Fan housing and inlet box construction shall be as follows:

• Carbon steel, ³/ ₁₆in. minimum thickness.

• Housing to be split design to permit removal of the rotor without dismantling the ductwork.

• Internal bolting to be self-locking.

• Interior walls to be painted.

Suction and discharge connections shall be flanged, with the joints designed for through-bolting and full-face gaskets.

Access doors shall be provided as follows:

• Hinged doors to allow insertion of lance for steam or water washing of fan impeller during operation.

• A minimum of one inspection door located in the lower half of the fan housing permitting access to the impeller.

• An inspection door located for access to the inlet guide vanes.

A valved drain connection shall be provided at the low point of the fan casing and inlet box.

Bearing housing shall be arranged for oil lubrication.

A pressurized lubrication system shall be provided for any fan unit supplied with a steam turbine or gear in the main drive system.

Non-pressurized oil lubricated bearing shall have constant level-sight feed oilers with transparent containers and protecting wire cages.

Wet sump or "purge mist" bearing housings shall have constant level oiler and a mark indicating oil level. Refer to oil mist instructions which will be supplied by owner.

Inlet guide vane components requiring periodic lubrication shall be furnished with lubrication fittings that are accessible for maintenance while the fan equipment is in operation.

Radial or thrust antifriction (rolling contact) bearings for the...