Pipe connection to a pump 2

[gnomik]

gnomik

In a seismic Zone 4 ca a Victaulic coupling act as a flexible connection of pipe to a pump?

 

[cvg]

probably not, but it is better than flanged

 

[Artisi]

I would agree with cvg - but there are certainly better way to do it. Check if there a standard or specification that addresses this problem.

Naresuan University
Phitsanulok
Thailand

 

[gnomik]

Thanks.

The problem is that the same Specifier who required in his Specs to accomodate 8" movement via flexible fortified hose later allowed substitution of flexible hose with Victualic couplings (three in a row). Each coupler has 1-1/2" rubberized gasket which would, at best, allow 4-1/2" verical movement. However, for the side-to side movement the Victaulic couplings do not hot have any flexibility, in my opinion.

 

[Zapster]

gnomik

Take a look at the Victaulic catalog. Rubberized gasket has nothing to do with available movement. It is the clearance between the clamp & groove in the pipe, and end clearance between the joined pipes that determines the flexibility of pipe.

For sprinkler systems flexible Victaulic couplings are often used in swing joint configuration for seismic joints. Note these seismic joints are intended to be located where structural design allows a building to move in different directions.

What size pipe it this? What is the service? Are you trying to make a FM compliant sprinkler design?

I recommend you consult with your pipe designer/engineer to resolve your question.

 

[gnomik]

To Zapster:

Yes, I had looked in the Victaulic catalog. Hence, my posing question to this learned forum. The size of pipe differs from 4 to 10 inches. This piping is for various pumps and chillers mounted on isolation pads.This spring supported isolation pads add to the unpredictability of movement in case of a seismic event.
Sprinkler system has a suspended system that forces it to swing along with the building, and therefore, is of no concern.
Finally, it is the designer/engineer, whose conclusion I question.

 

[cvg]

gnomik

with 3 in a row, you do have some flexibility and I believe it is the same in any direction. But - are you sure you will get 4.5 inches? As stated, you have grooved pipe and the coupling locks into the groove on each side of the joint. The rubber gasket only seals the gap to prevent leakage. Each joint will allow a certain amount of deflection. the length of the pipe spool in the middle will affect the amount of deflection that you can tolerate.

 

[Zapster]

gnomik

You have looked at the wrong Victaulic publication. Go to the Victaulic web site and download "Grooved Piping System - Design Data - 26.01" This publication illustrates how the Victaulic couplers are put together and the difference between the ridged and flexible couplings. In addition, 26.01 gives examples of how to calculate the amount of flexibility you get from one of their joints. With this information, you should be able to answer your own question.

You stated, “This spring supported isolation pads add to the unpredictability of movement in case of a seismic event.” Incorrect! When properly designed and installed, spring supported isolation pads have very predictable movements. You should have seismic snubbers to limit the seismic movement of your equipment. The following web site should give you days of reading some of the best information on the web about vibration isolation and seismic requirements:

http://kineticsnoise.com/

Once you understand how spring supported isolations systems should be designed, how snubbers limit travel, and the amount of flexibility Victaulic joints have: You should be able to answer your own question.

Your question started out asking about seismic moment and Victaulic couplers. Now the issue has changed to vibration isolation. A Victaulic flexible coupler should not be used for vibration isolation. The metal to metal contact through the joint will transmit the vibration from the isolated equipment into the piping system.

You also stated, “Sprinkler system has a suspended system that forces it to swing along with the building, and therefore, is of no concern.” Incorrect! Sprinkler systems do have some movement that is independent of the building and it is for this reason, the flexible couplers are used in strategic locations to prevent pipe failure and the resulting water damage during seismic events. FM Global has requirements that are more stringent than NFPA 13 regarding the placement of anchors and flexible couplers used in sprinkler systems. If you question the need for flexibility in sprinkler piping systems, FM Global has a lot of information, especially information about insurance claims from broken sprinkler pipes during earthquakes. Water damage can create substantial insurance claims.

Regards,

 

[Artisi]

Zapster
An excellent response to the posting - certainly worth a vote as a valuable post.

Naresuan University
Phitsanulok
Thailand