"(g) Limitation on barrier removal obligations.

"(1) The requirements for barrier removal under §36.304 shall not be interpreted to exceed the standards for alterations in subpart D of this part."

"§ 36.403 Alterations: Path of travel.

"(a) General...

"(2) If a private entity has constructed or altered required elements of a path of travel at a place of public accommodation or commercial facility in accordance with the specifications in the 1991 Standards, the private entity is not required to retrofit such elements to reflect the incremental changes in the 2010 Standards solely because of an alteration to a primary function area served by that path of travel."

So it is clear that any incremental changes to the requirements for an element type are not required to be brought into compliance with the 2010 Standards.  So, what is an "element"? 

The definition can be found in the 2010 ADA Standards under 106.5 Defined Terms

Additional clues about how to define elements and to apply the safe harbor exception to those "elements" can be found in the following language from the Department of Justice:

2010 Guidance and Section-by-Section Analysis

"Element-by-element safe harbor for public accommodations...

"...The 2010 Standards introduce technical and scoping specifications for many elements that were not included in the 1991 Standards. Accordingly, public accommodations will have to consider these supplemental requirements when evaluating whether there are covered barriers in existing facilities, and, if so, remove them to the extent readily achievable. Also included in the 2010 Standards are revised technical and scoping requirements for elements that were addressed in the 1991 Standards. These incremental changes were made to address technological changes that have occurred since the promulgation of the 1991 Standards, to reflect additional study by the Access Board, and to harmonize ADAAG requirements with the model codes..." and

"Safe harbor for qualified small businesses.

"...The Department has not expanded the scope of the element-by-element safe harbor beyond those elements subject to the incremental changes..."

So the safe harbor clearly applies to elements that had requirements under the 1991 ADA Standards but not to those that had none.

From my conversations with technical assistance staff at the US Access Board and the Department of Justice's Disability Rights Section, examples of "elements" in their opinion, would include such things as

A) a door (with all of its specific parts included as part of the door element),

B) a toilet compartment (with the fixture, controls, clearances, and accessories as part of the compartment element),

C) a sales or service counter (including one that met all of the specific requirements for equivalent facilitation under the 1991 ADA Standards),

D) a drinking fountain, and

E) a control panel in an elevator car. (This one is specifically mentioned in the Access Board's 2014 Guide to the ADA Standards here.)

Incremental changes to the requirements in the 2010 ADA Standards for these elements like adding kickplate and vision light requirements for doors would not trigger changes until the door is altered or replaced.

It is important to remember that if any part of an element was not in full compliance with the 1991 ADA Standard by 3/15/2012, the element is not eligible for the safe harbor exception.

2) This interpretation and application of the element by element safe harbor provision for other facility types are the same.  So commercial facilities undergoing alteration projects and public entity facilities undergoing alterations or considering their program access obligations can apply the safe harbor concept the same way.  And elements in public entity facilities that met the full Uniform Federal Accessibility Standard (UFAS) by 3/15/2012 are also considered safe harbored until altered for other reasons.