How to Calculate Grade, Fall, and Length for the Trades Person. Inches per foot, percent, and ratio

[@denisewhite478]

Ty Ty Ty. You have saved me a lot of aggravation. Plus you didn’t make me feel like a total idiot😊

[@ColfaxMath]

Glad to hear it, good luck

[@lojomarketing9025]

Thank you, Mr. Schwartz, I was just about to do a plumbing project and install a drain pipe and I was trying to figure out how to make sure the slope was correct. I came across this video started to watch and thought to myself. Hey this guy looks familiar. Then I realized it was Colfax math and you were my pre-calculus teacher when you first started at Colfax. Great video by the way! Seems like I’m still learning from you after all these years!

[@ColfaxMath]

Great to hear

[@noahfigueroa3534]

You were born to teach! Great video. Thanks.

[@ColfaxMath]

Thank you

[@DottieA]

i,ve watched lots of videos on this subject and this is the only one i understand, THANK YOU1

[@ColfaxMath]

Great to hear, thank you

[@davidbarber5356]

You are great, explaining it so anyone can understand your math. Thank you so much.

[@ColfaxMath]

Great to hear, thank you

[@readplanet23]

Thank You sir for the educational video. I have been a fan of Trigonometry for many years. Keep up the good work. Have A Good Day!

[@ColfaxMath]

Thank you, have a great day

[@dominickquitoni8668]

Thank you. I have an existing water main in conflict with new stormwater drainage. Your lesson helped determine the exact elevation that conflict occurs and help facilitate an approved redesign with minimal owner expense.

[@ColfaxMath]

Great to hear the video was helpful

[@genis8530]

Learned this in heavy equipment Operator school but haven't used it in awhile a good refresher I'm mostly doing slopes 3to1 4to1 grade.

[@ColfaxMath]

Good to hear

[@thomassmearcheck2819]

you are a very good teacher !

[@ColfaxMath]

Thanks again

[@diamondstateexcavationllc6478]

This was a great video! Just bought my first rotary laser and this helped a lot!! thanks!!

[@ColfaxMath]

Glad to hear it

[@joshuawelborn7936]

About the clearest explanation!!

[@ColfaxMath]

Thank you

[@osslv]

Thank you! You keep it simple.

[@ColfaxMath]

Thank you

[@mateusrosa1]

Awesome explanation

[@ColfaxMath]

Thank you

[@thomassmearcheck2819]

you are a great teacher !

[@ColfaxMath]

Thank you

[@Skashoon]

Good stuff, thanks. I’m installing a tankless water heater and it requires a 3 degree slope for the exhaust pipe to prevent rain from flowing back into the combustion chamber. Now I’m befuddled. I used to know all this from geometry and trigonometry but that was in 1971-72. All I want to figure out (or be told) how much drop in inches do I need for a 16” length pipe?

[@ColfaxMath]

Thank you

[@masterroberts5]

Hi there, do you have a video of this formula in millimeters? Chhers

[@ColfaxMath]

Not sure how it is done in metric except direct conversions

[@masterroberts5]

@@ColfaxMath no worries thanks, great video by the way.

[@MikeBonham-s6y]

I’m in the middle of a public sidewalk replacement that passes through my driveway going down hill. Target cross slope of 1.5% with maximum cross slope of 2%. I had no idea what the additional lines on level were for. So on a 4’ level and bubble is about at the outside line to high side means ?

[@MikeBonham-s6y]

Sounds from the video I’m at 1/4 drop per ft which is approximately 2% slope

[@ColfaxMath]

You can check it by finding a level surface and getting a 1inch block and put the level on it over 48 inches, see what the level does, should go to the line.

[@MikeBonham-s6y]

@@ColfaxMathyes I did that and also a 1/4” block. I really like your content. I want to take all the classes. I became rusty over the years. Thanks for doing what you do!

[@krismettrick6371]

I want to learn how to calculate grade for water drainage on a slope. Water is running downhill into our basement. I am excavating in front of our house to prevent water from draining under our house by reversing the slope in front of our house. thank you for helping me with the calculations. it made sense. Does anyone know the slop needed in compacted granite/dirt etc to drain water away from..

[@ColfaxMath]

Not sure how the water actually travels through different types of soil,

[@MoffatLisimba]

Am not aware of the numbers,do we have constants?

[@ColfaxMath]

Just the measurements that you get off the site

[@MoffatLisimba]

What's the formula?

[@genebush791]

Great video

[@ColfaxMath]

Thank you

[@-stealthy-cricket8209]

So, if you have a 6” pipe at an 1/8 “ slope what percentage is 1/8” ? There are no lengths available.

[@ColfaxMath]

If you do 6 divided by 1/8 you get a slope about 1 in 48 which is about 2 percent

[@teewithey5879]

What about if I only know the length and have to work out the fall by only knowing the degree at which it should fall at?

[@ColfaxMath]

If you have one length and angle have to use trigonometry to find the other pieces. There is a table you can use, or similar triangles

[@teewithey5879]

@@ColfaxMath could you elaborate on what to google because I’ve struggled finding anything like it. Could I convert degree to a percentage and work it out that way?

[@ColfaxMath]

@@teewithey5879 Tee, I'll try and get around to making a video on it.

[@irmaguzman4586]

Thank you

[@ColfaxMath]

Thanks for watching

[@aammiranda]

Basic math but great presentation; very helpful

[@ColfaxMath]

Glad it was helpful

[@t.n.1953]

You explained that a 1% slope is the same as 1/100 but how is it expressed as a ratio? Can you explain how ratios are used to express slope, for example a "3:1 slope." Is it for every unit of fall (3) there's a unit (1) of run? That seems extremely steep. Also, how does that translate to percentage?

[@ColfaxMath]

1 over 100 is a ratio. Rise of 1 and a run of 100

[@t.n.1953]

@@ColfaxMath Thank you for your reply. So is a 3:1 slope a rise or fall of 3 and a run of 1? I hear this used in instances where it would make for sense to be a 1:3 slope

[@TheBigdoggg33]

3 to 1 pitch is 3inches of drop for every foot of run. 1st number represents inches

[@harryrantz6748]

I'm building a N scale Talmadge Bridge and coming off the Bridge it has a left hand curve then straight for about 2ft with a 2 inch fall. I'm trying to figure out what the grade should be, and what would the angle be in order for it to go from a 2 inch to a 0 degree with a curve at the top. Is that even possible? Can you help me out? Harry

[@ColfaxMath]

You can measure the height and calculate the run and get the average slope that way

[@bentleynabigon-froese4484]

I was trying to understand this for my own math class, but I'm confused! The total length seems to be a horizontal distance (as in your diagram) but you later refer to total length as the length of the pipe! In fact the pipe will be longer than the "total length" from your diagram, because the pipe is your "hypotenuse". Is this a mistake or am I missing something? Thanks for the video though, it is very helpful!

[@ColfaxMath]

Yes that is correct

[@samanthafranklin9159]

How many inches difference 24 feet2% the fall So what’s the cut to the toe?

[@ColfaxMath]

2% is 2 in a hundred or 1 in 50 or 1/2 in 25 approximately. If you 2% grade you would have to drop a half inch in 25 inches.

[@stepheneurosailor1623]

Very helpful.

[@ColfaxMath]

Glad to hear it

[@kennydixson7851]

I knew all of that. What I really wanted to know was how much length you lose on account of the grade.?!?

[@ColfaxMath]

If I understand your question correctly, you lose the difference between the hypotenuse and the bottom leg

[@reddye2331]

Bro takes the longest way home every day I guarantee u tht.

[@ColfaxMath]

Probably