installation requirementsGas vent types (Type B, BW, L) and their application requirementsAppliances not required to be vented and aggregate input rating limitsMasonry chimney requirements including lining, cleanouts, and inspectionDraft hoods, draft controls, and mechanical draft system requirements
2018 International Fuel Gas Code (IFGC) - Chapter 6
5 Q · 5%
Clearances and location requirements for specific appliances (wall furnaces, floor furnaces, unit heaters, unvented heaters)Clothes dryer exhaust duct installation requirements (materials, maximum length, fittings, termination)Listing and testing standards for specific appliances (ANSI/CSA/UL references by appliance type)Unvented room heater restrictions (prohibited locations, oxygen-depletion safety, input rating limits, room volume requirements)Forced-air warm-air furnace installation (prohibited return-air sources, dampers, plenum and duct sealing)Vented and unvented decorative appliance and fireplace requirements (flame safeguard devices, chimney damper free opening area)Direct-fired industrial air heater installation (nonrecirculating vs. recirculating, air supply, relief openings, purging)Sauna heater installation requirements (location, combustion air, temperature controls, timers, ventilation openings)
2018 International Fuel Gas Code (IFGC) - Chapter 7
5 Q · 5%
Gaseous hydrogen system definitions and scopePressure relief device requirements and configurationHydrogen piping system design, materials, and installationTesting procedures for hydrogen piping systems (hydrostatic and pneumatic)Purging procedures for hydrogen piping systemsContainers, cylinders, and tanks: design, construction, and storage limitationsLocation requirements for indoor and outdoor gaseous hydrogen systemsOperation, maintenance, and electrical requirements for hydrogen systems
Key Distinctions
Type I HoodvsType II Hood
Type I hoods collect grease vapors and smoke and are equipped with a fire suppression system, while Type II hoods are general hoods for collecting steam, vapor, heat, and odors without a fire suppression requirement.
2018 International Mechanical Code (IMC), Chapter 2, Section 202Low-Pressure Steam BoilervsLow-Pressure Hot-Water Boiler
Low-pressure steam boilers operate at pressures not exceeding 15 psi, while low-pressure hot-water boilers operate at pressures not exceeding 160 psi and temperatures not exceeding 250°F.
2018 International Mechanical Code (IMC), Chapter 2, Section 202Brazed JointvsSoldered Joint
A brazed joint uses metallic alloys that melt above 1,000°F (538°C), while a soldered joint uses alloys that melt between 400°F (204°C) and 1,000°F (538°C).
2018 International Mechanical Code (IMC), Chapter 2, Section 202Low-Heat AppliancevsMedium-Heat Appliance
A low-heat appliance has flue-entrance combustion products at 1,000°F or less, while a medium-heat appliance has temperatures above 1,000°F but not greater than 2,000°F.
2018 International Mechanical Code (IMC), Chapter 2, Section 202General Requirement (IMC)vsSpecific Requirement (IMC)
When a general requirement and a specific requirement conflict, the specific requirement governs; when different sections specify different materials or methods, the most restrictive governs.
2018 International Mechanical Code (IMC), Section 102.1, Chapter 1Permit Application AbandonmentvsPermit Expiration
A permit application is deemed abandoned 180 days after filing if not pursued in good faith or a permit is not issued, while an issued permit expires if authorized work is not commenced within 180 days of issuance or is suspended for 180 days after commencement.
2018 International Mechanical Code (IMC), Section 106.3.3, Chapter 1Induced DraftvsNatural Draft
Induced draft uses a fan or blower located between the appliance and the chimney/vent termination to create pressure difference, while natural draft relies on the natural buoyancy of combustion gases without mechanical assistance.
2018 International Mechanical Code (IMC), Chapter 2, Section 202High-Probability Refrigeration SystemvsDirect Refrigeration System
A high-probability system is one where a refrigerant leak from a failed component will enter an occupancy-classified area other than the machinery room, while a direct refrigeration system is one where the evaporator or condenser is in direct contact with the air or substance being conditioned.
2018 International Mechanical Code (IMC), Chapter 2, Section 202Portable Heating Appliance (Permit Exempt)vsPermanently Installed Heating System (Permit Required)
Portable heating appliances are explicitly exempt from permit requirements under the IMC, while permanently installed mechanical systems require a permit before work commences.
2018 International Mechanical Code (IMC), Section 106.2, Chapter 1Double Island Canopy HoodvsStandard Canopy Hood
A double island canopy hood is placed over back-to-back cooking appliance lines and is open on all sides overhanging both fronts, while a standard canopy hood serves a single appliance line.
2018 International Mechanical Code (IMC), Chapter 2, Section 202Code Provisions vs. Referenced Standards (Conflict)vsGeneral vs. Specific Code Requirements (Conflict)
When the IMC code provisions conflict with referenced standards, the IMC code provisions apply; when a general requirement conflicts with a specific requirement within the code, the specific requirement governs.
2018 International Mechanical Code (IMC), Section 102.8.1Class 1 Refrigerant (Flammability)vsClass IA Flammable Liquid
A Class 1 refrigerant does not show flame propagation when tested in air at 14.7 psia and 140°F, while a Class IA flammable liquid has a flash point below 73°F and a boiling point below 100°F.
2018 International Mechanical Code (IMC), Chapter 2, Section 202Key Terms
Purpose of the IMC (Section 101.3) 2018 International Mechanical Code (IMC), Section 101.3, Chapter 1
The 2018 IMC, Section 101.3 establishes minimum standards to provide a reasonable level of safety, health, property protection, and public welfare by regulating the design, construction, installation, materials, location, operation, and maintenance of mechanical systems.
Permit Exemption – Portable Equipment (Section 106.2) 2018 International Mechanical Code (IMC), Section 106.2, Chapter 1
Per 2018 IMC Section 106.2, permits are not required for portable heating appliances, portable ventilation appliances and equipment, portable cooling units, or self-contained refrigeration systems containing 10 lbs or less of refrigerant or actuated by motors of 1 HP or less.
Permit Application Abandonment (Section 106.3.3) 2018 International Mechanical Code (IMC), Section 106.3.3, Chapter 1
Per 2018 IMC Section 106.3.3, a permit application is deemed abandoned 180 days after the date of filing unless pursued in good faith or a permit has been issued; extensions of additional 180-day periods may be granted by the code official.
Penalty for Commencing Work Without a Permit (Section 106.5.1) 2018 International Mechanical Code (IMC), Section 106.5.1, Chapter 1
Per 2018 IMC Section 106.5.1, any person who commences work on a mechanical system before obtaining the necessary permits shall be subject to 100 percent of the usual permit fee in addition to the required permit fees.
Emergency Permit Exception (Section 106.1 Exception) 2018 International Mechanical Code (IMC), Section 106.1 Exception, Chapter 1
Per 2018 IMC Section 106.1 Exception, where equipment or appliance replacements or repairs must be performed in an emergency situation, the permit application shall be submitted within the next working business day of the mechanical inspection department.
Successive Inspection Rule (Section 107.2.3) 2018 International Mechanical Code (IMC), Section 107.2.3, Chapter 1
Per 2018 IMC Section 107.2.3, work shall not proceed beyond the point indicated in each successive inspection without first obtaining approval of the code official, and non-compliant portions shall not be covered or concealed until authorized.
Historic Buildings Exemption (Section 102.6) 2018 International Mechanical Code (IMC), Section 102.6, Chapter 1
Per 2018 IMC Section 102.6, mandatory provisions relating to construction, alteration, repair, or restoration do not apply to buildings identified and classified as historic where the code official judges them safe and in the public interest.
Alternative Materials Approval (Section 105.2) 2018 International Mechanical Code (IMC), Section 105.2, Chapter 1
Per 2018 IMC Section 105.2, alternative materials not specifically prescribed by the code may be approved if the code official finds the design satisfactory, compliant with the intent of the code, and not less than equivalent in quality, strength, fire resistance, durability, and safety.
Reuse of Materials and Equipment (Section 105.5) 2018 International Mechanical Code (IMC), Section 105.5
Per 2018 IMC Section 105.5, materials, equipment, appliances, and devices shall not be reused unless they have been reconditioned, tested, and placed in good and proper working condition and approved; visual inspection alone is not sufficient.
Breathing Zone 2018 International Mechanical Code (IMC), Chapter 2, Section 202
The region within an occupied space between planes 3 and 72 inches above the floor and more than 2 feet from the walls of the space or from fixed air-conditioning equipment.
Standard Air 2018 International Mechanical Code (IMC), Chapter 2, Section 202
Air at a standard temperature of 70°F (21°C) and a pressure of 29.92 inches of mercury (101.3 kPa).
Modular Boiler 2018 International Mechanical Code (IMC), Chapter 2, Section 202
A steam or hot-water-heating assembly consisting of a group of individual boiler modules, each limited to a maximum input rating of 400,000 Btu/h gas, 3 gallons per hour oil, or 115 kW electric.
Conditioned Space 2018 International Mechanical Code (IMC), Chapter 2, Section 202
Per 2018 IMC Section 202, a conditioned space includes areas indirectly heated or cooled, such as spaces separated from a conditioned space by uninsulated walls, floors, or ceilings.
Ductless Mini-Split System 2018 International Mechanical Code (IMC), Chapter 2, Section 202
A heating and cooling system comprised of one or multiple indoor evaporator/air-handling units and an outdoor condensing unit connected by refrigerant piping and electrical wiring, capable of conditioning rooms without traditional ductwork.
Required Inspections (Section 107.2) 2018 International Mechanical Code (IMC), Section 107.2, Chapter 1
Per 2018 IMC Section 107.2, the three required inspections are: (1) underground inspection before backfill, (2) rough-in inspection after framing and concealed components are complete but before wall or ceiling membranes are installed, and (3) final inspection upon completion.
Undefined Terms – Where to Look (Section 201.3) 2018 International Mechanical Code (IMC), Chapter 2, Section 201.3
Per 2018 IMC Section 201.3, terms not defined in the IMC shall have meanings as defined in the International Building Code, International Fire Code, International Fuel Gas Code, or International Plumbing Code.
Formulas to Know
Permit Penalty Fee (Work Started Without Permit)
Total Fee = Required Permit Fee + 100% of Usual Permit FeeBreathing Zone Height Range
Breathing Zone = 3 inches to 72 inches above floor AND more than 2 feet from walls or fixed AC equipmentLow-Pressure Steam Boiler Limit
Max Steam Pressure ≤ 15 psi (103 kPa)Low-Pressure Hot-Water Boiler Limits
Max Water Pressure ≤ 160 psi (1103 kPa) AND Max Temperature ≤ 250°F (121°C)Brazed vs. Soldered Joint Temperature Threshold
Brazed: alloy melting point > 1,000°F (538°C); Soldered: alloy melting point 400°F–1,000°F (204°C–538°C)Permit Application Abandonment / Permit Expiration Period
Abandonment or Expiration = 180 days (from filing date for application; from issue date or last work date for issued permit)Modular Boiler Maximum Module Input
Max Input per Module = 400,000 Btu/h (gas) OR 3 gal/hr (oil) OR 115 kW (electric)Low-Heat vs. Medium-Heat Appliance Flue Temperature
Low-Heat: flue temp ≤ 1,000°F (538°C); Medium-Heat: 1,000°F < flue temp ≤ 2,000°F