75. Test of Separators. At each of —— points, near —— outlets on different risers selected by the architect’s representative, the contractor shall furnish and spread on the floor, evenly covering an area of approximately 50 sq. ft. for each outlet, a mixture of 6 lbs. of dry sharp sand that will pass a 50-mesh screen, 3 lbs. of fine wheat flour and 6 lbs. of Portland cement.
75b. Fifty feet of hose shall be attached to each of the —— outlets, and the surfaces prepared for cleaning shall be cleaned simultaneously by operators provided by the contractor until all of the sand, flour and Portland cement has been taken up, when the exhauster shall be stopped and the dirt removed from the separator and spread on the floor again, and the operation of cleaning repeated until the mixture has been handled by the apparatus four times.
The bag contained in the separator must not be disturbed until after completion of the capacity test, which will be made with material in place in the separator after being picked up the fourth time. After completion of the capacity test the contents of separator will be removed. During test of separators a dampened cloth will be held over the exhaust from pump. If such cloth indicates dirt passing through the separator, same will be rejected.
76. To test the capacity of the plant, one hose line 100 ft. long shall be attached to inlet farthest from the separator with standard vacometer, with ¹⁄₂-in. opening in end of hose. .... hose lines shall be attached to other outlets, each with 50 ft. hose and vacometers in end of hose, .... vacometers having ¹⁄₂-in. opening and .... vacometers having ⁷⁄₈-in. opening. Under these conditions 4 in. mercury must be maintained in vacometer at end of 100 ft. of hose.
77 and 78. Same as for Class 1.
Modifications of Specifications when Alternating Current is Available.
—When alternating current is available, instead of direct, modify specifications as follows:
23. Motor to be wound for .... volts, .... cycle, .... phase alternating current.
23a. Bidders must name efficiency and power factor of motor at one-half and full load.
24. Motor to have phase-wound rotor with collector rings for insertion of starting resistance.