(129c) Technical Analysis of Tents Sited in Accordance with API RP 756

The American Petroleum Institute
(API) Recommended Practice 756, Management of Hazards Associated with
Process Plant Tents (API RP 756) provides guidance for the siting of tents
at onshore facilities covered by OSHA 29 CFR 1910.119 and is primarily
focused on process related hazards (e.g., explosions, fires and toxic material
releases).  For the siting of tents that could be impacted by potential
explosions, API RP 756 specifies different zones defined by the standoff distances
from the edges of congested volumes to the edges of the tents being sited. 
This paper summarizes the types of tents that can be sited in these different
zones and provides details on the different levels of technical analyses
required.

For siting of most tents in
either Zone 1 or Zone 2, detailed structural analysis is typically required to
demonstrate that adequate tent performance is provided if the tent is subjected
to blast loading.  This paper shows that a detailed structural analysis utilizing
finite element analysis techniques, which fully couples the blast wave propagation
and the structural response, is particularly useful in demonstrating the
performance of light weight structures (such as tents) subjected to blast
loading.  The interaction between a tent and a blast wave is substantially
different than the interaction of a rigid structure and a blast wave.  Finite
element analysis calculations demonstrate how the blast wave moves through the
tent and influences the tent response.  In addition, this fully-coupled
analysis technique can highlight aspects of a design that may otherwise not be
considered (e.g., the development of significant net uplift forces on the tent
anchorage).