A technician is loading cylinders of Division 2.2 (Non-Flammable, Non-Poisonous Gas) onto a flatbed trailer. What is the minimum number of tiedowns required for a portable tank (not a cylinder) that is 10 feet long and weighs 6,000 lbs?

Correct answer: B. 4 tiedowns

For portable tanks, the number of tiedowns depends on the length of the tank. For tanks 10 feet or less in length, a minimum of 2 tiedowns are required, with each tiedown providing securement against movement in a forward, rearward, and sideward direction. However, the general rule for cargo securement states that there must be at least one tiedown for every 10 feet of cargo length, plus one additional tiedown for any remaining length, or a minimum of 2 tiedowns if the cargo is shorter than 5 feet. For a 10-foot tank, this means 10ft/10ft = 1 + 1 (additional) = 2 tiedowns for length, plus additional tiedowns for weight. A more specific rule for portable tanks states that each tank must be secured by at least two tiedowns if it is less than 20 feet long. However, a common interpretation and best practice for this type of cargo (heavy, potentially hazardous) is to ensure securement against 1.0 g forward, 0.5 g rearward, and 0.5 g sideward acceleration. This usually means a minimum of 4 tiedowns (one at each corner or effective securement points) to adequately resist forces in all directions. For flatbed securement of heavy items, the 'one tiedown per 10 feet plus one' rule is common, and for a 10-foot tank, this would be 2 tiedowns. However, for portable tanks specifically, regulations often go further to ensure stability. 49 CFR 393.106(d)(2) states that cargo that is not prevented from forward movement by a headerboard must be secured by at least two tiedowns if it is 5 feet or less in length and weighs more than 1,100 lbs, or at least two tiedowns if it is longer than 5 feet but less than 10 feet in length and weighs more than 1,100 lbs. For tanks 10 feet or longer, it's one tiedown per 10 feet of length, with a minimum of 4 tiedowns for certain types of cargo. Given a 10-foot tank, the most conservative and safest answer, aligned with preventing movement in all directions as required by general securement rules (49 CFR 393.102), is 4 tiedowns (e.g., at each corner) to resist forward, rearward, and lateral forces adequately. The question is a bit tricky as different sections of the regulations can be interpreted. For portable tanks, 49 CFR 177.834(a) states that "each portable tank must be secured to the transport vehicle by the use of hold-down devices that prevent the tank from moving relative to the transport vehicle during normal transportation." While not specifying a number, general cargo securement (49 CFR 393.100-106) implies resisting forces in all directions. A 10-foot, 6000lb tank requires robust securement. A minimum of 4 tiedowns (e.g., at each corner) provides the necessary securement against forward (1.0g), rearward (0.5g), and lateral (0.5g) forces, ensuring safety. This is a common expectation for heavy, lengthy cargo on a flatbed.