STORAGE FACILITIES
water for fire fighting should be provided by gravity storage wherever
possible. Using elevation as the means for developing proper water pressure in
water mains and hydrants is reliable, not dependent on pumps that could fail or
be shut down as a result of an electrical outage. Storage can be provided
through one or more large reservoirs or by multiple smaller reservoirs
throughout the community that are linked together.
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Elevation
In establishing a proper elevation for reservoirs, one can calculate that
every foot of head will produce .434 p.s.i. of pressure. Therefore to generate
65 p.s.i. in the water distribution system, storage reservoirs must be located
at an elevation of approximately 150 ft. above the service area. Adequate system
pressures are generally accepted to be between 65 and 85 p.s.i. Accordingly,
reservoirs should be placed at elevations between 150 and 200 ft. above service
areas.
Since most communities are not perfectly flat, there will be some variation
in service pressure. While it may be possible to establish a reservoir level to
most of a hilly community, it is often possible to design a system where the
predominance of the community falls within the 65 - 85 p.s.i. range with
pressures in some portions experiencing less desirable but acceptable ranges as
low as 50 p.s.i. and as high as 120 p.s.i. In locations where pressure gradients
may fall outside these less desirable pressure ranges, additional reservoirs
should be set at appropriate elevations to serve these areas or main-line
pressure regulators should be installed to protect low-lying areas from
overpressurization.
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Reservoir Size
Most municipal water systems for fire fighting provide combination service
for fire hydrants and domestic (private and commercial) use. Thus the
determination for volume of water stored is based on a number of factors.
Reservoirs should have adequate capacity to provide continuous domestic flow
in the event of a disruption of the reservoir refilling system. They must also
have adequate storage to provide anticipated fire flows for a reasonable
duration.
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| A reasonable rule of thumb is that storage should be sufficient to
provide at least two days of peak domestic consumption plus required fire flows
as determined by the Fire Chief. For example, in a typical residential
neighborhood with no unusual hazards, storage based on a fire flow of 1,000 GPM
(3785 L/min) for two hours may be appropriate. In commercial, industrial or
urban-wildland interface zones, flows on the order of 5,000 GPM (19,000 L/min)
for 3 hours may be required.
Reserve capacity may have to be balanced by water quality issues. There must
be sufficient water changeover in reservoirs to keep water fresh and healthful.
In communities where water use and fire risk are seasonal, multiple small
reservoir tanks can be employed. During periods of peak use and fire risk, all
the tanks can be used for storage. During low use / low danger periods, an
appropriate number of tanks can be emptied and left "off-line." |
Pumping Facilities
The primary role of pumping facilities should be to maintain appropriate
levels in reservoirs. With adequately sized pumps and reservoirs, pumping can
generally take place late at night and early morning when electricity demand is
light.
Pumps need to be protected from vandalism and appropriately reinforced for
seismic stability. Automatic stand-by generators should be provided, or at
minimum, an ability should be provided to rapidly connect a mobile generator in
the event of a long term power failure. Connections should also be provided so
that a portable pump can be installed in the event the pump itself fails.
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WATER DISTRIBUTION SYSTEMS
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Getting water distributed adequately and reliably to points of use is a
product of sound engineering practices and an understanding of water
distribution principles to support fire fighting operations.
Grid Systems
The most reliable means to provide water for fire fighting is by designing
redundancy into the system. There are several advantages gained by laying out
water mains in a grid, with feeder and distributor mains interconnecting at
roadway intersections and other regular intervals.
- Water will still be distributed through the system if a single section
fails. the damaged section can be isolated and the remainderof the system will
still carry water.
- Water supplied to fire hydrants will feed from multiple directions. Thus
during periods of peak fire flow demand, there will be less impact from
"friction loss" in water mains as the velocity within any given section of main
will be less since several mains will be sharing the supply.
- Hydrants will not be supplied by "dead end" mains so that discharges will
remain more stable when multiple hydrants are in use simultaneously.
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Each geographic point of the distribution system should be
supplied by primary feeders which are typically 16 in. (400 mm) in diameter.
Secondary feeders which are typically 12 in. (300 mm) in diameter would be
appropriate to supply specific neighborhoods. 8 in. (200 mm) diameter
distributor mains would typically be used to supply water to individual streets
and to the fire hydrants on those streets. Hydrant laterals should not be less
than 6 in. (150 mm).
Street valves should be provided at every junction for all mains branching
from those junctions. In this manner any single section of main can be taken out
of service in the event of breakage and for repair without disrupting water
service beyond the affected section of pipe. By having the system completely
interconnected, even the loss of a section of primary feeder would not result in
a complete loss of water delivery as the other components of the system would
provide a "bypass" around the outage.
Specific pipe sizes used may vary from these standards based on local
conditions and projected demands upon the system. In any event, no distributor
mains should be smaller than 6 in. (150 mm) and unless they are cross-connected
into the grid at least every 600 ft. (180m), they should be no less than 8 in.
(200mm) in diameter.
Construction Materials
Sleection of pipeline construction materials may vary based on a number of
factors including geological conditions, operating pressures and locally
available. Concrete lined steel is most adequate for feeder mains while PVC
provides reliable service for distributor mains. Additionally, PVC is easy to
work with with respect to adding service and hydrant connections after the mains
have been installed. |
Regulator Systems
It may be necessary to regulate pressure to small, low lying areas where
installation of separate reservoirs is not feasible. These regulator systems are
reliable when properly designed.
To prevent upsystem damage from "water hammer," pressure regulation on water
mains should be accomplished by means of a parallel array of regulators known as
a regulator set. Ranging in size from 2 in. (51mm) to 6 in (150mm), the sets
should be configured so that the smaller regulators open first, then the larger
regulators open in sequence as demand increases, and then the regulators close
in sequence as demand decreases in the portion of the system being regulated.
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Aside from the general purpose of delivering water for fire fighting, the
hydrant design selected must be based on a number of operational elements. Some
issues to consider include:
- How much water (GPM or L/min) is needed for fire fighting.
- How many and what size hose connections are required.
- The established hose sizes and coupling threads in the region.
- Current (and future) configuration of fire apparatus.
- Issues of clearance and visibility.
- Operating characteristics of the hydrants.
- Amount of head (static pressure) that is present in the system.
- Climatic conditions in the area.
Generally speaking, water supply systems in residential areas should be
designed to deliver no less than 1000 GPM (3785 L/min) at each individual
hydrant. In commercial and multi-story apartment zones, this volume should
increase based on the required fire flows of the buildings being protected. If
the required fire flows are several thousand GPM, the required flow will usually
have to be met by two or more hydrants flowing simultaneously.
The operations of the fire department or fire brigade must be taken into
consideration. In instances where new hydrant systems are replacing poor or
nonexistent systems, new fire fighting approaches need to be developed to make
proper use of the new system. Hydrant designs should capably and easily provide
necessary water to fire engines currently in service as well as more modern fire
engines which may be purchased in the future. For example, a fire brigade may
have smaller engines equipped with medium diameter hose and 750 GPM (2850 L/min)
pumps, however with a suitable water supply system, the brigade may upgrade to
engines equipped with large diameter hose and pumps with a capacity of 1250 GPM
(4732 L/min) or greater. Accordingly it may be appropriate to specify fire
hydrants which have medium diameter hose outlets as well as a large diameter
pumper outlet. |
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In the event of a major emergency, fire companies may be requested from
multiple jurisdictions. Hydrant outlet threads should meet the regional standard
for compatibility among all fire engines, regardless of origin. If no large
diameter outlet size and thread has been established, we recommend the 5" Storz
configuration.
Hydrants need to be readily recognizable and accessible. Placement and
installation considerations should take into account the shape of the hydrant as
well as the positions of valves and outlets. Specific suggestions regarding
hydrant placement are presented later in this feature. |
| Hydrants must be simple and reliable to connect to and to operate. Operating
nuts should be pentagonal or triangular in design to reduce tampering by
unauthorized persons. Discharge valves should be specified to open by turning
counter-clockwise and close clockwise. (Underground valves on water mains and on
the hydrant branch line should operate according to local or regional
standards.)
Hydrant designs must be appropriate for the amount of head (static pressure)
that is applied to them. The minimum working pressure rating of any fire hydrant
should be 150 p.s.i. Hydrants installed in higher pressure installations should
be rated appropriately. All fire hydrants should be static tested at twice the
rated working pressure. |
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In temperate climates where hard freezing is not an issue, the most
efficient hydrant design is the "wet barrel" hydrant where valves are located
above ground and can be independently controlled. In colder climates, dry barrel
hydrants will be required which use a single operating valve that is located
below ground in the base of the riser and which charge all outlets
simultaneously when turned on. |
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Standard" Hydrant Spacing
Standard practice involving hydrant placement is to install hydrants every
500 ft. For practical application, this standard is a guideline and minor
deviations in this spacing may be appropriate.
When determining locations to place fire hydrants, consideration should be
given to accessibility, obstructions, proximety to structures protected,
driveway entrances and other circumstances where adjustments to a specific
hydrant's location would be warranted.
In jurisdictions where all fire engines are equipped with 4 in. (100mm) or
greater large diameter hose (LDH), the maximum spacing between hydrants can be
equal to the smallest in-service compliment of LDH carried. For example, if the
smallest compliment of LDH carried on any engine is 900 ft., it is acceptable to
increase hydrant spacing, where necessary, to 900 ft. This allowance may provide
considerable cost savings. |
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In a circumstance where the most practical locations to place hydrants
may be 800 ft. apart, The LDH allowance precludes the need to place three
hydrants 400 ft apart in order to stay within the 500 ft. rule. If the fire
agency carries at least 800 Ft. of LDH on every engine, two hydrants spaced 800
ft. apart would be considered adequate.
For reasons of public safety, it should not be the objective of hydrant
system engineers to attempt to maximize the spacing between fire hydrants.
Especially in locations where structures are set back from public roadways, some
consideration should be given to ensure that all structures are within "reach"
of appropriate hydrants utilizing standard hose lays. To so do may require
hydrants to be strategically placed at driveway entrances or that laterals be
run from street mains into complexes so that hydrants will be in reasonable
proximety to the structures being protected.
"Risk Based" and Practical Hydrant Placement
There also needs to be a sufficient number of hydrants to provide the
required fire flow for large or high hazard structures. The combined flows of
two or more hydrants may be required to meet these fire flows and each of these
hydrants must be within 500 ft. or LDH hose lay distance of the structure,
whichever is greater.
Another consideration is preservation of vehicle access. If possible,
hydrants should be placed in locations where engines and hose lays connected to
them will not block critical accessways.
Preservation of hydrant access is an important issue. A hydrant isn't useful
if when the project is completed, it is isolated by a fence, gate or other
obstruction which makes it impractical to utilize to protect one or more of the
structures for which it was intended. Walls, gates, fences and other
obstructions should appear on preliminary development plans and if these
improvements affect the use of proposed hydrants, adjustments to the hydrant
locations or placement of additional hydrants should be considered.
Finally, whenver possible hydrants should not be placed so close to
structures that they cannot be used if the structures are heavily involved with
fire. In circumstances where structures are built right next to the roadway, the
500 ft. rule should be employed since a hydrant located a safe distance from the
involved structure may have to be utilized.
Before plotting the specific locations for new fire hydrants, the fire chief
or his/her designate must be consulted to ensure that all of the operational and
practical issues have been considered prior to final placement of hydrants.
There are a number of common errors made with respect to the
installation of new fire hydrants. Most have to do with variations between
preliminary grading designs and final grading. Others involve specific uses of
areas near where hydrants are installed. If these issues are not monitored,
hydrants can end up being situated in such a manner that they at best look
strange and at worst are difficult or impossible to operate.
Hydrant installation details need to be coordinated among all parties
involved at the construction site. If hydrants are being installed in areas to
be landscaped or if final grading elevations are not clear, the hydrant design
that is specified should easily accommodate placement of riser extensions of
various lengths so that the final hydrant installation is compatible with the
final grade elevation.
Coordination should be made with utility companies in order to ensure that
utility poles, vaults and cabinets will not interfere with access to fire
hydrants or impede the operation of the hydrants. As a general rule, no
equipment or facilities should be within 3 ft. (1m) of the hydrant body nor be
placed in front of any hydrant outlet, nor be placed between the hydrant and the
roadway. Those persons who are landscaping near hydrants should be apprised of
these conditions as walls, plants and other landscape materials must be kept
outside the hydrant's clearance space.
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In the West we're puzzled by the use of underground hydrants in
locations where there is sufficient space to install an above ground hydrant on
the sidewalk or shoulder of the road. We're not sure how the fire brigade is
supposed to connect to the underground hydrant pictured on the right!
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Body Colors:
Since they are needed upon an immediate basis during an emergency, fire
hydrants should be immediately recognizable to fire fighting forces as well as
to the general public. The National Fire Protection Association (NFPA) specifies
that fire hydrants are to be painted chrome yellow, however it accepts other
body colors which were already in use at the time the standard was adopted in
the 1970s. Other highly visible colors which have been used include white,
bright red, chrome silver and lime-yellow.
In jurisdictions where no standard color has been established, the most
important aspect is consistency. Standard colors should be adopted which,
preferably, are the same throughout the region.
NFPA also recognizes that there are often functional differences in service
provided by municipal and private hydrant systems. Therefore NFPA specifies that
non-municipal hydrants be painted a color that distinguishes them from municipal
hydrants. Furthermore, violet has been established as the international color
code for non-potable water. Therefore hydrants supplied by non-potable sources
should be painted violet (light purple).
FireHydrant.Org recommends the following body colors for fire hydrants:
Supply
Municipal System:
Private System:
Non-Potable System: |
Body Color
Chrome Yellow
Red
Violet (Light Purple) |
Flow Indicators
The NFPA standard calls for bonnets and caps to be color-coded to indicate
the hydrant's available flow at 20 p.s.i.
Standard color codes are as follows:
NFPA 291, Chap. 3
| Class C |
Less than 500 GPM |
Red |
| Class B |
500-999 GPM |
Orange |
| Class A |
1000-1499 GPM |
Green |
| Class AA |
1500 GPM & above |
Light Blue
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Additional NFPA Language reads:
Hydrants rated at less than 20 psi (1.4 bar) should have the rated pressure
stenciled in black on the hydrant top.
In addition to the painted top and nozzle caps, it may be advantageous to
stencil the rated capacity of high volume hydrants on the top.
The classification and marking of hydrants provided for in this chapter
anticipate determination based on individual flow test. Where a group of
hydrants can be used at the time of a fire, some special marking designating
group-flow capacity may be desirable.
Fire hydrants that are permanently inoperative or unusable should have
barrels, nozzle caps, tops, and all visible parts painted black.
Fire hydrants that are temporarily inoperative or unusable should be wrapped
or otherwise provided with temporary indication of their condition. |
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| While it may seem insignificant, outlet orientation can
have a pivotal impact on the efficiency of fire crews making hookups to
hydrants. In locations where main pressures are sufficient to allow fire
companies to lay supply lines directly to engines at the scene, outlet
orientation is primarily an issue of convenience and getting lines past parked
vehicles. In locations where main pressures are low and engines have to pump
directly from fire hydrants, how outlets are oriented can make the difference
between a fast and efficient hookup versus a complicated procedure. |
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| As a general rule, hydrants are either oriented with
the pumper outlet perpendicular to the curb which faces the street, or with the
pumper outlet set at a 45 degree angle to the street. Whether an agency chooses
a perpendicular or 45 degree configuration depends on the type of hydrant
chosen, the operations of the fire department, and prevailing conditions such as
on-street parking that may restrict hydrant access. |
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| Many newer fire apparatus are equipped with gated
preconnected front suctions for making direct hydrant connections. This suction
connection is often located at the extreme right side of the front of the
apparatus cab. This design is most compatible with a hydrant that has a pumper
outlet that faces away from the engine at a 45 degree angle. This configuration
allows the fire engine to spot relatively close to the curb, blocking less of
the street (which may be needed by other fire apparatus) and at the same time
minimizing the chance of kinking the supply hose and adversely impacting fire
flows. |
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A hydrant orientation where the pumper
outlet faces away from the apparatus at a 45 degree angle has several
operational advantages over "mirror" orientations where the outlet faces toward
the apparatus. When positioning the apparatus at the hydrant, a correct position
will usually be obtained when the hydrant is just forward of the right hand
windshield "A" post in the driver's view. Taking a hydrant on the right side of
the street (with the pumper outlet facing away) will result in a nice, rounded
semi-horseshoe layout that is not likely to kink. |
| Taking a hydrant on the left side of the street (with
the pumper outlet facing toward the apparatus) usually involves spotting the
apparatus when the hydrant is just forward of the left hand windshield "A" post
in the driver's view. Since there is greater distance between the front suction
connection and the hydrant, a nearly straight and kink-free hookup is obtained.
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From the standpoint of training and field performance, it is advantageous
for hydrant spotting points of reference to be consistent. Also, with respect to
taking the hydrant on the left hand side of the street, a mirror image
configuration (pumper outlet facing away from the apparatus) will often leave
the hookup "short." Unless the hydrant is right at the curb line, the front
suction line may not reach the pumper outlet and a more time consuming side
hookup will have to be executed. If an engine can't nose up to the hydrant due
to parked cars, the 45 degree outlet orientation still provides adequate
clearance to extend a hose line between the cars to the engine.
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degree offset provides room to attach large diameter hoses, adapter fittings and
other equipment such as 4-way valves.
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With older apparatus that do not have gated front suctions, the 45 degree
offset works more efficiently than a perpendicular orientation for most side
hookups. The hookup is slightly offset which minimizes kinking. If the pumper
outlet faces away from the approaching apparatus, the engine can spot where the
hydrant is approximately even with the rear axle for a good hookup every time.
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Applicable Uniform Fire Code (UFC)
Sections
The following sections taken from the Uniform Fire Code, 1997 edition,
either contain references to fire hydrants and fire hydrant systems or are
referenced by other sections that address fire hydrants and fire hydrant
systems.
SECTION 901 -- GENERAL
901.1 Scope. Fire department access and water supply shall be in
accordance with Article 9.
901.2 Permits and Plans
901.2.1 Permits. A permit is required to use or operate fire hydrants
or valves intended for fire-suppression purposes which are installed on water
systems and are accessible to public highways, alleys or private ways open to or
generally used by the public. See Section 105. Permit f.1.
901.2.2. Plans.
901.2.2.2 Fire Hydrant Systems Plans and specifications for fire
hydrant systems shall be submitted to the fire department for review and
approval prior to construction.
901.4 Required Marking of Fire Apparatus Access Roads, Addresses and
Fire-Protection Equipment.
901.4.3 Fire-protection equipment and fire hydrants. Fire-protection
equipment and fire hydrants shall be clearly identified in an approved manner to
prevent obstruction by parking and other obstructions.
When required by the chief, hydrant locations shall be identified by the
installation of reflective markers.
See also Section 1001.7.
SECTION 903 -- WATER SUPPLIES AND FIRE HYDRANTS
903.1 General. Water supplies and fire hydrants shall be in accordance
with Sections 901 and 903.
903.2 Required Water Supply for Fire Protection. An approved water
supply capable of supplying required fire flow for fire protection shall be
provided to all premises upon which facilities, buildings or portions of
buildings are hereafter constructed or moved into or within the jurisdiction.
When any portion of the facility or building protected is in excess of 150 feet
(45.72m) from a water supply on a public street, as measured by an approved
route around the exterior of the facility or building, on-site fire hydrants and
mains capable of supplying the required fire flow shall be provided when
required by the chief. See section 903.4.
903.4 Fire Hydrant Systems.
903.4.1 General.
903.4.1.1 Applicability. Fire hydrant systems and fire hydrants shall
be in accordance with section 903.4.
903.4.1.2 Testing and maintenance. Fire hydrant systems shall be
subject to such periodic tests as required by the chief. Fire hydrant systems
shall be maintained in an operative condition at all times and shall be repaired
where defective. Additions, repairs, alterations and servicing shall be in
accordance with approved standards.
903.4.1.3 Tampering and obstruction See Sections 1001.6 and 1001.7.
903.4.2 Required installations. The location, number and type of fire
hydrants connected to a water supply capable of delivering the required fire
flow shall be provided on a public street or on the site of the premises or both
to be protected as required and approved. See Appendix III-B.
Fire hydrants shall be accessible to the fire department apparatus by
roads meeting the requirements of Section 902.2.
903.4.3 Protection, marking and obstruction of hydrants. Fire hydrants
subject to possible vehicular damage shall be adequately protected with guard
posts in accordance with Section 8001.11.3. For marking, see Section 901.4.3.
For obstruction see Section 1001.7.
903.4.4 Maintenance and Use of Hydrants. See Sections 1001.5 and
1001.6.2.
1001.4 Installation Acceptance Testing. Fire alarm systems; fire
hydrant systems; fire extinguishing systems, standpipes, and other fire
protection systems and appurtenances thereto shall meet the approval of the fire
department as to installation and location and shall be subject to such
acceptance tests as required by the chief.
1001.5 Maintenance, Inspection, Testing and Systems Out of Service
1001.5.1 Maintenance. Fire sprinkler systems, fire hydrant systems,
standpipe systems, fire alarm systems, portable fire extinguishers, smoke and
heat ventilators, smoke removal systems, and other fire protective or
extinguishing systems or appliances shall be maintained in an operative
condition at all times and shall be replaced or repaired where defective.
Fire-protection or fire extinguishing systems coverage and spacing shall
be maintained according to original installation standards. Such systems shall
be extended, altered, or augmented as necessary to maintain and continue
protection whenever any building so equipped is altered, remodeled or added to.
Additions, repairs, alterations and servicing shall be in accordance with
recognized standards.
1001.5.2 Inspection and testing. The chief is authorized to require
periodic inspection and testing for fire sprinkler systems, fire hydrant
systems, standpipe systems, fire alarm systems, portable fire extinguishers,
smoke and heat ventilators, smoke removal systems and other fire-protection or
fire-extinguishing systems or appliances.
Automatic fire extinguishing systems shall be inspected and tested at
least annually. See Appendix III-C. Fire alarm systems shall be inspected and
tested at least at frequencies specified in UFC Standard 10-2. Standpipe systems
shall be inspected and tested at least every five years.
Reports of inspections and tests shall be maintained on the premises and
made available to the chief when requested.
1001.5.3. Systems out of Service. The chief shall be notified when any
required fire-protection system is out of service and on restoration of service.
1001.6 Tampering with Fire-protection Equipment, Barriers, Security
Devices, Signs and Seals.
1001.6.1 Fire department property. Apparatus, equipment and
appurtenances belonging to or under the supervision and control of the fire
department shall not be molested, tampered with, damaged or otherwise disturbed
unless authorized by the chief.
1001.6.2 Fire hydrants and fire appliances. Fire hydrants and fire
appliances required by this code to be installed or maintained shall not be
removed, tampered with or otherwise disturbed except for the purpose of
extinguishing fire, training, recharging or making repairs, or when allowed by
the fire department. When a fire appliance is removed as herein allowed, it
shall be replaced or reinstalled as soon as the purpose for which it was removed
has been accomplished.
1001.7 Obstruction and Impairment of Fire Hydrants and Fire-Protection
Equipment.
1001.7.1 General Posts, fences, vehicles, growth, trash, storage and
other materials or things shall not be placed or kept near fire hydrants, fire
department inlet connections or fire department control valves in a manner that
would prevent such equipment or fire hydrants from being immediately
discernible. The fire department shall not be deterred or hindered from gaining
access to fire-protection equipment or hydrants.
1001.7.2 Clear space around hydrants. A 3-foot (.9144m) clear space
shall be maintained around the circumference of fire hydrants except as
otherwise required or approved.
1001.8 Marking of Fire-protection Equipment and Fire Hydrants.
Fire-protection equipment and fire hydrants shall be clearly identified in an
approved manner to prevent obstruction by parking and other obstructions. See
also Section 901.4.3.
NFPA 291 Marking of Fire Hydrants. Bonnets and caps shall be coded as
follows:
| COLOR |
CLASS |
AVAILABLE FLOW
@ 20 p.s.i. residual |
| BLUE |
AA |
1500 GPM or more |
| GREEN |
A |
1000-1499 GPM |
| ORANGE |
B |
500-999 GPM |
| RED |
C |
Below 500 GPM |
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