# Need help with school/math?



## 778 Plumber (Jan 17, 2013)

I have the next couple weeks off, in between big jobs. I've pulled some of my school books/codebook out to review. If anyone has any questions regarding information taught in 1,2,3,4 year tests or the IP in Canada, specifically BC- let me know and I'll see if I can help. By asking questions you'll help yourself understand better, help someone else that might have the same question but doesn't want to ask it and help me by refreshing information I haven't specifically used in a while. 

Here are some constants, all in one spot, that may help you along the road someday:

1 foot = 12 inches
1 yard = 3 feet
1 mile = 1760 yards
1 mile = 5280 feet
1 pound = 16 ounces
1 ton = 2000 pounds
1 inch = 25mm
1 inch = 2.5cm
1 meter = 3.28 feet
1 sq foot = 144 inchs
1 sq yard = 9 sq feet
1 acre = 4840 sq yards
1 sq mile = 640 acres
1 cu foot = 1728 inches
1 cu yard = 27 cu feet
1 psig = 2.31 feet
1 psig = 6.89 kPa
1 US gal = 3.831 litres
1 imp gal = 4.5451 litres
1 KwH = 34.12 BTU
1 US gal = 8.33 pounds
1 Imp. gal = 10 lbs
1 cu foot = 7.48 US gal
1 cu foot = 6.24 Imp gal

*F = (*C x 9/5) + 32 (To get Fahrenheit from Celsius)
*C = (*F - 32) x 5/9 

Anyways, not sure if it will be but I hope its useful to some.


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## rjbphd (Feb 5, 2010)

778 Plumber said:


> I have the next couple weeks off, in between big jobs. I've pulled some of my school books/codebook out to review. If anyone has any questions regarding information taught in 1,2,3,4 year tests or the IP in Canada, specifically BC- let me know and I'll see if I can help. By asking questions you'll help yourself understand better, help someone else that might have the same question but doesn't want to ask it and help me by refreshing information I haven't specifically used in a while.
> 
> Here are some constants, all in one spot, that may help you along the road someday:
> 
> ...


I get my information from Burnham heating helper book to figure out my Weil Mclain heating jobs.


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## U666A (Dec 11, 2010)

Again, must contact my ex for my teaching syllabus...


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## Relic (Sep 30, 2012)

I can't believe you typed that all out lol.


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## revenge (Jun 30, 2011)

That guy is trying to give knowledge give you props buddy


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## 778 Plumber (Jan 17, 2013)

no takers?


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## rjbphd (Feb 5, 2010)

I just use my sliding folding ruler..


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## SewerRat (Feb 26, 2011)

778 Plumber said:


> no takers?


We're just scratching our balding scalps trying to think of something we don't already know but nothing comes to mind. May take some time.

:jester:


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## Gettinit (May 9, 2012)

OK, here is one for you. I know what it takes in my state.

What does it take to get your licensing board to amend the plumbing codes with your ideas?


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## Gettinit (May 9, 2012)

Strictly plumbing?


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## SewerRat (Feb 26, 2011)

Math question (not plumbing)- If you could pull a string all the way around the earth and then stake another string 6" off the surface directly above the other string, how much longer would the top string be than the bottom string after encircling the entire planet?


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## plbgbiz (Aug 27, 2010)

sewerrat said:


> math question (not plumbing)- if you could pull a string all the way around the earth and then stake another string 6" off the surface directly above the other string, how much longer would the top string be than the bottom string after encircling the entire planet?


37-45/64" (rounded to the nearest 64th of an inch)

((2 * pi) * additional height units)


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## TX MECH PLUMBER (May 27, 2011)

6.28 feet. You have to use radius pie and circumface I can't spell or type but math I can do !!!


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## TX MECH PLUMBER (May 27, 2011)

Is that rite ???


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## plbgbiz (Aug 27, 2010)

Adding 6" to the height of the circle....

((2 * pi) * 6") = 37 79/113" = 3 16/113' 

Or approximately 3' 11/16" of additional string.


Using the calculator on my iPad allows for a lot of decimal points on pi and crazy fractions but the formula is pretty simple.


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## TX MECH PLUMBER (May 27, 2011)

O I thought he said a foot


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## TX MECH PLUMBER (May 27, 2011)

6.28/2 is 3.14. I was so wrong but so close !!! Lol.


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## dclarke (Dec 22, 2012)

TX MECH PLUMBER said:


> 6.28/2 is 3.14. I was so wrong but so close !!! Lol.


You may have just been doing 3.14 while he may have used the longer version

Sent from my Galaxy Nexus using Plumbing Zone


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## TX MECH PLUMBER (May 27, 2011)

C= 2 TT (r). Then add 1' 

C= 2 TT R +1'


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## dclarke (Dec 22, 2012)

I'm not great with math. A lot of it looks like hieroglyphics

Sent from my Galaxy Nexus using Plumbing Zone


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## plbgbiz (Aug 27, 2010)

dclarke said:


> I'm not great with math. A lot of it looks like hieroglyphics
> 
> Sent from my Galaxy Nexus using Plumbing Zone


I found this. 

http://www.abc.net.au/science/surfingscientist/pdf/conundrum17.pdf


It explains the ring around the earth thing pretty well. Once you get it, it really is pretty simple.

I had a math teacher in the 6th grade that was always coming up with silly stuff like this so we would see how practical math is. After all, who doesn't need to now how to measure a rope around the earth 6" off the ground.


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## TX MECH PLUMBER (May 27, 2011)

Circumference. = diameter x 3.1416. So for this answer. Add 1' to the diameter (6" for both sides) but you have to know the radius or o.d. Of the earth.


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## dclarke (Dec 22, 2012)

plbgbiz said:


> I found this.
> 
> http://www.abc.net.au/science/surfingscientist/pdf/conundrum17.pdf
> 
> ...


As soon as I looked at it the first thing that came I to my head.....the earth isn't round. Its oval. The equatorial circumference and polar circumference are different.

Sent from my Galaxy Nexus using Plumbing Zone


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## rjbphd (Feb 5, 2010)

dclarke said:


> As soon as I looked at it the first thing that came I to my head.....the earth isn't round. Its oval. The equatorial circumference and polar circumference are different.
> 
> Sent from my Galaxy Nexus using Plumbing Zone


No way!! Its flat as the map showed on paper!


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## SewerRat (Feb 26, 2011)

TX MECH PLUMBER said:


> Circumference. = diameter x 3.1416. So for this answer. Add 1' to the diameter (6" for both sides) but you have to know the radius or o.d. Of the earth.


No you don't. Like you said circumference equals diameter x pi. You add one foot to the diameter no matter what the total diameter of the earth is. Thus, the top string would be 3.1416' longer no matter if you are increasing the diameter of the earth by a foot or something smaller like a water heater.


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## BigDave (Mar 24, 2012)

778 Plumber said:


> no takers?


Please provide the ratio to convert CFH to BTUs


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## plbgbiz (Aug 27, 2010)

BigDave said:


> Please provide the ratio to convert CFH to BTUs


1 CF equals approximately 1000 BTU's


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## Gettinit (May 9, 2012)

plbgbiz said:


> 1 CF equals approximately 1000 BTU's


Approximately because it may be different in different places.


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## alberteh (Feb 26, 2012)

or 2500 btus propane


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## Tommy plumber (Feb 19, 2010)

plbgbiz said:


> 1 CF equals approximately 1000 BTU's


 







That was a question on my state exam. Propane is approx. 2500 BTU's per CF. That's why propane delivery lines are smaller than for natural gas.


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## plbgbiz (Aug 27, 2010)

alberteh said:


> or 2500 btus propane


Yep, I was thinking NG.


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## BigDave (Mar 24, 2012)

Can't figure where I got this, but I've been using 1,020 for YEARS
It's funny how we get things in our heads and then are humbled by
the realization of our mistakes:blush:
At least I was not THAT far off the mark...


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## Gettinit (May 9, 2012)

BigDave said:


> Can't figure where I got this, but I've been using 1,020 for YEARS
> It's funny how we get things in our heads and then are humbled by
> the realization of our mistakes:blush:
> At least I was not THAT far off the mark...


That is also what I use after verifying it with my local gas company. When I travel outside of their service area I always call and ask. In fact my start up reports requires me to provide the amount for each job.


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## TX MECH PLUMBER (May 27, 2011)

Gettinit said:


> That is also what I use after verifying it with my local gas company. When I travel outside of their service area I always call and ask. In fact my start up reports requires me to provide the amount for each job.


Can y'all explain. What y'all use this for. Is it sizing pipe ?? Sizing units like heaters. Flue pipe ??? I no it's all on the masters and have seen it a bit. I get what btu is. Cfh. Cubic feet per hour. Rite ??? How about some math lessons. Lol


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## Gettinit (May 9, 2012)

TX MECH PLUMBER said:


> Can y'all explain. What y'all use this for. Is it sizing pipe ?? Sizing units like heaters. Flue pipe ??? I no it's all on the masters and have seen it a bit. I get what btu is. Cfh. Cubic feet per hour. Rite ??? How about some math lessons. Lol


It is needed when sizing gas lines, flue pipe and tuning a gas burner.


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## plbgbiz (Aug 27, 2010)

TX MECH PLUMBER said:


> Can y'all explain. What y'all use this for. Is it sizing pipe ?? Sizing units like heaters. Flue pipe ??? I no it's all on the masters and have seen it a bit. I get what btu is. Cfh. Cubic feet per hour. Rite ??? How about some math lessons. Lol


We're gonna need a much bigger thread for that. :laughing:


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## Plumbus (Aug 4, 2008)

Actually, the BTU value is a moving target. My utility (PG&E) says they deliver at anywhere between 750 and 1150 btu's per cubic foot with a monthly average of 1000 to 1060btu's.


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## 778 Plumber (Jan 17, 2013)

BigDave said:


> Please provide the ratio to convert CFH to BTUs


Calorific values:

Natural Gas (CH4) 1000btu/ft3
Propane (C3H8) 2520btu/ft3
Butane (C4H10) 3260btu/ft3

"A furnace is rated at 70,000 btuh and runs on propane. What is the required flow rate in cubic feet per hour?"

70,000 btuh / 2520 btuh/ft3 = 27.78cfh


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## Gettinit (May 9, 2012)

Plumbus said:


> Actually, the BTU value is a moving target. My utility (PG&E) says they deliver at anywhere between 750 and 1150 btu's per cubic foot with a monthly average of 1000 to 1060btu's.


I have never heard such a thing, that is quite a swing . They should stay out of Canada then. That much of a swing would really muck up equipment calibrations.


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## 778 Plumber (Jan 17, 2013)

Heres a question for some of you guys. try to answer it without googling it. im heading to the gym and ill post the answer after

"A 20lb propane tank is used to run a BBQ rated at 25,000 BTUH. How long will the propane tank be able to fire up the BBQ?"


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## phishfood (Nov 18, 2012)

How do you solve for the square root of a number?


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## TX MECH PLUMBER (May 27, 2011)

Hit the root button !!!lol


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## phishfood (Nov 18, 2012)

Du-huh, why didn't I think of that?

Actually, I do a lot of math in my head, and if I can understand the square root formula, maybe I can break it down to do that in my head.


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## plbgbiz (Aug 27, 2010)

phishfood said:


> Du-huh, why didn't I think of that?
> 
> Actually, I do a lot of math in my head, and if I can understand the square root formula, maybe I can break it down to do that in my head.


I remember this being taught in school and I think I forgot how as soon as the bell rang.

There are two ways to do it. One is basically a process of elimination and there is a long-hand version involving a multi-step algorithm.

This link explains the process pretty simply>>
http://www.homeschoolmath.net/teaching/square-root-algorithm.php


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## phishfood (Nov 18, 2012)

Don't think I will be doing that one in my head anytime soon....


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## plbgbiz (Aug 27, 2010)

phishfood said:


> Don't think I will be doing that one in my head anytime soon....


Me either. Somewhere in history there was a 6th grade genius that said, "Screw this! I'm going to invent a button that does it for me." I think his last name was Tandy.


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