How Qatium infers roughness values

Updated

Roughness based on material

If the installation date can’t be found, Qatium will infer the roughness based on material only.

Material HW CM DW
AC: Asbestos Cement 140 0.011 0.10000
ARO: Abrasion Resistant Outerwrap 148 0.0148 0.14800
CI: Cast Iron 130 0.012 0.80000
COPP: Cooper 130 0.011 0.10000
CWOSMJ: Concrete Without Sheet Metal Jacket 140 0.011 0.18
CWSMJ: Concrete With Sheet Metal Jacket 135 0.013 0.36000
DI: Ductile Iron 130 0.012 0.30000
DIL: Lined Ductile Iron 130 0.0148 0.25000
FE: Iron 148 0.0148 0.14800
GI: Galvanized Iron 120 0.016 0.15000
GIL: Lined Galvanized Iron 120 0.0148 0.15000
HDPE: High Density Polyethylene 150 0.009 0.01000
L: Lead 140 0.011 0.01000
LDPE: Low Density Polyethylene 150 0.009 0.01000
MDPE: Medium Density Polyethylene 150 0.009 0.01000
NA: Not available 150 0.0148 0.14800
PC: Prestressed Concrete 150 0.011 0.18000
PE: Polyethylene 150 0.009 0.01000
PE80: Polyethylene 80 150 0.009 0.01000
PE100: Polyethylene 100 150 0.009 0.01000
PVC: Polyvinyl Chloride 150 0.009 0.05000
PVCO: Orientated PVC 150 0.0148 0.05000
RC: Reinforced Concrete 140 0.0148 0.18
S: Steel 150 0.0148 0.10000
SI: Spun Iron 150 0.0148 0.60000
SS: Stainless Steel 150 0.011 0.14800
UNK: Unknown 148 0.0148 0.14800
UPVC: Unplasticized PVC 150 0.009 0.05000

Roughness based on installation date

The value calculated from the material will then be amended based on the pipe’s age, i.e. the number of years since its installation date.

Depending on the head loss formula applied, this is how this works:

H-W: InferredRoughness = Roughness(material)*(1-Age/180)
Value range: [50 ;+∞]

D-W: InferredRoughness = Roughness(material)/(1-Age/180)
Value range: [0.05 ; 50]

C-M: InferredRoughness = Roughness(material)/(1-Age/180)

Value range: [0 ; 0.05]

What if the resulting roughness value is out of range?

Qatium would use the value of the range limit for the corresponding headloss formula.
E.g. For H-W, if the value calculated is 40, the inferred value would be 50.