BS EN 806 -2006

Hi Liam

It is quite a complex procedure. You need to consider that there are two equations. One that works exclusively with the LU of the outlet, the second that works with the peak outlet in a section.

For LU's larger than 300:

dim = loading units

m = (log(9)-log(1.7)) / (log(5000) - log(300))

c= log(1.7)-m*(log(300)

flowrate  = exp(m * log(dim) +c)

For LU's smaller than 300:

pdim = peak loading units for section

m = (log(1.7) - log(pdim)/10)) /(log(300)-log(pdim))

c = log(pdim/10) - m * log (pdim)

flowrate  = exp(m * log(dim) +c)

This differs substantially from BS 6700:

For LU's larger than 2000:

dim = loading units 

flow = specified flow rate (if any)

m = 11.2 + (dim-2000) * 0.0039

flowrate = flow + m

For LU's smaller than 2000:

dim = loading units 

flow = specified flow rate (if any)

m = .0.0532 * dim ^ 0.7

flowrate = flow + m

For further information on the pipe sizing standards, please consider this document. For more information about the methods considered by BS 6700, please see this document. 

Best regards,

Hi Liam

It is quite a complex procedure. You need to consider that there are two equations. One that works exclusively with the LU of the outlet, the second that works with the peak outlet in a section.

For LU's larger than 300:

dim = loading units

m = (log(9)-log(1.7)) / (log(5000) - log(300))

c= log(1.7)-m*(log(300)

flowrate  = exp(m * log(dim) +c)

For LU's smaller than 300:

pdim = peak loading units for section

m = (log(1.7) - log(pdim)/10)) /(log(300)-log(pdim))

c = log(pdim/10) - m * log (pdim)

flowrate  = exp(m * log(dim) +c)

This differs substantially from BS 6700:

For LU's larger than 2000:

dim = loading units 

flow = specified flow rate (if any)

m = 11.2 + (dim-2000) * 0.0039

flowrate = flow + m

For LU's smaller than 2000:

dim = loading units 

flow = specified flow rate (if any)

m = .0.0532 * dim ^ 0.7

flowrate = flow + m

For further information on the pipe sizing standards, please consider this document. For more information about the methods considered by BS 6700, please see this document. 

Best regards,