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HEPA filter versus biohazard

Discussion in 'Model S' started by SDRick, Jul 16, 2016.

  1. SDRick

    SDRick Member

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    I have a few questions regarding the air filtering systems.

    Am I correct assuming that the HEPA filter is always active? Also, when selecting the biohazard setting, is the air recirculating or is it fresh air and does the fan speed have to be on full?
     
  2. Saghost

    Saghost Active Member

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    Biohazard mode attempts to develop a pressure differential between the inside and outside of the car, so that any air leaks will go from the clean inside to the dirty outside. That means that it does need high fan speeds, and that it has to use additional air from outside (run through the filters) to make the extra pressure.

    I'm not 100% certain about the filters - my assumption is that they are always used when the car draws air from outside, but I haven't seen that documented one way or the other. Note that it isn't just a HEPA filter - there are also activated carbon filters in the intake sequence.
     
  3. Cosmacelf

    Cosmacelf Active Member

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    I do know that in regular mode, the Model X allows far less smells than the Model S. I only need to turn on biohazard mode when something really bad is happening outside, like a truck engine going haywire or a bush fire nearby. Both normal and biohazard modes are the real deal and make a big difference.
     
  4. SDRick

    SDRick Member

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    I would say that if something "bad" was happening relative to air quality the system would shut off all outside air intake and highly purify what is ever inside until the hazard has passed.
     
  5. Saghost

    Saghost Active Member

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    Assuming your filters are up to the task, Tesla's Biohazard is a better bet.

    The car's seals aren't sufficient to prevent intrusion of something while you're recirculating the air (no current car is,) but Biohazard mode can stop things from getting in - if the filters are adequate.

    The only way to be safer would be better sealing (at substantial cost in both money and weight/volume) and/or a stored canister of clean air to build the overpressure with.

    Of course, it won't let you drive into a cloud of carbon monoxide - or even into an area where all the oxygen has been consumed. But what do you expect from a car?
     
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  6. SDRick

    SDRick Member

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    Makes sense.
     

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