PROPERTY, PLANT AND EQUIPMENT, NET

9 Months Ended

Sep. 30, 2013

PROPERTY, PLANT AND EQUIPMENT, NET

PROPERTY, PLANT AND EQUIPMENT, NET

5. PROPERTY, PLANT AND EQUIPMENT, NET

As of September 30, 2013 and December 31, 2012, property, plant and equipment consisted of the following:

(In millions)	September 30, 2013		December 31, 2012
Machinery and equipment	$	2,306.9	$	1,492.6
Buildings		223.9		203.7
Depletable land and land improvements		291.2		90.4
Construction-in-progress		97.6		33.6
Property, plant and equipment, at cost		2,919.6		1,820.3
Less: accumulated depreciation		1,270.3		1,182.6
Property, plant and equipment, net	$	1,649.3	$	637.7

Depreciation expense is computed using the straight-line method over the estimated useful lives of the assets. We periodically monitor actual experience to determine whether events and circumstances have occurred that may warrant revision of the estimated useful lives of property, plant and equipment. Effective January 1, 2013, we changed the useful lives of certain property, plant and equipment as a result of our historical experience which demonstrated longer useful lives for certain classes of assets. The change was accounted for as a change in estimate and applied prospectively. For the three months ended September 30, 2013, the effect of the change decreased depreciation expense by $5.2 million, increased net income attributable to Axiall by approximately $3.3 million and increased diluted earnings per share by $0.05. For the nine months ended September 30, 2013, the effect of the change decreased depreciation expense by $16.0 million, increased net income attributable to Axiall by approximately $10.1 million and increased diluted earnings per share by $0.15.

The estimated useful lives of our property, plant and equipment are as follows:

Buildings	27-39 years
Depletable land and land improvements	15-25 years
Machinery, plant and equipment	2-25 years
Dies and moulds	3-10 years
Office furniture and equipment	2-10 years
Computer equipment and software	3-10 years