Table 503 - Type of Construction

[DJYork]

I think I understand all aspects of this table, except what is the A or B under the respective types?

 

[henri2]

The building elements under A have a higher fire resistance rating requirement than is the case for B. Refer to IBC chapter 6 and also Table 601

 

[AegisFPE]

Before the IBC, we had the UBC on the west coast. IBC's B's can be considered to be similar to UBC's N's (which meant Not rated), A's generally represent fire rated construction (i.e. 1-hour).

 

[wireman48]

"A" is sprinklered, "B" is not, thus the ability to area increase.

 

[AegisFPE]

Careful Wireman...it is possible to utilize sprinkler protection in lieu of the fire-resistance rating of "A" vs. "B", but Exception 2 of 2003 IBC Section 506.3 does not allow an increase in area on top of sprinkler substitution for fire protection.