15. Cooling. The rotary type of exhauster must be provided with the necessary water connections to properly seal and cool the pump. Fan type of exhauster must be designed to operate continuously without a rise of temperature over 100° F. above room temperature.
16. Speed. Rotary exhausters shall not exceed a peripheral speed of 1,100 ft. per minute at tips of impellers.
17. Centrifugal fans shall not exceed peripheral velocity of 22,000 ft. per minute when running under specified full-load conditions.
18. Mounting. The exhauster, motor and separators shall be mounted as a unit on suitable cast-iron base plate, either mounted on legs or resting on the basement floor.
19. Drive. The exhauster shall be driven by an electric motor, which may be direct connected to the exhauster shaft or be operated with an oak-tanned leather belt, or by cut gearing. Belt and gearing are to be of ample size and strength for their work and must run without undue noise or wear. Means shall be provided to take up the slack of the belt. Furnish and place a suitable metal guard over belt and pulley wheels that shall prevent oil being splashed outside of the base plate and prevent clothing being caught.
20. If the exhauster is operated through cut gearing, the gearing must be inclosed in an oil and dust proof case, which shall be fitted with means for copious and continuous lubrication of same.
21. Finish. The air exhauster and motor and the base plate shall be finished in a first-class manner, filled, rubbed down and painted at least one coat at the shop, and after installation shall receive two more coats, finishing tint to be as directed.
22. Electric Motor. Motor to be of such size that when operating under test conditions it will not be under less than three-fourths nor more than full-load condition. It is to be of standard make, approved by the architect.
23. Motor to be wound for .... volts direct current.
24. Armature to be of toothed-core construction, with windings thoroughly insulated, and securely fastened in place, and must be balanced both mechanically and electrically.