Free building-code guides for architects, engineers, and designers.
Occupant load under IBC 1004 is floor area divided by the occupant load factor for each use. Here's how to calculate it, with examples.
Read guide →Egress & OccupancyA means of egress is the continuous path to a public way — exit access, exit, and exit discharge. How occupant load sets exit count, width, and separation under IBC Chapter 10.
Read guide →Plan ReviewThe most common reasons plans get returned in review — egress and occupant-load errors, accessibility clearances, missing information, energy-code gaps, and code-edition mismatches — and how to catch them before submittal.
Read guide →Egress & OccupancyIBC minimum corridor width (44 in, 36 in under 50 occupants, 96 in for I-2 bed movement) and door clear width (32 in), and why the §1005 capacity calculation can override the dimensional minimum.
Read guide →Egress & OccupancyThe IBC Table 1004.5 occupant load factors by function — business 150 gross, retail 30/60 gross, assembly 7/15 net, classroom 20 net — and the gross-vs-net and function-vs-classification rules that trip designers up.
Read guide →Equipment & MEPWhat an equipment schedule (EQ sheet) is, the columns plan reviewers expect — tag, description, manufacturer/model, qty, plumbing, electrical (volts/phase/amps/watts/connected load) — and why 'basis of design, or approved equal' matters.
Read guide →Equipment & MEPType I hoods capture grease and smoke from cooking equipment; Type II handle heat, steam, and moisture. Which equipment needs which, and the core IMC Chapter 5 exhaust requirements.
Read guide →Equipment & MEPWhy foodservice equipment drains through indirect waste with an air gap to floor sinks, what needs indirect waste, and the core IPC requirements that protect the potable system.
Read guide →Equipment & MEPWhy foodservice fixtures that discharge grease need a grease interceptor, what connects to it, and the IPC framework for sizing — so fats, oils, and grease don't reach the sewer.
Read guide →Equipment & MEPWhat connected load (VA) means on an equipment schedule, why voltage and phase must be verified per model, and how the electrical engineer uses the schedule to size circuits and service.
Read guide →Plumbing FixturesRequired plumbing fixtures come from occupant load × occupancy ratios in IBC Table 2902.1 / IPC Table 403.1. The step-by-step method: occupant load, split by sex, apply the ratio for your occupancy, round up.
Read guide →Plumbing FixturesHow many restrooms a commercial space needs, when separate facilities by sex are required, travel distance to toilet rooms, and customer vs. employee access — under IBC Chapter 29.
Read guide →Plumbing FixturesWhen the code allows a single-user toilet room to satisfy requirements, how single-user/all-gender rooms count for both sexes, and the signage and accessibility rules that apply.
Read guide →Plumbing FixturesWhy most commercial occupancies must provide at least one service sink (mop sink), what counts as one, and where it goes — a small required fixture that's easy to forget on a plan.
Read guide →Plumbing FixturesWhen commercial spaces must provide drinking fountains, how many, the accessible bi-level (hi-lo) requirement, and when bottle fillers count — under the plumbing fixture tables and A117.1.
Read guide →Plan ReviewWhat a commercial tenant improvement submittal needs to clear plan review: scope and code analysis, egress and occupant load, accessibility, MEP, and the completeness items that cause most TI rejections.
Read guide →Plan ReviewWhen converting a space to a new use changes its occupancy classification, what that triggers — egress, accessibility, fire protection, structural, and energy — under the IBC and Existing Building Code.
Read guide →Plan ReviewWhat a building-department plan reviewer actually looks for on a commercial set — life safety, accessibility, completeness, and code-edition correctness — and how to self-check before you submit.
Read guide →Plan ReviewWhat sheets and information a commercial permit set needs — code/life-safety sheet, architectural, MEP, structural, accessibility details — plus the title-block and stamp requirements that cause completeness rejections.
Read guide →Plan ReviewThe accessibility essentials a commercial TI must address — accessible route and path of travel, restroom clearances and grab bars, reach ranges, and door maneuvering — under IBC Chapter 11, A117.1, and the ADA.
Read guide →Building & OccupancyHow the IBC sorts every space into an occupancy group (A, B, E, F, H, I, M, R, S, U) — the classification that drives nearly every other code requirement.
Read guide →Building & OccupancyThe five IBC construction types, what separates them, and the fire-resistance ratings each requires for structural frame, walls, and floors.
Read guide →Building & OccupancyHow construction type, occupancy, and sprinklers set allowable area, height, and stories — plus frontage and sprinkler increases.
Read guide →Building & OccupancySeparated vs. nonseparated occupancies, required separation ratings from Table 508.4, and when accessory occupancies don't need separation.
Read guide →Fire & Life SafetyFire walls, barriers, partitions, and horizontal assemblies — plus opening protectives (716) and through-penetration firestops (714).
Read guide →Fire & Life SafetyThe occupancy, fire-area, occupant-load, and story thresholds that trigger a sprinkler system under IBC 903 — and NFPA 13 vs. 13R.
Read guide →Fire & Life SafetyWhen a fire alarm or detection system is required by occupancy and occupant load, and the notification basics under IBC 907 and NFPA 72.
Read guide →Fire & Life SafetyFire apparatus access roads, water supply and hydrants, fire department connections, and key boxes under IFC Chapter 5.
Read guide →StructuralDead, live, snow, and rain loads, ASCE 7 load combinations, and identifying the lateral force-resisting system on a set.
Read guide →StructuralSeismic design category, site class, and the detailing that follows — what a plan reviewer looks for under IBC 1613 / ASCE 7.
Read guide →StructuralDesign wind speed, exposure category, and components-and-cladding — and the wind certifications that often live only on a notes sheet.
Read guide →StructuralFlood hazard zones, base flood elevation, required elevation, and flood-resistant construction under IBC 1612 and ASCE 24.
Read guide →StructuralGeotechnical basis, allowable bearing, footings, and when deep foundations are needed — matching foundation type to site conditions.
Read guide →MechanicalRequired outdoor-air rates by occupancy, demand-controlled ventilation, and when natural ventilation is permitted under IMC Chapter 4.
Read guide →MechanicalType I/II kitchen hoods, grease ducts, and restroom/specialty exhaust — the IMC Chapter 5 requirements a reviewer checks.
Read guide →EnergyU-factors, R-values, SHGC, and air-leakage requirements by climate zone under IECC C402 (commercial) and IRC N1102 (residential).
Read guide →EnergyThe compliance path (prescriptive vs. COMcheck), commissioning, and the plan documentation reviewers require under the IECC.
Read guide →AccessibilityRequired accessible and van stall counts, stall and access-aisle dimensions, and signage under IBC 1106 and ICC A117.1.
Read guide →AccessibilityRoute width, turning space, door maneuvering clearances, reach ranges, and protruding objects under IBC 1104 and A117.1.
Read guide →AccessibilityToilet and bathing-room clearances, grab bars, accessible fixture counts, and fountains under IBC 1109 and A117.1.
Read guide →Egress & OccupancyIBC 1011 stairway geometry: 4–7 inch risers, 11 inch treads, 3/8 inch uniformity, 44 inch width, 80 inch headroom, and required landings.
Read guide →Egress & OccupancyHandrails (IBC 1014) at 34–38 inches with extensions, and guards (IBC 1015) at 42 inches with the 4-inch sphere rule — what each does and where.
Read guide →Egress & OccupancyExit access travel distance (IBC 1017) and common path of egress travel (1006.2.1) — the limits, how they're measured, and why they drive exit layout.
Read guide →Egress & OccupancyHow many exits a space needs under IBC 1006–1007, the single-exit conditions, and the remoteness rule requiring exits separated by half the diagonal.
Read guide →Egress & OccupancyWhere illuminated exit signs are required under IBC 1013, the 100-foot visibility limit, directional signage, and the 90-minute emergency power rule.
Read guide →Egress & OccupancyIBC 1008 requires 1 foot-candle along the egress path, backed by emergency power for 90 minutes on loss of normal power.
Read guide →Egress & OccupancyEgress ramp geometry under IBC 1012: 1:12 maximum slope, 30-inch maximum rise per run, 1:48 cross slope, landings, and handrails.
Read guide →Egress & OccupancyIBC 1009 accessible means of egress, areas of refuge and two-way communication — and the sprinkler exception that removes the refuge requirement.
Read guide →Egress & OccupancyExit discharge under IBC 1028: discharging to a public way, the 50-percent-through-lobby allowance, and egress courts.
Read guide →Building & OccupancyIBC Chapter 8 interior finish classes A, B, and C by flame-spread index — and why the required class gets stricter closer to the egress path.
Read guide →Building & OccupancyIBC 2406 safety glazing: the hazardous locations that require tempered or laminated glass, and the permanent labeling reviewers look for.
Read guide →Building & OccupancyIBC Chapter 15 roof covering fire classes A/B/C by construction type, plus penthouses and rooftop structures — and when a penthouse counts as a story.
Read guide →Building & OccupancyIBC 705 ties exterior wall ratings and allowable openings to fire separation distance — the site-plan-to-elevation coordination reviewers check.
Read guide →Building & OccupancyIBC Chapter 4 special occupancies: high-rise (403), atriums (404), and covered malls (402) — the thresholds that pull in added requirements.
Read guide →Building & OccupancyThe IEBC scales requirements to scope: Level 1, 2, and 3 alterations, change of occupancy, additions, and historic-building pathways.
Read guide →Fire & Life SafetyIBC 905 standpipes: Class I, II, and III, the height and occupancy triggers, and how they tie into the sprinkler riser and stair design.
Read guide →Fire & Life SafetyIBC 904 and UL 300 wet-chemical suppression for Type I hoods — nozzle coverage matched to appliances and interlocked fuel/power shutoff.
Read guide →Fire & Life SafetyIBC 414–415 maximum allowable quantities and control areas — and the threshold where hazardous materials trigger a Group H occupancy.
Read guide →StructuralIBC Chapter 17 special inspections and the Statement of Special Inspections — what it must cover and why it belongs in the permit set.
Read guide →StructuralIBC Chapter 23 wood framing, lateral wall bracing and shear walls, and the fastening schedule reviewers expect as a clear table.
Read guide →MechanicalIMC Chapter 6 fire, smoke, and combination dampers where ducts penetrate rated assemblies — the classic mechanical/architectural coordination gap.
Read guide →EnergyIECC C405 lighting power density plus required controls — occupancy sensors, automatic shutoff, and daylight-responsive controls.
Read guide →EnergyIECC C403 minimum equipment efficiencies, economizers, demand-controlled ventilation, and the controls that surface in COMcheck mechanical.
Read guide →Equipment & MEPIBC 2702 and NEC 700–702: emergency, legally required standby, and optional standby — and which life-safety loads need a true emergency source.
Read guide →AccessibilityIBC 1105 accessible entrances: the 60-percent rule plus the specific entrances — parking, transit, tenant — that must be accessible.
Read guide →Upload a plan set and InstaPreView flags likely code issues — occupant load, egress, and more — before you submit to the AHJ.
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