Roof Sailing Wind and Weather Assessment 1 — Questions and Answers
Question 1: Which Beaufort wind scale number corresponds to a sustained wind speed of approximately 25–31 mph (fresh breeze)?
- Force 3
- Force 4
- Force 5 (Correct answer)
- Force 6
Correct answer: Force 5
Beaufort Force 5 (fresh breeze) corresponds to sustained winds of approximately 19–24 knots (25–31 mph), causing small trees to sway.
Question 2: What weather condition creates the most significant ice hazard on roofing surfaces in the US?
- Freezing rain (glaze ice) (Correct answer)
- Light snowfall
- Heavy snowfall
- Frost
Correct answer: Freezing rain (glaze ice)
Freezing rain creates a thin, nearly invisible glaze ice layer that is far more slippery than packed snow or frost.
Question 3: What is the primary danger of working on a roof during thunderstorm conditions?
- Reduced visibility
- Lightning strike risk — workers are the highest point (Correct answer)
- UV radiation exposure
- Dehydration
Correct answer: Lightning strike risk — workers are the highest point
Workers on rooftops are elevated and exposed, making them prime lightning strike targets during thunderstorms.
Question 4: Which type of cloud formation is the most reliable indicator of imminent severe weather requiring work stoppage?
- Cirrus
- Cumulus
- Cumulonimbus (Correct answer)
- Stratus
Correct answer: Cumulonimbus
Cumulonimbus clouds are towering storm clouds that produce lightning, heavy rain, hail, and tornadoes — all requiring immediate work stoppage.
Question 5: What relative humidity level begins to significantly increase the risk of heat stroke for workers performing heavy physical labor on rooftops?
- Above 40%
- Above 60% (Correct answer)
- Above 80%
- Above 90%
Correct answer: Above 60%
Relative humidity above 60% significantly reduces the body's ability to cool itself through sweat evaporation, increasing heat stroke risk.
Question 6: What is wind-driven rain's primary structural impact on roofing systems?
- Reducing UV degradation
- Forcing water under laps and flashings, causing leaks and structural damage (Correct answer)
- Cooling hot roofing surfaces
- Improving adhesion of roofing membranes
Correct answer: Forcing water under laps and flashings, causing leaks and structural damage
Wind-driven rain can force water under lap seams and flashings at angles that gravity-fed rain cannot reach, causing leaks and deterioration.
Roof Sailing Wind and Weather Assessment 1
Which Beaufort wind scale number corresponds to a sustained wind speed of approximately 25–31 mph (fresh breeze)?