Routing, submetering, and efficiency overlay
Before computing the allowance: C405.1 determines which spaces use the C405 path vs. R404.1 (dwelling/sleeping) or C403.10 (walk-ins). C405.5 requires per-unit submetering in R-2 commercial buildings. C406.3 (reduced lighting power) reduces the C405.3 allowance by 10%; C406.4 (enhanced digital lighting controls) is a controls-based package with no power effect.
Choose your allowance method
Per C405.3, a building complies where its total connected interior lighting power (C405.3.1) is not greater than the interior lighting power allowance (C405.3.2). The allowance is determined by one of two methods for all areas of the building covered in permit.
Calculate your power budget
Total connected interior lighting power
Per C405.3.1, the total connected interior lighting power (TCLP) is the sum of the connected wattage of every interior luminaire and lighting source, determined per Equation 4-10. Define each fixture family below; exempt sources (see the reference list below) are flagged per fixture during assignment and dropped from TCLP automatically.
- TCLP
- Total connected lighting power, in watts.
- LVL
- For luminaires with lamps connected directly to building power (e.g. line-voltage lamps), the rated wattage of the lamp.
- BLL
- For luminaires incorporating a ballast or transformer, the rated input wattage of the ballast or transformer when operating that lamp.
- LED
- For light-emitting diode luminaires with integral or remote drivers, the rated wattage of the luminaire.
- TRK
- For lighting track, cable conductor, rail conductor, and plug-in busway systems that allow luminaires to be added or relocated without rewiring, the wattage is the greatest of: the specified luminaire wattage, but not less than 8 W per linear foot (25 W/lin m); the wattage limit of the permanent current-limiting devices protecting the system; or the wattage limit of the transformer supplying the system.
- OTHER
- The wattage of all other luminaire and lighting sources not covered above and associated with interior lighting, verified by manufacturer data or other approved sources.
Exemptions from TCLP calculation (C405.3.1) — reference list
The connected power associated with the following is not included in TCLP. To apply one, select it on the individual luminaire (the wattage is then subtracted automatically). Items marked cond. require a condition to be met — see the luminaire notes field. The tool does not auto-detect these; the designer flags each fixture.
- 1Television broadcast lighting for playing areas in sports arenas
- 2Emergency lighting automatically off during normal building operation
- 3Lighting for occupants with special lighting needs (visual impairment, medical, age-related)
- 4Casino gaming areas
- 5Mirror lighting in dressing rooms
- 6Task lighting for medical/dental, in addition to general lighting, on an independent control devicecond.
- 7Display lighting for exhibits in galleries/museums/monuments, in addition to general lighting, on an independent control devicecond.
- 8Lighting for theatrical purposes — performance, stage, film, video production
- 9Lighting for photographic processes
- 10Lighting integral to equipment or instrumentation, installed by the manufacturer
- 11Task lighting for plant growth or maintenance
- 12Advertising signage or directional signage
- 13Lighting for food warming
- 14Lighting equipment that is for sale
- 15Lighting demonstration equipment in lighting education facilities
- 16Lighting approved because of safety considerationscond.
- 17Retail display windows enclosed by ceiling-height partitionscond.
- 18Furniture-mounted supplemental task lighting controlled by automatic shutoffcond.
- 19Exit signs
Define each fixture family once; it becomes available to assign to any room below. Fixture Watt is the connected input wattage — the value that drives the load (lamps × watts/lamp is descriptive).
Create rooms and allocate areas
An area (step 02) is a code space type with a total floor area; a room is a physical space. Allocate each area type into its rooms here — e.g. a Conference area of 1,600 ft² split into five conference rooms. Fixtures are assigned in the next step.
Use + Room on a type to add another, set each room's area inline, remove with ×. Compliance context (daylight, exemptions) is set later in Review.
Assign fixtures to rooms
Add fixtures from your schedule to each room created in step 04. The per-fixture C405.3.1 exemption (if any) is selected on the fixture line and dropped from TCLP automatically.
Additional interior lighting power
Per C405.3.2.2.1, additional power shall be permitted for specific lighting that is installed and automatically controlled separately from the general lighting, to be turned off during nonbusiness hours. This additional power shall be used only for the specified luminaires.
Triggered by:
Total additional allowance: 0 W
Set lighting controls per room — daylight, exemptions, specific application
C405.2 requires lighting controls per one of two paths. Choose the path, then set each room’s controls context (daylight, exemptions, specific application) below — these drive the required-controls schedule you review next.
Review the required-controls schedule
This schedule is generated automatically from your chosen path (step 06) and each room’s context — review the required controls per room here. Installation and C408.3.1 functional testing are verified later during commissioning, outside this tool. Three top-level exceptions skip the entire C405.2 evaluation for a space (continuously-lit security/emergency areas, interior exit stairways/ramps/passageways, normally-off emergency egress) — set those in step 06.
| Room | Type | Area | GL W | Status | |
|---|---|---|---|---|---|
| Add luminaires in the Assignment step to populate the room schedule. | |||||
Compliance determination
Per C405.3, a building complies where its total connected interior lighting power calculated under Section C405.3.1 is not greater than the interior lighting power allowance calculated under Section C405.3.2. Controls per C405.2 are mandatory and must be independently satisfied.