Download Standard Bus Procurement Guidelines

Standard Bus Procurement Guidelines
Provision shall be made to apply shop air to the bus air systems using a standard tire inflation
type valve. A quick disconnect fitting specified in attachments to Part 5: Technical
Specifications, shall be easily accessible and located in the engine compartment and near the
front bumper area for towing. Retained caps shall be installed to protect fitting against dirt and
moisture when not in use. Air for the compressor shall be filtered through the main engine air
cleaner system. The air system shall be protected by a pressure relief valve set at 150 psi and
shall be equipped with check valve and pressure protection valves to assure partial operation in
case of line failures.
5.3.4.2
AIR COMPRESSOR
The engine-driven air compressor shall be sized to charge the air system from 40 psi to the
governor cutoff pressure in less than 3 minutes while not exceeding the fast idle speed setting of
the engine.
5.3.4.3
AIR LINES AND FITTINGS
Air lines, except necessary flexible lines, shall conform to the installation and material
requirements of SAE Standard J1149 for copper tubing with standard, brass, flared or ball sleeve
fittings, or SAE Standard J844 for nylon tubing if not subject to temperatures over 200 degrees
F. Nylon tubing shall be installed in accordance with the following color-coding standards:
Green.
Red.
Brown.
Yellow.
Black.
Indicates primary brakes and supply
Indicates secondary brakes
Indicates parking brake
Indicates compressor governor signal
Indicates accessories
Line supports shall prevent movement, flexing, tension strain, and vibration. Copper lines shall
be supported to prevent the lines from touching one another or any component of the bus. To
the extent practicable and before installation, the lines shall be pre-bent on a fixture that prevents
tube flattening or excessive local strain. Copper lines shall be bent only once at any point,
including pre-bending and installation. Rigid lines shall be supported at no more than 5-foot
intervals. Nylon lines may be grouped and shall be supported at 2-foot intervals or less.
The compressor discharge line between power plant and body-mounted equipment shall be
flexible convoluted copper or stainless steel line, or may be flexible Teflon hose with a braided
stainless steel jacket. Other lines necessary to maintain system reliability shall be flexible Teflon
hose with a braided stainless steel jacket. End fittings shall be standard SAE or JIC brass or
steel, flanged, swivel type fittings. Flexible hoses shall be as short as practicable and
individually supported. They shall not touch one another or any part of the bus except for the
supporting grommets. Flexible lines shall be supported at 2-foot intervals or less.
Technical Specifications
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1/22/08