NFPA 24 Sections
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ScribdTranslationsNFPA 24 Parts (2010 Edition)
Chapter 7 Hydrants
7.1* General.
7.1.1 The hydrants must be of the approved type and have a connection diameter of
the main pipes not less than 6 inches (152 mm).
7.3 Installation.
7.3.1* Hydrants must be placed on flat stones or concrete slabs and
provided with small stones (or equivalent) placed near the drain to
guarantee drainage.
7.3.2 Where the soil is of such nature that the hydrants do not drain properly
with the provision specified in 7.3.1 or where the groundwater (water table) is
at levels higher than the drain, the hydrant drainage must be blocked in the
moment of its installation.
The center of a hose outlet must be no less than 18 inches (457
above the final slope or where they are located situated in a booth
from the hose, 12 inches (305 mm) above the ground.
7.3.4 The hydrants must be secured to the pipe and anchored according to the
requirements of Chapter 10.
7.3.5 Fire hydrants must be protected if they are subject to mechanical damage.
7.3.6 The protection means for the hydrant must be arranged in such a way that they do not
interfere with the connection to, or operation of hydrants.
7.3.7 It should not be installed on the connection between the hydrant and the supply pipe
water deprived, the following:
Check valves
Non-return valve detector
Backflow prevention valves
Other similar accessories
Plastic Pipe
Pressure Pipe made of Polyvinyl Chloride (PVC) from 4 inches to 12 inches,
for Water and Other Liquids.
Pressure Pipes and Accessories in Polyethylene (PE), 4 inches (100 mm) up to 63
inches (1575 mm) for Water Distribution and Transportation
10.1.5* Working Pressure. The piping, fittings, and other components of the system
They must be classified for the maximum working pressure of the system to which they are subject.
exposed, but such classification cannot be less than 150 psi (10.3 bars).
10.2 Accessories.
10.2.1 Standardized Accessories. The accessories must comply with the standards in the Table
10.2.1(a) or be in accordance with 10.2.2. In addition to the rules in Table 10.2.1
(b), the CPVC accessories must also be in accordance with 10.2.2 and with the
parts of the ASTM standards specified in Table 10.2.1 (b) that apply to the service
fire protection.
10.2.3 Pressure Limits. Listed accessories for the pressures must be allowed.
of the systems as specified in their listings, but not less than 150 psi (10
10.2.5* Buried Accessories. The accessories must be of an approved type.
unions and pressure class rates compatible with the pipe used.
10.4.3 In those places where freezing is not a factor, the depth of
Coverage must be no less than 2 ½ feet (0.8 m) to avoid mechanical damage.
10.4.4 The pipe under access ways must be buried at a minimum depth
3 feet (0.9 m).
10.4.6 The coverage depth must be measured from the top of the pipe to
the level of finish and consideration must always be given to the future or final level and
nature of the soil.
10.6 Protection Against Damage.
10.6.1 The pipe must not pass under buildings.
10.6.2 Where the piping must pass under buildings, precautions must be taken.
specials, including the following:
Arching the foundations of walls over the pipes
Passing the pipe inside covered trenches
Providing valves to isolate sections of piping under buildings
10.7.10 If the ground is soft or of a shifting nature, precautions must be taken.
special supports for the piping.
10.7.11 The valves and fittings used with non-metallic piping must be supported.
and embedded in accordance with the manufacturer's specifications.
10.8 Embedding of Joints.
10.8.1 General.
10.8.1.1* All tees, plugs, caps, elbows, reducers, valves, and branches of
hydrants must be embedded against movement using push blocks in
compliance with 10.8.2 or systems for embedding joint systems accordingly
with 10.8.3.
10.8.1.2 Pipes with cast, threaded, grooved or welded joints do not
additional embedding is required, as long as such joints can pass the test
hydrostatics of 10.10.2.2 without pipe disturbances or excessive leakage of the
allowed quantities.
10.8.1.3 Steep Slopes. On steep slopes, the main pipes
They must also be embedded to prevent slipping.
10.8.1.3.1 The pipes must be embedded in the bottom of a mound and in any
turn (lateral or vertical).
10.8.1.3.2 The embedding specified in 10.8.1.3.1 must be in natural rock or in
appropriate stirrups built on the inclined side of the bell.
The rounded ends must be installed facing upward.
Straight sections on slopes must be embedded as necessary
determined by the design engineer.
10.8.2* Push Blocks.
10.8.2.1 The thrust blocks must be considered satisfactory where the soil is
suitable for use. 10.8.2.2 The push blocks must be made of a mixture of
concrete that has no less than one part of cement, two and a half parts of sand and
five stone parts.
10.8.2.3 The thrust blocks must be located between unaltered earth, not
intervened and the accessory to be embedded must be able to withstand the forces
calculated thrust.
10.8.2.4 Where possible, the push blocks should be placed so that
the joints should be accessible for repair.
ANNEX NFPA 13 (SOME SECTIONS OF THE PUSH BLOCKS)
A.10.8.2 Thrust Blocks. Concrete thrust blocks are one of the methods
most common fasteners used today, as long as they prevail.
stable soil conditions and space requirements allow for its placement. The
successful blocking depends on factors such as location, availability, and the
placement of concrete, and the possibility of disturbance by excavations
futures.
Resistance is achieved by transferring the pushing force to the ground through the greatest
support surface of the block so that the resulting pressure against the ground does not
overcame the horizontal support resistance of the ground. The design of the thrust blocks
it consists of determining the appropriate support area of the block for a set
particular conditions.
The parameters involved in the design include the diameter of the pipe, the pressure
of design, the angle of the curve (or the configuration of the involved accessory), and the
horizontal soil support resistance.
Table A.10.8.2(a) shows the nominal thrust in fittings of various diameters
ductile iron and PVC pipes. Figure A.10.8.2(a) shows an example of how
the thrust forces act on a elbow of a pipe.
Push blocks are generally categorized into two groups - support blocks.
and gravity. Figure A.10.8.2(b) represents a typical support thrust block
on a horizontal curve.
The following are general criteria for the design of the support block:
The support surface should, when possible, be resting against the ground.
that has not been touched.
When it is not possible to lay the support surface against a ground that has not
has been touched, the filling between the supporting surface and the ground should not touch
compact to at least 90 percent of the Standard Proctor density.
The height of the block (h) should be equal to or less than half of the depth.
total to the bottom of the block (Ht) but no less than the diameter of the pipe
(D).
The height of the block (h) should be chosen so that the calculated width of the block
(b) vary between one and two times the height.
Gravity support blocks can be used to resist thrust at elbows.
vertical downwards. In a block of support by gravity, the weight of the block is the
force that provides equilibrium with the thrust force.
The design problem is then to calculate the required volume of the thrust block.
of a known density. The vertical component of the buoyant force in the Figure
A.10.8.2(c) is balanced by the weight of the block. For the required areas of blocks
horizontal, see Table A.10.8.2(a).