Interpretation ID: nht80-3.22

DATE: 07/23/80

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Toyo Kogyo USA Office

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your recent letter asking questions concerning the strength and location requirements under Safety Standard No. 210 for anchorages used with automatic seat belt systems.

Your first question asked about the force loads required for testing anchorages for a Type 1 lap belt (manual belt) and for testing a single diagonal automatic belt, when the two belts are used in conjunction with one another as part of a total system. The agency has stated in the past that the anchorages for a single diagonal automatic belt should be tested with a 3,000-pound force for purposes of Safety Standard No. 210, in accordance with the test procedures of paragraph S5.2. This is the same force that is required for testing the upper torso portion of a Type 2 seat belt system. This force requirement is applicable whether the single diagonal automatic belt is used alone or whether it is used in conjunction with an manual lap belt. The anchorages for the manual lap belt, however, would be required to withstand test forces of 5,000 pounds under paragraph S4.2.1 of Standard No. 210, not 3,000 pounds as indicated in your letter. The anchorages for the manual lap belt and for the automatic belt must separately meet their respective force requirements and would not have to be tested simultaneously since they are separate systems.

In your second question, you asked about the number of anchorages that are required for various combinations of systems. Paragraph S4.1.1 of Safety Standard No. 210 requires anchorages for a Type 2 seat belt assembly to be installed for each forward-facing outboard designated seating position in passenger cars. This is true regardless of whether the seating position is equipped with an air bag and a lap belt, with a single diagonal automatic belt or with any other system. Safety Standard No. 210 is independent of Safety Standard No. 208, Occupant Crash Protection. Thus, in your hypothetical designated "A", case "A-2" is correct. Three anchorage points are required by Safety Standard No. 210, even though Safety Standard No. 208 only requires that a lap belt be installed. The presence of the Type 2 anchorages in vehicles will allow vehicle owners to install easily Type 2 belts at their own initiative if they desire to do so for whatever reason. For example, if a single diagonal automatic belt system has been damaged, an owner may wish to replace it with a Type 2 manual belt system.

Under paragraph S4.3 of Safety Standard No. 210, anchorages for automatic belts are exempted from the location requirements of the standard. This exception was provided for in the standard to allow manufacturers to experiment with various automatic belt designs to determine the optimum anchorage locations in terms of both effectiveness and comfort (43 FR 53440, Nov. 16, 1978). If, however, the anchorage points for an automatic belt do not fall within the locations specified in the standard for Type 2 belts, the manufacturer would have to provide additional anchorage points that could be used by a properly located Type 2 manual belt.

In response to your hypothetical question deignated "B", case "B-b-1" would not comply with the requirement for Type 2 anchorages since there are only two points. Case "B-b-2" would comply if all three anchorages points comply with the location requirements of the standard for Type 2 belts. Case "B-b-3" would require five anchorage points if points "1" and "2" could not qualify as properly located points of a Type 2 anchorage system.

In your question designated "B-C", cases "B-C-1", "B-C-2" and "B-C-3" would all comply with Safety Standard No. 210 if all points indicated in each example are within the locations specified for Type 2 anchorages. In case "B-C-4", the system would comply if point "1" is within the location specified in the standard for Type 2 belts, and point "4" would not be necessary if both points "1" and "2" are within the proper locations. All the anchorage points indicated in "B-C-5" are necessary if points "1" and "2" are not in the proper locations.

I hope this has been responsive to your inquiry. If you have any further questions, please contact Hugh Oates of my staff at 202-426-2992.

SINCERELY,

MAZDA

Toyo Kogyo U.S.A. Representative Office Detroit Branch

May 5, 1980

Chief Counsel National Highway Traffic Safety Administration

Dear Sir,

Subject: Question concerning the seat belt anchorages.

We have some questions concerning the strength and location of the seat belt anchorages which are used for the automatic seat belt system.

QUESTION 1 - The strength of the anchorages for automatic seat belt.

According to FMVSS No. 210, there is not a definition or a specification for the two point automatic seat belt which is called a diagonal belt. Our interpretation is shown below. We would like to know whether it is correct.

-Each belt is subjected to the load of 3000 lbs. simultaneously.

(Graphics Omitted)

Reason:

According to the current FMVSS No. 210, the 3 point seat belt system (Type 2) is required to withstand the load of 3000 lbs. for each lap and upper torso portion. In the case of the two point automatic seat belt, there are two ways to wear it. One manner is to wear it with the active lap belt, and the other is to wear it without the active lap belt.

When the seat belts are worn in the first manner, the load condition during an accident for each belt is nearly equal to the condition of the 3 point belt system.

Even if the seat belt is worn in the latter manner, the load for the diagonal seat belt is nearly the same compared to the upper torso portion of the 3 point belt system, because of the existance of the knee bolstor which is expected to support the load of the lower occupants body, and which has the same function of the active lap belt.

Therefore, we think the load condition of the anchorages for the two point seat belt system may be the same as the condition for the 3 point belt system.

QUESTION 2 - The location and the number of the anchorages for the automatic seat belt system.

According to the provision of FMVSS No. 210 Sec. 4.1.1, each forward facing outboard seating position in passenger cars is required to install the anchorages for type 2 seat belt assembly.

According to the provision of FMVSS No. 208, if we adopt the automatic belt system as the second option (Sec. 1.2.2) for the passive restraint system, we have to install the anchorages for the type 1 or type 2 seat belt. Although in this case, the location of the anchorage is exempt but the total number of the anchorages is not clear from the standpoint of No. 208, 209.

(A) When we adopt the air cushion restraint system how many anchorages are required?

Case A-1

2 lap anchorages for lap belt required by FMVSS 208 4.1.2.1.b2)

Case A-2

3 anchorages for type 2 required by FMVSS 210 4.3.

(Graphics omitted)

(B) When we adopt the 2 point automatic seat belt system, which is correct?

B-b 2 point automatic seat belt without active lap belt.

(Graphics omitted)

* Remarks

* - The anchorages marked this way, may or may not comply with the requirement of FMVSS 210 4.3.

* - The anchorages marked this way, must comply with the requirement of FMVSS 210 4.3.

(3)(4)(5) - are additional anchorages for the active type 2 seat belt required by FMVSS 210.

B-C 2 point automatic seat belt with active lap belt.

Case

(Graphics omitted)

* Remarks

The meanings of marks * and * are the same as B-b.

(4)(5) are additional anchorages for the active type 2 seat belt required by FMVSS 210.

M. Ogata Branch Manager Toyo Kogyo USA Office

cc: B. SMITH -- OFC. OF VEHICLE STANDARDS CRASHWORTHINESS DIV.