How to Navigate the New CIF Heat Stress Policies: Webinar + FAQs

Differences Between Handheld WBGT Instruments and Stationary Weather Stations

1. Acclimation and Calibration

• Handheld Devices: Require frequent calibration and acclimation when moved between different environments. For example, if a handheld device is taken from a 72°F indoor environment to outdoors, it takes time for the sensor to adjust to the new conditions.

• Stationary Weather Stations: Since it’s stationary and permanently installed outdoors, it eliminates the need for acclimation and provides consistent and immediate readings without acclimation and constant recalibration.

2. Radiation Shield

• Stationary Weather Stations: Weather stations come equipped with a radiation shield to allow airflow and prevent direct sunlight from affecting temperature and humidity sensors, ensuring more accurate readings. 
• Handheld Devices: Handheld devices lack this radiation shield that allows airflow to go through without being impacted or impaired by direct sunlight. As a result, handheld devices are susceptible to massive spikes and inaccurate readings.

3. Convenience and Time Efficiency

• Handheld Devices: Require manual measurements multiple times a day, which is labor-intensive and time-consuming. For instance, guidelines might suggest taking readings every 30 minutes. 
• Stationary Weather Stations: Continuously monitor conditions without the need for manual intervention, saving time and effort.

4. Sensor Size and Accuracy

The ISO standard for the black bulb sensor, which measures the WBGT, is six inches. The reason it’s that size is because it represents how the body heats itself and cools itself down.

• Handheld Devices: Often use smaller black bulb sensors that heat and cool quickly, leading to massive spikes and overestimation of temperatures.
• Stationary Stations: Utilize standard-sized sensors as per ISO standards, which correspond more accurately to how the body heats and cools, providing reliable data for WBGT calculations.

5. Human Error and Data Integrity

• Handheld Devices: Prone to human error during manual data collection and recording, which can affect data integrity.
• Stationary Weather Stations: Automated data collection minimizes human error, ensuring more reliable and accurate data.

6. Fluctuations in Readings

• Handheld Devices: Can show massive fluctuations in temperature and humidity due to their lack of shielding and smaller sensors.
• Stationary Weather Stations: Provide stable readings thanks to their protective features and consistent monitoring environment.

7. Long-Term Monitoring and Analysis

• Handheld Devices: Less practical for long-term data logging and trend analysis due to manual data collection.
• Stationary Stations: Enable continuous data logging, making it easier to analyze WBGT trends and plan accordingly.

Handheld WBGT devices require a specific acclimation period before providing accurate readings. Understanding this timeframe is essential for effective heat stress management.

Key Takeaways

• Acclimation time varies: The exact acclimation time for handheld WBGT devices can differ depending on the specific model.
• General guideline of 30 minutes: A common recommendation is to allow approximately 30 minutes for the device to acclimate to its environment.

Impact of frequent movement: Constantly moving the device between indoor and outdoor environments can disrupt acclimation and affect measurement accuracy.

Understanding how different surfaces affect Wet Bulb Globe Temperature (WBGT) readings is crucial for accurate heat stress monitoring. Here’s a breakdown based on scientific studies and Colin and Tim’s expert insights:

1. Surface Variability

Different surfaces like grass, turf, and composite tennis courts can show variations in temperature and humidity.

• Grass and Turf Fields: These surfaces might have slightly different ambient temperatures and humidity levels. For example, grass might be cooler, while turf could retain more heat.

• Composite Tennis Courts: These tend to have higher ambient temperatures but lower humidity compared to grass or turf. Dr. Gruenstein’s studies highlight these distinctions but note that the overall WBGT readings remain similar due to compensating factors.

• For instance, the surface of the stove is considerably hotter than the air just a few inches above it. Similarly, different outdoor surfaces react differently to sunlight. Grass and artificial turf, for example, absorb and retain heat at varying rates. This difference in surface temperature directly impacts the WBGT reading.

2. Scientific Studies

Extensive research by Dr. Gruenstein at the University of Georgia has demonstrated that the variations in WBGT readings across different surfaces are minimal.

• Study Findings: Composite tennis courts may show higher temperatures but lower humidity, whereas grass or synthetic turf may exhibit the opposite. These variations neutralize each other in the WBGT calculation, which includes five different variables. This approach ensures that the final readings are reliable and consistent regardless of the surface.

3. Measurement Height

The height at which WBGT readings are taken significantly influences the results.

• Surface vs. Shoulder Height: Measurements taken directly on the surface, like turf, can show extremely high temperatures, as seen in examples where sideline reporters use infrared guns during games. 

• However, readings at shoulder height, where athletes experience the air, are less affected by surface heat. The air above the surface mixes well, leading to more accurate WBGT readings. 

4. Practical Implications

The choice of equipment impacts the accuracy and reliability of WBGT data.

• Handheld Devices: These require manual measurements at multiple points and times, which can be influenced by the immediate surface temperature and are labor-intensive.
• Stationary Units: These are installed at a consistent height and provide continuous, reliable data unaffected by surface-level heat variations. For example, stationary units on press boxes or field houses offer consistent readings without the need for constant manual intervention.

When Wet Bulb Globe Temperature (WBGT) readings fluctuate in and out of policy zones during outdoor workouts, it’s important to maintain safety while adhering to guidelines. Here are the key takeaways and examples from the discussion:

1. Starting and Continuing Practice

Once practice begins within a specific WBGT category (green, yellow, red, black), it is generally recommended to continue within those parameters, regardless of subsequent fluctuations.

• Policy Adherence: Begin practice according to the WBGT category at the start time.

• • Example: If practice starts at 3:00 PM and the WBGT is in the red zone (89.1°F), limit the session to one hour.
• Monitoring Fluctuations: Continuously monitor the WBGT, especially if it fluctuates between categories.
  • Example: If cloud cover causes the WBGT to drop into the orange zone, maintain the one-hour practice limit from the initial red zone reading.

2. Decision-Making During Fluctuations

• Safety First: Always prioritize athlete safety and be mindful of WBGT fluctuations.

• • Example: If the WBGT unexpectedly reaches the black zone, consider pausing practice and reassessing after 30-45 minutes.
• Consistency in Practice: Maintain the practice duration based on the initial reading but adjust if severe changes occur.
  • Example: If practice starts in the yellow zone, it’s unlikely to shift to the black zone within a short period, ensuring consistency in the practice routine.

3. Understanding the Margins

• Minimal Impact of Small Changes: Minor fluctuations (e.g., from 92.1°F to 92°F) don’t significantly impact safety but should be monitored.

• • Example: A slight dip from the red to the orange zone shouldn’t drastically alter the practice plan but should be observed for further changes.

4. Addressing District Variability

Different Climates: Schools within the same district may experience varied climates, requiring tailored approaches towards acclimatization. Schools near the coast may have cooler temperatures compared to those in the valley or mountains, despite being under the same heat stress policy.

Choosing the right location for a stationary weather station is crucial to obtain accurate and reliable WBGT readings. The ideal placement should provide an overview of the campus without any obstructions for measurements like wind speed and sunlight.

Key Points

1. Campus Representation
   • Ensure the weather station represents the overall campus climate.
   • At Perry Weather, our aim is to place the station where it can capture data relevant to all areas of the campus.
2. Unobstructed Measurements
   • Place the station in a location free from obstructions to accurately measure wind speed and sunlight, which significantly impact WBGT readings.
   • Tim’s campus has the station mounted on a press box, ensuring it’s high enough to avoid obstructions but still accurately represents campus conditions.
3. Height Adjustment and Recalibration
   • Objective: When placing the station at higher elevations, adjust the wind speed measurements to reflect ground-level conditions accurately.
   • Example: Perry Weather recalculates wind measurements from higher placements (like rooftops) down to a two-meter wind speed to maintain accuracy.
4. Specific Campus Examples
   • Example: One campus has their weather station on top of the gym, providing excellent data representation and reliability.

Example: Another station is positioned on a press box, where recalibration ensures accurate wind data while capturing climate conditions.

Off-campus facilities, such as beach volleyball courts, aquatics centers, and cross-country tracks, pose unique challenges for monitoring and managing WBGT readings. Ensuring accurate readings in these diverse locations is crucial for maintaining athlete safety.

Key Points

1. Site-Specific Measurements
   • Objective: Obtain accurate WBGT readings directly from the off-campus site.
   • As per the bylaw, someone must go to the site and take the readings unless there’s a nearby weather station available for use.
   • For instance, a school with a beach volleyball program can use a nearby weather station within five miles to gather WBGT readings, ensuring the data reflects the conditions accurately.
2. Using Nearby Weather Stations
   • Objective: Utilize existing weather stations within proximity to gather accurate WBGT data.
   • Example: If a nearby weather station is within a reasonable distance (approximately four to five miles), it can provide reliable readings for the off-campus location.
3. Perry Weather Network Integration
   • Objective: Leverage the Perry Weather platform to access a network of weather stations.
   • Clients using Perry Weather can access data from the nearest Perry Weather Station within their network, ensuring accurate readings even when off-campus.
4. Portable Solutions
   • Objective: Use handheld devices for sites without permanent weather stations.
   • For ultimate safety, taking handheld WBGT readings at the actual site ensures the most accurate measurements.

Access to real-time WBGT data is exclusive to Perry Weather subscribers. However, Perry Weather is actively working closely with organizations like the CIF and other state athletic associations to share historical data to inform potential rule changes and provide valuable insights into heat stress conditions.

Perry Weather stations are designed for minimal upkeep. It requires zero maintenance and calibration. They are easily installed within an hour and once installed with a power source (either direct or solar), the stations operate autonomously and transmit data seamlessly to the Perry Weather web and mobile platforms. 

While handheld WBGT devices might seem more intuitive for field use, stationary weather stations can offer the same level of accuracy when equipped with appropriate features and adjustments even if it’s not directly on the field or playing surface. 

• Handheld devices have limitations: Handheld WBGT devices can be less accurate due to factors like lack of radiation shielding and smaller black bulb measurements, leading to more variable readings.
• Stationary systems with adjustments can be accurate: Stationary weather stations, when equipped with proper wind speed adjustments for height, can provide accurate WBGT readings even when placed on elevated structures like press boxes.

Real-world comparisons support accuracy: Field tests and studies have shown that stationary systems with height-adjusted wind calculations produce WBGT readings comparable to those from handheld devices placed directly on the field.

Although heat-related acclimatization issues have not been prevalent in Los Angeles for Tim, they make sure they take proper precautions and preventive measures to avoid heat stress. Here are a few heat illness prevention strategies Tim Moscicki suggests: 

• Focus on Heat Acclimatization
• Stay hydrated
• Take preventative measures to avoid heat stress

Selecting the appropriate WBGT device is crucial for accurate heat stress monitoring. While various options exist, understanding the key differences and considerations can help athletic trainers make informed decisions.

Key Takeaways

• Kestrel is a popular choice: The Kestrel brand is widely recognized and most commonly used in the field of athletic training for WBGT measurement. These tend to be more time-consuming to acclimate and calibrate
• Perry Weather offers potential advantages: Many users have reported higher accuracy and convenience with Perry Weather stations compared to handheld devices.

Consider factors beyond accuracy: Ease of use, data management, and cost should also be considered when selecting a WBGT device.

 Grants may be available to assist in purchasing WBGT devices, including both Kestrel and Perry Weather models. These grants allow you to get the devices at a considerably reduced price through the CIF.

• Recommended 30-minute waiting period: Although there is no standardized wait time, experts suggest waiting at least 30 minutes before resuming activities after leaving the black or red categories.
• Prioritize safety: The decision to resume activities should ultimately be based on a combination of WBGT readings, athlete conditions, and professional judgment.

We’re over a hundred units now, and we’re currently working closely with over 50 different schools and districts across the state with many more coming on board. Each of those districts have multiple stations distributed across their geographic area, so that number is growing. If you’re interested in taking Perry Weather for a test drive with a 2-week free trial, click here.

Yes! Perry Weather tracks not only the wet bulb globe temperature every 15 minutes, but also records it historically in 15-minute increments.

For instance, if you needed to go back and look at the WBGT values between June 1st and June 30th, you can go into the historical data log and export it into a CSV file with the values and correlated time. This takes away the need for manual tracking and physical documentation. Athletic trainers can use this information to forecast and adjust practice schedules, informing coaches about potential changes based on the trends.

Tim says, “It makes things way easier and I can tell my coaches between 12 and 2:30, you might not want to practice during those times because they’re starting to go into the different categories in different zones. It’s completely objective, so it’s hard to argue with the machine and the computer.”

Schools in the East Bay area face unique challenges with high temperatures and poor air quality due to wildfires. It’s essential to monitor WBGT to ensure the safety of students during outdoor activities.

1. Daily Monitoring Recommended
   • Wet bulb globe temperature should be monitored daily, especially as soon as temperatures begin to climb.
   • Tim emphasizes that waiting until temperatures reach 90°F is too late. Start monitoring when temperatures hit 70-75°F to avoid heat stress risks.  If you wait until you get to the 90°F, you’re already a little too late.
2. Temperature Thresholds
   • Begin tracking WBGT when temperatures reach 70-75°F.
   • Even at these lower temperatures, the risk of entering a critical WBGT zone increases as temperatures rise.
3. Air Quality Monitoring
   • Use AQI sensors to monitor air quality during wildfire season in wildfire-prone areas.
   • Example: Schools in the Bay Area use AQI sensors to set thresholds and receive alerts according to CIF guidelines.

This would depend on how far the practices are. If they’re just a few miles apart, you can track the WBGT from one location. If they’re more than a few miles away, you will have to go to each site to track it with the most accuracy.

If you are interested in giving Perry Weather a spin or trying it out, click here for a free two week trial.