Safety Grate Design
Safety Grate Design
(OP)
I have been asked to design a safety grate for fall protection. The grates are over a hopper which holds biosolids (75% water & 25% biosolids). The biosolids have the consistency of mashed potatoes. The biosolids are 60-pcf and are dumped in 25-ton loads at a rate of 25-ton/minute. I know how to design the grates for the fall protection loads but I'm not sure how to figure the loading due to the flow of the biosolids through the grates? I plan to space the bar grates at about 10-inches on center to allow the material to flow easily through the grates. However, how do I determine if material build-up due to bridging may occur?
Thanks in advance
Thanks in advance






RE: Safety Grate Design
RE: Safety Grate Design
RE: Safety Grate Design
Also, I should meantion that I dont think OSHA walking and working surfaces standard would appy here. You just don't want someone to pass through. Maybe there are some other applicable OSHA requirements.
RE: Safety Grate Design
There are at least three good reasons to be conservative:
1. Someday the grating may plug (from out of spec material, etc.) and load will increase.
2. The grating will be eroded by material flow over time, reducing it's crossection.
3. The day will come when the plant will ask you something like this: "We want to lay steel plates over the grating and drive a motorized man-lift onto the plates to paint the overhead steel. Is that ok?"
Suggest that you use engineering judgment to assume a conservative uniform static depth of material and size the grating to safely support that load.
www.SlideRuleEra.net![[idea] idea](https://www.tipmaster.com/images/idea.gif)
RE: Safety Grate Design