Are There Any Safety Concerns With Using Vapor Barriers?

Moisture Accumulation and Hypothermia

When using vapor barrier clothing in cold conditions, the primary concern is the accumulation of moisture between the barrier and the skin. This can happen when the body sweats, and the vapor barrier prevents the moisture from escaping. If the moisture is trapped, it can lead to a decrease in the body’s ability to regulate its temperature, increasing the risk of hypothermia. In extreme cases, hypothermia can set in as quickly as 30 minutes to an hour. To mitigate this risk, it’s essential to wear vapor barrier clothing in conjunction with a breathable layer, such as wool or fleece, to allow moisture to escape.

Choosing the Right Vapor Barrier

When selecting a vapor barrier, consider the activity level and the expected level of moisture production. For low-intensity activities, a lightweight, breathable vapor barrier with a water-resistant treatment may be sufficient. For high-intensity activities, a more robust vapor barrier with a higher breathability rating is recommended. Look for vapor barriers with a water vapor transmission rate (WVTR) of at least 20,000 g/m²/24h to ensure adequate breathability. Additionally, consider the temperature rating and adjust accordingly. A general rule of thumb is to choose a vapor barrier with a temperature rating 10-15°F (5-8°C) lower than the expected ambient temperature.

Preventing Frostbite

Frostbite is another potential risk when using vapor barrier clothing in cold conditions. If the vapor barrier becomes wet or is not breathable, it can lead to a buildup of cold air next to the skin, increasing the risk of frostbite. To prevent this, ensure the vapor barrier is completely dry before use, and consider wearing a base layer of moisture-wicking fabric to keep the skin dry. Additionally, avoid exposing the vapor barrier to cold water or snow, and consider using a vapor barrier with a built-in water-repellent treatment to minimize the risk of wetting.