THMG266 – AP4C

We can’t believe we forgot one of the handiest meters we can carry. Everyones favorite flame spectroscoper. Take a listen to find out a little more about what this can do for you.

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  1. What is the AP4c
    1. The original or previous versions of this meter were actually 2 separate meters. How ever they both did the exact same thing so they were merged together to create one super meter… ok not super meter but a good meter
    2. The originals meters where the ap2c. This was a military meter for chemical warfare agents. The second was the TIMs which stood for toxic industrial materials. This was the same meter but told you the bond types instead of the chemical warfare agent.
    3. So all the principles are the same. AP4C, AP2C, and the TIMS.
  2. This is one of our favorite meters. But in order to understand why it’s important to understand why and how it works and what it is really trying to pick up.
    1. Works of Flame spectroscopy
      1. Big word but what it is. To help explain this we are going to over simplify. Every time a molecule gets excited it releases energy as it starts to go back down to a ground state. We see this the time when things burn.
        1. Fireworks are the best example of this. Ever wonder how fireworks get the colors they do. Well they burn very specific chemicals in the explosion to get the colors they are looking for. 
          1. Red is from Strontium salts
          2. Orange is from calcium salts
          3. Yellow is from sodium salts
          4. Green is from barium salts
        2. So what makes Barium salts green? Where does the color come from?
          1. Well it comes from the bond the chemical makes as well as the energy levels of those molecules associated with valence electrons.

When we engerize the energy state of an electron we cause it to gain energy and expand outward away from the nucleus. You can think of this energy level like a floor in a building. If I were to start on the ground floor of a skyscraper and go up 3 levels, I will have put energy into me. Now if i jump off that 3rd floor onto the ground floor i am going to hit the ground with energy that is directly related to how many stories up i was when i jump. If I am a person I go splat, but if I am an electron I give off a photon. Which is another word for light… kind of.

  1. Ok lets stay with the building analogy for a second. Do all buildings have the same amount of height between floors? The answer is clearly no. Some buildings might be 9 feet between floors, some mights be 12 feet. Every building has different heights of their floors. Therefore a 3rd story drop from one building is not going to have the same splatter effect as 3 story jump off another. The same is true with atoms and molecules. These different energy levels are going to be different depending on the molecule. This difference in energy levels energy is why magnesium burns bright white while copper chloride burns blue.
  2. Flame spectroscopy uses this concept that a molecule with a specific element bonded with it will give off specific colors when excited to determine whether or not an element is present in the sample.
    1. The AP4c burns hydrogen. And the sample is placed in the flame. IT then analyzed the light coming off for very spifiic frequencies or colors of light. If that frequency is present it lets you know as well as a very crude rating of how much is present.
  3. Now remember the meter is almost telling you the ingredients or some of the ingredients to let’s say a cookie. It’s not going to tell you hey fatty you have a chocolate chip cookie. It will say I don’t know what you have but it has chocolate chips in it!. ITs then up to you to determine what the chemical could be based upon the ingredients.
    1. Let’s look at the ingredients it will pick up.
      1. Phosphates
        1. These are the key ingredients in nerve agents. They are the organophosphates that give us the slugem that we know and love so well.
        2. But they are in more than just nerve agents. They are also a key ingredient in pesticides and other fun liquids that wipe small creatures off the face of this earth.
          1. But when we get large doses of pesticides we are doing essentially the same things as a nerve agent. Have you ever actually looked in the back of a peside that is bought at the hardware store. It’s like 99.9 percent water and .1% some organophosphate that can wipe you of the earth. 
          2. We also see Detergents, fertilizers and acids like phosphoric acids on the toxic industrial side.
        3. The group of V agents will also come up on this channel.
      2. HNO
        1. This is the nitroxyl group. This channel will respond when we have NH or NO bonds present in a compound.
          1. From a CWA stance we are looking at blood agents such as hydrogen cyanide, Blister agents like nitrogen mustard, and choking agents like ammonia
          2. Toxic Industrial Compounds would include
            1. Fertilizers, explosives and ammonia
      3. CH
        1. This channel which really isn’t a channel, it’s just a light will go off in the presence of hydrocarbons. Its basily looking for flammable material and that’s how you should interpret is as “hey buddy you got a possible flammable 
      4. Arsenic
        1. Arsenic is used as precursor to 3 types of CWA
          1. Arsine which is a blood agent
          2. Lewisite which is a blister agent
          3. Adamsite which is a vomiting agent
        2. There are some pesticides that will contain arsenic
      5. Sulfur
        1. This channel for chemical ware agents will be
          1. Lewisite blister agent
          2. Mustard Lewisite another type of blister agent
          3. Distilled mustard which is a blister agent
          4. Phosgene for choking agent
          5. VX
        2. In the TIC world we see sulfur compounds in 
          1. Fossil fuels
          2. Petroleum
          3. Coal
          4. Natural Gas
  4. How to read the meter?
    1.  5bars
      1. 1 yellow
      2. 4 red
      3. Overload
    2. If multiple bars light up 2 possible scenarios
      1. 1 chemical with two different bond types in it
      2. Multiple chemicals
  1. So how are we using this meter?
    1. As a meter in primary search
    2. As decon on persons
    3. As decon on materials
  2. Liquid sampling

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