Adding vehicle rear seating systems

From an NTEA member What regulations do we need to consider when assessing requirements for adding rear seating to a cargo van to create a combination passenger/cargo vehicle? Adding occupant seating requires assessment of several Federal/Canada Motor Vehicle Safety Standards (F/CMVSSs). Along with seating and restraint requirements, there are other occupant safety standards that must be met, as well as effects due to the presence of more passengers. Seat additions will increase vehicle unloaded weight and designate occupant weight that must be accounted for in a thorough weight analysis. As an initial step, weight analysis results will aid in compliance determinations for many F/CMVSSs with weight-based compliance implications. “What is a seat?” is a common question in these situations. Regulations address it by defining a “designated seating position” (see definition at end of article). The definition expands into references for other requirements, including dimensional thresholds to be considered in S571.10 when a seating surface contains multiple seating positions. Seats/restraints F/CMVSS 207, 208, 209 and 210 should be part of an initial review when considering seat additions. F/CMVSS 208 will establish the form of restraint system the seat requires based on gross vehicle weight rating (GVWR), vehicle type and seating system orientation/position (forward/rearward/side-facing, outboard, etc.). Note, adding seats to the van would likely result in the vehicle type designation of multipurpose passenger vehicle, assuming total number of designated seating positions is no more than 10 (including the driver), even if the vehicle was originally completed as a truck by the OEM. F/CMVSS 209 contains requirements for the restraints, including webbing and attachment hardware. F/CMVSS 207 and 210 set performance requirements for seating and restraint system integrity, respectively, including anchorages to the vehicle structure. If you are not manufacturing your own seating systems, seek assistance from your seating and restraint supplier(s) for compliance with these standards for your particular vehicle application, as they may have equivalent test results. These F/CMVSSs apply to all vehicles, but other standards must be reviewed for vehicles with a GVWR of 10,000 pounds or less, such as most cargo vans. Although not an all-inclusive list, the following standards have occupant-related requirements. F/CMVSS 110: Tire Selection and Rims for Motor Vehicles with a GVWR of 4,536 Kilograms (10,000 Pounds) or Less. As well as accounting for additional passenger weight, the vehicle placard required by this standard lists total number of occupants and a separate breakout of front and rear. More information may be required for the owner’s guide. FMVSS 202a/CMVSS 202: Head Restraints. This standard sets performance requirements for head restraints that may be required for your seating system. F/CMVSS 205: Glazing Materials. This standard specifies requirements for materials used in windows. Windows added in conjunction with the seating systems will require compliance. F/CMVSS 206: Door Locks and Door Retention Components. This standard’s requirements “apply to all side and back doors, that lead directly into a compartment that contains one or more seating accommodations.” The additional seats may subject OEM doors to the requirements of the standard where previously not applicable, and OEM representations relative to the door systems will need to be reviewed. F/CMVSS 214: Side Impact Protection. This standard is composed of three different tests. Depending on van GVWR, the vehicle may be subject to all three. While each test has exclusions, the door crush resistance portion of the standard may be required with the addition of the seat — where the rear side door(s) of the original vehicle may not have been previously subject — and the specific door system may not have been designed and/or tested to meet these requirements. F/CMVSS 225: Child Restraint Anchorage Systems; CMVSS 210.1: User-Ready Tether Anchorages for Restraint Systems and Booster Seats; and CMVSS 210.2: Lower Universal Anchorage Systems for Restraint Systems and Booster Seats. Required accommodations for child seat anchorages are based on factors including number of seating locations, possibly requiring extra anchorages in added seats. F/CMVSS 226: Ejection Mitigation. This newer standard was established to “reduce the likelihood of complete and partial ejections of vehicle occupants through side windows during rollovers or side impact events.” The additional seating location and, potentially, window openings will likely necessitate more ejection target locations than required for the original vehicle. F/CMVSS 302: Flammability of Interior Materials. This standard applies to all motor vehicles with an occupant compartment, regardless of GVWR, to establish burn resistance requirements for interior materials, including those used in the additional seating systems. Given the volume of implications, working with your seating system supplier(s) and reviewing incomplete vehicle documents, body builder information and other OEM materials are critical components in evaluating vehicle modifications as well as determining necessary testing and which requirements may be covered by prior testing and/or other compliance rationale. Definition Designated seating position means: “(2) For vehicles manufactured on and after September 1, 2011, designated seating position means a seat location that has a seating surface width, as described in §571.10(c) of this part, of at least 330 mm (13 inches). The number of designated seating positions at a seat location is determined according to the procedure set forth in §571.10(b) of this part. However, for trucks and multipurpose passenger vehicles with a gross vehicle weight rating greater than 10,000 lbs, police vehicles as defined in S7 of FMVSS No. 208, firefighting vehicles, ambulances, and motor homes, a seating location that is labeled in accordance with S4.4 of FMVSS No. 207 will not be considered a designated seating position. For the sole purpose of determining the classification of any vehicle sold or introduced into interstate commerce for purposes that include carrying students to and from school or related events, any location in such a vehicle intended for securement of an occupied wheelchair during vehicle operation is regarded as four designated seating positions.”

Adding vehicle rear seating systems

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