An airborne infection isolation room exhaust system is being designed. The discharge point will be equipped with an accessible HEPA filter upstream of the exhaust fan, rated at 99.97% efficiency via the DOP method. What is the minimum required distance this discharge point must be from an operable window?

• 25 feet, unless a reduced distance is specifically approved by the enforcing agency
• 50 feet
• 7 feet above the roof
• 10 feet