at installation. The minimum baffle spacing is the greater of 50.8 mm or one fifth of the inner shell diameter. The maximum baffle spacing is dependent on material and size of tubes. The Tubular Exchanger Manufacturers Association sets out guidelines. There are also segments with a "no tubes in window" design that affects the acceptable spacing within the design. An important design consideration is that no recirculation zones or dead spots form – both of which are counterproductive to effective heat transfer. References (Editors)Perry, R.H. and Green, D.W. (Oct,2007) Perry's Chemical Engineers' Handbook (8th ed.) McGraw-Hill Wolverine Tube Inc, (2008) Heat Transfer Data Book Available Professor J. Kavanagh (2009) Heat Transfer Lectures 4&5 Usyd Chemical Engineering Department Heat exchangers