Male vs. Female - Dry Hydrants, Adapters & Hose
Dry Hydrant Selection:
The question often arises as to what style of thread makes the best choice for a Dry Hydrant, male or female. Why is one better or worse than the other? While we may have a preference, the following information is being presented to show the pro's and con's of either selection. We strongly suggest that you review all of the information before making a selection.
States like Alabama, Georgia, Missouri, Louisiana, Pennsylvania and Arkansas have standardized on the "male": National Standard Hose Thread (NH or NST). This standard has usually evolved because of large Dry Hydrant installation programs by local RC&D Councils. Georgia selected the 5" male while all others have chosen the 6" male. In all cases, a minimum design of 1,000 gpm flow rate is needed and was the goal for these installations.
In the Northeastern region of the USA most departments are using large 1,250-1,500 gpm engines having 6" suction. For many of these departments the 6" Female appears to be the Dry Hydrant of choice. However, we have also observed the NE does not appear to have any standard, as 4 ½" thru 6" (both male and female) Dry Hydrants are being used. This creates a big issue for automatic and mutual aid companies as a wide variety of adapters must be carried on each engine. If your state has not selected a "“Standard", they should. See write up entitled "Sizing and Standardization", also on this web site, for more information regarding standardization.
Female Hydrants, Pro's & Con's
Pro's:
- "If the same size", may be connected using standard suction hose (male/female) without adapters.
Con's:
- More expensive by $75 - $125 each.
- Has moving parts requiring lubrication and maintenance.
- Has a gasket requiring replacement and inspection.
- May prevent drafting or cause delays, if gasket is missing due to theft or deterioration.
- Requires longer connection time as snap caps are not available and wrenches are needed for cap removal.
- By design, the opening is smaller, creating higher friction loss. The 6" size has a 5" opening etc. Strainer area is also less.
- Hose connection, to a different size, requires more expensive adapters, which are usually not a standard item. Increasers & reducers must have a male thread to fit the female dry hydrant.
- Conical strainer is usually not an option due to reduced waterway opening.
- For a one-person connection to a female hydrant, one must think to turn the swivel counterclockwise as you face the hydrant. In addition, since most people are right handed, one will have to swing across the hose to tighten the swivel. This is more awkward for most. To uncouple the hose, one must also pause and think, "which way does the swivel turn". In a pressure situation, this may cause confusion and actually delay connection times.
- In tightening the female connection, the entire hose also has a tendency to rotate. This then requires an additional wrench to hold the hose collar to prevent it from rotating. More times than not this winds up being a two-man operation. Usually male hydrants do not cause this problem, as the hose stays in place and does not rotate with the swivel.
Male Hydrants, Pro's & Con's
Pro's:
- Least expensive.
- No moving parts.
- Full waterway passage with larger strainer area.
- May use conical or flat plate strainer.
- Available in snap cap or rocker lug cap. Snap cap reduces
connection time. - No special maintenance required. No gaskets or swivels.
- For a one-person connection to a male hydrant, the swivel on the hose turns clockwise. Most have been taught, "righty tidy" , so it’s natural it should tighten when turned to the right. To uncouple the hose, it is also natural, "lefty loosy".
In a pressure situation, this may make the difference whether or not the attack team runs out of water.
Other Comments:
In considering what to buy several other factors should be considered:
- Is manpower a factor? Lightweight flexible suction hose, capable of being handled by one fireman, should be used.
- Is speed a necessity? ISO states you must have 250 gpm flowing
within 5 minutes of the first arriving engine. Additional water
flow must be established within 15 minutes. Your on-board water
supply can buy you some additional time but usually connection
speed is a consideration. Having a flex hose with proper connectors
or fittings, pre-connected and ready to go sure helps in reducing
the connection time.
Some departments use Storz or Cam Lock Connectors to speed connection time. While these are highly recommended for tanker connections, they are not as important for suction hose connections. If it's a choice between the hard rigid suction hose and quick connects however, your choice should be a flex hose. Since this is a one-time connection, saving 10-15 seconds with a quick connect is not that big of a deal. Usually connecting the suction hose is done simultaneously with engagement of your on-board water supply so there is plenty of time for the connection. Having a flex hose on the other hand is a tremendous time and manpower saver and prevents multiple truck placements for rigid hose alignment. - Can you presently connect to a dry hydrant or is this your first encounter with a dry hydrant? Do you plan to use hose or adapters you already have? If you are attempting to adapt what you have to make it work, consider this cost against your ideal system of choice. Often times you will find there is little difference.
- What is your SOP? We normally think of jobs and how they relate to our SOP's. If possible design your supply system; of hose and adapters, in a manner that works best with your equipment. Do not overlook the fact however, that it may be your neighbor, acting in a support role, who actually supplies you water from your dry hydrant. Likewise, you may be supplying water for your neighboring department when they have a structure fire. If this is the case then you must look at the overall impact on multiple departments. SOP's may require modification to fit the overall goals and objectives of multiple departments or countywide tanker operations.
Best Choice!
Now that you have reviewed the pro's and con's of each, here is the sales data regarding what most departments buy. By far, 95% of the sales are 6" Male with Snap Caps. All things considered, this is the simplest and least expensive way to go. It provides maximum flow with little to no maintenance and as you purchase larger engines, the water system will not need upgrading.
Connecting to a male dry hydrant is very easy and is a one-person operation. Usually a double female adapter is all that is required. If a new flex hose is needed look at getting a double female hose. This will eliminate an expensive adapter.
If you have an existing flex hose, consider buying a new female connector and shank to replace the male connector and shank. Most flex hose couplings can easily be changed out by removing the collars. You can also buy a 6" swivel made on a 5" shank. Therefore, you could have a hose with a 6" end for the dry hydrant and a 5" end for your pump. A new hose end is also much cheaper than a double female adapter.
If using an adapter it should be pre-connected to your hose ready to connect.
Still confused? Give us a call and we will be glad to help.