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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

§ 393.108: How is the working load limit of a tiedown, or the load restraining value of a friction mat, determined?

(a) The working load limit (WLL) of a tiedown, associated connector or attachment mechanism is the lowest working load limit of any of its components (including tensioner), or the working load limit of the anchor points to which it is attached, whichever is less.
(b) The working load limits of tiedowns may be determined by using either the tiedown manufacturer's markings or by using the tables in this section. The working load limits listed in the tables are to be used when the tiedown material is not marked by the manufacturer with the working load limit. Tiedown materials which are marked by the manufacturer with working load limits that differ from the tables, shall be considered to have a working load limit equal to the value for which they are marked.
(c) Synthetic cordage (e.g., nylon, polypropylene, polyester) which is not marked or labeled to enable identification of its composition or working load limit shall be considered to have a working load limit equal to that for polypropylene fiber rope.
(d) Welded steel chain which is not marked or labeled to enable identification of its grade or working load limit shall be considered to have a working load limit equal to that for grade 30 proof coil chain.
(e)(1) Wire rope which is not marked by the manufacturer with a working load limit shall be considered to have a working load limit equal to one-fourth of the nominal strength listed in the Wire Rope Users Manual.
(2) Wire which is not marked or labeled to enable identification of its construction type shall be considered to have a working load limit equal to that for 6 × 37, fiber core wire rope.
(f) Manila rope which is not marked by the manufacturer with a working load limit shall be considered to have a working load limit based on its diameter as provided in the tables of working load limits.
(g) Friction mats which are not marked or rated by the manufacturer shall be considered to provide resistance to horizontal movement equal to 50 percent of the weight placed on the mat.

Tables to §393.108

[Working Load Limits (WLL), Chain]

Size mm (inches)WLL in kg (pounds)
Grade 30 proof coilGrade 43 high testGrade 70 transportGrade 80 alloyGrade 100 alloy
1. 7 (14)580 (1,300)1,180 (2,600)1,430 (3,150)1,570 (3,500)1,950 (4,300)
2. 8 (516)860 (1,900)1,770 (3,900)2,130 (4,700)2,000 (4,500)2,600 (5,700)
3. 10 (38)1,200 (2,650)2,450 (5,400)2,990 (6,600)3,200 (7,100)4,000 (8,800)
4. 11 (716)1,680 (3,700)3,270 (7,200)3,970 (8,750)  
5. 13 (12)2,030 (4,500)4,170 (9,200)5,130 (11,300)5,400 (12,000)6,800 (15,000)
6. 16 (58)3,130 (6,900)5,910 (13,000)7,170 (15,800)8,200 (18,100)10,300 (22,600)
Chain Mark Examples:     
Example 1347810
Example 230437080100
Example 33004307008001000
 

Synthetic Webbing

Width mm (inches)WLL kg (pounds)
45 (134)790 (1,750)
50 (2)910 (2,000)
75 (3)1,360 (3,000)
100 (4)1,810 (4,000)
 

Wire Rope (6 × 37, Fiber Core)

Diameter mm (inches)WLL kg (pounds)
7 (14)640 (1,400)
8 (516)950 (2,100)
10 (38)1,360 (3,000)
11 (716)1,860 (4,100)
13 (12)2,400 (5,300)
16 (58)3,770 (8,300)
20 (34)4,940 (10,900)
22 (78)7,300 (16,100)
25 (1)9,480 (20,900)
 

Manila Rope

Diameter mm (inches)WLL kg (pounds)
10 (38)90 (205)
11 (716)120 (265)
13 (12)150 (315)
16 (58)210 (465)
20 (34)290 (640)
25 (1)480 (1,050)
 

Polypropylene Fiber Rope WLL (3-Strand and 8-Strand Constructions)

Diameter mm (inches)WLL kg (pounds)
10 (38)180 (400)
11 (716)240 (525)
13 (12)280 (625)
16 (58)420 (925)
20 (34)580 (1,275)
25 (1)950 (2,100)
 

Polyester Fiber Rope WLL (3-Strand and 8-Strand Constructions)

Diameter mm (inches)WLL kg (pounds)
10 (38)250 (555)
11 (716)340 (750)
13 (12)440 (960)
16 (58)680 (1,500)
20 (34)850 (1,880)
25 (1)1,500 (3,300)
 

Nylon Rope

Diameter mm (inches)WLL kg (pounds)
10 (38)130 (278)
11 (716)190 (410)
13 (12)240 (525)
16 (58)420 (935)
20 (34)640 (1,420)
25 (1)1,140 (2,520)
 

Double Braided Nylon Rope

Diameter mm (inches)WLL kg (pounds)
10 (38)150 (336)
11 (716)230 (502)
13 (12)300 (655)
16 (58)510 (1,130)
20 (34)830 (1,840)
25 (1)1,470 (3,250)
 

Steel Strapping

Width × thickness mm (inches)WLL kg (pounds)
31.7 × .74 (114 × 0.029)540 (1,190)
31.7 × .79 (114 × 0.031)540 (1,190)
31.7 × .89 (114 × 0.035)540 (1,190)
31.7 × 1.12 (114 × 0.044)770 (1,690)
31.7 × 1.27 (114 × 0.05)770 (1,690)
31.7 × 1.5 (11× 0.057)870 (1,925)
50.8 × 1.12 (2 × 0.044)1,200 (2,650)
50.8 × 1.27 (2 × 0.05)1,200 (2,650)
 


Disclaimer:

Although we make every effort to assure that the information we provide is complete and accurate, it is not intended to take the place of published agency regulations. Regulations issued by the U.S. Department of Transportation and its Operating Administrations are published in the Federal Register and compiled in the U.S. Code of Federal Regulations (CFR). Copies of appropriate volumes of the CFR in book format may be purchased from the Superintendent of Documents, U.S. Government Printing Office, or examined at many libraries.

The CFR may also be viewed online at http://ECFR.gpoaccess.gov.