Mr. Jeff Kennedy
Four Winds International
701 C.R. 15
Elkhart, IN 46516
Dear Mr. Kennedy:
This is in response to your letter dated March 3, 2003, in which you asked about the strength requirements applicable to Type 2 and Type 2a seat belt assemblies installed in the driver and front passenger seat locations. As explained below, Type 2a belts are generally prohibited, however, your understanding of the strength requirements for Type 2 belts appears correct.
In your letter you stated that you are developing upgrades for the new models of your recreational vehicles and plan on using a "Type 2 or Type 2a seat belt assembly at the driver seat and front passenger seat locations." You stated that Federal Motor Vehicle Safety Standard (FMVSS) No. 210, Seat belt assembly anchorages, "does not appear to list any strength requirements for the anchorages used to locate the upper torso restraint [of a Type 2a seat belt]." You further stated that you understood that the "anchorages, attachment hardware, and attachment bolts" for both the lap and shoulder portions of Type 2 seat belt assemblies are subject to the strength requirements of S4.2.2(b) of FMVSS No. 210.
Generally, installation of Type 2a shoulder belts is prohibited. FMVSS No. 209, Seat belt assemblies, defines a Type 2a shoulder belt as "an upper torso restraint for use only in conjunction with a lap belt as a Type 2 seat belt assembly."The agency has determined that the integrated assemblies of Type 2 seat belts are safer than the Type 2a shoulder belts. Original equipment Type 2a shoulder belts may only be used at the driver seating position of vehicles intended to accommodate a wheel chair.(59 Federal Register 25826; May 18, 1994.) Since a Type 2a shoulder belt may not be used as you had intended, there is no need to further address your question regarding the strength requirements applicable to these types of belts.
Your understanding of the strength requirements for Type 2 seat belt assemblies is correct. Under S4.2.2, the anchorages, attachment hardware, and attachment bolts for Type 2 seat belt assemblies shall:
[W]ithstand a 3,000 pound force applied to the lap belt portion of the seat belt assembly simultaneously with a 3,000 pound force applied to the shoulder belt portion of the seat belt assembly, when tested in accordance with S5.2 of this standard.
S5.2 establishes the positioning, force, and duration requirements for testing Type 2 seat belt assemblies under S4.2.2.
I hope you find this information helpful.If you have any further questions please call Mr. Chris Calamita of my staff at (202) 366-2992.
CC: NCC-110 Subj/Chron, Redbook (2), interp. stds. 208, 210