NATURAL RESOURCES CONSERVATION SERVICE

**Idaho**

**CONSTRUCTION SPECIFICATIONS**

**FOR**

**SUSPENSION FENCE**

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(Owner/Operator) (Project Title)

GENERAL

Installation shall be in accordance with an approved plan. Details of
construction shown on the drawings but not include herein are considered
as part of these specifications. Construction activities shall be in
accordance with applicable OSHA regulations.

When planning fences in know sage grouse habitat, consult with
biologists from Idaho Department of Fish and Game regarding fence
placement and lek location. Consultation is required under the
Memorandum of Understanding between NRCS and Idaho F&G dated 1990.

Prior to construction the fence lines shall be cleared of any possible
obstruction that would hinder the fence placement and operation.

The soil surface along the fence line shall be relatively smooth such
that placement of the bottom fencing member does not exceed the maximum
fence member to soil surface spacing specified.

The fence materials shall have an expected life of 10 years with routine
maintenance. All wood materials except Orange Osage, Western Red Cedar,
Juniper and Black Locust that have contact with the soil shall be
treated with an EPA-registered wood preservative. Wood posts shall be
treated from the butt end of the post to distance of at least 30 inches
for line posts and 36 inches for all corner, gate and brace posts. Refer
to Table 1 for the life expectancy of treated versus untreated wood
posts.

MATERIALS

[Wood Posts]{.underline}. Line posts shall have a minimum top diameter
of 3 inches and shall be a minimum of 6 feet in length. Corner, gate and
brace posts shall have a minimum top diameter of 6 inches and shall be a
minimum of 8 feet in length. Braces shall have a minimum top diameter of
4 inches and shall be a minimum of 6 feet in length.

Table 1. Life Expectancy of Untreated and Treated Fence Posts (Years)

+------------------+-----------+------------+------------+-----------+
| Kind of Wood     | U         | Pressure   | Hot and    | Cold Soak |
|                  | n-treated |            | Cold Bath  |           |
|                  |           | Treated    |            |           |
+------------------+-----------+------------+------------+-----------+
| Western Red      | 12-15     | 20-25      | 20-25      | \-        |
| Cedar            |           |            |            |           |
+------------------+-----------+------------+------------+-----------+
| Lodgepole &      | 2-4       | 20-25      | 15-20      | 10-20     |
| Ponderosa Pine   |           |            |            |           |
+------------------+-----------+------------+------------+-----------+
| Aspen or         | 1-3       | 15-20      | 10-15      | 5-10      |
|                  |           |            |            |           |
| Cottonwood       |           |            |            |           |
+------------------+-----------+------------+------------+-----------+
| Douglas Fir &    | 3-6       | 20-35      | 15-25      | 10-20     |
| Western Hemlock  |           |            |            |           |
+------------------+-----------+------------+------------+-----------+

[Steel Posts]{.underline}. Steel line posts shall be the "T", "U" or "Y"
type with a welded or riveted anchor plate near the bottom (minimum 18
inches square area) and have suitable corrugations, knobs, studs or
grooves for fastening the wire. Line posts shall weigh at least 1.33
pounds per linear foot of length and shall be a minimum of 5.5 feet
long.

[Steel Pipe Posts]{.underline}. Steel pipe corner, gate or brace posts
shall be a minimum diameter of 2 inches, Schedule 40 (2.375-inch O.D.)
and at least 7 feet long. Bracing shall be a minimum of 1-1/2 inch
nominal diameter, Schedule 40 pipe. Brace fittings and clamps shall be
galvanized.

[Angle Section Posts]{.underline}. Angle section posts shall have
nominal sectional dimensions of 2.5 by 2.5 by 0.25 inches thick and at
least 7 feet in length. Braces shall be of the same size dimensions as
corner and gate posts and shall be a minimum of 6 feet in length.

[Barbed Wire]{.underline}. Barbed wire shall be composed of two strands
of 12.5 gauge zinc coated wire wrapped around each other, with 2-point
14 gauge barbs spaced no more than 5 inches apart conforming to ASTM A
121.

[Smooth Wire]{.underline}. Smooth wire shall be a single steel wire of 9
gauge or heavier, two wrapped strands of 12.5 gauge or heavier wire.
Wire shall have a minimum tensile strength of 45,000 psi.

[Wire Panel Fasteners]{.underline}. Staples shall be 9 gauge or heavier
and have a minimum length of 1.5 inches, except 1.0 inch staples are
allowed n very hard woods. Fasteners for use with steel posts shall be
12 gauge or heavier zinc coated wire.

[Stays]{.underline}. Wire stays shall be 9.5 gauge or heavier, zinc
coated, twisted wire. The length shall be at least two inches longer
than the distance between the top and the bottom strands of the fence.
Wood stays shall be sound, straight pieces at least 2 inches in
diameter.

INSTALLATION

The fence shall be reasonably straight and shall not deviate more than
12 inches between any corner and gate or line brace assembly.

[Post Depth]{.underline}. Line steel posts shall be set a minimum depth
of 1.5 feet and wood line posts shall be set to a minimum depth of 2
feet, unless otherwise specified. Gate, corner and brace posts shall be
set to a minimum depth of 3 feet, unless otherwise specified. Steel pipe
and angle section posts shall be embedded in a 12-inch circular or
square concrete pier, except when set in firm rock.

Suspension fences should be constructed with approximately a 3-inch sag
in the wires between posts to permit maximum sway of the fence.

[Post Spacing]{.underline}. The maximum post spacing interval shall not
exceed 100 feet.

[Line Bracing]{.underline}. Line brace assemblies shall be located at
all corners, gates and abrupt changes in vertical topography (generally
considered as 15 degrees). On straight reaches of fencing line braces
shall be installed at a spacing of no more than 1300 feet.

[Wire Spacing]{.underline}. Wire spacings are as follows, unless
otherwise specified:

Table 2. Barbed Wire Fence

  ---------------------- ------------ --------- --------- --------- ---------
  Fence Type             Spacing                                    
                         Measured                                   
                         from                                       
                         Groundline                                 
                         (inches)                                   

  3-wire                 16           28        40                  

  4-wire                 14           22        30        42        

  5-wire                 5            12        20        30        42
  ---------------------- ------------ --------- --------- --------- ---------

Note: Where the movement of antelope is a concern, the minimum height of
the bottom wire shall be 16 inches from the groundline and the wire may
be smooth. Antelope crossings shall be provided if sheep-tight fences
are built.

[Wire Fasteners]{.underline}. Staples shall be driven diagonally into
the wood grain of the post. Space shall be left between the post and the
staple to allow movement of the wire. Fasteners on steel posts shall be
snug enough to prevent vertical movement of the wire on the post.

[Stays]{.underline}. The maximum distance between stays and/or line,
corner, gate or brace posts shall not exceed 15 feet.

[Drainageways]{.underline}. In crossing drainageways or depressions a
weight or deadman anchor shall be fastened to the fence to maintain the
required spacing interval or additional wires shall be added to maintain
the required minimum wire height from the groundline.

WILDLIFE FENCES

In areas commonly used by wildlife, fencing should be designed to
facilitate passage of wildlife species without injury. The bottom wire
will be smooth and a minimum of 16" from the ground to allow for the
passage of antelope and fawn deer. Spacing between the top two wires
will be 12" to reduce instances of entanglement (see Table 4). If
practical use a top wood rail instead of barbed wire where elk are a
concern. Replace woven wire with barbed or smooth wire when possible,
otherwise refer to Table 5.

When fencing in areas where sage grouse are present do not install
fences closer than 0.6 miles to a lek location. In areas where leks are
present improve visibility of wires by using reflective tagging.

Table 4 - Wildlife Barbed Wire

  ------------------------------ ------------ --------- ---------- ----------
  Wire Description               Spacing                           
                                 Measured                          
                                 From                              
                                 Groundline                        
                                 (inches)                          

  3 -wire                        16           26        38         

  4 -wire                        16           21        26         38
  ------------------------------ ------------ --------- ---------- ----------

Table 5 -- Wildlife Woven wire

  --------------------------- ------------- ---------- --------- ---------
  Wire Description            Spacing                            
                              Measured From                      
                              Groundline                         
                              (inches)                           

  26-inch woven               Ground        26         26 wire   38 wire

  32-inch woven               Ground        no wire              
  --------------------------- ------------- ---------- --------- ---------

ADDITIONAL SPECIFICATIONS