In this episode, we answer the following questions:
- How does humidity affect our metering devices?
- Why can’t we calculate water density using molecular weight?
- Can we transport a leaking vessel containing a hazmat?
- If alpha radiation is blocked by the skin, how do we know if it’s inside us?
Complete Show Notes
00:55 Question #1 – How Does Humidity Affect Our Metering Devices?
- Humidity has the most significant negative effect on photoionization detectors – very high humidity decreases their sensitivity
- Some detector tubes lose sensitivity because the humidity interferes with the chemical reaction taking place in the tube
- Many types of tubes come with a humidity “correction” chart, which allows you to modify the readings under a different humidity condition – be sure to review the operating manual
- Calibration checks help assess the effects of temperature, humidity, and barometric pressure on each particular meter – perform calibrations in the same environmental conditions the meter will be used in
2:30 Question #2 – Why Can’t We Calculate Water Density Using Molecular Weight?
- Molecular weight is used in air because it’s usually very thin – allows us to determine the actual physical weight of a product and compare it to the weight of air (29)
- If it’s more than 29, the product sinks, and if it’s less than 29, the product rises
- Doesn’t work with water because even dense products (like huge steel ships) can float
- When you compare the total volume of the heavy object (i.e. a ship) with the total volume of water that it’s displacing, the ship is lighter
- You may have a very large, heavy molecule, but if its weight per unit volume is less than water, it floats
- Molecular weight almost always shows something as sinking, but this isn’t the case with a lot of heavy molecules out there (most of them float)
6:10 Question #3 – Can We Transport a Leaking Vessel Containing a Hazmat?
- Check out 49 CFR (Code of Federal Regulations), which handles DOT commerce rules and regulations
- 173.301a2 – “A cylinder that has a crack or a leak, is bulged, has a defective valve, has a leaking defective pressure valve, or bears evidence of physical abuse, fire, or heat damage, or has detrimental rusting or corrosion may not be filled or offered transportation”
- Bob contacted Mike Moore from STTS for more information
- Yes, we can transport a leaking hazmat vessel
- However, it must be escorted by state or local law enforcement
- Ask yourself:
- What’s the rate of the leaking material?
- Is the leaking material a product that will immediately vaporize to a gas?
- What are the vapor densities – heavier or lighter than air?
- Is the material liquid?
- Can the material be temporarily captured in an absorbent patch?
- Most commercial motor vehicles with a LP motor tank are mounted low – allows the gasses to fall to the ground without passing through or around the vehicle
- Vehicles using LNG usually have tanks that are mounted high – allows the gasses to float away without passing through or around the vehicle
- Emergency responders have to be familiar with the fuel systems and emergency loading and unloading features of these systems
- Always check with your AHJ (authority having jurisdiction) for more details
9:35 Question #4 – If Alpha Radiation is Blocked by the Skin, How Do We Know If It’s Inside Us?
- If it’s strictly an alpha source, there’s no way to determine if you’ve been contaminated
- Hardly anything in the world only gives off alpha radiation, though
- On the other hand, almost anything that gives off radiation produces alpha, beta, and gamma rays (which go right through the skin)
- This means you can assume you’ve been exposed to alpha radiation if you’ve been exposed to beta or gamma rays – this is an example of dual/multiple signatures
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