Research project 185 was the result of dissatisfaction on the part of the author with the usual line-sizing charts employing turning points on multiple diagonal lines. Research project 185 was undertaken to compile a booklet of charts covering refrigerants 12, 22, 502 and 717 based on a simple and more accurate chart. Preparation of the chart data led to related studies, including the effect from viscosity of superheated-vapor on pressure loss.