Impairment of Long-Lived Assets Income Taxes Revenue Recognition Product Revenue Long-lived assets, including property, plant and equipment, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If the carrying amount of an asset exceeds the estimated undiscounted future cash flows expected to be generated by the asset, an impairment charge is recognized by reflecting the asset at its fair value. No impairments of long-lived assets were recorded in 2014, 2013 or 2012. The Company accounts for income taxes using the asset and liability method. Current income taxes are provided on income reported for financial statement purposes, adjusted for transactions that do not enter into the computation of income taxes payable in the same year. Deferred tax assets and liabilities are measured using enacted tax rates for the expected future tax consequences of temporary differences between the carrying amounts and the tax basis of assets and liabilities. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. The Company recognizes product revenues from two methods: The Company uses the percentage-of-completion method on long-term project contracts that have the following characteristics: Revenues recognized under the percentage-of-completion method • product revenues recognized under the percentage-of-completion method; and • product revenues from the sale of products that do not qualify for the percentage-of-completion method. • The contracts call for products which are designed to customer specifications; • The structural designs are unique and require significant engineering and manufacturing efforts generally requiring more than one year in duration; • The contracts contain specific terms as to milestones, progress billings and delivery dates; and • Product requirements cannot be filled directly from the Company’s standard inventory. For each project, the Company prepares a detailed analysis of estimated costs, profit margin, completion date and risk factors which include availability of material, production efficiencies and other factors that may impact the project. On a quarterly basis, management reviews the progress of each project, which may result in revisions of previous estimates, including revenue recognition. The Company calculates the percent complete and applies the percentage to determine the revenues earned and the appropriate portion of total estimated costs. Losses, if any, are recorded in full in the period they become known. Historically, the Company’s estimates of total costs and costs to complete have approximated actual costs incurred to complete the project. Under the percentage-of-completion method, billings do not always correlate directly to the revenue recognized. Based upon the terms of the specific contract, billings may be in excess of the revenue recognized, in which case the amounts are included in customer prepayments as a liability on the Consolidated Balance Sheets. Likewise, revenue recognized may exceed customer billings in which case the amounts are reported in trade receivables. Unbilled revenues are expected to be billed and collected within one year. At December 31, 2014 and 2013, receivables included $68.0 million and $52.9 million of unbilled receivables, respectively. For the year ended December 31, 2014, there were 17 projects representing approximately 11% of the Company’s total 53