1. OBJECT [Pg 267]
Ascertain the specific object of the test, and keep this in view not only in the work of preparation, but also during the progress of the test, and do not let it be obscured by devoting too close attention to matters of minor importance. Whatever the object of the test may be, accuracy and reliability must underlie the work from beginning to end.
If questions of fulfillment of contract are involved, there should be a clear understanding between all the parties, preferably in writing, as to the operating conditions which should obtain during the trial, and as to the methods of testing to be followed, unless these are already expressed in the contract itself.
Among the many objects of performance tests, the following may be noted:
Determination of capacity and efficiency, and how these compare with standard or guaranteed results.
Comparison of different conditions or methods of operation.
Determination of the cause of either inferior or superior results.
Comparison of different kinds of fuel.
Determination of the effect of changes of design or proportion upon capacity or efficiency, etc.
2. PREPARATIONS
(A) Dimensions:
Measure the dimensions of the principal parts of the apparatus to be tested, so far as they bear on the objects in view, or determine these from correct working drawings. Notice the general features of the same, both exterior and interior, and make sketches, if needed, to show unusual points of design.
The dimensions of the heating surfaces of boilers and superheaters to be found are those of surfaces in contact with the fire or hot gases. The submerged surfaces in boilers at the mean water level should be considered as water-heating surfaces, and other surfaces which are exposed to the gases as superheating surfaces.
(B) Examination of Plant: