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Dry Gas Standard

Intoximeters recommends that external accuracy checks and calibrations be performed using either a dry gas or wet bath standard approved for use by both NHTSA and Intoximeters. (Wet bath simulators should be used with properly certified and maintained ethanol solutions).

In all cases the compressed gas tanks, simulators and simulator solutions should be used and maintained only in accordance with the quality assurance plans provided by their respective manufacturers to insure that they produce consistent and reliable samples.

Approved Dry Gas Standard

(Use only Dry Gas Standards approved by Intoximeters for use with Intoximeters instruments. Check label on tank).


  1. Pressurized approved dry gas tank/cylinder. (Tank contains a single-phased mixture of nitrogen and ethanol).
  • The front label of the gas standard states the value of the gas at sea level.
  • Used properly, a 108 liter tank should supply over 500 samples, and a 30 liter tank should supply over 100 samples.
  1. Small single staged approved regulator. (A regulator is a gauge that regulates the flow of vapor from the tank to an instrument).
  • The standard flow rate of the regulator is 1.5 liters per minute (LPM).  A high flow regulator barb (6 LPM) is available for use with the Alco-Sensor FST and Alco-Sensor V.
  1. True-Cal II device, optional.  A True-Cal Device used in the vicinity of the dry gas standard will display the true value of the standard at the time of the test. The True-Cal device is purchased based on the sea level value of the dry gas standard.


  1. The expiration date is stamped on the label of the dry gas standard. (Make note of this date so you remember to order a replacement tank prior to the expiration date).
  2. The front label lists the value of the gas in the tank at sea level. If you are using the tank at an elevation other than sea level, refer to the elevation chart on the rear label of the gas tank to determine the proper value for your elevation, or use the True-Cal Device. (Variations in absolute barometric pressure can alter the expected value of a pressurized dry gas standard, according to standard gas laws). Know the value of the dry gas standard prior to running an Accuracy Check or Calibration. This will be your target value.
  3. Store tanks in environments where the temperature range remains between 10° – 40° C.



  1. Prior to installing the regulator, inspect the valve on the top of the tank to insure there is no foreign matter (packing material, etc) inside the valve.
  2. Also inspect the regulator to verify there is an “0” ring on the threads of the regulator – an extra “0” ring is taped to the side of each tank. It is recommended that if you are replacing an empty tank with a new full tank, a new “0” ring should be placed on the threads of the regulator prior to mounting on the tank.

Note: When removing the old “0” ring DO NOT CUT IT OFF WITH A SHARP TOOL – this might mar the threads and cause future “0” rings to be damaged.



  1. Mount the regulator on the tank and hand tighten by turning the regulator clockwise – until it is snug. (DO NOT OVERTIGHTEN)
  2. Observe that the gauge on the regulator indicates at least 900 PSI – if it does not, contact Intoximeters at 1-800-451-8639.
  3. Please note that the regulator will indicate approximately 500 PSI when attached to the 30 liter tanks.  Since these tanks are smaller, less pressure is needed to fill them.


  1. If the gauge on the regulator is at or above the appropriate PSI level for its size, mark the needle’s position on the glass face of the gauge.  Let the tank stand for two hours and then observe the gauge and verify that the needle has not moved. (If the needle has moved, remove the regulator and contact Intoximeters.) Check it again every 24 hours for the first few days. If the needle is stable, your tank and regulator are not leaking.
  2. After the regulator is initially mounted, depress the regulator control button and allow the gas to purge the valve for several seconds.
  3. Leave the regulator on your tank unless it is absolutely necessary to remove it. This will reduce the possibility of leaky connections. (If you are transporting the tank, the regulator should be removed to avoid damage to the gauge).

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