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.
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