Interpretation ID: 21083-2.drn
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Dear [ ]
This responds to your request for an interpretation of requirements for heating/venting/air conditioning controls specified in Standard No. 101, Controls and Displays. Our answers are provided below.
Your request for confidentiality is being addressed in a separate letter. However, in an e-mail exchange between [ ], your legal counsel and Dorothy Nakama of this office, it was agreed that the following description of the system can be made public:
The vehicle's instrument panel has a row of several push button switches, each of which has two positions. This same set of push button switches operates several different vehicle systems. The system to be operated by the switches at a given time is selected by the driver or passenger.
Above the push button switches is a video screen that shows an image of the switches. The video screen also shows the functions of the switches, which vary depending upon the system selected. There is a one-to-one correspondence between each switch and its image on the video screen.
One of the vehicle systems operated by the push button switches is the air conditioning system. In order to select this system, the driver or passenger pushes a separate button labeled "PUSH A/C." There are two such buttons, each of which is located away from the row of push button switches. There is an outer ring around each of these buttons which is used to adjust the interior temperature. This function is identified by blue and red lines on the buttons. The selected interior temperature is shown in digital format on the video screen. Rotating the outer ring (as indicated by blue and red lines on the buttons) raises or lowers the interior temperature. Each outer ring can be rotated to either the right or the left indefinitely. However, since there are limits on the extreme hot and cold interior vehicle temperatures which can be selected, rotating the button past certain points will have no effect on the selected temperature.
When the air conditioning system is selected, identification for the functions of the various push button switches is provided on the video screen, on the images of the switches and/or directly above the images of the controls. For example, the fan speed is controlled by one switch. The speed is increased by pressing the top of the switch and decreased by pressing the bottom of the switch. The four-bladed fan symbol appears on the image of this switch. An upward arrow appears on the image of the top of the switch, and a downward arrow appears on the image of the bottom of the switch. The relative speed of the fan is shown by illuminated bars on the screen above the switch. The fan speed is indicated by the number of bars that are illuminated.
In another case, a switch controls the opening of various vents. Certain identification is provided on the image of the switch, and a pictogram showing the vents relative to an occupant appears above the switch. As the switch is pressed, the pictogram changes to show the vents which are selected.
Your first question concerns whether the identification for the push button switches is considered "on or adjacent" to the controls, as required by S5.2.1(a) of Standard No. 101.
The answer is yes. The video screen that shows the images corresponding to the switches, and identification for the switches, is directly above the switches. Although there is a small unavoidable break between the video screen and the switches, no control, display or other potential source of distraction appears between the video screen and switches. For these reasons, we conclude that the proximity between the switches and the images/identification is so close that they are "adjacent" to each other.
Your second question concerns whether the system meets the requirement in S5.2.2 that identification be provided for each function of any heating and air conditioning control, and for the extreme positions of any such control that regulates a function over a quantitative range. So far as we can tell, it appears that identification is provided for each function of the various controls.
You asked about the requirement for identification of the extreme positions of any such control that regulates a function over a quantitative range in connection with the fan controls and temperature controls. We note that when this particular requirement was written, fan controls and temperature controls of the type provided in your system were not contemplated. While these controls regulate a function over a quantitative range, they do not have extreme positions in the traditional sense of a lever or button that moves only within a limited range, where the ends of the range represent the extreme positions. In the case of the two fan controls, the top of a switch is pressed to increase fan speed and the bottom of the switch button is pressed to decrease fan speed. A display indicates the relative fan speed, including the extremes. In the case of the temperature controls, a display indicates the selected temperature, including the extremes, but the outer rings can be rotated indefinitely.
Applying S5.2.2 to the type of control in your system, it is our opinion that the requirement to identify the extreme positions is met so long as there is a means by which the driver can know when the extreme positions have been reached. We believe your system provides such a means for both the fan and temperature controls. In the case of the fan controls, the driver can know when the extreme positions have been reached by viewing the display which indicates the relative fan speed. In the case of the temperature controls, the driver can know when the extremes have been reached by viewing the display of the selected temperature. When a driver rotates the outer ring of the temperature control to increase or decrease temperature, the selected temperature will increase or decrease up to the point where the extreme has been selected, at which point further movement of the outer ring in the same direction will not change the selected temperature.
Your third question was whether the identification of the heating/air conditioning system controls meets the requirement in S5.3.3 that means be provided for making controls and their identification visible to the driver under all conditions. You asked about this given the fact that identification of the heating/air conditioning controls may not be visible unless one of the knobs marked "PUSH AC" is pressed.
The answer to this question is yes. Standard No. 101 specifies at S5.3.3(a) that "means shall be provided for making controls ... and the identification of those items visible to the driver under all driving conditions." Although the images are not always displayed, the heating/air conditioning controls would meet this requirement because the images providing identification appear when the knob marked "PUSH AC" is pressed. (1)
I hope this information is helpful. If you have any further questions, please feel free to contact Dorothy Nakama of my staff at this address or by telephone at (202) 366-2992.
Sincerely,
Frank Seales, Jr.
Chief Counsel
ref:101
ref.101
d.6/8/00
1. I note that for purposes of this answer,[ ] has confirmed that the brightness of the video screen can be adjusted by the driver "to provide at least two levels of brightness, one of which is barely discernible to a driver who has adapted to dark ambient roadway conditions."
[ ] also confirmed that the air conditioning control is illuminated at night.