“Suction” - Water Supplies
General Requirements - for "Suction Supply" Use
Generally, a suction water supply may be recognized for fire fighting when:
- There is a good volume of water available.
- It is readily accessible by the fire dept. apparatus all the
- It can be expected to be available all year, including during
- The fire department has sufficient equipment to provide the
necessary flow rates at draft.
A "suction supply" may be used
by several methods, some are as follows:
- Direct from the source by laying a hard suction hose into the
- Connection to a Dry Hydrant.
- Connection to a pump, which may be a permanent or mobile installation.
Each of these setups usually has an impact on connection times
and as such, may have an effect on your overall water supply operation.
Connecting to a fixed or permanent installation such as a dry hydrant
is usually the safest and quickest method. Additionally it opens
up avenues whereby other ISO points can be generated.
For ISO approval the following information is required:
A. Mapping Requirement:
- A street map, with a scale, showing the locations of the suction
water, suction water supply point (s) and of the responding fire
- This requirement can be satisfied with a county map showing
hydrant locations and the fire district (or station) boundaries
(response areas). Also, identify each dry hydrant and/or suction
source (letter/no., etc.). It is best to keep the ID's separate
for each type source.
B. Suction Supply Requirements:
- The location (address) with the nearest intersecting street
name of the pumping site.
- For an impounded supply, cistern, tank or other storage facility;
the minimum storage available (at not over 15 ft lift) during
a drought with an average 50 yr. frequency (certified by a registered
professional engineer or soil conservationist). The maximum rate
obtainable using the pumper (s) and hose arrangement scheduled
to be used at this point (supported by test results).
- For a supply from a flowing stream, the minimum rate of flow
available (at not over 15 ft. ) during a drought with an average
50 yr. frequency (certified by a registered professional engineer
or soil conservationist). The maximum rate obtainable using a
pumper (s) and hose arrangement scheduled to be used at this point
(supported by test results).
- A description of the year-round accessibility for pumper (s)
of the suction water supply point. Describe the arrangement of
a dry hydrant, if provided.
- The number of pumpers that can operate simultaneously at the
- A statement, signed by the owner of any private suction water
supply point, authorizing its use by the fire department.
- When the use of a suction water supply point (at times) depends
upon creating an opening in ice, the maximum known thickness of
ice shall be given. A statement shall be provided explaining the
equipment used, apparatus carrying the equipment, and the estimated
time necessary to provide a drafting site when the ice is at the
C. Fire Department Information Required:
- The name, mailing address and daytime telephone number of the
fire chief of the nearest responding fire department.
- A list of apparatus responding on first alarm for fires in buildings
in the vicinity of the water supply points. When the response
varies, list the response to each suction water supply point.
Automatic Aid units responding should also be listed.
- A separate Apparatus and Equipment list for each apparatus.
Forms provided by ISO should be used in making this list.
- List the length and diameter of the hard suctions carried by
each pumper and describe their strainers. Remember and be sure
to list whether the suction hose is flexible. It makes a big difference
when it relates to "connection time" from the dry hydrant
to the suction intake. Also remember the use of two sections (20
ft.) will affect the maximum flow rate.
- You will note there are no requirements to actually "test"
the actual time to position the pumper, connect the hose, pull
prime, lay out hose and pump to the structure. You are required
to do this within 5 minutes upon arrival of the drafting site.
ISO will determine how far water credit (in feet) will be given
at each site. You may also be asking to take a pumper to a particular
draft site and make it ready to pump water. For this reason it
is wise to know your actual times to connect and flow water as
noted above. These forms are also available from ETT, L.L.C. at
no charge. Call toll free 877-827-2797.
Additional Detail Information
A. Point of use Coverage/Structures:
- List address (es) of structures that will be protected (within
1,000 ft. radius). Show reasonable scale diagram and ensure that
any terrain features are shown which will necessitate any hand
laying of suppression hose (s) and approximate distance (s) of
each in these ranges; 0-300 ft., 301-600 ft., 601-1,000 ft. The
distances will be so that the end of the lst hose allows water
to be applied to the structure with a nozzle.
- The best way to list "intersecting street names" is
to list the name of the road on which a dry hydrant is located
first and then the road on which the first responding pumper would
be using to reach the turnoff second. Try to circle this intersection
on your map.
B. Dry Hydrant Supply Information:
- Maximum flow rate available when you flow tested the dry hydrant
using the pumper that will respond to that dry hydrant.
- List the hose arrangement used and manner of test (i.e. deluge
gun with . . . . tip)
- Based on the description required of the dry hydrant site, make
sure you enumerate whether you will be using the front, left or
right side suction intake when drafting using a midship pumper.
(Some variables can be found with some pump manufacturers and
- List the water available at the site from the strainer upwards
to the water level during a drought with an average 50 year frequency.
(certified by a registered professional engineer or soil conservationist).
This data should be in the upper right hand corner of any dry
hydrant drawing if made by the ASCS in the RC&D program.
- List the same information, except use what is considered the
normal water level when not at a 50 year drought level.
- For dry hydrants located in lakes used for power generation
the strainer intake must be located below the seasonal operation
low water mark in which the water will be lowered. This level
must be obtained by the engineer of that dam or company. Strainer
depth below surface must be adequate to pump maximum flow rates
C. Dry Hydrant Construction Requirements:
- A turn around area or maneuver space is needed to position the
pumper for hook up to the dry hydrant.
- This turn around area should be graveled or be an all weather
- Any dips, uneven terrain, steep ways in the roadway to the dry
hydrant must be graveled (crushed asphalt, etc.).
- Provide any drawing of the dry hydrant which may have been made
showing the traveled direction to the dry hydrant / suction source.
Also include distance, ground surface, width, obstacles to travel
or hookup and type of hose lays etc.
- Photo's work very nice in showing much of the above information
and are highly recommended.
D. Automatic-Aid Source Locations:
- If there is to be automatic-aid at suction source locations,
information for this requirement will be necessary. Test data,
drafting gpm etc. will be needed if a dry hydrant is used by responding
- Under small department SOP’s, where manpower or equipment
is limited, usually the first-in engine will go directly to the
scene and start the initial attack. The Automatic-Aid department
will usually be the one connecting to the water source, thus providing
the water supply needs.
E. Permission to use Water Source:
- Permission to use water from a private source should always
be obtained prior to any construction or survey of the source.
Samples of forms for "Owner permission" can be obtained
from ETT, L.L.C. free of charge, call toll free 877-827-2797.
In some areas additional permitting or permission may be required
before dry hydrants can be installed or water removed from a source
for fire fighting.
F. Freeze Conditions & Protection:
- Ice (applies only to freezing climates of the country) can
hamper the use of a water source and damage dry hydrant installations
if not properly designed. Generally ice is not a problem for dry
hydrants, if the standing water is below the frost line. For those
few installations where it is a problem, this can be overcome
by creating an air lock or gap, adding insulation or using other
innovative techniques. Call ETT, L.L.C. for additional information
on this issue, Toll Free 877-827-2797.
- If special procedures are required in preparing a dry hydrant
for use in freezing conditions these procedures must be written
down and each responding fire department must have them and be
able to operate same.
- When the use of a suction water supply point depends upon creating
an opening in ice, the maximum known thickness of ice shall be
given. A statement shall be provided explaining the equipment
used, apparatus carrying the equipment, and the estimated time
necessary to provide a drafting site when the ice is at the maximum
G. For additional documentation consult:
- The "ISO Fire Suppression Rating Schedule" available
from ISO Headquarters.
- NFPA 1142 "Standard on Water Supplies for Suburban and
Rural Fire Fighting" available from NFPA.