4 replies to this topic

[krishnamurthy]

I am currently doing  one adequacy check project, wherein i need to check the line sizing for 30 years old pipe. For new pipes we can use the roughness factor for line sizing,  but for the 30 year old exisiting pipe,the roughness factor would have changed.What we need to do in this scenario?.Please explain me.

[varunpassi]

Material Nature of Material      Roughness [mm]    Roughness [inch]         Steel pipe drawn, new 0.02 - 0.1 0.0008 - 0.004   welded, new 0.05 - 0.1 0.002 - 0.004   galvanized, new 0.15 0.006   used, cleaned 0.15 - 0.2 0.006 - 0.008   lightly corroded 0.1 - 0.4 0.004 - 0.016   severely corroded 0.4 - 3 0.016 - 0.12   light scaling 1 - 1.5 0.04 - 0.06   heavy scaling 1.5 - 4 0.06 - 0.16   bitumed coated 0.05 0.002         cast - iron pipe new 0.25 - 1 0.01 - 0.04   corroded 1 - 2 0.04 - 0.08   with scaling 1 - 4 0.04 - 0.16         concrete pipe smooth finish 0.3 - 1 0.012 - 0.04   rough 1 - 3 0.04 - 0.12         Sheet steel smooth 0.07 0.0028         Glass, lead, copper, brass   0.0001 - 0.0015 4·10^-6 - 60·10^-6
 

Try the above values.. Hope this may be useful to you.

[varunpassi]

Try this link also. It gives a better clarity on the values.

 

http://www.engineeri...ents-d_798.html

 

Regards,

Varun 

[katmar]

See the very comprehensive replies by Art Montemayor in the thread "Ductile Iron Pipe Roughness"

 

http://www.cheresour...pipe-roughness/

 

 

[Root]

I done for 40 year old  30'' dia pipe, i used scan analysis for pipe thickness. you need to ask your inspection and reliability department for latest inspection reports and then rerate the lines for new operating conditions.

Cheers

Toor