Document nkzmERnEJEeOeX43pKnjDeJDG

American Society of Heating and Ventilating Engineers Guide, 1930 Iron or steel. Earth. Bronze, brass, copper and compositions. White metal. Aluminum, zinc, lead, babbitt and alloys. Rock. Sand. Electric insulation. Vulcanite, fibre, mica, Bakelite, etc.. Sound or heat insula tion. Cork, hair-felt, wool, asbestos, magnesia, etc. Flexible material. Fabric, felt, rubber, etc. Water and other liquids. Across grain') Wood* With grain / Concrete. *The symbols for wood may bo used for sections and outside Wows. fo'rUsseecdtiofnosr. outside views but not Brickorstone masonry. SE Brick.4 Fire-brick and refrac tory material. Stone.4 Marble, slate, glass porcelain, etc. 526 V' 4k Transparent material.4 Glass, celluloid, etc. Chapter 34--Symbols and Abbreviations SYMBOLS FOR HEAT AND THERMODYNAMICS8 General Principles 1. It is urged that a complete table of symbols and units used by an author be included at a convenient place in each book, chapter, or paper. 2. In most cases the same symbol shall be used, regardless of systems of units. Thus t is specific volume, whether cc per gram, cc per mol, cu ft per lb, etc. 3. In cases where more than one system of units is used in a discussion, a single symbol may be used, with addition of subscripts, superscripts, or indices to denote units other than the primary one, such as* p, />t, p'f p". 4. The same symbol should be used for a given concept, regardless of the number of special values which occur, and subscripts or superscripts should be used to designate them. 5. Letter subscripts should be used to denote values under special conditions or at special states, such as: Specific heat at constant pressure....... ......................................... .cp Specific heat at constant volume............................... Thermal efficiency.--....................................................................... &t Mechanical efficiency.--.................... .............................. .......... :..em cv 6. Numerical subscripts should be used to denote values at designated points in an apparatus, process or cycle, such as: Initial pressure...................................................................... i......... pt Final pressure................................................................................... p9 Weight of a major item.................................................................. W Weights of auxiliary items......... ................................... Wt, Wt, W9 7. In order to increase the clarity of printed matter, which is practically always Roman, symbols alone or in equations should be printed in Italics. 8. Where possible, capital letters denote total quantities and small letters denote specific quantities, or quantities per. unit; Thus, S may be entropy of any mass, and s may be entropy of unit mass. General Symbols Acceleration due to gravity. In ternationally adopted standard value 980.665 cm/sec* or 32.1740 ft/sec.*-- .__________ Acceleration due to gravity. Where it is not necessary to distinguish between the stand ard value and the exact local value............................................ Time............ ................................... Angular Velocity........................... Velocity..................................... . Revolutions per Unit Time.JV or Length. Distance.______________ Diameter__.___ __!__ .____...._____ Radius.__ ______________________ Area. Surface.....________________ go g t (omega) V n L D r A Symbols for Force, Weight, Work, Power Force, Total Load.._____________ F Pressure; Absolute Pressure; Gage Pressure; Force per Unit Area p Mean Effective' Pressure_______ pm Total Quantity of Fluid, Water, Gas, Heat; Quantity by Vol ume....0 Volume ' Rate per Unit Time; Rate at which Quantity of Material passes through a Ma chine; Quantity of Heat per Unit Time; Quantity of Heat per Unit Weight--.______ -- Q Total Weight------- -------- W Weight Rate; Weight per unit of Power; Weight per unit of Time--.__--...........-................... to -Mass, W/g~............................... m Total Work...... ................... W Work per Unit Weight._______- to Power; Work per Unit Time.____ P Efficiency-------- ---------- ---------1 or -13 (eta) Symbols for Properties Molecular Weight--.--._______ M Concentration; Amount of Par ticular Constituent per given amount of Mixture_.C 'Proposed symbols prepared by Sectional Committee on Scientific and Engineering Symbols and Abbreviations. 527 VI