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  • § 393.1
    Scope of the rules in this part.
  • § 393.3
    Additional equipment and accessories.
  • § 393.5
    Definitions.
  • § 393.7
    Matter incorporated by reference.
  • § 393.9
    Lamps operable, prohibition of obstructions of lamps and reflectors.
  • § 393.11
    Lamps and reflective devices.
  • § 393.13
    Retroreflective sheeting and reflex reflectors, requirements for semitrailers and trailers manufactured before December 1, 1993.
  • § 393.17

    Lamps and reflectors—combinations in driveaway-towaway operation.

  • § 393.19
    Hazard warning signals.
  • § 393.20
  • § 393.22
    Combination of lighting devices and reflectors.
  • § 393.23
    Power supply for lamps.
  • § 393.24
    Requirements for head lamps, auxiliary driving lamps and front fog lamps.
  • § 393.25
    Requirements for lamps other than head lamps.
  • § 393.26
    Requirements for reflectors.
  • § 393.27
  • § 393.28
    Wiring systems.
  • § 393.29
  • § 393.30
    Battery installation.
  • §§ 393.31-393.33
  • § 393.40
    Required brake systems.
  • § 393.41
    Parking brake system.
  • § 393.42

    Brakes required on all wheels.

  • § 393.43
    Breakaway and emergency braking.
  • § 393.44
    Front brake lines, protection.
  • § 393.45
    Brake tubing and hoses; hose assemblies and end fittings.
  • § 393.46
  • § 393.47
    Brake actuators, slack adjusters, linings/pads and drums/rotors.
  • § 393.48
    Brakes to be operative.
  • § 393.49
    Control valves for brakes.
  • § 393.50
    Reservoirs required.
  • § 393.51
    Warning signals, air pressure and vacuum gauges.
  • § 393.52
    Brake performance.
  • § 393.53
    Automatic brake adjusters and brake adjustment indicators.
  • § 393.55
    Antilock brake systems.
  • § 393.60
    Glazing in specified openings.
  • § 393.61
    Truck and truck tractor window construction.
  • § 393.62
    Emergency exits for buses.
  • § 393.63
  • § 393.65
    All fuel systems.
  • § 393.67
    Liquid fuel tanks.
  • § 393.68
    Compressed natural gas fuel containers.
  • § 393.69
    Liquefied petroleum gas systems.
  • § 393.70
    Coupling devices and towing methods, except for driveaway-towaway operations.
  • § 393.71
    Coupling devices and towing methods, driveaway-towaway operations.
  • § 393.75
    Tires.
  • § 393.76
    Sleeper berths.
  • § 393.77
    Heaters.
  • § 393.78
    Windshield wiping and washing systems.
  • § 393.79
    Windshield defrosting and defogging systems.
  • § 393.80
    Rear-vision mirrors.
  • § 393.81
    Horn.
  • § 393.82
    Speedometer.
  • § 393.83
    Exhaust systems.
  • § 393.84
    Floors.
  • § 393.85
  • § 393.86
    Rear impact guards and rear end protection.
  • § 393.87
    Warning flags on projecting loads.
  • § 393.88
    Television receivers.
  • § 393.89
    Buses, driveshaft protection.
  • § 393.90
    Buses, standee line or bar.
  • § 393.91
    Buses, aisle seats prohibited.
  • § 393.92
  • § 393.93
    Seats, seat belt assemblies, and seat belt assembly anchorages.
  • § 393.94
    Interior noise levels in power units.
  • § 393.95
    Emergency equipment on all power units.
  • § 393.100
    Which types of commercial motor vehicles are subject to the cargo securement standards of this subpart, and what general requirements apply?
  • § 393.102
    What are the minimum performance criteria for cargo securement devices and systems?
  • § 393.104
    What standards must cargo securement devices and systems meet in order to satisfy the requirements of this subpart?
  • § 393.106
    What are the general requirements for securing articles of cargo?
  • § 393.108
    How is the working load limit of a tiedown, or the load restraining value of a friction mat, determined?
  • § 393.110
    What else do I have to do to determine the minimum number of tiedowns?
  • § 393.112
    Must a tiedown be adjustable?
  • § 393.114
    What are the requirements for front end structures used as part of a cargo securement system?
  • § 393.116
    What are the rules for securing logs?
  • § 393.118
    What are the rules for securing dressed lumber or similar building products?
  • § 393.120
    What are the rules for securing metal coils?
  • § 393.122
    What are the rules for securing paper rolls?
  • § 393.124
    What are the rules for securing concrete pipe?
  • § 393.126
    What are the rules for securing intermodal containers?
  • § 393.128
    What are the rules for securing automobiles, light trucks and vans?
  • § 393.130
    What are the rules for securing heavy vehicles, equipment and machinery?
  • § 393.132
    What are the rules for securing flattened or crushed vehicles?
  • § 393.134
    What are the rules for securing roll-on/roll-off or hook lift containers?
  • § 393.136
    What are the rules for securing large boulders?
  • § 393.201
    Frames.
  • § 393.203
    Cab and body components.
  • § 393.205
    Wheels.
  • § 393.207
    Suspension systems.
  • § 393.209

    Steering wheel systems.

Part 393
PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION

§ 393.136: What are the rules for securing large boulders?

(a) Applicability. (1) The rules in this section are applicable to the transportation of any large piece of natural, irregularly shaped rock weighing in excess of 5,000 kg (11,000 lb.) or with a volume in excess of 2 cubic-meters on an open vehicle, or in a vehicle whose sides are not designed and rated to contain such cargo.
(2) Pieces of rock weighing more than 100 kg (220 lb.), but less than 5,000 kg (11,000 lb.) must be secured, either in accordance with this section, or in accordance with the provisions of §§ 393.100 through 393.114, including:
(i) Rock contained within a vehicle which is designed to carry such cargo; or
(ii) Secured individually by tiedowns, provided each piece can be stabilized and adequately secured.
(3) Rock which has been formed or cut to a shape and which provides a stable base for securement must also be secured, either in accordance with the provisions of this section, or in accordance with the provisions of §§ 393.100 through 393.114.
(b) General requirements for the positioning of boulders on the vehicle. (1) Each boulder must be placed with its flattest and/or largest side down.
(2) Each boulder must be supported on at least two pieces of hardwood blocking at least 10 cm × 10 cm (4 inches × 4 inches) side dimensions extending the full width of the boulder.
(3) Hardwood blocking pieces must be placed as symmetrically as possible under the boulder and should support at least three-fourths of the length of the boulder.
(4) If the flattest side of a boulder is rounded or partially rounded, so that the boulder may roll, it must be placed in a crib made of hardwood timber fixed to the deck of the vehicle so that the boulder rests on both the deck and the timber, with at least three well-separated points of contact that prevent its tendency to roll in any direction.
(5) If a boulder is tapered, the narrowest end must point towards the front of the vehicle.
(c) General tiedown requirements. (1) Only chain may be used as tiedowns to secure large boulders.
(2) Tiedowns which are in direct contact with the boulder should, where possible, be located in valleys or notches across the top of the boulder, and must be arranged to prevent sliding across the rock surface.
(d) Securement of a cubic shaped boulder. In addition to the requirements of paragraphs (b) and (c) of this section, the following rules must be satisfied:
(1) Each boulder must be secured individually with at least two chain tiedowns placed transversely across the vehicle.
(2) The aggregate working load limit of the tiedowns must be at least half the weight of the boulder.
(3) The tiedowns must be placed as closely as possible to the wood blocking used to support the boulder.
(e) Securement of a non-cubic shaped boulder—with a stable base. In addition to the requirements of paragraphs (b) and (c) of this section, the following rules must be satisfied:
(1) The boulder must be secured individually with at least two chain tiedowns forming an “X” pattern over the boulder.
(2) The aggregate working load limit of the tiedowns must be at least half the weight of the boulder.
(3) The tiedowns must pass over the center of the boulder and must be attached to each other at the intersection by a shackle or other connecting device.
(f) Securement of a non-cubic shaped boulder—with an unstable base. In addition to the requirements of paragraphs (b) and (c) of this section, each boulder must be secured by a combination of chain tiedowns as follows:
(1) One chain must surround the top of the boulder (at a point between one-half and two-thirds of its height). The working load limit of the chain must be at least half the weight of the boulder.
(2) Four chains must be attached to the surrounding chain and the vehicle to form a blocking mechanism which prevents any horizontal movement. Each chain must have a working load limit of at least one-fourth the weight of the boulder. Whenever practicable, the angle of the chains must not exceed 45 degrees from the horizontal.

Citation: [67 FR 61225, Sept. 27, 2002, as amended at 78 FR 58484, Sept. 24, 2013]