A test chamber or box made of plywood, plastic, or other suitable material and sealed against the test specimen. Test chambers mounted on the interior must be made so that interior surfaces and joints of the specimen can be easily observed for water penetration during the test. No part of the testing chamber shall come in contact with or restrict any point where water pentration may occur. At least one static air pressure tap shall be provided to measure the chamber air pressure versus the ambient (interior-exterior) air pressure and shall be so located that the reading is unaffected by exterior impinging wind, or by the velocity of air supply to or from the chamber. The air supply opening into or exhaust from the chamber shall be arranged so that air does not impinge.
directly on the test specimen with any significant velocity. A
means of access into the chamber may be provided to facilitate
adjustments and observations after the chamber has been
installed.