Lead caulked joints on C.I. pipe
Lead caulked joints on C.I. pipe
(OP)
Are lead caulked joints as encountered in older cast iron water main lines (such as Class 250 or AWWA Class A pipe) considered to be restrained joints? Looking at the geometry of the joint, it looks like it should be self-restraining. It also looks like any movement caused by external force could unseat the joint. Can anyone recommend good reference material on this obsolete pipe joining system? My company has a private water distribution system for irrigation, parts of which have been in service for about 100 years. We have encountered C.I. elbows as large as 8" that have been in service for many decades with no thrust blocking.





RE: Lead caulked joints on C.I. pipe
It has been hypothesized that Rome's dependence on lead water pipes lead to its decline. It has been suggested that the aristocracy died off from nothing more complicated than simple lead poisoning. This is not true. Since almost all of the lead absorbed by the human body is deposited in bones, investigators have studied the bones of ancient Romans. While some studies did indicate above normal concentrations of lead, it seems unlikely that water pipes were a contributing factor. Hodge (1981) has correctly pointed out that lead pipes would not have caused contamination for two reasons: (1) because the Roman water contained high concentrations of calcium which formed deposits inside the pipes, insulating the lead and (2) because lead will never greatly affect running water.
Now, in all seriousness, making new lead joints are now illegal in some states,
http://dnr
In 1985 the EPA banned the use of lead in new public and private water systems and in plumbing repairs.
Modelling lead creep i nwater pipe joints,
http://www
Axial Behavior Characteristics of Pipe Joints under static loading,
ht
Here is an AWWA doc you might be interested in springing for, Potential Techniques for the Assessment of Joints in Water Distribution Pipelines [Project #2689]
http:/
A history of pipe joining methods,
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and lastly, some tools you may be needing soon.
http://www.mephistotool.com/caulkingIrons.html#n
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com
RE: Lead caulked joints on C.I. pipe
RE: Lead caulked joints on C.I. pipe
I understand that the older caulked joints of cast iron water mains were probably of the spigot and socket type, and caulked with lead, and that flanged joints were used for connecting to valves and other fittings. Judging from the number of leaks that have occurred, you would have to say that these joints were not restrained.
h
RE: Lead caulked joints on C.I. pipe
The cross sectional cut photo shown in the article on FE analysis of joint creep is also interesting. It seems to show that the lip on the spigot end was probably present to confine the oakum rope, and keeping it from migrating into the pipe when the it is being placed into the back of the joint. In my copy of Handbook of Water Control (F.E. Marimon, California Corrugated Culvert Company, 1944) it shows the same AWWA standard joint, as well as another variation that they call Super deLavaud centrifugally cast pipe. This version does not have the lip on the spigot end. Instead, the back .3-.5” of the bell-end socket necks down to create a more narrow gap. I would think that even without the lip, the pipe would still be unlikely to slip, due to the rough surface of the casting. Also, because of the v-shape of the bell-end groove, it would seem like any thrust force pulling on the pipe would just drive the lead seal even harder into the spigot surface.
According to ACIPCO, this joint was "obsolete" by the 1950’s, but I have a Mueller catalog from 1980 and they were still offering valves with caulk joints at that time. My company’s maintenance department was reportedly still making these types of joints in the 1970’s, and at least until a few years ago we still had some of the supplies and tools. I think our current operator may have discarded them, foolishly thinking he would not be needing them! (LOL) I know there are bell joint repair clamps available for leaks at these types of joints. I wonder if a leak could be repaired by just using an appropriate caulking iron to re-seat the lead seal? In the article linked by Bimr, I wonder exactly what the cause of failure was in these joints – corrosion? Excessive joint deflection from differential settlement? Here is study on this type of pipe in gas service:
http
They found that excessive leakage would occur after about .34 degrees of joint deflection.
My inquiry is not solely academic. For an upcoming project, I will be making a new connection to the end of a 8” C.I. service lateral installed sometime in the 30’s or 40’s. It presently has two 6” sprinkler valves on the end of it for watering the lawn. I’ll be removing the valves and connecting a new irrigation system, but need to verify that the lateral is truly restrained. Pouring a thrust block at the end of the lateral is not an option. I know from experience that the lateral will have either caulked joints or flanged joints (or both), but will not know for sure until we expose the entire length. If there are caulked joints that cannot be easily replaced, my preference is to leave them alone. If they are theoretically capable of safely restraining themselves (as they have been for decades) given working pressures, etc., I will leave the lateral as-is. If they are theoretically not capable of self-restraint, I will likely choose to cut out and replace portions of the lateral in order to install satisfactory inline thrust blocking, etc. I will consider purchasing the AWWA report as recommended by BigInch, in addition to seeking information from ACIPCO.
RE: Lead caulked joints on C.I. pipe
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com
RE: Lead caulked joints on C.I. pipe
I have attempted to explain also in my prior post that it is extremely difficult for ACIPCO or anyone else to know exactly what you have in the ground. ACIPCO is one of several current producers of iron pipes, and I have even heard that prior to 1900 or five years before ACIPCO was founded, there were nearly a hundred other foundries producing gray cast iron pipes for a rapidly growing nation! The reason even quite strong gray cast iron material pipe is by many authorities more prone to overload failure than ductile iron pipe is that the gray cast iron material is roughly half as strong in tension, stronger in impact and bending strength, and ductile (as its name implies) unlike gray iron will by its nature yield or give some instead of break (of course within limits). For such reasons, I believe ACIPCO produced its last piece of gray cast iron pipe nearly thirty years ago and some time even prior to that would not produce any fabricated flange pipe without ductile iron flanges (I pre-date that just a little, so I have at least a little knowledge of this history and prior systems).
If you feel you need/must confirm the restraint ability of the old piping, would it be possible for you to somehow load or pressure/load test same e.g. at the terminus of the old piping, before you continue with the new (if a problem were to occur somewhere in the old piping, perhaps it would be good to find out about and fix this when the line was thus not in operation?) Also, at least based on what information has been provided thus far, I am having a little trouble visualizing why it might not even be possible to insulate the old piping some from thrust loads, e.g. with a “thrust collar” welded or clamped a short distance into the new piping and a transverse concrete thrust wall around same (that I would not think would normally need to be huge or hard to construct for 8” water piping loads). I hope this information is helpful.
RE: Lead caulked joints on C.I. pipe
I realize that neither ACIPCO nor anyone else has no way of knowing what we have in the ground. I don’t even know who manufactured the pipe. However, given the information that I do have, including the approximate time period of the installation, it appears to me to be a reasonable *assumption* that the installed pipe conforms to the AWWA C108 dimensions. My inquiry would be limited to the question of whether AWWA C108 caulk joint cast iron pipe when properly installed is self restraining, and if so, then under what pressure criteria. If I’m able to get an answer, I will post it in case anybody else is interested.
rconner, my description is difficult to visualize, but you are doing a good job. The thrust collar solution to isolate existing joints is basically the solution that I was alluding to in my previous post. The new piping immediately tees off at the end of the existing service lateral. Due to spatial constraints, I cannot install a thrust block there. That is why I would have to go back a distance into the existing lateral piping, cut it out and install new piping with a thrust collar and concrete TB. This is likely what I’ll end up doing. Another possible solution is to install a ductile iron wedge-style restraint on the existing cast iron pipe, and use that as a thurst collar. I don’t particularly care for that idea, as it’s viability depends greatly on the condition of the pipe (another unknown). Pressure testing is out of the question in this case. The isolation valve was either abandoned or never installed, so I have no way of isolating the lateral from the 2000’ long 14” C.I. mainline. Hopefully, when we saw-cut the pavement and expose the lateral, it will have only flange joints. That would simplify things a bit.
RE: Lead caulked joints on C.I. pipe
RE: Lead caulked joints on C.I. pipe
RE: Lead caulked joints on C.I. pipe
RE: Lead caulked joints on C.I. pipe
RE: Lead caulked joints on C.I. pipe
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Lead caulked joints on C.I. pipe