Interpretation ID: 86-5.45
TYPE: INTERPRETATION-NHTSA
DATE: 11/14/86
FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA
TO: Dr. Ernst
TITLE: FMVSS INTERPRETATION
TEXT:
Dr. Ernst Westfalische Metall Industrie, KG Hueck & Co. Postfach 28 40 4780 Lippstadt Federal Republic of Germany
Dear Dr. Ernst:
This is in reply to your letter of February 18, 1986, to August Burgett of this agency, asking for an interpretation of Federal Motor Vehicle Safety Standard No. 108 with respect to a center highmounted stop lamp that your firm has developed. Your design contains "a large number of integrated fixed miniature bulbs...a device with a small height and a large width." It has been reported to you by a prospective purchaser that the device may not be permissible because the height is too low in relation to the width, and because the use of fixed bulbs is prohibited.
Standard No. 108 does not establish permissible dimensions for center high-mounted stop lamps, and a manufacturer may establish whatever height/width relationship it wishes, as long as the effective projected luminous area is not less than 4 1/2 square inches. However, the agency's research which substantiated the efficacy of the concept was limited to lamps of a rectangular design narrower than the one you contemplate. Some agency research has indicated that the width of the device should not be more than seven times its height.
As for the issue of fixed or replaceable bulbs, this question arises in the context of paragraph S4.1.1.41(e) of Standard No. 108 which requires that the lamp "provide access for convenient replacement of the bulb without the use of special tools". This paragraph was written with the thought that center high-mounted stop lamps would be equipped with a single bulb or light source. If your lamp is sealed, so that the individual bulbs cannot be replaced in the event of burnout but is nevertheless designed so that the entire unit may be replaced with a new lamp without the use of special tools then your lamp design would appear to meet the intent of paragraph S4.1.1.41(e).
I hope that this answers your questions.
Sincerely,
Erika Z. Jones Chief Counsel
Subject ACTION: Interpretation of Sealed Bulb Date
Reply to Attn of Burgett 426-1351
From Barry Felrice Attn of Burgett Associate Administrator for Rulemaking
To Erika Z. Jones Chief Counsel
The attached request for interpretation has been received from Hella. The issues are similar to those that have been raised in she request from Stanley Electric Company for interpretation relative so use of Light Emitting Diodes. If feasible, we suggest combining both interpretations into a single response.
Attachment
Mr. Dr. August Burgett c/o National Highway Traffic Safety Administration Department of Transportation 400 Seventh Street S.W. Washington, DC 20590 USA
K1 DrE/lb 7300
February 18, 1986 High Mounted Stop Lamps
Dear Dr. Burgett,
Long before High Mounted Stop Lamps became mandatory in the US, we were concerned with this subject. We now understand from Mercedes Germany that your agency does not approve of our design.
In order to keep vision through the rear windshield as unimpaired as possible we have developed a design with reduced dimensions and, in particular, with a reduced height.
This design makes use of special miniature bulbs with increased durability. These special bulbs have been used in a display, produced by our company, with excellent results for many years. They have a life of more than 2000 hours.
We are sure that this is much more than the expected durability of a car.
For safety, technical, and cost reasons we designed a HMS with a large number of integrated, fixed miniature bulbs. This enables us to realise a device with a small height and a large width. The attached drawings show this design.
The objections of NHTSA to a design of this type, as reported by Mercedes, are
1. The relation Width: Height must be fixed within certain limits.
If this is true, it would prohibit our design.
2. The use of fixed bulbs is prohibited, replaceable bulbs being obligatory.
We cannot find any paragraph concerning these matters, neither in MVSS 108 nor in any other regulation or standard.
Moreover, we argue that signal lamps with fixed bulbs in sealed units are known and available on the market. They are approved by US testhouses. Examples are described in the attached copies of catalogues.
We should be grateful if you would kindly consider this matter and give us binding information.
With best regards
Westfalische Metal Industrie Kommanditgesellschaft Hueck & Co.
ppa. Dr. Ernst