WEBVTT

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Hello, I'm Alex Brown, and I'd like to introduce you to the Bar Grating Design

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Aid. This tool allows you to design the most appropriate grating size and

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type for structural, vehicle, or stair tread use.

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It takes your scenario and either selects a grating size for you or

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verifies if your selected size is suitable. Let's jump in.

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Starting at the top, you'll see two tabs here, one for bar grating design and the

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other for stair tread design.

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So that's a little more specialized use of grating, but that can help for

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number of stair treads and how to size them.

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And then coming down a little bit, you can input a project name, job number, your

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name as the engineer, and then that will all be printed on the final

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analysis package. And that's going to be a PDF download of all of

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my inputs and outputs.

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These are optional fields though. You can leave them off if you desire.

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Then coming down a little bit more, the left half is going to be all of my inputs.

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So what I'm using the grating for, what kind of conditions I have, what type of

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configuration I need, and then on the right side will show my

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outputs. So, if it's selecting a size for me, that's printed

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here, or if I'm manually specifying a grating type

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and a loading condition, it will tell me if it works or not.

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As you're making changes, just watch this top right area for a loading

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icon that pops up,

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and that just shows that it's actively thinking at that moment.

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So I'll go ahead and go through some of these inputs here.

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So for application, either structural or vehicular can be selected,

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and generally, you want to work from top to bottom as you punch the stuff in.

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For the usage,

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catwalk, fire escape, stairway, or a walkway, not an exit.

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Those are all provided there. Those have different requirements and suggestions.

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This tool does handle imperial and metric.

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And we'll go ahead and we'll just select a few options

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here in metric.

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For the configuration, you can see here we've got standard, close mesh,

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ADA compliant, and then their associated configurations, so 30 W

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102 with three and five bar. And the way to read that,

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that's going to be 30 millimeters for your bearing bar spacing.

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Your cross bar spacing, in this case, 102

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millimeters from bar to bar.

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And then your bearing bar sizes are going to be three millimeters and five

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millimeters.

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And then those change depending on the usage.

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So you can see the heavy duty or extra wide.

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All of those are going to impact bar sizes and spacing.

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Once my configuration is selected, I can select a specific bar

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size, so a 25 millimeter by three millimeter if I want to,

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or upsize from there, or I can just select Pick for me, and it will

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select the appropriate size for the given loading I'm looking at.

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And for that, I do need a clear span, so we'll put in 1.5 meters.

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Surface can be smooth or serrated, depending on the

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usage of the grating.

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And then based on those inputs, it'll suggest an optimal size for me, so a

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30 W 102, 32 by 3.

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Jumping to the stair tread tool. This one has a different

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layout. So here you actually select a design standard, so

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International Building Code, OSHA, or NAAMM MBG 534 Assumptions from the stateside.

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Those all have different requirements for stairs as far as minimum

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rises, runs, sizes. So you can select an appropriate one here.

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And then based on that,

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you communicate what the stair rise is, the width, the flight,

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and then based on that, the tool will recommend the number of stairs needed and

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the size that's needed.

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All of these inputs and outputs can be printed with the Print Analysis

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button here and saved as a PDF.

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So let's jump into an example. We'll go back to the Bar Grating Design

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tab. Structural is good. Maintenance catwalk is good.

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Metric and one and a half meters. That's all well and good.

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For the configuration, we will continue to look at a 30 W 102.

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And bar size, Pick for me. We'll change the surface back to smooth here.

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And then based on all of that, we still have that 30 W 102, 25

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by 3.

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And that's based on this uniform load here of 1.92

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kilopascals. That comes from NAAMM MBG 534,

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a reference from the United States.

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If we wanted to bump that up to something heavier, let's say seven.

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Based on that heavier loading, the tool did increase the suggested size

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here to a 32 by 5. So a little bit deeper of a bearing

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bar. If we were looking at a vehicular usage instead of

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structural, we can change that here.

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And then that's going to have different usage options as well.

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Let's say it's just a passenger vehicle.

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And now with that same 1.5 meters, no good size is

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available. The loading is much heavier, with much different

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deflection criteria.

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Based on that, and you can see all the assumptions here,

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nothing will work with our standard grating configuration.

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So a couple of changes that we can make.

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If we just tighten that span up to half of a meter.

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Now, that is a short enough span that I am able to make a standard

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configuration bar grating work. 44 by 5 is the bearing bar

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size.

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But if we have to have that 1.5 meter,

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maybe a different configuration is required.

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We can bump that up to a heavy duty configuration.

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And now, 30 HW for heavy duty, 102 76

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by 6 grating does work.

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And I can print my analysis as a PDF

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I'm able to download that right here

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with all of my inputs, outputs, and assumptions listed out here for my

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reference that I can put into a project calculation package.

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Jumping over to the Stair Tread tab,

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let's say you were working on something stateside, so Imperial units, just

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following OSHA standard guidelines.

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For surface type, we'll say smooth.

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And then the stair rise, we'll do 60 inches, which is about 5 feet

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or 1.5 meters.

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Stair flight, you'll notice is listed.

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That can be between 50.35 inches and 103.92

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inches.

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So we'll go ahead, we'll say 60 inches as well.

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The rise and the run are the same.

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Again, for the width, there's a requirement here per OSHA standard of 22

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inches, and let's say that it is 30 inches wide.

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And then the step run here,

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we've got a min and a max, and then it automatically generates what that step run

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is.

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So you can see that defined here in the diagram, that run dimension.

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The depth can be overridden,

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and the bar spacing can also be overridden.

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But otherwise, based on all of this geometry, and again, based on that

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OSHA design standard,

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I'm looking at six stairs using

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19W4 two by 3/16 bar grating, so a

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two-inch by 3/16 bearing size, 19/16

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spacing there,

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eight bars wide, 30 inches long. So all of that is defined here.

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So I can print this calculation, and I can hand it over to someone to fabricate

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and supply this material for me now.

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I do want to point out how important the design standard is because it does change

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from spec to spec. So OSHA standard, everything was fine,

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but if instead I was using IBC occupancy group

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I-3, F, S, H, or occupancy less than 50,

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that has different requirements.

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So you can see that stair flight, that has a higher minimum 93 inches

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now, so my 60 inches is not sufficient and no

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good for my treads needed. The calculation doesn't come through.

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And that's the bar grating design aid.

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It's a great tool that addresses three scenarios where bar grating is commonly

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used, from structural loading for human occupancy, to being driven on by

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vehicles or forklifts, to a regular flight of stairs.

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And with that, happy specifying.