75. To test the capacity of the plant, .... hose lines each 100 ft. long will be attached to outlets on the system and each hose fitted with a standard vacometer. .... vacometers shall have ¹⁄₂-in. opening and .... vacometers shall have ⁷⁄₈-in. opening. Under these conditions 4 in. vacuum must be maintained at vacometers having ¹⁄₂ in. opening.
75a. 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 1 lb. of finely pulverized charcoal.
75b. Fifty feet of hose of size required by the system shall be attached to each of the —— outlets, and the surface or surfaces prepared for cleaning shall be cleaned simultaneously by operators provided by the contractor until all of the sand, flour and charcoal has been taken up, when the exhauster shall be stopped and the dirt removed from the dry separator and spread on the floor again, and the operation of cleaning repeated until the mixture has been handled by the apparatus four times. If, after thoroughly flushing the system at completion of above run, any dust or mud is found in the cylinder, ports, or valve chambers of the displacement exhauster, or if less than 95% of the dirt removed is found in the dry separator, it shall be deemed sufficient ground for the rejection of the separators.
76 and 77. 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 starter resistance.
Omit 25, 26 and 27.