Q338. For Tier 3, if I have multiple combustion sources using a single fuel type, should I enter this as an aggregation of units?
A338. While it is possible for an aggregation of units to use Tier 3 for certain fuel types, it is important to remember that the aggregation of units option is only allowed if each unit in the group is smaller than 250 mmBtu/hr. If the use of Tier 3 is required because any given unit is larger than 250 mmBtu/hr, the use of the aggregation of units option would not be allowed; however, you would be able report combined emissions for these units using the common pipe configuration if these units combust the same type of liquid or gaseous fuel and the fuel is fed to the individual units through a common supply line or pipe. (See §98.36(c)(1) and §98.36(c)(3).)