Exam Cheat Sheet · Quick Reference
Idaho - HVAC SPECIALTY 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
50
Passing score
70%
Exam time
120 min
Administered by
PSI Services Contractor
Format
Reference materials allowed
Idaho State Portion 50 questions
2018 International Fuel Gas Code (IFGC) - Chapter 1
6 Q · 12%
Scope of code applicability for fuel gas piping systems and appliancesInstallations and systems excluded from IFGC scopePermit requirements, application process, and exemptionsDuties and powers of the code official including inspections and right of entryRequired inspection types: underground, rough-in, and finalViolations, stop work orders, and unsafe installation proceduresApplicability rules for existing installations, alterations, and repairsPermit expiration, extension, suspension, and revocation
2018 International Fuel Gas Code (IFGC) - Chapter 2
6 Q · 12%
Definitions of appliance types and classifications (vented, unvented, fan-assisted, automatically controlled)Venting system terminology and vented appliance categories (Category I–IV, Type B, BW, L, special gas vents)Gas piping system terminology (piping, tubing, connectors, valves, regulators, point of delivery)Combustion-related definitions (combustion air, combustion products, draft, draft hood, flue, 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 connector definitions (factory-built, masonry, metal chimneys; barometric draft regulator)Fuel gas and measurement definitions (fuel gas types, BTU, cubic foot, specific gravity, demand, pressure drop)
2018 International Fuel Gas Code (IFGC) - Chapter 3
7 Q · 14%
Combustion air requirements and calculation methods (indoor, outdoor, and combination methods)Appliance location restrictions and prohibited locationsClearances to combustible construction and clearance reduction methodsAccess and service space requirements for appliances in attics, under-floor spaces, and roofsElectrical bonding requirements for gas piping and CSSTCondensate disposal systems, materials, and drain requirementsAppliance installation requirements including ignition source elevation in garagesListing, labeling, and label information requirements for appliances
2018 International Fuel Gas Code (IFGC) - Chapter 4
9 Q · 18%
Gas pipe sizing methods and table selection (longest length, branch length, hybrid pressure)Allowable pressure drop and maximum operating pressure limits for piping systemsApproved piping materials and tubing types (steel, copper, CSST, polyethylene, aluminum)Pressure testing requirements, test medium, test pressure values, and test durationPiping installation requirements (prohibited locations, underground burial depth, protection against physical damage)Shutoff valve placement and requirements for appliances, meters, and multiple-tenant systemsPurging procedures for piping systems (indoor vs. outdoor discharge, combustible gas indicators)Piping support intervals and overpressure protection device requirements
2018 International Fuel Gas Code (IFGC) - Chapter 5
8 Q · 16%
Venting system type selection and appliance category matching (Table 503.4)Sizing of Category I venting systems using tables (Section 504)Vent and chimney termination location requirementsVent connector materials, clearances, and installation requirementsGas vent types (Type B, BW, L) installation and termination rulesAppliances not required to be vented and aggregate input limitsMasonry chimney requirements, lining systems, and inspectionDraft hoods, draft controls, and mechanical draft system requirements
2018 International Fuel Gas Code (IFGC) - Chapter 6
7 Q · 14%
Installation requirements and listing standards for specific appliancesClearances to combustible materials for specific appliancesClothes dryer exhaust duct requirements including maximum length and fitting equivalentsUnvented room heater restrictions including prohibited locations and oxygen-depletion safety systemsVented wall furnace and floor furnace placement and clearance requirementsForced-air warm-air furnace prohibited return-air sourcesDuct furnace and unit heater installation and ductwork requirementsSauna heater location, combustion air, and heat/time controls
2018 International Fuel Gas Code (IFGC) - Chapter 7
7 Q · 14%
Gaseous hydrogen piping materials, design, and installation requirementsPressure relief device requirements and configurationTesting of hydrogen piping systems (hydrostatic and pneumatic leak tests)Purging procedures for gaseous hydrogen piping systemsCompressed gas container, cylinder, and tank requirementsLocation requirements for indoor and outdoor gaseous hydrogen systemsPiping identification, marking, and prohibited locationsOperation and maintenance of gaseous hydrogen systems
Key Distinctions
Natural Gas Piping Max PressurevsLP-Gas Piping Max Pressure
IFGC covers natural gas piping at 125 psig or less, but LP-gas piping only at 20 psig or less (except per Section 402.7).
2018 International Fuel Gas Code (IFGC), Section 101.2.2Category I AppliancevsCategory IV Appliance
Category I operates with nonpositive vent static pressure and avoids excessive condensate; Category IV operates with positive vent static pressure and produces excessive condensate.
2018 International Fuel Gas Code (IFGC), Chapter 2, Section 202Low-Heat AppliancevsMedium-Heat Appliance
Low-heat appliances have flue entrance combustion temperatures of 1,000°F or less; medium-heat appliances exceed 1,000°F but do not exceed 2,000°F.
2018 International Fuel Gas Code (IFGC) (Idaho), Chapter 2, Section 202Hot Water Heating BoilervsSteam Heating Boiler
A hot water heating boiler circulates hot water at no more than 160 psig and 250°F; a steam heating boiler generates steam at no more than 15 psig.
2018 International Fuel Gas Code (IFGC), Chapter 2, Section 202Direct-Vent AppliancevsStandard Vented Appliance
A direct-vent appliance draws all combustion air from outdoors and discharges all flue gases outdoors; a standard vented appliance (e.g., Category I with Type B vent) uses indoor air and a conventional vent system.
2018 International Fuel Gas Code (IFGC) (Idaho), Chapter 2, Section 202General RequirementvsSpecific Requirement
Where there is a conflict between a general requirement and a specific requirement in the IFGC, the specific requirement governs.
2018 International Fuel Gas Code (IFGC), Section 102.1Normal Permit WorkvsEmergency Permit Work
Normal work requires a permit before commencing; emergency appliance/equipment replacement allows work to start immediately but the permit application must be submitted within the next working business day.
2018 International Fuel Gas Code (IFGC), Section 106.1 ExceptionPrivate Garage Appliance InstallationvsPublic Garage Appliance Installation
Private garages require a minimum clearance of 6 feet above the floor; public garages require at least 8 feet above the floor, or 1 foot higher than the tallest vehicle door opening if vehicles pass under the appliance.
2018 International Fuel Gas Code (IFGC), Section 305.5Standard Method (Indoor Combustion Air)vsTwo-Permanent-Openings Method (Outdoor Combustion Air)
The Standard Method requires 50 cubic feet of indoor volume per 1,000 Btu/h of input; the Two-Permanent-Openings Method requires each opening to have at least 1 square inch of free area per 4,000 Btu/h of total input.
2018 International Fuel Gas Code (IFGC), Section 304.5.1BrazingvsSoldering
Brazing uses a nonferrous filler metal with a melting point above 1,000°F (but below the base metal); soldering uses filler metals with a melting point below 1,000°F.
2018 International Fuel Gas Code (IFGC) (Idaho), Chapter 2, Section 202Rough-In InspectionvsUnderground Inspection
Underground inspection is made after trenches are excavated and piping is installed before backfill; rough-in inspection is made after framing and fireblocking are in place but before wall/ceiling membranes are installed.
2018 International Fuel Gas Code (IFGC), Section 107.2Existing Lawful InstallationvsNew Installation
Existing installations lawfully in place at code adoption may continue without being required to comply with all current IFGC requirements; new installations must fully comply with the current code.
2018 International Fuel Gas Code (IFGC), Section 102.2Key Terms
Maximum Permit Commencement Period 2018 International Fuel Gas Code (IFGC), Section 106.5.3
Per 2018 IFGC Section 106.5.3, a permit becomes null and void if authorized work is not commenced within 180 days of issuance, or is suspended/abandoned for 180 days after commencement.
Penalty for Commencing Work Without a Permit 2018 International Fuel Gas Code (IFGC), Section 106.6.1
Per 2018 IFGC Section 106.6.1, any person who starts work before obtaining the necessary permit is subject to an additional fee equal to 100 percent of the usual permit fee on top of required permit fees.
Emergency Permit Submission Rule 2018 International Fuel Gas Code (IFGC), Section 106.1 Exception
Per 2018 IFGC Section 106.1 Exception, when appliance/equipment replacement or repair is required in an emergency, the permit application must be submitted within the next working business day of the Department of Inspection.
Alternative Material Denial Response 2018 International Fuel Gas Code (IFGC), Section 105.2
Per 2018 IFGC Section 105.2, if the code official does not approve an alternative material, design, or method, the official must respond in writing stating the reasons for denial.
Change of Occupancy Certification 2018 International Fuel Gas Code (IFGC), Section 102.5
Per 2018 IFGC Section 102.5, the code official must certify that a structure meets the intent of the code provisions for a proposed new occupancy and that the change does not create hazards to public health, safety, or welfare.
Existing Installation Continuance 2018 International Fuel Gas Code (IFGC), Section 102.2
Per 2018 IFGC Section 102.2, the code does not require removal, alteration, or abandonment of existing installations that were lawfully in place at the time of code adoption.
Specific vs. General Requirement Conflict Rule 2018 International Fuel Gas Code (IFGC), Section 102.1
Per 2018 IFGC Section 102.1, where a general requirement and a specific requirement conflict, the specific requirement governs.
Undefined Terms Rule 2018 International Fuel Gas Code (IFGC), Chapter 2, Section 201.3
Per 2018 IFGC Section 201.3, terms not defined in the IFGC but defined in the International Building Code, Fire Code, Mechanical Code, or Plumbing Code shall have the meanings ascribed in those codes.
Oxygen Depletion Safety Shutoff System (ODS) 2018 International Fuel Gas Code (IFGC) (Idaho), Chapter 2, Section 202
A system that automatically shuts off gas supply to main and pilot burners if oxygen in the surrounding atmosphere drops below a predetermined level.
Point of Delivery (Natural Gas) 2018 International Fuel Gas Code (IFGC) (Idaho), Chapter 2, Section 202
The outlet of the service meter assembly, or the outlet of the service regulator or service shutoff valve where a meter is not provided.
Bonding Jumper 2018 International Fuel Gas Code (IFGC) (Idaho), Chapter 2, Section 202
A conductor installed to electrically connect metallic gas piping to the grounding electrode system.
BTU (British Thermal Unit) 2018 International Fuel Gas Code (IFGC) (Idaho), Chapter 2, Section 202
The quantity of heat required to raise the temperature of 1 pound of water 1°F.
Type B Vent 2018 International Fuel Gas Code (IFGC) (Idaho), Chapter 2, Section 202
A vent listed and labeled for use with appliances with draft hoods and other Category I appliances listed for use with Type B vents.
Condensate Drain Pipe Minimum Diameter 2018 International Fuel Gas Code (IFGC), Section 307.3
Per 2018 IFGC Section 307.3, condensate waste and drain line shall be not less than 3/4-inch internal diameter and shall not decrease in size toward the point of disposal.
Condensate Piping Minimum Slope 2018 International Fuel Gas Code (IFGC), Section 307.2
Per 2018 IFGC Section 307.2, condensate piping must slope at least 1/8 unit vertical per 12 units horizontal (1-percent slope) in the direction of discharge.
Attic Passageway Maximum Length 2018 International Fuel Gas Code (IFGC), Section 306.3
Per 2018 IFGC Section 306.3, an attic passageway to an appliance shall not exceed 20 feet in length unless the passageway is at least 6 feet high for its entire length, in which case 50 feet is permitted.
Formulas to Know
Standard Method – Minimum Indoor Air Volume for Combustion
Minimum Volume (ft³) = (Appliance Input Rating in Btu/h ÷ 1,000) × 50Two-Permanent-Openings Method – Minimum Free Area per Opening
Min Free Area (in²) = Total Appliance Input Rating (Btu/h) ÷ 4,000Condensate Pipe Slope
Min Slope = 1/8 in vertical per 12 in horizontal (1% slope)Penalty Fee for Work Without Permit
Total Fee = Required Permit Fee + (100% × Usual Permit Fee)Public Garage Appliance Height (vehicles passing under)
Min Height (ft) = Tallest Vehicle Door Opening (ft) + 1 ft [minimum 8 ft absolute]Private Garage Appliance Minimum Height
Min Height = 6 ft above floor