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R-3312 Foam Maximum Depth Rating

Hello Team,

I’m presently trying to design a vehicle for a 200m+ depth rating. As stated in the product description of foam R-3312, it is tested up to 182m with coating. I would like to know the actual operating range of R-3312, whether it can withstand greater depths or whether it was tested only up to 182m. R-3312 has a compressive strength of 2750 psi. Does it mean it can withstand a depth of 270 m without any property change? or does any other factor needs to be considered?

Please provide some insight.

Thank you
Nirmal Thomas

Hi Nirmal,

The ratings for this foam come directly from the manufacturer, General Plastics. In our experience, the failure mode that happens past the rated depth is increased water absorption, reducing the buoyancy. Basically it becomes waterlogged at greater depths.

I’m not sure how much safety factor was added to the rating by General Plastics, but I think there is at least a little margin.

-Rusty

At 200m depth the pressure is only 306 psi.

http://www.calctool.org/CALC/other/games/depth_press

Hi Rusty,

Thank you for your valuable information.

Hi Darrell,

Thank you for pointing out the error.

Hey Rusty

Have you performed “crushinator” study for R3312 foam beyond the 182m pressure rating. And cound you share the results post 182m, if available. Particularly the the water absorbed by the foam etc…

Thanks

Hi Nirmal,

We did do some tests a long time ago, but I don’t have good documentation of the results, unfortunately. At the time we were evaluating other (less expensive) types of polyurethane foam from other manufacturers that were being advertised as buoyancy foam. We found that those typically absorbed much more water than the R-3312 foam, even at much lower depths. The R-3312 absorbed the least water of any foams we tried.

I’m sorry I don’t have any more info than that.

-Rusty