(43b) Vapor Cloud Explosion Test of Air-Inflated Fabric Structure

Portable buildings have become of increasing interest to refining and chemical processing facilities with respect to facility siting requirements.  While trailers and blast resistant modules (BRMs) can be used for some modular applications, tents and fabric structures have also become desired for certain situations.  However, the blast response of fabric structures is not yet clearly defined and understood throughout the blast design community.  The American Petroleum Institute (API) has formed a committee to develop a Recommended Practice (RP) to provide guidelines for the siting of tents and other soft-sided structures.

One type of modular fabric structure is an air-inflated tent.  A specimen of this type has recently been subjected to the effects of a vapor cloud explosion (VCE) in a controlled test environment.  The VCE for this test was initiated inside a three-walled cubicle, referred to as the Deflagration Load Generator (DLG) test rig, using propane and an internal matrix of congestion.  The test involved a deflagration event that imparted a thermal flux and a free-field blast load of 2.9 psi for 34 msec at the front wall of the structure.  The reduced blast loads and thermal effects inside the tent were compared to those outside the tent.  In addition, the attenuation of blast loads behind the tent was also examined, as well as shielding effects of the tent.  The structural response of the tent was captured with high-speed video, and observations on the motion of the tent are provided.