Encased in PVC Pipe?

[+msrubble]

Some descriptions of Minnesota Department of Transportation survey markers end with a note saying something like, "The rod is encased in a 6-inch PVC plastic pipe that is flush with the ground surface."

 

For example, COSP RM 3 (QP1160).

 

Does this mean that:

1. The pipe is conformed to the rod.
   
2. The pipe is conformed to the rod, and the disk is covered.
   
3. The rod is driven approximately in the center of a pipe.
   

I haven't found any benchmarks that MnDOT or the NGS say are encased in PVC pipes. I have found two that are approximately centered in PVC pipes. I think it would be worth mentioning in the description, if Option C is what is meant by "encased." One of them can be spotted from across the street.

[mloser]

I am going for door C, unless I get a chance to pick what Jay has in the box, or perhaps curtain 1, but my history tells me I will get the donkey and cart full of hay.

 

Seriously, the rod should be centered in the PVC pipe. When I say "centered" I don't mean precisely--the pipe is there to protect the top of the rod. It is really not part of the setting. The pipe may even have a cap on it, so bring a wrench. I have had little luck opening them with bare hands as the threads get dirty and they stick.

 

Take a look at KW2665. This one doesn't have the cap any more, but you can get the idea of what they look like. Note that the description does nto mention it being in a pipe though. Some do, some don't.

Edited October 3, 2006 by mloser

[+Black Dog Trackers]

msrubble -

 

I don't know what you mean by "conformed". If you mean the pipe touching the rod, then no.

 

These rods are pounded a good distance into the ground; I've seen some PID descriptions mentioning depths in 20 meters or more. Others are just a few feet. This pounding must require special equipment. I'm imagining that IF the rod is successfully pounded to an acceptable depth, THEN a pipe is installed around it, and the pipe would be much shorter than the rod itself. Rod markers are protected by pipes and fancier cylinders to make it so the rod can be accessed simply by opening a lid instead of digging to, and hitting, the rod.

 

I don't know the answer to the question - which came first - the pipe or the rod. I suspect the rod comes first. Maybe one of the professional surveyors can answer this.

[StripeMark]

I've even found a few of the newer ones in Minnesota, where the rod has a greased sleeve around it and then is encased in a PVC pipe with a cover. In this case, the ground, PVC pipe, and sleeve can rise and drop with the freezing and flawing ground, and the rod stays in place.

[+msrubble]

I don't know what you mean by "conformed".

 

Shaped to fit the pipe (and disk).

[+Black Dog Trackers]

This mark must be one of the ones where the rod is capped with the type of disk that fits onto a rod instead of being made to be mounted in wet cement. The usual rod has no disk cap, but apparently this one does.

 

Here is a diagram from the Berntsen catalog of a rod marker in a pipe. The drawing indicates that the rod itself goes deeper than the pipe.

 

In contrast, the usual disk to be mounted in cement is like these shown here in the same catalog.

Edited October 3, 2006 by Black Dog Trackers

[+GEO*Trailblazer 1]

I have run across quite a few of them.

 

Some have stainless steel rods and some have benchmarks.

 

DOOR # 1

Flange encased stainless steel rod.

CY1296 SILVERAIR

 

DOOR # 2

Encased vertical control disk.

CY0802 Q 365

 

DOOR # 3

Says flange encased rod but it is a disK.

CX1231 U 362

[mloser]

My previous link was a poor example because you can't see the disk in the sleeve. KW2666, just up the road, is an example where the disk is at the top of the pipe.

[+k5knt]

Take a look at KW2665. This one doesn't have the cap any more, but you can get the idea of what they look like. Note that the description does nto mention it being in a pipe though. Some do, some don't.

 

What type of paint did you use and is this a recomended practice?

[mloser]

I don't paint them. I leave that to surveyors, if they want to do it. My thinking is that leaving them alone is better then calling attention to them. That disk was painted by another benchmark hunter though.

[Bill93]

In most cases I would agree that it is better to not call attention to them.

 

I have, however, painted around a couple that were obviously in danger of being disturbed by nearby work, in the hope that it would lead someone to think they were important enough to work around them. I need to get back to one of those to see what happened.

[+k5knt]

I don't paint them. I leave that to surveyors, if they want to do it. My thinking is that leaving them alone is better then calling attention to them. That disk was painted by another benchmark hunter though.

 

And if I had looked closer at the log, I would have realized that.

That's what I get for trying to watch the news and read the fourms at the same time.

 

Kent