I85PREP
⌘ K
Colorado CDL Hazmat study materials
Colorado CDL Hazmat study resources

Colorado CDL Hazmat: Segregation and securement

Colorado CDL Hazmat · Work through your exam, one topic at a time.

All guide sections

Segregation and securement

This domain tests how to keep incompatible hazardous materials apart and how to secure packages so they cannot move in transit. The segregation table in 49 CFR 177.848 is the core rule; the cargo securement rules in 49 CFR 393.100–393.136 supply the performance standard.

Reading the segregation table

  • The table uses X and O. X means the materials may not be loaded together in the same vehicle. O means they must be separated by at least 2 feet or by a barrier.
  • A blank cell means no general segregation requirement, but you still must prevent leaks from contacting other packages.
  • Special rules apply: cyanides must not be loaded with acids; Division 6.1 PG I and Division 2.3 materials must not be loaded with foodstuffs; explosives have their own compatibility groups.

Securement

  • Cargo must be secured against shifting, sliding, and tipping. The usual performance criteria are 0.8 g deceleration forward, 0.5 g rearward, and 0.5 g laterally.
  • Use load bars, straps, dunnage, blocking, and bracing. Do not use the rear doors as the only restraint; doors are not a load-bearing wall.
  • Check the load after the first few miles and after any hard braking or evasive action.

Worked example

A driver is offered 1,000 pounds of a Division 5.1 oxidizer and 800 pounds of a Class 3 flammable liquid. The segregation table marks Class 3 and Class 5.1 as X, so the two may not be loaded together in the same vehicle; the driver must split the load or leave one material behind. If the table had shown O, the driver could load both only with at least 2 feet of separation or a barrier. For securement, drums must be blocked and braced so they cannot slide into the doors; a 0.8 g forward deceleration can generate enough force to break through an unbraced door.

Traps

Assuming separate packages equal segregation is wrong; X prohibits mixed loading. Ignoring O separation and relying on packaging alone loses marks. Using only straps over smooth drums without blocking can allow shifting. Do not load foodstuffs with toxic or poisonous materials.