ID: nht76-1.9

DATE: 08/09/76

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Clayton Dewardre Company Limited

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Clayton Dewandre Company's May 20, 1976, request for confirmation that its "Dual Brake Booster" system is designed to conform to the definition of "split service brake system" and the requirements of S5.1.2 and S5.1.3 specified in Standard No. 105-75, Hydraulic Brake Systems. In unimpaired braking, the Dual Brake Booster system supplies two separate brake circuits, the primary circuit which is initially powered by the driver's application of pedal force and subsequently supplemented by pressurized fluid from the pump accumulator system, and the secondary circuit which is powered by pressurized fluid from the pump accumulator system. In the event of a primary circuit failure, a mechanical connection unimpaired by a loss of reservior fluid continues to modulate the secondary circuit. In the event of the a secondary circuit failure, the driver's pedal application continues to actuate the primary circuit by muscular effort alone. A single master cylinder reservoir is provided to supply the primary circuit. A single pump reservoir supplies the pump, accumulator, and secondary circuit.

As you are no doubt aware, the National Traffic and Motor Vehicle Safety Act does not authorize a "type approval" of vehicle design as the basis for certification (15 U.S.C. @ 1397(a)(1)(A)). Our comments on the description of your system do not relieve the vehicle manufacturer of its responsibility to design a system for each of its products that actually complies with the standard's requirements.

From your description of the system, it would appear to qualify as a "split service brake system" as that term is defined in S4 of the standard. You state that, in the event either subsystem is failed, the other subsystem is capable of indefinite operation. This conforms to the

2

NHTSA's September 14, 1973, letter to Citroen on the meaning of "unimpaired operation" of a subsystem.

With regard to partial failure performance, you state that the vehicle can meet the requirements of S5.1.2 (inadvertently designated as S5.1.1 in your letter) using either of the two subsystems.

With regard to the requirements of S5.1.3 (for inoperative brake power assist unit or brake power unit), you indicate that the vehicle is capable of stopping within the specified distances of column IV of Table II "purely by muscular effort of the driver". By this we assume you mean that the vehicle conforms to the condition required for testing under S5.1.3.1, i.e., with one power unit inoperative and deleted of all reserve capability. Please note that the NHTSA regards the "pump and accumulator" energy source to constitute a "brake power unit" and not a "brake power assist unit", because the described unit "provides the energy required to actuate the brakes, either directly or indirectly through the auxiliary device, with the operator action consisting only of modulating the energy application level." (S4 definition of "brake power unit").

We are assuming that Clayton Dewandre does not object to making public the designs described in your May 20 letter. The NHTSA will place the materials in the public docket three weeks after the date of this letter unless we hear otherwise from you.

Yours truly,

ATTACH.

Clayton Dewandre Company Limited

May 20, 1976

James B. Gregory -- Administrator, National Highway Traffic Safety Administration, U.S. Department of Transportation

Dear Sir,

Request for advice on the conformities of New Design equipment to the revised Hydraulic Brake System Standard FMVSS 105-75

Clayton Dewandre would like to take this opportunity to introduce to you our newly developed Hydraulic Brake Booster and associated system, (Illegible Word) on behalf of our potential customers, we seek clarification from you regarding its compliance with the revised Hydraulic Brake Standard FMVSS 105-75.

We would refer to section S4 and the definition of a "Split Service Brake System" which includes a statement that a failed sub-system, quote "shall not impair the operation of any other sub-system".

Our interpretation of the expression "impair" is "reduce (Illegible Word) prescribed effective level", and that same implied level is quantified under requirements S.5.1.1. Partial Failure and S.5.1.3. In-operative Brake Power Assist Unit. Both the latter clauses call for the same level of performance i.e. stopping distances from a vehicle speed of 60 m.p.h. without exceeding a pedal force of 150 lbs. Vehicle Cars Trucks<10000 lbs. trucks>10000 lbs. Stopping 456' 517' 613' distance (.263g) (.233g) (.195g)

We would like to show, with reference to the attached description of the Dual Brake Booster, that with a power failed situation or rear brakes failed, we have the same residual secondary braking i.e. the front brakes, being activated purely by muscular effort of the driver, with chamber (a) acting as a conventional master cylinder. The designed performance for this condition in the case of a 2000 Kg (4,400 lbs) gross weight vehicle would be .3g for a pedal force 71 lbs (316N). This meets the prescribed performance tabled above.

Should a failure occur in the other sub-system (Illegible Words) mechanically by further movement of the pedal (approximately 12 mm.) for full output to "knee point". Fluid under pressure is delivered by the valve in proportion to pedal effort. Again in this case, the system is tuned to provide an acceptable performance. The attached figures show a retardation of .3g for 52 lbs (231N) pedal force, which is well within the prescribed limits.

2

(Illegible Text)

Yours faithfully,

W. M. PAGE -- Senior Engineer - Systems Engineering

[Attachments Omitted.]

ID: nht76-2.1

DATE: 05/04/76

FROM: AUTHOR UNAVAILABLE; Mark Schwimmer; NHTSA

TO: FILE

TITLE: FMVSS INTERPRETATION

TEXT: SUBJECT: TELEPHONE CONVERSATION CONCERNING STANDARD NO. 120, TIRE SELECTION AND RIMS FOR MOTOR VEHICLES OTHER THAN PASSENGER CARS

On April 20, 1976, I received a telephone call from Mr. John McCuen, an attorney for Kelsey-Hayes (313 941-2000). He asked the following questions concerning Federal Motor Vehicle Safety Standard No. 120:

1. "Is use of the 'DOT' symbol permitted on rims manufactured before the August 1, 1976, effective date for the standard's rim marking requirements?" I replied that the agency's present position is as it has been in the past, namely, that such use is not permitted. I added that this interpretation is being reevaluated.

2. "Some rims are capable of being used on passenger cars as well as on multipurpose passenger vehicles. Is it permissible to label such rims pursuant to Standard No. 120, even though some might then be mounted on passenger cars?" I requested that Mr. McCuen send in a request for a written interpretation of that aspect of the standard.

3. "May rims manufactured before August 1, 1976, be sold in the replacement market after that date?" I replied that they may.

ID: nht76-2.10

DATE: 09/02/76

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Blue Bird Body Company

COPYEE: TRUCK BODY AND EQUIP. ASSOC.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Blue Bird Body Company's July 20, 1976, question whether the NHTSA's redefinition of "school bus" (40 FR 60033, December 31, 1975) includes buses designed for intercity transportation utilized in charter operation to transport school children to and from school or related events, and what constitutes "interstate commerce" as that term is used in the redefinition. A second July 20, 1976, letter from Blue Bird Body requests reconsideration of two NHTSA interpretations of Standard No. 221, School Bus Body Joint Strength, that were issued in an April 26, 1976, letter.

The redefinition of school bus (effective April 1, 1977) states:

"School bus" means a bus that is sold, or introduced in interstate commerce, for purposes that include carrying students to and from school or related events, but does not include a bus designed and sold for operation as a common carrier in urban transportation.

The definition is not intended to include intercity type buses on regular common-carrier routes, although they may be used in some circumstances to transport school students to and from school or related events. This bus type has never been considered a school bus under existing motor vehicle safety standards or Pupil Transportation Standard No. 17 (43 CFR 1204). In light of the major standard-setting activity undertaken by Congress for school buses under the Motor Vehicle and Schoolbus Safety Amendments of 1974 (the Act) (15 UVS.C. @ 1392(i), it is unlikely that such a board change of regulatory direction would be contemplated by Congress without explicit discussion in the legislative history. The boundaries of coverage of the redefinition are explicitly left by the statute to agency determination, and the agency did not include the intercity buses you describe in the redefinition.

The meaning "interstate commerce" in the redefinition is the same as for that term in @ 108(a)(1)(A) of the Act, which states that no person shall "manufacture for sale, sell, offer for sale, or introduce or deliver for introduction in interstate commerce, or import" non-complying vehicles. While the legislative history of the Act does not directly address the meaning of the term, the House of Representatives Committee Report stated:

. . . The purpose of this section is to prohibit the manufacture, sale, or importation into this country of vehicles . . . that fail to meet the Federal safety standards . . . (H.R. Rep. No. 1776, 89th Cong., 2d Sess 22 (1966))

The agency adopts the existing construction of the term set forth in Katzenback v. McClurg, 379 U.S. 294 (1974). To answer your specific question, however, it should be clarified that only the classification of the bus as a school bus is determined by the ambit of "interstate commerce" in those infrequent cases where a sale does not occur. Blue Bird Body's responsibilities to conform to the standards arise directly from its manufacturing activities under @ 108(a)(1)(A). For example, a bus built in Georgia must conform to the school bus standards if it is sold to a Georgia school for use in transportation of school students, even if it never leaves the State.

Your second July 20 letter requests reconsideration of the NHTSA's April 26, 1976, decision that the area of contact between headlining panels and the "header" over the windows qualifies as a body joint subject to the requirements of the standard. You assert that the area of contact is not such a joint because it is covered by a molding and therefore does not "enclose occupant space" and cannot be considered a "surface component".

"Body panel joint" is defined in the standard to mean, with several exceptions, the area of contact or close proximity between the edges of a body panel and another body component. Whether or not the joint itself is covered is not relevant to its status. The separate definition of "body panel" does refer to the surface of the exterior or interior of the bus and to use of the panel in enclosing the bus occupant space. Thus, it is the body panel and not the joint which must form part of the exterior or interior surface of the bus. In the case you describe, the head-lining panel does enclose the bus occupant space and constitutes a part of the interior surface of the bus. Thus it does form a "body panel joint" at the point of contact with the header (a separate body component).

You also suggest that the requirements do not apply to a joint where the edges of the body panel join a body component at a point other than at the edge of the body component. Your interpretation is incorrect. In the case you describe, the floor panel's edges form a right angle that is attached to a central portion of the tag panel at some distance from its edges. The definition of "body panel joint" refers to contact between the edges of the body panel and another body component, without regard to the proximity of the edges of the body component.

You also request confirmation that a statement on rubrails in our April 26 letter is fulfilled by ensuring that, in testing a complex joint to which rubrails are fastened, the rubrails are modified so that they are not held by the gripping fixture of the tensile strength test machine. Your interpretation is correct.

In a related matter, the NHTSA would like to advise you of failure in our April 26, 1976, letter to respond fully to Blue Bird Body Company's February 13, 1976, letter. You asked if the cove molding that is attached at the border of the bus body floor against the sidewall of the bus body would qualify as a surface component whose edges form a joint subject to the standard's requirements. From your description of the cove molding and its use at the edge of the floor, the agency considers that it does not have a function in enclosing the occupant space and is therefore not considered a body component for purposes of the requirements. A copy of your illustration of this component is attached for the benefit of interested persons.

Finally, I would like to acknowledge receipt of your July 28, 1976, letter to the Administrator, asking that the new definition of "school bus" become effective on April 1, 1977, instead of October 27, 1976. Your request has been granted by a recent notice of rulemaking.

YOURS TRULY,

BLUE BIRD BODY COMPANY

July 28, 1976

John Snow, Administrator National Highway Traffic Safety Administration

The Motor Vehicle and School Bus Safety Amendments of 1974, Public Law 93-492, precipitated a number of Federal Motor Vehicle Safety Standards as well as an amended definition of a school bus (Section 201). We have noted that Public Law 94-346 has changed the effective dates of the new standards from October 26, 1976 to April 1, 1977, but apparently the school bus definition remains effective October 26, 1976. We believe that this must be an oversight and probably wouldn't achieve the uniformity of a consistent change that you would desire. We do feel that this difference in dates will cause confusion and hardship. Therefore, we request that the new school bus definition also be changed to be effective April 1, 1977.

Thanks for your consideration in this matter.

W. G. Milby Staff Engineer

C: BYRON CROMPTON; TBEA

BLUE BIRD BODY COMPANY

July 20, 1976

Thomas W. Herlihy National Highway Traffic Safety Administration

The purpose of this letter is to clarify certain questions pertaining to definition of a school bus which becomes effective October 27, 1976.

First, we would like to know exactly what constitutes "Interstate Commerce" as it is used in the school bus definition. The question has been raised: do the new school bus standards only apply to buses which cross state lines while transporting students?

Another question relates to the scope of the exception clause which states that a school bus . . . "does not include a bus designed and sold for operation as a common carrier in urban transportation." Are we correct in assuming that this exception does not extend to Greyhound or Trailways type buses which are chartered for the purpose of ". . . .carrying students to and from school . . . related events. . . ."?

Thank you for your early reply to these important questions.

W. G. Milby Staff Engineer

BLUE BIRD BODY COMPANY July 20, 1976

Thomas W. Herlihy National Highway Traffic Safety Administration

REFERENCE: 1. Letter W. G. Milby to R. B. Dyson, dated 2-13-76

2. Letter Frank Berndt to W. G. Milby, dated 4-26-76; N40-30

The purpose of this letter is to question several of the interpretations NHTSA has given us in reference 2 regarding FMVSS 221.

Item 4, page 2 of reference 1 pertains to the area where the header and headlining come in contact. As explained in reference 1, this area of contact is completely covered and, therefore, isolated from the bus occupant space by the wire molding. In reference 2 NHTSA said "the terms which establish the applicability of the requirements of the standard to a particular section of a school bus body are defined in S4 of the standard. Read together they establish the following test. If the edge of the surface component (made of homogeneous material) in a bus that encloses the bus' occupant space comes into contact or close proximity with another body component the requirements of S5 apply. . .".

In our opinion the area of contact between the header and headlining does not meet this criteria for two reasons:

1. Because it is completely enclosed by the wire molding, it cannot be construed to be "a surface component".

2. Also because it is covered by the wire molding it does not "enclose the bus occupant space".

Therefore, we would ask NHTSA to reconsider its interpretation given to us in reference 2 and rule that the area of contact between the header and headlining is not a joint which must meet the requirements of S5.

Item 15, page 5 of reference 1 pertains to the area of contact between the tag panel and the floor. In our opinion this does not meet the criteria required for a joint because the area of contact between the tag panel and the floor is several inches from the edge of the tag panel. This fact was overlooked in the preparation of reference 1. Hence in reference 2 NHTSA ruled that this would be a joint subject to the requirements of S5. Since the area of contact is several inches from the tag panel, we are proceeding on this not being a joint. I am including it in this letter merely to document the reason for our not considering it to be a joint after having received the interpretation given in reference 2 which was based on incomplete information.

In reference 2 NHTSA ruled that rubrails ". . . are not themselves considered to have a function in enclosing the occupant space and, therefore, are not considered body components for purposes of the requirements. For purposes of testing the complex joints to which they are fastened, they should be modified as necessary to prevent them from affecting testing of the underlying joint." In the many hundreds of joint tests we have run in preparation for compliance with FMVSS 221 we have come to the conclusion that it's virtually impossible to modify the rubrail in such a way that it does not have any effect on the underlying joint. We also feel that it is unrealistic to attempt to modify the rubrail so that it has no effect on the underlying joint. This is because that in order for the underlying joint to fail on a vehicle the rubrail must also fail. Therefore, in our testing of joints which include a rubrail we have modified them in such a way that the gripping fixture of the tensile testing machine only grips the panel portion of this specimen and in no way contacts the rubrail. In this way the tensile load is imparted wholly to the panel specimen. However, we cannot guarantee that the rubrail section has no effect on the underlying joint. We are confident that our testing method is more severe than any kind of loading that could even be imparted in an accident. Further we are confident that our testing method meets the full spirit of FMVSS 221. I include this discussion again simply to document our testing methodology and to indicate that we do not feel it is possible or reasonable to construct and test a sample joint in which the rubrail has no effect on the underlying joint.

Thank you for your consideration of the header to headlining and we look forward to your early reply.

W. G. Milby Staff Engineer

(Graphics omitted)

TOLERANCE ON ALL DIMENSIONS IS, PLUS (Illegible Word) OR MINUS (Illegible Word) UNLESS OTHERWISE SPECIFIED

INACTIVATES NOS.

REPLACED BY NOS.

RELEASED

BLUE BIRD BODY CO. FORT VALLEY, GEORGIA, U.S.A.

(Illegible Word)

COVE MOLDING TO FLOOR

(Illegible Words)

SIZE:

ID: nht76-2.11

DATE: 11/24/76

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Sheller-Globe Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Sheller-Globe Corporation's August 31, 1976, question whether 5 described intersections in a bus body qualify as "body panel joints" subject to the requirements of Standard No. 221, School Bus Body Joint Strength.

The windshield fence that you describe in section A of your letter connects the window glazing seal to the bus body and is considered to be a portion of the window by the NHTSA. Windows are excluded from the definition of "body panel joint" found in S4 of the standard. Therefore, the fence would be excluded from the requirements of the standard.

The "trim molding" described in section B of your letter constitutes a body panel that encloses occupant space. The fact that the trim is decorative does not place it within the exclusion of "spaces designed for ventilation or other functional purpose." Since the "trim molding" is a body panel and is connected to a body component, it creates a joint subject to the requirements of the standard. The fact that the molding, like every other part of the bus, has a function does not exclude it from the ambit of the joint requirement under the exception for "ventilation or other functional purpose."

In section C of your letter, your acknowledge that the joint where the skirt panel connects to the outside upper body panel falls within the ambit of the standard. You request an exception from the standard's requirements for this joint based upon a perceived lack of safety hazards resulting from failure of this joint in a crash situation.

To implement the Congressional mandate for school bus safety, the NHTSA drafted Standard No. 221 to cover all joints that are potentially dangerous in a crash situation. The agency adopted this broad coverage of joints to avoid the more piece-meal approach of analyzing each joint for possible safety problems, because it is impracticable to test every joint in every possible accident configuration. Therefore, since the joint you describe falls within the parameters of the standard, it must meet the requirements specified.

The joint described in section D of your letter where the vent eves connect to the outside roof panel is a joint within the definition of the standard. The outside roof panel is a "body panel" as defined in S4. The junction where a "body panel" connects to a "body component," the vent eves, constitutes a joint regulated by the standard.

With regard to section E of your letter, the NHTSA agrees that the joint where the outside and inside lower panels connect is within the scope of the standard. Whether or not the joint itself is covered by trim molding is not relevant to its status. It is still a joint within the definition of the standard and subject to all of the requirements therein.

I trust these interpretations fully answer your questions.

SINCERELY,

SHELLER-GLOBE CORPORATION Vehicle Planning and Development Center

August 31, 1976

Administrator National Highway Traffic Safety Administration

Reference: Federal Motor Vehicle Safety Standard 221 - School Bus Body Joint Efficiency

Sheller-Globe Corporation respectfully requests interpretation on whether or not certain junctions within the framed structure of the Superior School Bus Body are "joints" by definition, and whether or not these junctions are subject to the requirements of the above referenced Federal Motor Vehicle Safety Standard.

Attached you will find an isometric drawing provided for purposes of your locating the area where these junctions in question are located within the framed structure of the Superior School Bus Body.

Also attached you will find section and part drawings identifiable by section to the isometric drawing provided.

A. Upper Pillar to Windshield Fence - Section 3-3:

The windshield fence is not a body structural member, its only function is to retain the windshield corner glass seal. As can be seen on the isometric drawing provided (Section 3-3), this part is not located within the bus occupant space. It is forward of the drivers seating position in the cab area. This part is fastened to the Number 1 Pillar by are welding.

Sheller-Globe Corporation feels that inasmuch as this part is for functional purposes as referred to in Paragraph S4. Definitions - "Body Panel Joints' and therefore is not subject to the requirements of the above referenced Federal Motor Vehicle Safety Standard.

B. Pillar Facing to Side Body Pillar - Section 5.5, 5.5A and Drawing 62975-B:

This part is not a body structural member, it is as is defined: a "facing", a "trim molding". Its' function is purely decorative as can be seen on Section Drawings 5-5, and 5-5A. This part by virtue of its' construction (rolled or hemmed edges) would provide no sharp, harmful and/or cutting edges in the event of a crash condition. This part is retained to the side body pillar by four (4) rivets, two at the roof rail and two at the sill (see Drawing 62975-B).

Sheller-Globe Corporation feels that inasmuch as this part is for a functional (decorative) purpose as referred to in Paragraph S4. Definitions - "Body Panel Joints" and, therefore, is not subject to the requirements of the above referenced safety standard.

C. Outside Lower Body - Section 9-9: The Superior "Bus Body" sets on the chassis rails (chassis frame) at the lower surface of the underbody main crossmembers (the "O" body line - reference Section Drawing 9-9).

As Paragraph S4. Definitions ("Bus Body") defines the parameters of a bus body, all joints located within these parameters would be required to-comply to the requirements of the above referenced safety standard.

In an interpretation issued by the NHTSA, the fastening of body side rub rails to the outer bus body were excluded from the requirements of the above referenced safety standard. Section Drawing 9-9 (encircled area) depicts where the Skirt Panel is fastened to the Outside Upper Body Panel at the junction where the Body Rub Rail is fastened to the Skirt Panel.

Sheller-Globe Corporation realizes that this junction falls within the defined parameters of a "Bus Body", and accordingly shoull comply with the requirements of the above referenced safety standard. However, Sheller-Globe Corporation requests that this specific junction of the Superior School Bus be exempt from the requirements of the above referenced safety standard for reasons as follows:

A) This junction is located in an area within the structural frame-work of the Superior School Bus Body where probably the highest amount of structural integrity exists, at the bus body floor line perpendicular to the underbody main crossmembers.

B) The steel floor, the Skirt Panel and the underbody main crossmembers are fastened to one another by the 3/8" bolts and nuts, 4 at each body section as can be seen on Section Drawing 9-9.

C) Additionally, the steel floor is joined to the Skirt Panel (upper) in compliance to the requirements of the above referenced safety standard.

D) The Skirt Panel (upper) is joined to the Upper Inside Panel, at the Seat Rail in compliance to the requirements of the above referenced safety standard.

E) All interior and exterior longitudinal panel joints are joined, panel to panel, in compliance to the above referenced safety standard.

F) The steel floor is joined to the underbody main crossmembers in compliance to the requirements of the above referenced safety standard.

Most States require, in their State Specifications, that Rub Rails be installed at the floor-line of School Buses. Denial of this exemption would require that Sheller-Globe Corporation re-engineer this junction configuration, re-engineer and re-tool for the Rub-Rails and Outside Body Panels.

Sheller-Globe Corporation feels that if this junction failed in a crash condition, no loss of body structural integrity would result. Further, feature of this junction in a crash condition would not likely produce edges harmful to the occupants] of the School Bus.

D. Body Rail (Vent Eves) to Outside Roof Panel - Section 12-12A: Section 12-12A depicts where the outside roof panels insert into the roof rail at the vent eves. As further can be seen on Section 15-15, and the isometric drawing provided, the outside roof panels are all fastened as required by the above referenced Federal Motor Vehicle Safety Standard, i.e., 60% Joint Efficiency. The outside roof panels are joined to one another and to the roof bow facings as required by the above referenced Federal Motor Vehicle Safety Standard. Inside roof panels are also joined to one another and to the roof bow facing as required by the above referenced Federal Motor Vehicle Safety Standard.

Presently, where the outside roof panels (as shown on Section 12-12A) inserts into the roof rail (the vent eves), Sheller-Globe Corporation feels that inasmuch as this outside roof panel edge would not, in the event of a crash condition, provide a harmful and/or cutting edge, the junction in reference does not form a part of the body structure, and further inasmuch as all junctions surrounding the junction in reference are joined as required by the above referenced safety standard, the junction in reference would not be required to comply to the requirements of the above referenced safety standard.

If the referenced junction is required to comply to the requirements of the above referenced safety standard, Sheller-Globe Corporation would be required to redesign and retool this area of the bus body structure and its' surrounding structure. The progress of "plug-welding" has been evaluated in joining in this area, however, the results of this process has not been satisfactory in complying with the requirements of the above referenced safety standard. Additionally, "plug-welding" in this area creates an eye-sore and is conducive to rust.

Sheller-Globe Corporation requests interpretation and guidance of the NHTSA pertinent to whether the referenced junction is or is not required to comply with the requirements of the above referenced safety standard.

E. Outside Lower Panel to Inside Lower Panel - Sections 11-11 and 11-11-A:

Sheller-Globe Corporation realizes that where the outside and inside lower panels are joined according to normal interpretation, this joint would be required to comply to the requirements of the above referenced safety standard.

However, Sheller-Globe Corporation requests guidance on whether this joint, inasmuch as it is covered/protected by the trim moulding that is joined to the lower inside panel as required by the requirements of the above referenced safety standard, so that in a crash condition no harmful and/or cutting edges could be produced, need comply to the requirements of this safety standard.

If this joint that is formed by the outside and inside lower panels is required to comply to the requirements of the above referenced Federal Motor Vehicle Safety Standard, Sheller-Globe Corporation would be required to re-design and re-tool this area and its' surrounding structure, possibly to include a re-design and re-tooling of all passenger windows.

Sheller-Globe Corporation solicits the NHTSA's expedient response to this matter, inasmuch as product engineering and tooling engineering for the 1977 model year Superior School Bus is pending an expedient response.

George R. Semark - Manager Vehicle Safety Activities

(Graphics omitted)

APP APP. SYM. REVISIONS DATE CK. DR.: B DATE: 7-27-76 CK. APP. APP. BUS-FRONT END YEAR: 76 (Illegible Words)

(Illegible Words)

3000 MODEL 1000

SECTION 5-5A

(Graphics omitted)

(Graphics omitted)

ID: nht76-2.12

DATE: 04/14/76

FROM: AUTHOR UNAVAILABLE; S. P. Wood; NHTSA

TO: Blue Bird Body Company

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Blue Bird Body Company's March 15, 1976, request for confirmation that calculation of the material tensile strength of body panels under S6.2(a) of Standard No. 221, School Bus Body Joint Strength, is based on the minimum thickness permitted by American Society for Testing and Materials (ASTM) Standard 525 for the thickness specified in ordering the material. This response also reflects the April 1, 1976, meeting held between Blue Bird representatives and National Highway Traffic Safety Administration (NHTSA) personnel at Department of Transportation headquarters.

Under ASTM standards, the thickness of listed materials is permitted to vary from the specified or "nominal" thickness by a small amount. If the thickness tolerance of a material is specified by the ASTM, the NHTSA bases its determination of thickness on the "minimum thickness" specified for that material in the 1973 edition of the Annual Book of ASTM Standards. If the thickness tolerance of a material is not specified by the ASTM, the NHTSA uses the minimum thickness permitted by the school bus manufacturer's material specification.

YOURS TRULY,

BLUE BIRD BODY COMPANY

March 15, 1976

Mr. Richard B. Dyson Assistant Chief Counsel National Highway Traffic Safety Administration

SUBJECT: FMVSS 221 - SCHOOL BUS BODY JOINT STRENGTH

In S6.2(a) the subject standard makes provision for the manufacturer to determine the material tensile strength as published by the ASTM. This information is required before a manufacturer can design body joints and tooling to manufacture those joints in compliance with the subject standard.

Material tensile strength as published by the ASTM has a tolerance and we need to know to which end of the tolerance we must design. The standard adequately addresses this problem in S6.2(a) by stating ". . . .the relative tensile strength for such material is the minimum tensile strength specified for that material in the 1973 Edition of the Annual Book of ASTM Standards."

This only addresses half of the tolerance problem. The ASTM standards show tolerances for metal thickness ranges. In the absence of specific guidelines of this problem and because we must commit for tooling immediately, we are using the minimum thickness based on our specified thickness and tolerance in ASTM A525-73. This approach seems to be justified in light of the tensile strength guidelines given in S6.2(a).

If this approach is not satisfactory, please contact us by telephone immediately. We will also appreciate a written reply to this letter at your earliest convenience.

W. G. Milby Staff Engineer

cc: Bob Williams; Jim Moorman; Jim Swift

ID: nht76-2.13

DATE: 04/30/76

FROM: AUTHOR UNAVAILABLE; S. P. Wood; NHTSA

TO: Transportation Design & Technology, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your November 14, 1975, request to know how the tensile strength at a joint is determined under S6.2 of Standard No. 221, School Bus Body Joint Strength, in the case of more than two body components joined by the same fastener.

An extensive discussion of joint strength requirements and test procedures was recently sent to Blue Bird Body Company. Your question is addressed in that discussion and a copy is enclosed for your information.

YOURS TRULY,

Transportation Design & Technology, Inc.

14 November 1975

Mr. Frank A Berndt Acting Chief Counsel U.S. Department of Transportation National Highway Traffic Safety Administration

I have been asked to contact your office for a clarification of the joint integrity ruling. Where two pieces of sheet metal overlap to form a joint and are also attached to a body post of a much higher yield material, does the joint calculations apply to the surface metals only or should the higher yield material of the inner post be taken into account?

There appears to be some doubt in the minds of several people I have spoken with and therefore, I would appreciate your comments at your earliest convenience.

L. W. Smith President

ID: nht76-2.14

DATE: 02/13/76

FROM: AUTHOR UNAVAILABLE; James B. Gregory; NHTSA

TO: Hon. J. E. Moss - H.O.R.

TITLE: FMVSS INTERPRETATION

TEXT: Thank you for your January 19, 1976, letter asking for further explanation of the National Highway Traffic Safety Administration's (NHTSA) position on a school bus seating standard that specifies both passive compartmentalization and the installation of seat belt anchorages.

The NHTSA has issued its school bus seating standard (Standard No. 222, School Bus Seating and Crash Protection) in a form that requires compartmentalization of vehicle occupants but does not require installation of seat belt anchorages. There is not sufficient information in the record on which to determine what percentage of school districts would utilize seat belts. The limited evidence available to the NHTSA indicates that only a small fraction of school buses would have belts installed and properly used, and that the decision to mandate seat belt anchorage installation should await further information as to the extent to which belts would be installed and properly used.

The issue of whether the NHTSA is on "safe legal ground in mandating a requirement that in itself does not contribute to motor vehicle safety but requires further action on the part of local officials" has become less urgent in view of the standard's promulgation without anchorage requirements. I would like to respond generally that the NHTSA has always held the opinion in construing the National Traffic and Motor Vehicle Safety Act (the Act) that safety performance requirements that require further action by vehicle users are entirely appropriate. While some safety devices (such as bumpers) are in place and operate passively, most devices, (such as lights and seat belts) require occupant action to gain protection. Seat belt anchorages require more action than simple use to gain their benefits, but this does not appear to be a logally significant distinction. In this case, I decided that substantial controversy over the appropriateness and legality of this protection should not continue to create uncertainty over the ultimate form of the standard, endangering the ability of manufacturers to comply with Congress' maximum 9-month leadtime for upgrading school bus seating systems. We have, of course, left the issue of restraints in school buses.

While the decision on passive restraints could negate the value of seat belt training during the adult years, it should be noted the NHTSA is not proposing passive protection for the rear seats of passenger cars where children are encouraged to ride. They would need to use the seat belts provided to increase their protection in a crash.

SINCERELY,

CONGRESS OF THE UNITED STATES

HOUSE OF REPRESENTATIVES January 19, 1976

Dr. James B. Gregory Administrator National Highway Traffic Safety Administration

Thank you for your letter of January 13, 1976, explaining your position on mandatory seat belt anchorages for school bus seats.

Protecting children who ride school buses from the risk of injury is a critical need, well established by the passage of the Motor Vehicle and Schoolbus Safety Amendments of 1974. I would agree that a zero fatalities/zero injuries record is a reasonable goal for school bus safety. Moreover, a properly conceived seat belt system for school bus seats could potentially offer a high level of protection to the young occupants using them. At the same time, I am compelled to address further questions to you regarding the proposal to require seat belt anchorages alone.

I understand clearly that the idea of requiring seat belt anchorages is to facilitate efforts on the part of local school districts deciding to install belt restraints in new school buses they buy. Moreover, it is clear that if a seat belt system ever becomes mandatory in new buses, the existence of anchorages in older buses will aid school districts deciding to bring buses they already own up to the standard by retrofitting belts into their existing fleet. Finally, I can see the wisdom of seat belts in school buses for training purposes, if we continue to mandate active restraint systems in passenger vehicles generally. Nonetheless, several questions concern me.

(1) Do you believe NHTSA to be on safe legal ground in mandating a requirement that in itself does not contribute to motor vehicle safety but requires further action on the part of local officials -- namely, having belts installed before the added safety feature becomes available for children to use?

(2) Is there evidence in the record of the rulemaking that school districts intend to exercise their option to have belt systems installed once the anchorages become available? If not, how is it possible to justify even the minor cost of this requirement given the absence of any projected benefits?

(3) Regarding the educational value of belt use in school buses, won't the need for this training decline over the next few years if passive restraints are mandatory for new passenger vehicles and gradually introduced into the vehicle population as new cars replace old ones?

I support entirely the "passive protection" approach reflected in the balance of the proposed standard as far as it goes and believe it will offer substantial additional protection to children riding buses. This approach makes particular sense if NHTSA decides to mandate passive restraints in all new passenger vehicles.

On the other hand, if active restraints -- in particular seat belt systems -- continue to be required for the general vehicle population, then it makes sense in school buses to mandate not just anchorages but appropriate and usable belt systems. An appropriate system is one that uses retractors so that belts are self-adjusting in use and stay clean when not in use; that has buckles located in or near the seat fold so that the heavy part of the buckle cannot be wielded in horseplay; and one that will target the child's head against a safe surface if the bus abruptly comes to a halt or crashes.

In short, if we are to protect the integrity of the NHTSA regulatory program, then we should be hesitant to introduce requirements such as this, which offer extremely marginal benefits at best, even by the most favorable analysis.

I have further questions relating to this rulemaking -- particularly whether it adequately meets the mandate established by the Congress in the 1974 Amendments. These questions are perhaps more substantial than the anchorage issue; however, the sufficiency of the balance of the standard is a question I will reserve for the Subcommittee's oversight hearing on NHTSA tentatively scheduled for February 6, 1976.

Thank you for your attention to the questions this letter raises.

JOHN E. MOSS Chairman Oversight and Investigations Subcommittee

ID: nht76-2.15

DATE: 11/10/76

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Thomas Built Buses, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in response to your letter of September 2, 1976, in which you ask whether the definition of "Contactable surface" in Standard No. 222, School Bus Passenger Seating and Crash Protection, includes areas on the front of the seatback located more than three inches from the top of the seat.

Your interpretation of "contactable surface" is correct. The standard states in paragraph S4 that only the uppermost three inches of area on the front of the seatback is considered part of the "contactable surface." The remainder of the front of the seatback is not considered part of the "contactable surface" and need not meet the head impact requirements of S5.3.

SINCERELY,

Thomas BUILT BUSES, INC.

September 2, 1976

Tim Hoyt National Highway Traffic Safety Administration U. S. Department of Transportation

Enclosed are two (2) prints that show our interpretation of the MVSS #222 seat impact regions. In a previous letter, we were informed that the head impact region (marked "H") extends downward to the "12 inch level" above the S R P on the aisle of the seat. The front of the seat was not mentioned.

Our interpretation of S 4. definitions.

"Contactable Surface" is that we do not need to meet the head impace requirements on the front of the seatback below the "H" region. This region is shaded and dimensioned 3" on the print. Is this interpretation correct?

Thanking you in advance for your services, we remain,

L. T. Mitchell, Jr. Engineering Department

H - HEAD IMPACT REGION

K - KNEE IMPACT REGION

(Graphics omitted)

H - HEAD IMPACT REGION

K - KNEE IMPACT REGION (Graphics omitted)

ID: nht76-2.16

DATE: 07/30/76

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Thomas Built Buses, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Thomas Built Buses' June 4, 1976, question whether the requirements in S5.1.3 and S5.1.4 of Standard No. 222, School Bus Seating and Crash Protection, to "Apply additional force . . . through the . . . loading bar until (a specified number) of inch-pounds of energy has been absorbed in deflecting the seat back . . ." can be satisfied in part by the energy that is returned to the load bar as it is withdrawn from the seat back. You also ask if there are minimum or maximum time limits on withdrawal of the loading bar from the seat surface.

The requirement for the absorption of a minimum amount of energy in (Illegible Word) the seat back in the forward and rearward directions is calculated to provide adequate measurement of the energy involved in the impact between the bus occupants and the seating in a percentage of school bus crashes. The agency calculated the amount of energy to be consumed by the seat back that would result in adequate protection. The specification requires the seat to "absorb" (i.e., receive without recoil) a specific amount of energy. This value is represented by the amount of energy that is not returned to the loading bar as it is withdrawn. Described graphically, the area that represents returned energy under the seat back force/deflection curve must be subtracted from the entire area that lies under the curve in order to calculate the energy "absorbed" by the seat back.

With regard to your second question, no time limits have been established for withdrawal of the loading bar. The agency intends to utilize a withdrawal time that is not more than five minutes so that creep will not be a significant factor in determining energy absorption. Because the time is not specified, the manufacturer is free to use any reasonable time that does not significantly affect the elastic and plastic components of the seat back loading.

thomas BUILT BUSES, INC.

June 4, 1976

Mr. Bob Krause Office of Standards Enforcement Motor Vehicle Programs U.S. Dept. of Transportation National Highway Traffic Administration

Re: Part 571 - Federal Motor Vehicle Safety Standards - Para. 571.222 S5.1.4.1 & S5.1.4.2

Our engineering department is in the process of developing testing and analysis techniques for demonstration of compliance with the referenced section of FMVSS. To ensure that these techniques will meet all requirements, we are in need of further clarification of the paragraphs pertaining to seat back load application. Accordingly, we would appreciate answers from your department on the following specific questions:

(1) Para. 571.222 S5.1.4.2 specifies energy absorption of the seat back deflection during load application. What is the significance of or treatment required of the energy returned during the backing off of the loading bar?

(2) Are there any requirements regarding elapsed time interval for the load back-off?

(3) Same questions re Para. 571.222 S5.1.3 thru S5.1.3.4 - Seat Performance Forward.

Thank you for your prompt assistance in answering these questions.

Malcolm B. Mathieson Engineering Manager

ID: nht76-2.17

DATE: 12/14/76

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: School Bus Manufacturers Institute

TITLE: FMVSS INTERPRETATION

TEXT: This is in response to your letter of November 2, 1976, in which you ask for an interpretation of the term "absorbed" as it is used in Standard No. 222, School Bus Passenger Seating and Crash Protection. Further, you request that the NHTSA withdraw its earlier interpretation of the same term made on July 30, 1976, to Thomas Built Buses.

In your letter, you outline data showing that a seat may meet the energy absorbtion requirements of S5.1.3 when recoil energy is included, while failing those same requirements when recoil energy is subtracted from the total energy. You further argue that the NHTSA interpretation of July 30, 1976, which explained the subtraction of recoil energy, is at variance with the wording of the standard, because the standard does not explicitly require the subtraction of recoil energy and speaks only to the application of force upon the seat. Moreover, you suggest that plotting the recoil energy results in insufficient area under the force/deflection curve to meet S5.1.3. For these reasons, you request that the term "absorbed" be defined as the total energy received by the seat without subtracting energy that is returned through recoil.

The NHTSA declines to adopt the interpretation that you suggest. The dictionary definition of the term "absorbed" is "to receive without recoil." This definition, when applied to energy absorbed by a seat, contemplates the subtraction of recoil energy in the computation of absorbed energy. The NHTSA intentionally chose the term "absorbed" to denote exactly this meaning. Therefore, according to the common usage of the term "absorbed," the standard does require the subtraction of recoil energy even though those express words are never used.

Your assertion that plotting the recoil energy results in a force/deflection curve that falls within the prohibited zones indicates a misunderstanding of the force/deflection zone requirements. The force deflection zone requirements (S5.1.3(a), S5.1.3(b), S5.1.4(a), and S5.1.4(b)) prescribe limits within which the seats must perform only during the force application phase of the test procedure.

SINCERELY,

SCHOOL BUS MANUFACTURERS INSTITUTE

November 2, 1976

Frank A. Berndt Office of Chief Counsel National Highway Traffic Safety Administration

On July 30, 1976, the National Highway Traffic Safety Administration issued an interpretation to Thomas Built Buses, Inc. (Item 1) defining the term "energy absorbed in deflecting the seat back" as it relates to the new FMVSS 222 School Bus Passenger Seating (Item 2). The Agency's definition of this term is based on the concept that the absorbed energy equals the amount of energy received less the energy associated with recoil.

The School Bus Manufacturers Institute representing the six major manufacturers of school buses takes exception to this terminology being applied to the present configuration of FMVSS 222. We do not disagree with the semantics but we do believe that there is a definite conflict between the definitions interpretation and the test procedures outlined within the standard.

Our disagreement is not just a recent development. As early as September 1974 through discussions with National Highway Traffic Safety Administration Legal and Engineering, the SBMI indicated that a seat demonstrating purely elastic properties could be constructed to meet the then proposed FMVSS 222.

On a number of occasions since that time, this question has been reviewed by National Highway Traffic Safety Administration personnel. Nevertheless, on January 22, 1976, the final draft of FMVSS 222 was issued without any reference to rebound or recoil adjustments to the test procedure.

Based on the FMVSS 222 test criteria, the SBMI members have designed, developed and tested an entirely new generation of school bus seats. The Thomas Interpretation drastically changes the test criteria used in compliance calculation.

FMVSS 222 Section S5.1.3 states:

Seat performance forward. When a school bus passenger seat that has another seat behind it is subjected to the application of force as specified in S5.1.3.1 and S5.1.3.2 and subsequently, the application of additional force to the seat back as specified in S.5.1.3.3 and S5.1.3.4:

(a) The seat back force/deflection curve shall fall within the zone specified in Figure 1;

(b) Seat back deflection shall not exceed 14 inches; (for determination of (a) and (b) the force/deflection curve describes only the force applied through the upper loading bar, and only the forward travel of the pivot attachment point of the upper loading bar, measured from the point at which the initial application of 10 pounds of force is attained.)

(c) The seat shall not deflect by an amount such that any part of the seat moves to within 4 inches of any part of another school bus passenger seat or restraining barrier in its originally installed position;

(d) The seat shall not separate from the vehicle at any attachment point; and

(e) Seat components shall not separate at any attachment point.

In order that we may more clearly define our objection to the Thomas Interpretation, a typical force/deflection seat test is enclosed (Item 3).

The shaded areas above and below the acceptable zone indicate a seat that is too rigid (upper shaded zone) or too limber (lower shaded zone) to manage the accident induced impacts. Therefore, the force/deflection characteristics properly designed seat will fall within the unshaded area.

Line A plotted on the force deflection curve (Item 3) indicates the amount of seat back deflection for a given loading.

Prior to the Thomas Interpretation line A would be a satisfactory test.

S5.1.3

(a) The curve fell within the specified zone

(b) The seat back deflection did not exceed 14"

(c) The seat did not encroach to within 4" of an adjacent seat

(d) The seat did not separate from the vehicle

(e) The seat components did not separate

The area below line A was above the minimums set by the National Highway Traffic Safety Administration.

Should the Thomas Interpretation be applied to this same seat test, the results are entirely different (Item 4). The new interpretation will require that the recoil of the seat after testing be measured and plotted on the graph-line B.

S5.1.3

(a) The curve fell within the shaded area

The area included within lines "A" and "B" is less than the limit allowed by the National Highway Traffic Safety Administration.

This example outlines one area of conflict between FMVSS 222 and the Thomas Interpretation. FMVSS 222 makes no mention of measuring and plotting rebound, as a matter of fact the test criteria requires only forward motion of the loading bar during the forward test and rearward motion during the rearward test.

The SMBI is now to the point of product verification based on the final draft of FMVSS 222. To revise the test levels at this late date will place an unjust economic burden on this industry.

If it is the Agency's intention to have school bus seats that "eat up" a given amount of energy during a crash, then this requirement should be spelled out within the standard and not within a private interpretation.

Because of the wide reaching effects of this interpretation, we ask that the National Highway Traffic Safety Administration withdraw the Thomas Interpretation and in its place introduce a proposal to revise FMVSS 222 to include the Agency's definition of energy absorption.

If we can be of any assistance in clarifying this matter please feel free to contact me.

Byron A. Crampton Manager of Engineering Services

ITEM 2

(Illegible Line) and Crash Protection FMVSS 222 Effective April 1, 1977

(Regulation Omitted)