All units must comply with Canadian Motor Vehicle Safety Standards (CMVSS) in Canada and Federal Motor Vehicle Safety Standards (FMVSS) in the USA.
The oldest method consists of a wood frame covered by a multi-piece outer aluminum skin, insulated and with wood panelling on the interior. This is held together by staples, nails, wood glue, and screws similar to an old truck camper. Stick and tin construction is a common term. During an incident, these units often come apart easily into hundreds of pieces and are not repairable.
Other MTC’s are made from pre-manufactured fiberglass panels with fiberglass on the exterior, Styrofoam or other core insulation center, and are finished with wood panelling on the interior similar to recreational vehicle construction with many meters of corner, edge and top joints. These tend to burst apart at the seams upon impact.
The strongest and most durable units are manufactured from a composite fiberglass mold with rounded corners. This combines massive integral strength and reinforcing. These units have two-piece construction, a molded top and bottom, joined with methacrylate adhesive “space age bonding”. This is very much the same as a molded fiberglass boat. During an incident, they have the inherent capability to stay together extremely well and are easily repairable. Another important note is that fiberglass reinforced plastic (FRP) increases up to 50% in strength when temperatures are below freezing.
In summary, MTCs made in many parts will be less durable and more prone to failure. Total failure is a risk to patients and attendants that no employer should take. It is a not a unit to be relied upon in an emergency. Off road durability is where MTCs are deployed. Let the MTC construction fit the conditions. Dust and moisture will penetrate joints and seams more readily. The fewer parts and pieces, the better. MTCs have to endure very challenging rescues/patient events in the most difficult conditions such as in remote terrain at night and in a snow storm. A well-constructed MTC will do the job safely and come through when it really counts.