Gate Valves, Ball Valves and LDH Adapters.

When gating the side ports of hydrants, some departments use gate valves, and some use ball valves.  Each has advantages and disadvantages.

Ball valves are made by several manufacturers.  Some have large knobs on the handle that lock the valve in the position it has been opened to.  Others are non-locking, and simply have a small knob on the end of the handle.  Ball valves are quarter turn, meaning they can quckly charge or shut a line off.  In most cases, this is a disadvantage, as water hammer can cause damage or injury from a valve that is quickly opened or closed.  The profile of the valve handle can often get in the way of large diameter hose adapters.  Typically, ball valves are best suited when you intend to connect 2 1/2" or 3" hose to them unless you have the right adapters.

Gate valves have a more reduced profile.  They allow a slower opening and closing, reducing the risk of water hammer.  Gate valves are generally the better option for use with LDH, as they are often cheaper in addition to the aforementioned reasons.

Adapting the valves for use with LDH is a critical function when flowing high volume, and we will discuss the adapters later in the article.


PHOTO 1. Pictured, are two styles of 2 1/2" ball valves and one style of gate valve

  

PHOTO 2. One style of ball valve, with a locking handle will not open all the way with a Storz adapter as shown.



PHOTO 3. This style of ball valve does not have a locking handle, and opens all the way.  The handle has narrow clearance to the 4" storz coupling.  A 5" coupling would not fit on this valve without an elbow.



PHOTO 4. This gate valve is pictured with a 4" storz adapter.  It has a much more reduced profile.



PHOTO 5. This ball valve, with locking handle, has been fitted with a 5" storz elbow, eliminating the obstruction that prevents it from opening all the way.

PHOTO 6. An elbow (which can be removed from an unused panel discharge) can be a benefitt, not only to clear a handle obstruction but to take stress off the hose coupling.



PHOTO 7. This 2 1/2" "Rigid" female x 4" storz adapter creates a lower profile when attached to the valve.  Use "Rigid" thread adapters when they will normally be attached to valves, the rig or the hydrant and the hose will be connected to them.  Make sure any adapters used on the hose are "swivel" adapters.



PHOTO 8. The 2 1/2" x 4" Storz to 4" Storz x 4 1 2" NST Male adapter attached to a 2 1/2" gate valve.  Note the clearance to the hydrant bonnet is such that the valve is better oriented so the handle is off center.  This connection was flowing approximately 1030 GPM with additional residual pressure.

PHOTO 9. In this photo, you can see a ball valve and a gate valve in use.  They were appropriately selected so that the gate valve was used with the LDH adapter.

PHOTO 10. If you have, or purchase your storz adapters with male thread, using a 2 1/2" double female will extend the adapter far enough from the locking ball valve handle to operate it.

PHOTO 11. The tight clearance to the hydrant bonnet here is noted using gate valves, hence the one on the left is rotated off center.  The 5" storz adapter on the left is a "swivel" type where the one on the right is a "rigid" thread type.  The difference in their profile is notable. The pressure gauge in the photo is used for training to show students the residual pressure in the system.

The use of ball or gate valves on the side discharges of hydrants, is very critical if you have hydrants that are capable of high flows.  Because hydrants flow their greatest volume at the lowest pressure, splitting the flow between several hose lines will always provide a greater total flow.  It is a best practice to always attach gate or ball valves to the unused side discharges of hydrants.  Doing it every time makes it become a habit.

Adapters that are available for connecting large diameter hose to 2 1/2" gate and ball valves vary by manufacturer.  There are several options, some of which are pictured above.  The following list explains the most common types.

• Rigid.  A rigid female x storz adapter is best used when it is left attached to the valve.  Rigid adapters do not swivel, and therefore must be removed from hose to make the connection to the valve.  Rigid adapters must be tightened with a storz spanner wrench, as there are no rocker lugs on them.  Photo 7.
• Swivel.  A swivel female x storz adapter may be left attached to the valve or the hose.  The swiveling female connection allows the hose to be connected to the valve if it is already attached to the large diameter hose.  Swivel adapters may be left attached to the valve, but they have a larger profile and might pose storage issues in hydrant bags or buckets.  Swivel adapters may be purchased with long handles for better leverage without use of a wrench or with rocker lugs for use with a spanner wrench.  Photo 11.
• Male Thread.  Having male thread x storz adapters allows you to use the adapter in a variety of additional ways.  Coupling it with a 2 1/2" double female adapter makes it function as a female swivel adapter.  This will extend the profile of the adapter, but can be a money saver and the extra profile created by attaching the double female can avoid the locking handle of some ball valves from being blocked out of the fully open position.  Photo 10.
• Swivel Elbow.  A swivel elbow can have long handles or rocker lugs.  They are typically 30 degree drop and are a good tool to help reduce kinks when faced with sharp bends and for taking stress off the hose couplings.  You can use old chrome pump panel elbows in a pinch, but its best to try to obtain elbows specifically intended for use with LDH for the best efficiency.  Elbows also eliminate the issue of the locking ball valve handles being obstructed from opening fully.  Photo 5 and 6.

In summary, its important to know what options you have available to you on the rigs so that when you need to flow big water, you aren't stuck scratching your head or finding out that things don't fit together.  Whenever possible, use large diameter hose attached to your gate or ball valves rather than 2 1/2" or 3" hose.  While the restriction imposed by the valves and adapters might have some impact on total flow, using the smaller hose will have more significant implications.

For additional information or guidance on purchasing adapters please feel free to contact us at sendthewater1@gmail.com