the depreciable lives of production facilities within the merchant gases segment are principally 15 years . customer contracts associated with products produced at these types of facilities typically have a much shorter term . the depreciable lives of production facilities within the electronics and performance materials segment , where there is not an associated long-term supply agreement , range from 10 to 15 years . these depreciable lives have been determined based on historical experience combined with judgment on future assumptions such as technological advances , potential obsolescence , competitors 2019 actions , etc . management monitors its assumptions and may potentially need to adjust depreciable life as circumstances change . a change in the depreciable life by one year for production facilities within the merchant gases and electronics and performance materials segments for which there is not an associated long-term customer supply agreement would impact annual depreciation expense as summarized below : decrease life by 1 year increase life by 1 year .
what is the depreciation expense with the production facilities within the merchant gases segment accumulated in 15 years?
impairment of assets plant and equipment plant and equipment held for use is grouped for impairment testing at the lowest level for which there are identifiable cash flows . impairment testing of the asset group occurs whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable . such circumstances would include a significant decrease in the market value of a long-lived asset grouping , a significant adverse change in the manner in which the asset grouping is being used or in its physical condition , a history of operating or cash flow losses associated with the use of the asset grouping , or changes in the expected useful life of the long-lived assets . if such circumstances are determined to exist , an estimate of undiscounted future cash flows produced by that asset group is compared to the carrying value to determine whether impairment exists . if an asset group is determined to be impaired , the loss is measured based on the difference between the asset group 2019s fair value and its carrying value . an estimate of the asset group 2019s fair value is based on the discounted value of its estimated cash flows . assets to be disposed of by sale are reported at the lower of carrying amount or fair value less cost to sell . the assumptions underlying cash flow projections represent management 2019s best estimates at the time of the impairment review . factors that management must estimate include industry and market conditions , sales volume and prices , costs to produce , inflation , etc . changes in key assumptions or actual conditions that differ from estimates could result in an impairment charge . we use reasonable and supportable assumptions when performing impairment reviews and cannot predict the occurrence of future events and circumstances that could result in impairment charges . goodwill the acquisition method of accounting for business combinations currently requires us to make use of estimates and judgments to allocate the purchase price paid for acquisitions to the fair value of the net tangible and identifiable intangible assets . goodwill represents the excess of the aggregate purchase price over the fair value of net assets of an acquired entity . goodwill , including goodwill associated with equity affiliates of $ 126.4 , was $ 1780.2 as of 30 september 2013 . the majority of our goodwill is assigned to reporting units within the merchant gases and electronics and performance materials segments . goodwill increased in 2013 , primarily as a result of the epco and wcg acquisitions in merchant gases during the third quarter . disclosures related to goodwill are included in note 10 , goodwill , to the consolidated financial statements . we perform an impairment test annually in the fourth quarter of the fiscal year . in addition , goodwill would be tested more frequently if changes in circumstances or the occurrence of events indicated that potential impairment exists . the tests are done at the reporting unit level , which is defined as one level below the operating segment for which discrete financial information is available and whose operating results are reviewed by segment managers regularly . currently , we have four business segments and thirteen reporting units . reporting units are primarily based on products and geographic locations within each business segment . as part of the goodwill impairment testing , and as permitted under the accounting guidance , we have the option to first assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value . if we choose not to complete a qualitative assessment for a given reporting unit , or if the .