Quick Answer
Common misconceptions about vapor barrier clothing include the idea that it keeps you dry by preventing all moisture from escaping, and that it can be worn in situations where you're actively generating heat. In reality, vapor barrier clothing is designed to prevent moisture from escaping from your body, but it doesn't prevent moisture from being generated in the first place. This can lead to condensation inside the garment.
Moisture Management Myths
Vapor barrier clothing is often misunderstood as being waterproof or impermeable. In reality, it’s designed to be breathable, allowing moisture to escape from your body while preventing it from escaping from the outside environment. This is achieved through a process called vapor permeability, which allows for the passage of water vapor while keeping liquid water out. A good example of vapor barrier clothing is the eVent fabric, which allows for 10,000-20,000 g/m²/24 hours of moisture vapor transmission. This means that the fabric allows for the passage of moisture vapor at a rate of 10,000-20,000 grams per square meter per 24 hours.
Cold Weather Considerations
When using vapor barrier clothing in cold weather, it’s essential to consider the potential for condensation inside the garment. This can occur when the air inside the garment is colder than the temperature of your skin, causing moisture to condense on the inner surface of the fabric. To mitigate this, it’s essential to wear a breathable base layer under the vapor barrier garment, and to avoid wearing the vapor barrier garment in situations where you’re not generating enough heat to prevent condensation. In general, it’s recommended to wear a vapor barrier garment in temperatures above 32°F (0°C), and to avoid wearing it in situations where you’re likely to be exposed to cold, wet conditions for an extended period.
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