(a)

1. (1) In selecting boiler feed pumps, the fact that boilers are often operated two hundred percent (200%) or three hundred percent (300%) of their rating should be taken into consideration.
2. (2) The figures as outlined in Table 2 are of the actual boiler horsepower developed, based on thirty-four and one-half pounds (34.5 lbs.) of water evaporated per hour from and at two hundred twelve degrees Fahrenheit (212° F). TABLE 2 REQUIREMENTS IN U.S.G.P.M. BOILER FEEDING

   BOILER HP	GPM	BOILER HP	GPM
   5	.345	350	24
   10	.690	400	28
   15	1.03	500	34
   20	1.38	750	53
   25	1.72	1000	69
   30	2.07	1500	104
   35	2.41	2000	138
   40	3	2500	172
   50	4	3000	207
   75	5	3500	242
   100	7	4000	276
   150	10	4500	310
   175	12	5000	345
   200	14	10000	689
   225	16	15000	1034
   250	17	20000	1387
   275	19	25000	1723
   300	21	35000	2413

(b)

1. (1) Boiler feed pumps should have pressure in excess of the boiler rated pressure in order to compensate for frictional losses, entrance losses, regulating valve losses, and normal static head, etc.
2. (2) However, for estimating purposes, the following are fair values for feed pumps differential:

   Boiler	Feed Pump
   Pressure	Discharge Pressure
   200	250
   400	475
   800	925
   1200	1350