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-   -   Ball vs. Gate Valve (http://www.diychatroom.com/f7/ball-vs-gate-valve-7068/)

BigJimmy 03-12-2007 01:03 PM

Ball vs. Gate Valve
 
I'm getting ready to replace the water line in my house from the meter. Currently there are gate valves immediately up/downstream from the meter. Just out of curiousity, why would a gate valve be used instead of a ball valve? I always thought that gates were used in applications requiring throttling whereas balls are designed to be either fully open or shut.

Just curious.
Jimmy

majakdragon 03-12-2007 02:04 PM

Gate valves are not the best valves for throttling flow. They often chatter when used to pinch down the flow. For this application, a globe valve should be used. Gate valves were used before ball valves became widely accepted and available at a reasonable cost. Ball valves are my preference for use as a shut-off. Gate valves can get debris trapped in the bottom and restrict the gate from fully closing.

elitts 05-22-2007 02:59 PM

Make sure you check with your Water Dept. before using a Ball valve. Many water departments require the use of a Gate valve and will not service a water meter that uses a Ball.

The reason behind it is that a Ball valve allows the water to be cut with such speed and abruptness that if there are any structural problems with the plumbing system, a quick shut off can cause a plumbing rupture. Granted, you can cut the water slowly, but your average homeowner/renter won't, they just throw the handle.

**I Used to work for a Municipal Water Department in the meter repair division**

Ron The Plumber 05-22-2007 05:58 PM

Quote:

Originally Posted by elitts (Post 45885)
Make sure you check with your Water Dept. before using a Ball valve. Many water departments require the use of a Gate valve and will not service a water meter that uses a Ball.

The reason behind it is that a Ball valve allows the water to be cut with such speed and abruptness that if there are any structural problems with the plumbing system, a quick shut off can cause a plumbing rupture. Granted, you can cut the water slowly, but your average homeowner/renter won't, they just throw the handle.

**I Used to work for a Municipal Water Department in the meter repair division**

Ball valves are widely used, never seen or had such problems. must be in your area only cause there is no such requirement here.

elitts 05-22-2007 06:42 PM

I don't have a hard time imaging that this could be a regional peculiarity. I worked in Grand Rapids, MI. I would guess that the combination of a fairly high housing stock dating back to the early 1900's with the freeze/thaw we get all winter long might account for that requirement.

I will add that this only applies to the valve between the service into the house and the meter. Ball valves everywhere else are fine here too.

Daren 05-22-2007 08:41 PM

A gate valve is prone to wear in the seat/gate. If it is not opened all the way the bottom of the "gate", the part that lowers into the seat can be eroded by years of water flow (and like was mentioned the seat can fill with sediment)....when you need to shut it off, you can't.

I don't know about the valve being shut off too fast, if there is no flow it does not matter. If there is a leak positive shutoff is the key. I have never worked for a municipal water dept. Just put in 1000 miles of water main and made more main taps than I can count, the main tap is ALWAYS a ball valve. The valves in the meter pit are always balls too (state code in Illinois).

Sorry this is my first post. I should introduce myself. Daren Nelson, 3rd generation master plumber. I had my own plumbing business for a few years, but got burned out on it and now I run a sawmill/lumber business and tool sharpening shop.

I agree with the guys who said check with the water dept., the valves on either side and the meter itself is city property. The water line from the last valve to the house is yours. I cannot imagine it being any other way...If you are doing the work yourself in their meter pit spring for 3' of extra copper and go right around the meter, know what I mean? Save yourself some work and have them replace the service valves it is their meter. Most municipalities freak if they see a civilian with the lid off the meter pit anyway.

majakdragon 05-22-2007 09:17 PM

I worked for the City of Toledo water division as a Water Service tech for 5 years. The only valve allowed on new services was a locking ball valve. After the meter it was the contractors choice but most I inspected used ball valves.

Ron The Plumber 05-22-2007 09:56 PM

Lets scientific here for a minute, water under static pressure stays constant, 60 psi will be 60 psi no matter if you open and close the ball valve as fast as you can, this is not going to cause a surge of water on the distro system. it's not going to change the pressure before of after the ball valve, the only time you find a sudden change of pressure is when you have fast closing valve at the end of the branches, i.e. dishwasher, washer machines, or any other fast closing valves, we call this water hammer. In my line of work I will use a ball valve over a gate valve any day, as a matter of fact, we don't even carry gate valves on our trucks.

elitts 05-22-2007 10:17 PM

Well, when it comes to what's best in the world of plumbing, I certainly can't begin to argue; It took me about 4 hours to get my bathroom sink installed. But I stand by the idea that for anyone looking at replacing the service shut off in a municipal water system, it's worth checking to see if there are weird requirements.


And just so that people don't think I'm a complete crackpot, here is a link to the Grand Rapids Water System webpage with a picture of thier "meter assembly mockup" showing one gate valve on either side of the meter.

http://www.ci.grand-rapids.mi.us/ind...040#My%20Meter

That one Guy 05-24-2007 12:26 AM

Quote:

Originally Posted by Ron The Plumber (Post 45940)
Lets scientific here for a minute, water under static pressure stays constant, 60 psi will be 60 psi no matter if you open and close the ball valve as fast as you can, this is not going to cause a surge of water on the distro system. it's not going to change the pressure before of after the ball valve, the only time you find a sudden change of pressure is when you have fast closing valve at the end of the branches, i.e. dishwasher, washer machines, or any other fast closing valves, we call this water hammer. In my line of work I will use a ball valve over a gate valve any day, as a matter of fact, we don't even carry gate valves on our trucks.


:thumbsup:

wesselsf 06-02-2007 06:49 AM

No matter which valve you use, be sure to put a union between the street and the shutoff to eliminate any "wet" work later. PS, I definately go with ball valve!!


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