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Roof mounted AC units

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Post 28 Jan 2011, 14:01

Posts: 94
Location: dryden, ny
To: SMVI’s, MVI’s, Operators, Distributors, Manufacturers
From: Rusty Seastrum, Chief Technician NYSDOT
Subject: Roof Mounted Air Conditioner Components
School Buses and MFSAB’s
Date: January 28, 2011
Roof mounted air conditioning modules are allowed to be installed on school vehicles built to meet Federal Motor Vehicle Safety Standards as a school bus or MFSAB after assembly line completion if they are the newer style that will crush with relative ease and not cause significant intrusion into the passenger compartment if crushed. These modules are typically built with mostly aluminum parts and have a light weight fiberglass or plastic cover.
Support braces must be provided that span at least two roof bows and shall be fastened to both with bolts and nuts or fasteners with equivalent strength. Standard or self drilling sheet metal screws are not acceptable fasteners. Fasteners and other components that go through roof panels must be properly sealed to avoid intrusion of weather elements inside any area of the body.
Side wall seat support rails shall not be compromised to install pressure lines or wiring unless specific procedures are provided by an engineer representing the body manufacturer.
All interior pressure lines shall be covered so as to prevent direct flow of a solid stream of refrigerant onto passengers in the event of a leak or rupture. All wires shall be covered. Pressure lines and wires shall be secured at appropriate intervals to prevent vibration and/or movement that may cause failure or chaffing.
Any installation procedures that are provided by engineering staff representing the body manufacturer must be strictly followed unless they significantly deviate from these instructions. Said procedures are not required. However, in the absence of said procedures installation shall be done with common industry practice.
All components must be installed in a workmanlike manner.

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