Common Codes + Standards Reference
Why this matters
Every state + locality adopts national codes (often modified). Pulling permits + passing inspection requires knowing which code applies + the relevant section. The tech who can cite the code book chapter for the work being done builds credibility with inspectors + protects the customer. This is the field card.
Major code families (U.S.)
International Code Council (ICC) codes:
- IBC (International Building Code) - commercial + multi-family
- IRC (International Residential Code) - 1- + 2-family dwellings
- IPC (International Plumbing Code)
- IMC (International Mechanical Code)
- IFC (International Fire Code)
- IECC (International Energy Conservation Code)
- IFGC (International Fuel Gas Code)
- IPMC (International Property Maintenance Code)
NFPA codes:
- NEC (NFPA 70) - National Electrical Code; most-adopted electrical code in U.S.
- NFPA 13 - sprinkler system
- NFPA 51B - hot work
- NFPA 54 - National Fuel Gas Code
- NFPA 70E - electrical safety
- NFPA 101 - Life Safety Code
UMC + UPC (Uniform Mechanical + Plumbing Codes - IAPMO): legacy regional codes; some western states still use; many transitioned to IMC + IPC.
OSHA: workplace safety; federal + state-plan states.
ANSI + ASTM + UL: standards orgs; many specs referenced by code.
Code adoption (state-specific)
Each state adopts which codes apply + any amendments. Sample:
- California: CRC (CA Residential), CBC (CA Building) + state amendments
- Texas: IRC + IBC adopted
- Florida: FBC (FL Building Code) with hurricane provisions
- New York: NYS adopts ICC family
Local amendments: cities + counties layer on top. ALWAYS check local code before designing OR quoting.
Permits required (typical residential)
Building: structural changes, additions, conversions, garage to living, roof replacement (in some areas), pool, deck.
Electrical: panel upgrade, new circuit, EV charger install, service entry.
Plumbing: water heater replace, full repipe, gas line, fixture additions, sewer line.
Mechanical (HVAC): equipment replace (often required), new install, ductwork additions.
Specialty: pool, fence, irrigation, retaining wall.
Often exempt: minor repairs, like-for-like fixture replacement, painting.
Permit + inspection process
- Pull permit: licensed contractor (homeowner sometimes) submits permit application
- Plan review (larger work): inspector reviews drawings
- Approved permit: contractor can start work
- Inspection at milestones: foundation, rough-in (framing, electrical, plumbing, mechanical), insulation, final
- Inspector approval: signs off OR issues correction notice
- Final inspection + Certificate of Occupancy (new construction OR addition)
Penalty for unpermitted work: stop-work, fine, requirement to remove work, retrofit-to-code, lien on property.
IRC quick references
Stairs (R311): risers 7-3/4" maximum; treads 10" minimum; handrail 34 - 38" above tread nosing.
Window egress (R310): required in every sleeping room and in basements. Net clear opening 5.7 sq ft minimum (5.0 sq ft is allowed at a grade-floor opening). Sill height 44" MAXIMUM above the finished floor, not minimum. That is a ceiling on how high the opening can sit, because a person has to get out through it and a firefighter has to get in. Reading it as a minimum puts the window too high and fails the inspection for the opposite reason. The clear opening also has its own minimum width and height, and an opening that meets the square-footage number can still fail on one of those, so check all three.
Smoke alarm (R314): every sleeping room, outside each sleeping area, every level; interconnected in new construction. CO alarm (R315): outside sleeping areas where there is a fuel-fired appliance or an attached garage.
Headroom (R305): 7'-0" minimum for habitable space under current IRC. Older codes used 7'-6", so confirm the edition before you call an existing room non-compliant.
Exit door (R311): the code requirement is stated as net clear dimensions, 32" clear width and 78" clear height, which in practice means a 36" nominal door. Measure the clear opening with the door open at 90 degrees; a nominal 36" slab in a tight frame with a heavy stop can still miss 32" clear.
NEC quick references (residential)
Tamper-resistant outlets (406.12) all residential. GFCI (210.8): kitchen, bath, garage, outdoor, basement, laundry, within 6 ft of sink. AFCI (210.12): most habitable rooms. Bathroom 20A circuit (210.11) dedicated. Kitchen (210.52): 2 small-appliance 20A circuits min. Service entrance (230): 100A min new construction; 200A common. Panel clearance (110.26): 36" depth, 30" wide, 6'6" headroom.
IPC + UPC quick references
Pipe slope (P3005): 1/4" per ft (2" + smaller); 1/8" per ft (3" + larger).
Trap arm distance (P3105): per fixture; max varies (5 - 12 ft).
Vent through roof (P3103): 6" above roof; 10 ft horizontal OR 3 ft above doors/windows.
Backflow prevention (P608): required at potable water connections to non-potable.
Hot water temp (P504): set to ≤ 110°F at fixture (ASSE 1017 mixing valve common).
Water heater seismic strap (P504): in seismic areas (California: 2 straps).
IMC + IFGC quick references
Combustion air: the sizing figure depends on WHERE the air comes from, and quoting one number for all cases is the usual mistake.
- Indoor air, combining adjacent rooms on the same story: two openings, each 1 sq in per 1,000 Btu/hr of total input, with a minimum free area per opening. This is the 1-per-1,000 figure most techs remember.
- Outdoor air, two openings communicating directly or through vertical ducts: 1 sq in per 4,000 Btu/hr per opening.
- Outdoor air through horizontal ducts: 1 sq in per 2,000 Btu/hr per opening.
- Free area, not gross area. A louver or a screen eats a large fraction of the opening, so use the manufacturer's free-area rating or the code's default for the material.
Vent termination (IMC 503): outside flue, away from windows + doors.
Duct insulation (IECC C403): per climate zone.
Gas line shutoff (NFPA 54): at each appliance + accessible.
IECC (energy code)
Insulation R-values (vary by climate zone): R-30 to R-60 attic; R-13 to R-21 wall.
Window U-factor: 0.30 - 0.40 depending on zone.
Building envelope tightness: 3 - 5 ACH50 typical.
HVAC efficiency: minimum SEER + AFUE rises every code cycle.
Lighting: LED required new construction many jurisdictions.
OSHA mandatory standards (workplace)
Fall protection: > 6 ft construction (1926.501); > 4 ft general industry (1910.28); > 10 ft scaffolds (1926.451(g)(1)).
PPE (1910.132 - 138): job-hazard-assessment based.
LOTO (1910.147): energy isolation before service.
HazCom (1910.1200): SDS available for every chemical.
Bloodborne pathogen (1910.1030): if any potential exposure.
Confined space (1910.146): permit-required for hazardous spaces.
When code conflicts
Stricter rule wins: local amendment more strict than state, state more strict than national = local rule applies.
Permit specifies: code edition + amendments in effect when permit issued; later code change doesn't apply retroactively.
Grandfathering: existing buildings to original code; renovation triggers current code.
Common code violations (residential service)
Missing GFCI in required locations. Missing AFCI on required circuits. Improper venting (HVAC, plumbing, gas). No backflow prevention. Improper combustion air. Missing seismic strap (water heater). Missing TR receptacle. Skipping smoke / CO alarm. Improper egress.
Penalties for code violation
Stop-work order: project halted until correction.
Tear-out + redo: depends on inspector's discretion.
Insurance claim denial: insurance carrier may deny claim on un-permitted OR sub-code work.
Liability: damages from sub-code work may not be covered.
Criminal in severe cases: willful violation causing harm.
Code reference sources
ICC website (iccsafe.org): code editions purchasable.
Mike Holt (NEC interpretation): commentary on electrical code.
State / local building department: amendments + interpretations.
Trade associations: PHCC + NECA + ACCA publish code primers.
Code Check (Doug Carter): quick-reference field cards.
How to look up a code section
- Identify the relevant code (IRC, NEC, IPC, IMC)
- Identify the topic (e.g., GFCI requirements)
- Find the chapter / section (e.g., NEC 210.8)
- Read + understand the requirement
- Check for amendments at state / local level
References
- ICC (iccsafe.org)
- NFPA (nfpa.org)
- OSHA (osha.gov)
- State + local building departments
- Manuall internal: Residential Permit Process + Code Compliance, Electrical Box Sizing