R.S. Means Mechanical Cost Data, 2005, has the labor costs for closed cell foam insulation, 1/2" thick, for 1" pipe size at about $3.37/LF. If we add this to approx. $0.68/LF material costs and toss in O&P you could be at $6/LF. If you go with 3/8" thick insulation, it'll be more like $5/LF.