Air Permeability
Unwanted air leaks cause high heat loss, bad sound insulation and draughts. This is why tests are made on the air loss through the joints of a window for 1 hour, at a specified pressure difference (= wind velocity). Engels windows and terrace doors are perfectly airtight, and even with a hurricane wind velocity of 150 km/h, allow less air to pass through than is permitted by the strictest European standard for a soft breeze, (test report on request). For special applications such as burglary resistance, fireproofing or sun-shading windows, please contact us. Note: please make sure that with burglar proof windows you can still escape in the event of a fire.