Specifications include, but are not limited to: Blower Package Configuration: A. Installation Location: Outside B. Inlet Configuration: Ambient C. All components and instrumentation are to be mounted and pre-piped; no field installation shall be required by the contractor. The manufacturer shall be responsible for all aspects of the engineering, from the blower package’s air inlet to its discharge connection. 2.4 Blower Construction A. Blower type: 1. The bare blower shall be mounted for vertical air flow, be of the oil-free, positive displacement, rotary three lobe type, designed for air or other inert gas service, and belt driven via electric motor. 2. The blower assembly must operate at the effective value for vibration velocity in frequency range A and B, according to VDI 3836. B. Material: 1. AISI, ASTM, GJL, GLS, DIN, etc., numbers, types, and grades specified are typical of material composition and quality, equivalent materials will be considered. C. Housing: 1. The casing shall be made of high strength, close grained, cast iron, and shall be adequately ribbed to prevent casing deflection and facilitate cooling. Casing shall be of EN GG 20 material. 2. The casing shall be precision machined to allow for minimum clearances. 3. The casing shall include channels integrated on the discharge to reduce blower pulsation and dampen noise. 4. The casing shall include threaded atmospheric vent ports between its air-side and oil-side labyrinth seals for safe separation of the conveying and oil chamber. 5. Inlet and discharge ports shall be drilled and tapped for studs to allow solid connection of mating surfaces. Through bolting shall not be allowed. Flange style blower ports, which may be subject to loading, causing cylinder distortion, shall not be allowed. 6. Bearing fits shall be precision machined to ensure accurate positioning of the rotors in the casing. D. Rotors: 1. The rotors shall be precision machined out of a one-piece casting made of EN GGG 50 material. Stub shafts or two-piece impellers shall not be allowed. 2. The rotor assemblies shall be statically and dynamically balanced to ISO standard 1940/1- Q2.5 (turbine rotor). Modifications to the face of the rotors for balancing purposes are not acceptable. 3. The rotors shall be a tri-lobe design in order to minimize pulsation and noise. 4. The rotor must be solid or closed-end to prevent build-up of contaminants inside the rotor causing imbalance. 5. Cored rotors must be closed using threaded iron plugs which are permanently fixed. Impeller end caps of stamped sheet metal shall not be allowed. 6. The rotors shall have an integral sealing strip for improved efficiency. 7. The rotors shall operate without rubbing, liquid seals or lubrication in the air chamber...