could it be this be an ASPE ERROR?

[afa13]

this passage is taken from ASPE:

"A minimum slope of 1/4 in./ft (6.4
mm/m) should be provided for pipe 3 in. (80 mm)
and smaller, 1/8 in./ft (3.2 mm/m) for 4–6-in.
(100–150-mm) pipe, and 1/16 in./ft (1.6 mm/m)
for pipe 8 in. (200 mm) and larger."

If u convert any of the slopes given in english units u get a different value than its given equivalent in metric units as given.
For instance, if u convert 0.5 in/ft u get a slope percentage of 2%. Try and convert its given equivalent(the value between parentheses) 6.4mm/m u get a percentage of 0.64%.
it only works if u use a conversion factor on the upper part (in) and change the unit of the lower part without using a conversion factor for example let us take .25in/ft=6.25mm/ft=6.25 mm/m but that rules out proportionality...does anyone have an understanding of this?

 

[zdas04]

Yep, it looks like the number in parentheses is actually mm/ft. You found a mistake. It happens. Every standard I have on my shelves has an errata page. Send this to the ASPE. Use the correct value.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[BigInch]

1/2 inch per foot = 0.5 in/ft = 0.5 inches /12 inches = 0.04167
0.04167 x 100 = 4.2% slope, or 4.2 feet per 100 feet.
That is a 4.2% slope.


"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek