For certification of blast resistant windows, current tests consist of arena tests or large air gun tests. Arena tests involve the detonation of more than 1000 pounds of explosives with windows placed in the range of hundreds of feet. The result of an arena test is a loading on a window consistent with an expected industrial or terrorist blast. Due to the nature of this type of test, only a limited number of facilities are available and operational costs can be extremely high. Air gun tests involve the use of compressed air and a failing diaphragm fired through a large tube. Although this test is more cost effective and easier to administer with lower environmental impacts, it is not an explosive loading and does not create a negative phase on the tail of the pressure pulse. Simply using a small charge in close proximity to the window is not a viable option either. The pressure peak can be reached using this method, but the duration of the pressure pulse is such that the positive phase impulse is on the order of ten times less than that for an arena test. With an increased need for testing and certification of blast resistant windows, the University of Missouri at Rolla in conjunction with Winco Windows, an architectural window manufacturer in St. Louis, MO, has developed a method for providing an explosive air blast nearly identical to a large scale arena test using only 0.5 pounds of desensitized RDX. The simulator consists of a 60 foot long steel structure which is designed to channel blast energy from the explosive charge. The tube minimizes energy loss and dispersion associated with increased standoff, while allowing the wavelength of the blast wave to reach over 20 milliseconds. This duration mimics an arena test, while still obtaining the desired peak pressures. Essentially, the wave form replicates that of an arena test. This paper describes the development of the facility and includes examples of its use for testing blast resistant windows. Results of window testing ranging from varying degrees of success to spectacular failure are presented.