Separate facilities
(2) Separate facilities. The determination of what constitutes a separate facility must be made on the facts and circumstances of each individual case. Generally, each facility with respect to which a separate election is in effect under section 169 shall be treated as a separate facility for purposes of this paragraph. However, if the depreciation or amortization which would have been allowable without regard to section 169 with respect to any part of a facility is based on a different useful life, date placed in service, or method of depreciation or amortization from the other part or parts of such facility, such part is considered a separate facility for purposes of this paragraph. For example, if a building constitutes a certified pollution control facility and various component parts of the building have different useful lives, each group of component parts with the same useful life would be treated as a separate facility for purposes of this paragraph. Two or more facilities may be treated as one facility for purposes of this paragraph where, with respect to each such facility: (i) The initial amortization under section 169 commences on the same date, (ii) the facility is placed in service on the same date, (iii) the estimated useful life which would be the basis for depreciation or amortization other than under section 169 has continually been the same, and (iv) the method of depreciation or amortization which could have been used without regard to section 169 could have continually been the same. (3) Amount allowable under section 169. For purposes of the determination of the amount of the deduction allowable under section 169, see section 169 and the regulations thereunder. Such amount, however, does not include amortization allowable in the year in which the pollution control facility is disposed of. (4) Otherwise allowable deduction. (i) The determination of the amount of the depreciation deduction otherwise allowable under section 167 is made as if the taxpayer had depreciated the property under section 167 for each year of its useful life for which the property has been held. This amount may be determined under 1.167(a)-(11)(c) if the property is eligible property (as defined in 1.167(a)-11(b)(2)) and, during the taxable year in which the property was first placed in service, the taxpayer