Underground galvanized pipe protection
Underground galvanized pipe protection
(OP)
I have a situation in which my client is requiring that the potable water lines be underground. This is galvanized pipe and according to general specs from the client , underground pipe need to be sandblasted and covered with coal tar epoxi. is it required to do this? can I install this pipe naked?
gerardo
gerardo





RE: Underground galvanized pipe protection
The method suggested by your client may last longer but only if it is installed perfectly, any pinhole in the coating caused by either poor coating application or damage during installation or by the backfill material will cause an acceleratied corrosion at the point of defect. Additional requirement of holiday detection and cathodic protection typically are included in this type of corrosion protection system.
Hydrae
RE: Underground galvanized pipe protection
RE: Underground galvanized pipe protection
Almost all galvanized pipe failures occur in the following places:
THREADED JOINTS - Wherever the galvanized coating is removed as threads are cut, and the thread cutting reduces wall thickness by about 50%.
AIR WATER INTERFACE - Wherever there is an air water interface such as occurs where the pipe exits soil or where the pipe goes below a water table underground. The interaction of the air and water close together create extremely fast corrosion which many have seen as a line of crusty flaky rust right where the pipe enters the soil.
CONTACT WITH CONCRETE - Do not allow concrete to touch the galvanized, always sleeve the galvanized pipe where it passes through. This is especially true where the concrete may retain moisture such as floors.
Pay very close meticulous attention to those areas or all other efforts are useless.
PUMPDESIGNER
RE: Underground galvanized pipe protection
Is the client’s general specs for process piping? Do the specs fit the application you are trying to design? If not, discuss writing a new spec for underground potable water. Also, threaded galvanized steel pipe would not be my choice for above grade potable water, unless there was some compelling reason why it was necessary. Is there a reason why Type L copper is not used above grade?
RE: Underground galvanized pipe protection
I have a feeling (possibly wrong!) that this is a temporary site supply and the Client is making you comply with his general permanent works specs. If this is the case you could agree to remove or fill the line after use.
Zambo