Structural Load Analysis per ASCE 7 & PIP STC01015
PIP STC01015 recommends 40 PSF for preliminary design
ASCE 7-22 3-second gust. 115 mph typical for Risk Category II
From ASCE 7 seismic maps or USGS tool. 0 to skip seismic.
1.0 standard, 1.25 essential, 1.5 hazardous
Understand pipe rack structural design, load paths, ASCE 7 wind analysis, and foundation requirements
Pipe rack design must consider dead loads (pipe weight, insulation, contents, structure self-weight), live loads (cable trays, maintenance access), wind loads per ASCE 7 (velocity pressure on pipes and structure), seismic loads (base shear distributed vertically), thermal loads from pipe expansion, and occasional loads such as hydrotest. These are combined using ASCE 7 LRFD load combinations to determine the governing design case.
Typical pipe rack design loads range from 35-80 PSF per level for piping, 10-15 PSF for cable trays, and 15-25 PSF for structure self-weight. PIP STC01015 recommends using 40 PSF uniform piping load per level for preliminary design when individual pipe loads are not yet defined. Total gravity loads typically range from 60-120 PSF per level including all components.
Wind loads on pipe racks are calculated per ASCE 7. The velocity pressure qz = 0.00256 x Kz x Kzt x Kd x V-squared is applied to the projected area of pipes and structure. For multiple rows of pipes, shielding factors of 0.5-0.7 reduce wind on leeward rows. The exposure category (B, C, or D) determines the velocity pressure coefficient Kz at each elevation.
Pipe rack beams supporting piping are typically limited to L/240 for total load deflection and L/360 for live load deflection per AISC and PIP STC01015. For beams supporting sensitive equipment or instrumentation, L/360 total load may be required. The bay span (typically 20-30 ft) divided by the appropriate limit gives the maximum allowable deflection.