Friday, September 10, 2010

Factory Mutual 4020/4021

We have just released a new version of ITSdesign that includes a design for Factory Mutual 4020/4021 (December 2005) tanks. This is currently only in US units as we are working on the conversions for SI units that Factory Mutual did not provide. The Factory Mutual design is still being verified by one of our clients to make sure that we interpreted all of the standard correctly. We will be making changes to this design if any discrepencies are discovered. Factory Mutual has two different options for seismic design using live loads. We chose to use the 25% of live load option. They also require that the sloshing height not exceed the freeboard or you must do an evaluation of the loadings on the roof. We currently have only included the option to require that the freeboard exceed the sloshing height. We did find an error in the equation in 2.15.5 (c) for the design tension load on bolts for seismic. The equation should be multiplied by S rather than divided by S. We have incorporated this in our program.

If you are doing Factory Mutual tanks we would appreciate your evaluation of the design. If you do not currently use ITSdesign software, go to our website at and download a trial copy of our ITSdesign software.

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