CONTAINER CONSTRUCTION AND INSPECTION
15-1. INTRODUCTION. In order to inspect containers, cargo handlers must first be familiar with the many different types and their construction. They must also know the kinds of structural damage that would cause the container to be rejected during an inspection.
a. The closed-top, dry cargo container comprises the majority of the container fleet. It is made of steel, aluminum, plywood, plastic, fiberglass, or a combination of these materials. This container has hinged rear doors for stowing and unstowing cargo. Cargo is normally palletized or unitized.
(1) Steel container. Dry cargo type containers can be 20, 30, or 40 feet long by 8, 8 1/2, or 9 feet high. The 20- and 30-foot long containers often have forklift pockets; the 40-foot long container is not provided with forklift pockets. A typical steel container is made of corrugated sheet steel walls that are welded to the main structural top and bottom side rails and end frames that are of fabricated or shaped steel sections (Figure 15-1). The end frames have fittings (steel castings) at all eight corners that are usually welded to the four corner posts, top and bottom side and front rails, and rear doorsill and header. The roof can be flat or corrugated sheet steel welded to the top side and end rails and door header; it may have interior roof bows for support. The doors are usually plymetal (steel-faced wood) panels fitted with locking and antirack hardware and weatherproof seals. The floor may be soft or hard laminated wood, planking, or plywood either screwed or bolted to the cross members.
(2) Aluminum container. A typical aluminum container often referred to as aluminum/steel container usually has steel end frames, and steel-shaped or extruded aluminum side rails (Figure 15-2). The walls can be built of aluminum interior or exterior intermediate posts covered with sheet aluminum that is normally riveted to the posts. The inside walls have a plywood liner riveted to the intermediate posts. The nominal dimensions and many construction details are similar to those of steel containers. Roof bows, which support the aluminum roof panel, are aluminum extrusions that are bolted, riveted, or welded to the top rails. Cross members of shapes indicated for steel containers are either steel or aluminum that are bolted, riveted, or welded to bottom side rails.
Figure 15-2. Exploded view of a typical aluminum container
(3) FRP container. A typical FRP container is constructed of steel framing having FRP panels on the side walls, front-end wall, and roof. Normally, there are no roof bows used to support the roof panel. These panels are usually imbedded in a mastic, to provide watertightness, and are riveted to the top and bottom rails and the corner posts. The door panels are of FRP and provided with steel locking and antirack hardware and waterproof seals. The floor cross members can be box, C, Z, or I-beam sections. The floor may be of soft or hard laminated woods, planks, or plywood that is screwed or bolted to the cross members. The nominal dimensions and many construction details are similar to those of the steel container.
b. The open-top (bulk), dry cargo container (covered by a tarpaulin when loaded) is built like the closed-tip container except it may also be stowed or unstowed through the top. Cargo normally has physical characteristics which can be more efficiently stowed through the top of the container than through the door. Examples include heavy machinery, bulk grain, cement, fertilizer, and long lengths of pipe or lumber.
c. The flatrack container is essentially a platform with corner posts. It has a floor bed with front and back ends or posts but no side walls or roof. The corner posts or ends are collapsible, reducing shipping space when shipping empty flatracks. This container is useful for unit moves because it can handle equipment and vehicles that are too wide for an 8-foot wide container but which will fit in to selected container cells. Some flatracks are half height (4 feet high).
d. The refrigerated container is insulated with a refrigeration unit mounted internally or externally. This container normally has both refrigeration and heating ability. It has the same general construction as the closed-top container although capacity is reduced to accommodate insulation and the need for air circulation around or within the load. Cargo includes frozen foods, fresh produce, medical supplies, electronic equipment, and other items requiring stabilization of temperatures.
e. The insulated/ventilated container is an insulated container without a refrigeration unit, designed to prevent wide temperature variance within the container by permitting fresh air to circulate around the cargo. In extremely cold areas, a heating element prevents freezing of cargo.
f. The bulk liquid container is normally made of stainless steel insulated with fiberglass. The container shell is equipped with either a single or twin barrel with a 20-inch full-opening manhole for each barrel. It has a discharge valve at the rear and a heat panel for reheating contents. It accommodates liquid cargo or cargo capable of being liquified by heating. This container comes in varying capacities up to 5,000 US gallons.
15-3. CONDUCTING A CONTAINER ACCEPTANCE INSPECTION. When inspecting commercial containers, make every effort to conduct the inspection in the presence of the lessor or the owner's representative. This requirement does not apply to MILVAN.
a. Container Inspection Report. Cargo handlers fill out a container inspection report as the inspection progresses. These reports are made according to locally designed formats as there is no government-produced form for this purpose. Each report indicates the acceptance or reasons for rejecting a container.
NOTE: To hold the inspection time of a container to a minimum, once sufficient damage has been identified to cause rejection of the container, the inspection will stop.
- Holes, tears, and fractures.
- Any cracked or suspect welds in steel instruction.
- Loose or missing fasteners in aluminum construction.
- Dents or bends on any surface of the main structural members of 3/4 inch (19 millimeters) or greater in depth, regardless of length.
- Improper splices.
- More than two splices per bottom side rail or topside rail.
- More than one splice in bottom end rail or door header.
- Any splice in the doorsill.
- Corrosive failure.
- Broken or improper operation of the door locking rods, locking cams, handles, handle retainers, locking bar mounting brackets, hinges, or documentation holders.
- Missing or broken hinge pin or hinge pin weld.
- Missing or loose fasteners or brackets.
- Torn, leaking, distorted, or improperly spliced door seals (gaskets).
- Door panel having holes or improper repair.
- Door header or doorsill that is distorted, cut, or torn which would prevent watertight sealing of the doors.
- Crushed seal or broken, loose, or missing cam retainers.
- Corrosive failure of any part or major damage to rain gutter.
b. Rejection Criteria. Inspect the primary structure for major defects in the main structural members (top and bottom side rails, top and bottom end rails, doorsill and header, corner posts and corner fittings) which affect the structural integrity of the container. Look for-
c. Rejection Criteria for the Rear End and Door Assembly. When inspecting the rear end and door assembly, look for-
Figure 15-3 shows a damaged rear end frame and Figure 15-4 shows a damaged door assembly. Any one of the defects shown is reason for rejection.
Figure 15-3. Defects of rear end frame causing
Figure 15-4. Damaged rear end and door assembly
d. Container Inspection Steps. Providing the rear end of the container is acceptable, enter the container. Close the door and inspect for light penetration; then inspect the interior for damage to the floor. Look for stains from any substance which may damage cargo. Make sure there are no breaks, splits, or open joints in the boards where water may come through. Also make sure that boards are not rotted, splintered, or warped. Fasteners should be secure and free of corrosion. Also inspect the roof, roof bows (Figure 15-5), door, door seals, threshold plate, and interior walls.
(1) In MILVANs that are provided with an internal restraint system, inspect the slots in horizontal and vertical rails to ensure that they are not damaged, and that the locking mechanisms on the end of the load bracing cross beams are operational. Inspect to see that these beams have not been bent, crushed, or bowed (Figure 15-6).
(2) With no apparent damage to the interior, inspect the outside of the container: curb side, front end, then roadside. Inspect for damage to the top and bottom side rails, top and bottom rail ends, forklift pockets, corner posts and fittings, wall panels, repairs, markings, and data plates. Also, check for corrosion. Figure 15-7, shows forklift pocket damage.
Figure 15-5. Unacceptable interior roof damage
Figure 15-6. MILVAN-cargo restraint system
- Stenciled markings not indicating a gross weight of 44,800 pounds (20,320 kilograms) for a 20-foot container.
- Missing TIR approval/plate.
- Manufacturer's data plate missing or illegible.
- International CSC plate illegible, not indicating a maximum gross weight of 44,800 pounds (20,320 kilograms) for 20-foot container, or not showing a current inspection date.
e. Markings. These are numbers, symbols, and letters that identify the owner of the container, and the tare and gross weight of the container in kilograms and pounds. These markings should be located on both ends and sides of the container. Discrepancies on marking and data plates include-
Any discrepancies or omissions in these markings justify rejecting the container.
Figure 15-7. Examples of forklift pocket damage
(1) The TIR plate/marking shows approval for intermodal transport under regulations of foreign customs authorities for movement of containers across international borders.
(2) The manufacturer's data plate identifies container design.
(3) The International CSC plate indicates that the container is structurally safe.
f. Roofing Check. Inspect for holes, damage to corner fittings apertures (openings), and damage to reinforcement plates, topside rails, top end rail, door header, and roof panel. Also inspect for corrosion (Figure 15-8).
g. Understructure Inspection. Inspect for damage to the side and end rails, sill, and cross members (Figures 15-9 through 15-11). Also check for loose or missing floor fasteners, cracked or suspect welds, loose or missing bracket fasteners, and excessive corrosion.
h. Inspection Completion. Complete and sign the container inspection report when inspection is finished. This inspection procedure is designed to give you an acceptable sequence and a guide as to what to look for, and determine what is or is not acceptable. Many of your decisions for acceptance or rejection may be based on your own judgment. But at all times, inspect the container to protect the best interests of the government.
Figure 15-8. Examples of roof damage
Figure 15-9. Examples of cross member damage
Figure 15-10. Cross member damage requiring replacement
Figure 15-11. Cross member damage not requiring replacement
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