In this episode, Bob interviews Bob Metcalfe, a meteorologist and host of The Firefighter Podcast, to discuss the impact of weather on hazmat scenes.
Complete Show Notes
1:15 Introduction to Bob Metcalfe
- Host of The Firefighter Podcast
- Formerly an on-air meteorologist, which can play a significant role in hazmat
2:35 Is Weather a Hazmat Response Consideration?
- Yes! It plays just as significant of a role in hazmat as it does when responding to fires
- There are more scientific effects of weather on hazmat than there are in firefighting
4:10 How Does Temperature Affect Hazmat?
- Physical properties are obvious – phase changes (ice, liquid, and gas)
- Physical states and boiling points also play an important role in response
- Ideal gas law – pressure multiplied by volume has a direct relation to how many moles of a gas you have multiplied by a correlation and the temperature
- Just know that when temperature goes up, there’s either an increase in pressure or volume of a gas
- Ideal gas law also affects altitude – all of these factors change depending on where you live
10:00 Heat Index, Humidity, and Temperature
- The heat index factors in the humidity of the air – affects evaporation of moisture from your skin
- If the heat index is up, there’s a higher combination of heat and humidity in the air
- Humidity refers to how much moisture is in the air – any air mass can withhold certain amounts of moisture, and 100% humidity means that parcel of air can’t hold any more moisture
- Humidity does not equal rain, though – there must be a trigger for the rain (i.e. lifting or other trigger mechanisms)
14:30 How All of This Affects Hazmat
- Temperature has a direct effect on the pressurization of containers and the expansion of liquids or solids
- Humidity has a direct effect on whether things are hydrophoric and if they react with water
- Also affects techs in terms of the physiological effects of the heat index – heat index doesn’t really affect the world around us and what we’re working with
- Altitude also has an effect because it changes the physical and chemical properties of a lot of substances – affects boiling points, vaporization, viscosity, solubility, etc.
16:30 Wind and Hazmat
- The Emergency Response Guidebook (ERG) has information on how far we need to evacuate depending on the wind
- Distance of evacuation is based on whether it’s night or day – think of this as a lava lamp
- During the day, the air close to the ground becomes hot and lighter than the air above it – this produces clouds
- We don’t get those kinds of clouds at night because there’s no sun beating down on the ground
- Wind goes from high pressure to low pressure – there’s more atmospheric mixing during the day and a stirring effect that creates wind
- This isn’t a consideration at night because there’s less atmospheric mixing – as a result, there’s a larger evacuation range at night
- Major differences between urban, suburban, and rural settings – urban heat islands often exist in cities to create their own heat and storms
- Wind patterns are also different because large cities have buildings that form tunnels – this means the wind can’t move around as much
23:50 Which Weather Factor Has the Greatest Effect on Operators?
- Heat index is the most important thing we should be concerned with because it can have an adverse effect on us physiologically – puts more stress on our body than anything else weather-related
- We don’t know when we’re going to have to answer the call, which can be dangerous because we may not be prepared for the heat index
27:20 How Rain Affects Us as Hazmat Techs
- Runoff is a concern
- Rain also causes turbulence in the air, which can keep gasses and liquids from dispersing as much as they might otherwise
29:30 Resources That Bob M. Uses
- Paid app that’s clean, simple, and helpful
- No ads!
- The best weather resource out there is the National Weather Service and put in your zip
Have a question? Send an email to firstname.lastname@example.org or leave a message on our Haz Mat Guys comment hotline: 843-628-1484
- THMG036: ERG Review with The Firefighter Podcast
- THMG096: Hurricane Harvey Wrap-Up
- THMG047: Interview with Dave DeGregorio, Director of Massachusetts Hazmat