Quick Maths Flashcards
A 4” diameter stainless steel pipe is 26.5 m (86.9’) in length and requires hangers to be placed at 1.6 m (5.25’) intervals. How many hangers are required to support the pipe with hangers at both ends of the run?
18
six equally equally spaced lavatories are to be installed along a wall that is 530cm long and will be vented with dual vents. Determine the centre to center distance between vents if the fixtures are each 51cm wide?
166cm
what force would be exerted on the gate of a closed 6 inch gate valve if the water pressure acting on is measured 46 psi?
1300
A pipe has a slope of 0.75%. What would that be equivalent to?
1:133
what is the length of a run of pipe that has a total fall of 30“ if the pipe is installed at a grade of 1.5%?
166’ 7 15/16”
L= TF / G
what is the total fall on a drain line that is 146.5 feet long, installed at a grade of 1:100?
17 9/16”
TF=LxG
TF= 146.5x .01
TF= 1.465
A Watermain has internal pressure of 75 psi how far can it go up?
height = 2.31 x PSI
H= 2.31 x 75
H= 173.25’
Watermain has external pressure of 80 psi at what height is 20 psi available?
80-20=60
H= 2.31 x psi
H= 2.31 x 60
H= 138.6’
what is the unit pressure exerted by a riser that is 65‘ high?
Unit pressure = height x .433
UP= 65x.433
UP= 28.145 PSI
find the total force at the base of a 4” riser 150’ High
Total Force = UP X Area
A= 3.14 x R^2
A= 12.5
UP= H x .433
UP= 64.95
TF= UP x A
TF= 64.95 x 12.5
TF= 815.772 LBS
Find the total force on a 6 inch cap that has a pressure boosted to 125 PSI
TF= UP x A
TF= 125 x 28.26
TF= 3532.5 LBS
six equally spaced laboratories are to be installed along a wall that is 530 cm long and will be vented with dual vents. Determine the centre to centre distance between vents if the fixtures are each 51 cm wide.
51 x 6 =306
530 - 306 =224
224 / 7 =32
16+51+16+16+51+16 =166
166cm between dual vents
Pressure balanced, or thermostatic mixing valves shall be designed so that the outlet water temperature does not exceed ….
39C
49C
59C
99C
49C
A heating line is installed using steel pipe with the following information ….
COE : 0.0000067
Length = 200’
Installed temp = 55F
Operating temp = 180F
What is the amount of expansion on this heating line?
Expansion = length x delta T x COE
= 200 x 125 x 0.0000067
= 0.1675
x 12
= 2.01
what is the length of run of pipe that has a total fall of 30“ if the pipe is installed with a grade of 1.5%?
30 / 12 =2.5
1.5 / 100 =0.015
L = TF / Grade
L = 2.5 / 0.015 = 166.66
L = 166’ 7 15/16”
The scale on a blueprint is 1/4 per foot. What is the actual length of a waterline with a plain dimension of 5 5/8”
5.625 / .25 =22.5
A piece of baseboard heating element produces 350 BTUs / hr / ft at 180F. How many feet of element would be installed to handle a heat loss of 4900 BTU on a 30 foot long wall?
4900 / 350 =14
14’
what is the amount of linear expansion of a copper line that is 45M in length and changes temperature from 15 C to 92C (COE is 0.0000168 )
Answer In MM
45 x 77 x 0.0000168 =0.0582
0.0582 x 1000 =58.2 (there is 1000mm in a m)
58.21mm
how many BTUs are required to raise the temperature of 10 lbs of water from a temperature of 4°C (40f) to a temperature of 93°C (200f)?
BTUs = Mass X temperature differential X specific Heat (water = 1) (ice / steam 0.5)
BTU = 10 x 160 x 1 = 1600btu
