3.21.4 Wiring diagram. The electrical wiring diagram plates or decals shall be furnished on
the equipemnt, following TTMA Technical Bulletin No. 65 for the trailer and SAE J821 for the
3.21.5 Operating instruction. Operating instruction plates or decals shall be furnished and
shall be permanently affixed in a readable location near the applicable components. Instructions
shall be clear and concise and shall contain sufficient information to enable operation without
damage to the components or injury to personnel.
3.21.6 Trailer safety brake marking. When straight air brakes are provided for the trailer
chassis, a decal inscribed with the legend reading similar to "CAUTION Towing vehicle air
lines must be connected and air control valve opened or each chamber spring annually caged
before trailer parking brakes will release. Except during an emergency, DO NOT transport or
park trailers with the spring brakes caged" shall be affixed on the front of the trailer in the
vicinity of the gladhands. Legend shall incorporate minimum 1/8-inch-high lettering. Lettering
and color shall be as specified in 3.21.3 for ANSI requirments. In addition, a caution decal
describing the practice of caging of the spring brake chamber during prolonged plant operation,
shall be furnished in the same general area.
3.21.7 Engine sound level requirement. When the equipment includes a diesel engine, the
engine shall be furnished with noise reduction means including acoustical package and other
optional equipment, when available. The noise reduction means shall reduce the mean work
cycle sound level with operator present, to not greater than 85 dbA, as measured in accordance
with the SAE Recommended Practice, work cycle procedure, or J919. If the sound level exceeds
85 dbA, a warning plate as specified in 3.21.3 shall be affixed to the instrument panel and shall
be worded as follows:
EAR PROTECTION REQUIRED
WHEN THE EQUIPMENT IS OPERATING"
The plate coloring shall be the yellow and black, ANSI requirements.
3.22 Vehicle marking. As specified by the contracting activity for the appropriate service
(see 6.2 and 6.7), the registration numbers and other markings of the equipment shall be in
accordance with MIL-STD-642. The GVWR shall be marked on each forward side of the
equipment in manner to be discernible. The TRA Year Book's prescribed tire pressures shall be
marked on the side of the vehicle or subframe near the tires. Unless otherwise specified
(see 6.2), all marking shall be black on equipment painted forest green.
3.23 Vehicle weight classification. The contractor shall complete in the specified time
(see 6.2) and submit the Government-furnished vehicle weight classification forms (see 6.4), one
form covering each trailer chassis at GVWR or with the mounted equipment. The Government
will inform the contractor of the resulting vehicle weight classification numbers. A variable