IQ2 APPENDIX. 



and calculating the efficiency of a boiler are recommended. 

 They are : 



Heat absorbed per Ib. combustible 



1. Efficiency of the boiler = == 1^~ -^ rr- 



Heating value of I Ib. combustible 



2. Efficiency of the boiler and grate 



Heat absorbed per Ib. coal 

 Heating value of I Ib. coal 



The first of these is sometimes called the efficiency based 

 on combustible, and the second the efficiency based on coal. 

 The first is recommended as a standard of comparison for all 

 tests, and this is the one which is understood to be referred to 

 when the word " efficiency " alone is used without qualifica- 

 tion. The second, however, should be included in a report 

 of a test, together with the first, whenever the object of the 

 test is to determine the efficiency of the boiler and furnace 

 together with the grate (or mechanical stoker), or to compare 

 different furnaces, grates, fuels, or methods of firing. 



The heat absorbed per pound of combustible (or per pound 

 coal) is to be calculated by multiplying the equivalent evapo- 

 ration from and at 212 degrees per pound combustible (or 

 coal) by 965.7. 



In calculating the efficiency where the coal contains an ap- 

 preciable amount of surface moisture, allowance is to be made 

 for the heat lost in evaporating this moisture by adding to the 

 heat absorbed by the boiler the heat of evaporation thus lost. 

 The percentage of surface moisture used in this calculation is 

 that which is found in the manner described in Article XIV 

 of Code. 



XXI. The Heat-balance. An approximate "heat-bal- 

 ance," or statement of the distribution of the heating value of 

 the coal among the several items of heat utilized and heat 

 lost may be included in the report of a test when analyses of 

 the fuel and of the chimney gases have been made. It should 

 be reported in the following form : 



