IECC 2012 Overview

Scope of IECC 2012: Section C101 of the Standard describes what buildings and building systems (e.g. lighting) are covered under IECC 2012.  While the IECC 2012 covers both commercial and residential buildings, this summary shall only include the commercial buildings.

Lighting Scope: Section C405.1 of the Standard points out that lighting within certain dwelling units are exempt from this section of the Standard.

Interior Lighting Power Allowance: Section C405.5.2 of the Standard describes the two optional methodologies by which a user may calculate how many watts may be used for the interior lighting:

• Building Area Method: This method allows the user to look up (in Table C405.5.2(1) of the Standard) the allowance in watts per sq.ft based on building types (e.g. 'Office'); this allowance is then multiplied by the area of the building type to come up with the interior lighting power allowance.   Additional considerations include:
  • When a building has more than one building type, each building type must comply separately.
  • The standard describes when the user may claim additional allowance, in the case of retail situations, while using display accent lighting.
  • This method, while easier to use than the Space-by-Space Method, will typically yield a lower number of allowed watts.
• Space-by-Space Method: this method allows the user to look up (in Table C405.5.2(2) of the Standard) the allowance in watts per sq.ft based on space types (e.g. 'Office-Enclosed'); this allowance is then multiplied by the area of that space to come up with the interior lighting power allowance for the space.  The individual allowances should then be summed to come up with the interior lighting power allowance for the project. Additional considerations include:
  • This method will typically yield a greater number of allowed watts then the Building Area Method.
  • The standard describes when the user may claim additional allowance when using, in the case of retail situations, when using display accent lighting.

Exterior Lighting Power Allowance: Section C405.6.2 of the Standard describes a process similar to the method described above.  Individual area types are looked up in Table C405.6.2(2) and the listed allowance is then multiplied by either the square feet (e.g. of a parking lot) or linear feet (e.g. along street frontage) of that area.  Additional considerations include:

• Some area types are tradable in that the user may borrow watts from one area and use them in some other tradable area.
• Some area types are 'nontradable'; the watts in those areas are use-it-or-lose-it.
• Section C405.6.2 contains a list of exterior lighting that exempt from this section.

Installed Interior/Exterior Lighting Power: Section C405.5.1 of the Standard is then used to determine how many watts have been actually installed for the lighting.  Additional considerations include:

• The installed interior lighting power is calculated separate from the exterior.
• In general, the input watts to the luminaire must be used for these calculations, not the lamp watts.
• This section of the Standard contains a list of interior lighting that does not have to be included in this calculation
• The resultant requirement is that:
  • the interior lighting power allowance must be no less than the installed interior lighting power, and
  • the exterior lighting power allowance must be no less than the installed exterior lighting power

Mandatory Provisions:

• Lighting Controls:
  • Manual Controls: Each space shall have its own manual lighting control and the occupants of that space shall be able to reduce the light levels, in a uniform pattern, by at least 50% .
  • Auto Shutoff: the lighting in all buildings, with certain exceptions, must be on auto shutoff with occupant override.
  • Occupancy Sensors: are required in certain spaces.
  • Daylight Harvesting: is required per section C405.2.2.3 of the Standard
  • Sleeping Unit Controls: section C405.2.3 of this Standard mandates certain controls for all permanently wired lighting and all switched receptacles 
  • Specific Application Controls: a variety of additional applications listed in section C405.2.3 of the Standard are required to be controlled separately from the rest of the lighting in the space.
  • Exterior Lighting Controls: section C405.2.4 prescribes certain controls for exterior lighting based on whether or not that lighting is designated for dusk-to-dawn operation.
• Tandem Wiring: in certain situations, section C405.3 requires that the ballasts of linear fluorescent luminaires be tandem wired.
• Exit Signs: Section C405.4 sets an upper limit on how watts internally illuminated exit signs may use.
• Exterior Building Grounds Lighting: for exterior lighting not under the control of a motion sensor or exempted under section C405.6.2, Section C405.6.1 sets a minimum efficacy for the lamp(s) being used.

Additional Efficiency Package Options: all buildings are required to meet the requirements of at least one of three options.  The second option requires that the interior lighting power allowance be set using the LPDs in a more stringent table (Table C406.3).