With regard to the question of whether a large corporate training room is Group A, here are a couple of paragraphs from the 2015 IBC Commentary:
Colleges (educational occupancies for students above the 12th grade) may have spaces that have an occupant load of more than 50 in a room, but are ancillary to the place of education and used only for programs directly associated with training and education (Section 303.4). For college buildings, similar to other office buildings, if there are spaces with occupant loads greater than 50, such as cafeterias or lecture halls, by the character of the space and the level of fire hazard they would be appropriately classified as Group A-2 or A-3, respectively (see Section 302.1). Where lecture facilities for large groups (i.e., occupant load of 50 or more) are located within the same building as classrooms with an occupant load less than 50, the building is a mixed occupancy (Groups A-3 and B) and is subject to the provisions of Section 508.
In reference to JBI's response above ("In order to be regulated as an 'Assembly' space, the use must be an 'assembly' purpose as identified in the Code. Group B now includes (2015 IBC) Training and skill development, and the list of examples states 'shall include but not be limited to...' "), the Commentary clarifies the type of training and skill development that would be a Group B, and goes on to say that if the occupant load of the training classroom exceeds 50, a Group A classification may be appropriate:
Training and skill development is classified as a Group B occupancy due to the similarity in use of spaces between education above the 12th grade and professional consultation. Often unions provide training facilities for their members so they can keep up with new materials and updates of regulations. Other facilities can provide one-on-one tutoring such as remedial reading or math skills for students. Those receiving the training or skill development can include those whose ages are typically associated with grades 12 or earlier. The determination of the appropriate classification requires the building official to consider whether the training is given as part of a traditional educational program. Examples provided by the code allow a range of size in the numbers receiving the training from one-on-one tutoring to a large class of children learning martial arts or ballet. The presence of children does not automatically mean a classification as a Group E. Where the occupant load of a training classroom or space exceeds 50, a Group A classification may be appropriate for the space, especially if the space is to be used for different activities at different times. If the training room is used for a martial arts competition with spectators on an evening or weekend, then a Group A designation should also be considered.
Here is one more:
Also, since they most nearly resemble this occupancy classification, public and private spaces used for assembly are often classified in Group A-3. These include large courtrooms, meeting rooms and conference centers.
Why is a large corporate training room not Group A-3? I'm not trying to be argumentative...I have just always been taught (and taught others) that these rooms - used for large gatherings of people - are Group A.
