In a chlorine-fluxing installation in a large aluminum company, engineers are considering the replacement of existing plastic pipe fittings with more expensive, but longer-lived, copper fittings. The following table gives a comparison of the capital investments, lives, salvage values, and so on of the two mutually exclusive alternatives under consideration:

	Plastic	Copper
Capital investment	$5,000	$10,000
Useful ( class) life	5 years	10 years
Salvage value for depreciation purposes	$1,000 ( = SV5)	$5,000 ( = SV10)
Annual expenses	$300	$100
Market value at end of useful life	$0	$0

Depreciation amounts are calculated with the SL method. Assume an income tax rate of 40% and a MAR after-taxes of 12% per year. Which pipe fitting would you select and why? Carefully list all assumptions that you make in performing the analysis.