Interpretation ID: nht81-3.30

DATE: 11/02/81

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Meiji Rubber & Chemical Co., Ltd.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your recent letter regarding the use of flexible nylon tubes in vacuum braking systems. You ask whether such plastic hoses would qualify as "vacuum tubing connectors" for purposes of Safety Standard No. 106, Brake Hoses.

We recently received a letter asking this identical question from Tokai Rubber Industries of Japan. I am enclosing a copy of that letter for your information. I believe that it will answer all of your questions. You will see from the letter that these nylon tubes cannot qualify as "vacuum tubing connectors" and must comply with the requirements of Safety Standard No. 106.

Sincerely,

ENC.

TOKAI RUBBER INDUSTRIES, LTD.

April 20, 1981

Office of Chief Counsel -- NHTSA

Subject: Questionnaire Concerning the Application of All Plastic Vacuum Brake Hoses

Dear Sirs,

Our company, Tokai Rubber Industries, Ltd. is supplying vacuum brake hoses to Japanese automotive industries, which have both met the requirements of the standards of FMVSS-106(1974), S9 and been approved by your department.

As you know, it has began to make use of the variety of vacuum brake hose instead of conventional rubber vacuum hose in application to brake systems.

Tokai Rubber Industries, Ltd. has been developing and making plans for the supply of several kinds of plastic vacuum brake hoses which are composed of a single material and are molded in an exact, set shape for the specific application. We are intending to utilize two(2) flexible nylon tubes for a vacuum braking system, and our concept of assemblies is the following:

(Graphics omitted)

We have found, however, that these plastic vacuum brake hose does not meet several requirements of the FMVSS-106, S-9 due to the feat that their characteristics are different from the conventional type vacuum brake hoses, and therefore we would like to clarify the following points: (1) The molded plastic vacuum brake hose apparently does not meet the above mentioned requirements, such as Bend (S9.-2.7.) and Deformation (S9.2.10) of the FMVSS-106, S9. Is there any alternative standard or requirement?

(2) Based on the notice for amendment to the definition in the Standard No.106-74, a definition for 'vacuum tubing connector' is added. is our nylon flexible tube and assembly indicated above in a category of 'vacuum tubing connector'?

(3) If so, there is no federal rule concerning vacuum brake hoses to use in a vacuum brake booster system. Can we design a vacuum brake hose and assembly only based on manufacturer's performance standards ?

I thank you very much for your help and consideration in this matter and I am looking forward to hearing from you soon.

Very truly yours,

John Y. Yonezana -- Engineer - Development

cc: Mr. Sugimoto, Tokai

AMERICAN ASSOCIATION OF MOTOR VEHICLE ADMINISTRATORS

April 2, 1981

John Y. Yonezawa -- Tokai Rubber Industries, Ltd.

Dear Mr. Yonezawa:

Reference is made to your letter of February 20, 1981 in which you have requested our interpretation of the FMVSS-106 as it addresses brake hose and vacuum tubing connectors.

We have reviewed your questions and have tried to interpret the standard as it applies to your application and have contacted Mr. Vern Bloom at NHTSA for his interpretation of the 106 standard. Mr. Bloom (Illegible Words) your questions directly - the Office of Chief Counsel at NHTSA for a formal interpretation of the standard. This would preclude any misinterpretation which could be very costly to your firm.

AAMVA, as agent of the states and provinces, must use the FMVSS-106 for the certification of brake hose. If it is determined by NHTSA that the hose or device is not subject to the FMVSS-106, then it is not necessary to have it certified by us.

When NHTSA gives Tokai Rubber Industries their interpretation, we would appreciate receiving a copy for our reference.

We are sorry that we were not able to answer your questions in this matter.

Sincerely yours, George E. Walton -- Associate Director, Safety Equipment Services MEIJI RUBBER & CHEMICAL CO., LTD.

September 30, 1981 Our Ref. T-859/TT/tm

Messrs. Office of Chief Council

Dear sirs

RE: Inquiry to your interpretation on our plastic made vacuum brake hose through AAMVA

We are one of leading automobile hoses manufacturers in Japan, and developing new material's vacuum brake hose which made from Poly-amide resin to replace from conventional rubber hose.

However, you specify that vacuum brake hose must be conformed to all items of requirement in FMVSS 106, our nlyon made vacuum hose (not reinforced with any fiber, so we call it as "tube") don't satisfy S9.2.10 Deformation test and S10.6 Bend test.

This is the common problem of plastic made vacuum brake hose which developed by several manufacturers, we've asked the interpretation of yours against the adoption of this new material's hose to AAMVA.

Mr. George Walton Associate Director of AAMVA might request your interpretation to our inquiry that whether Nylon vacuum brake hose has a possibility of acceptance as vacuum brake hose which connect between rigid points or not.

We are awaiting your interpretation of Nylon vacuum brake hose, please inform us.

Enclosed please find the copies of our letter to Mr. Walton. Although we were asking him in our letter, it was also the question to you.

We must excuse our sudden request, but if you kindly inform us your interpretation or advise, it would be much appreciated for us.

We are looking forward to hearing from you at your earliest convenience, we remain,

Yours sincerely

T. Takano -- Chief of Development Dept.

Encl: Copies of our inquiry letter addressed to Mr. Walton AAMVA

c.c. to Mr. Walton

June 3, 1981 Our Ref. T-809/TT/tm

George E. Walton -- Assistant Director Safety Equipment Service, American Association of Motor Vehicle Administrators

Dear Mr. Walton Much appreciated for your kind reply in your letter dated April 7 to our question on plastic made Vacuum brake hose.

You've kindly enclosed latest FMVSS-106-74 and suggested us to carry the test in compliance with the standard out.

As the result, we have found that our plastic vacuum tube (not reinforced with any fiber, so we call this "tube") is conformed to the requirements such as High temperature resistance, Low temperature resistance, Ozone resistance, Burst strength, Vacuum and Swell test, but not conformed to Bend and Deformation tests.

Since we use Polyamide 11 material (fewer plasticizer contained), Kink phenomenon was happened when our vacuum tube was bent as way of bend test as specified. It was more than the collapse, completely yielded at the A point. In the Deformation test, our 3/8 inch I.D. tube was only conformed to the specification, but larger I. D. tubes 1/2 inch were not conformed.

Our technicals insist that so far as we use polyamide material to make the tube, it is inevitable to ocurr Kink phenomenon and inferior deformation restorative rate compared to rubber tube.

Notwithstanding such weak point, plastic tubes (mainly it is consisted with Nylon material) are available to automobile use. We hear Nylon made vacuum tube has been adopted to European vehicles before long and we can find particular specification of plastic tubing for its nominal diameter, end fittings and its assembly way in S9, Requirement-Vacuum brake hose of FMVSS 106.

In case of the appearance of developed products made by new material, it is usual to adapt the specification to new material, we believe.

Therefore we would like to ask you followings,

1. When your country import the vehicles which are installed Nylon made vacuum brake hose from Europe, you can accept them or not, we wonder. Because, European Nylon tube may also have inferior property against severe bend compared to conventional rubber made hose, we are afraid.

If you have special treatment for them, please inform us.

2. As FMVSS specifies particularly for plastic tube or assembly, we expect, you AAMVA or NHTSA might have some adaptation to introduce these new developed plastic vacuum brake tube, or your administrators may be planning to adapt existent specification or requirement to such a plastic made tube.

If so, could you please inform us such a tendency?

We are sorry to trouble you again, but if you would inform us your situation or tendency, it would be much helpful for us.

Yours sincerely

T. Takano -- Chief of Development Dept., MEIJI RUBBER & CHEMICAL CO., LTD.

July 7, 1981 Our Ref. T-826/TT/tm

George E. Walton -- Associate Director, Safety Equipment Services, American Association of Motor Vehicle Administrators

Dear Mr. Walton

Thank you so much for your kind answer and exertion to our question.

At the moment, we don't yet receive any interpretation from NHTSA, unfortunately.

One of our manufacturers of these sort of tube interprets that vacuum brake hose is not fixed between swinging part as like as hydraulic brake hose, only for connecting between stationary parts such as engine to cleaner. Therefore vacuum brake hose can be regarded as rigid piping. If so, Nylon vacuum brake hose is not required severe flexibility and severe bending.

We are not sure that his interpretation is acceptable with you or not, but we think, there is some truth in what he says as far as Nylon vacuum hose connect between stationary parts.

Sorry to trouble you so often, but could you please address his interpretation to National Highway Traffic Safety Administration?

Enclosed pleased find a piece of V. W. Golf GII Vacuum hose with plastic made check value for your reference.

We are looking forward to hearing from you and are always appreciating for your favour.

Yours sincerely

T. Takano -- Chief of Development Dept. MEIJI RUBBER & CHEMICAL CO., LTD.

Encl: a piece of sample