Holidays and Traditions Can Class E hard hats be vented? Can Class E hard hats be vented? CLASS E: Class E hard hats are designed to reduce exposure to high voltage conductors and offer protection up to 20,000 volts. These helmets cannot be vented. Related Posts:What is the latest ANSI standard for hard hats?How to Measure your head for a hat and how to measure your hat size.What is the voltage on each leg of 480 3 phase?How long does Snell rating last?