Current through Register Vol. 50, No. 9, September 20, 2024
A. An appropriate
casing shall be installed in every water well to prevent the wall of the hole
from collapsing, to house the pump, and to convey the water to the
surface.
B. General Criteria. The
selection of casing is dependent upon a number of factors that shall be
considered when designing and installing a well. Following are some of the
factors.
1. The casing shall be strong enough
to resist the forces imposed during installation and other forces that can be
expected after installation.
2. The
casing shall be of adequate diameter to accommodate the pump and convey the
required quantity of water.
3.
Joints of metal casing shall have threaded couplings or be welded to ensure
water tightness for the entire length of the casing.
4. The casing shall be reasonably plumb and
straight. The plumbness and alignment of the casing shall be checked in
accordance with accepted practices.
5. The casing shall be installed so as to
seal off water-bearing formations that contain undesirable water and to prevent
water from the surface and other aquifers from entering the well.
C. Materials. The casing materials
commonly used in Louisiana are metal and plastic. Concrete, clay tile, wood,
fiberglass, and other synthetic casings have been used in the past in some
areas for specific applications.
D.
Metal Casing. Steel is the material most frequently used for well casing in
drilled wells. The three principal classifications of steel used for water well
casing are as follows.
1. Standard and Line
Pipe. This material shall meet one of the following standard specifications,
including the latest revision thereof:
a. API
Spec. 5A, "Specifications for Casing, Tubing and Drill Pipe;"
b. API Spec. 5L, "Specifications for Line
Pipe;"
c. API Spec. 5LX,
"Specifications for High-Test Line Pipe;"
d. ASTM A53, "Specifications for Pipe, Steel,
Black and Hot Dipped, Zinc-Coated, Welded and Seamless Steel Pipe;"
e. ASTM A120 "Standard Specifications for
Pipe, Steel, Black and Hot Dipped Zinc-Coated (Galvanized) Welded and Seamless
Steel Pipe for Ordinary Uses;"
f.
ASTM A134, "Standard Specifications for Pipe Steel, Fusion (Arc)- Welded Steel
Pipe (Sizes NPS 16 and over);"
g.
ASTM A135, "Standard Specifications for Electric-Resistant Steel
Pipe;"
h. ASTM A139, "Standard
Specifications for Electric-Fusion (Arc)- Welded Steel Pipe (Sizes 4 inches and
over);
i. ASTM A211, "Standard
Specifications for Spiral-Welded Steel or Iron Pipe;"
j. AWWA C201, "AWWA Standard for Fabricated
Electrically Welded Steel Pipe;"
k.
AWWA C202, "Tentative Standard for Mill Type Steel Water Pipe;"
l. Underwriters Laboratories Standard
888.
2. Structural
Steel. This material shall meet one of the following specifications of the
American Society for Testing and Material, including latest revision thereof:
a. ASTM A36, "Standard Specification for
Structural Steel;"
b. ASTM A242,
"Standard Specification for High-Strength Low-Alloy Structural
Steel;"
c. ASTM 570-79, "Standard
Specifications for Hot-Rolled Carbon Steel Sheet and Strip, Structural
Quality;"
d. ASTM A283, "Standard
Specifications for Low and Intermediate Tensile Strength Carbon Steel Plates,
Shapes and Bars;"
e. ASTM A441,
"Standard Specification for High-Strength Low-Alloy Structural Manganese
Vanadium Steel."
(Abbreviations used are:
API-American Petroleum Institute;
ASTM-American Society for Testing and Materials;
AWWA-American Water Works Association.)
3. High Strength Carbon Steel. At
present, there is no standard specification concerning this material; however,
products are marked whose chemical and physical properties are similar. The
material shall contain mill markings which will identify the manufacturer and
specify that the material is well casing steel that complies with the chemical
and physical properties as published by the manufacturer.
E. Plastic Casing. Thermoplastic well casing
pipe may be used for well construction if it complies with the requirements and
restrictions of this Section.
F.
Pipe and Material Specifications
1. The
thermoplastic well casing pipe and couplings shall be new polyvinyl chloride
(PVC) material produced in accordance with the current AWWA Standard A-100 and
ASTM F-480 standard, except that the impact standards of the current ASTM
D-2241 may be substituted.
2. PVC
material shall be designated as PVC 1120 or PVC 1220 and shall include an
ultra-violet degradation inhibitor in its formulation.
3. Solvent cement shall conform to the
current ASTM D-2564 standard.
4.
Pipe may be joined by threaded joints, integral bell pipe or one piece
couplings. Solvent-weld tapered bell and spigot joints shall meet current ASTM
specification D-2672.
G.
Casing Wall Thickness and Diameters
1. The
pipe shall have a standard dimension ratio (SDR) of 26, 21, or 17, and shall be
equivalent to at least Schedule 40 or 80, depending upon use, construction
techniques, depths and strength requirements.
2. Casing collapse pressures recommended by
the manufacturer shall not be exceeded in any phase of well construction. Due
consideration shall be given to extreme conditions that may result from the use
of high density cement grouts, high pressure cement grouting and high
temperature from the heat of hydration in cement grouts.
3. Where threaded joints are used, wall
thickness shall not be less than the equivalent of Schedule 80.
H. Marking and Approval
1. The well casing pipe and couplings shall
be marked in accordance with the current ASTM F-480 standard.
2. Where applicable, the well casing pipe,
couplings, cement, primer and other compounds shall be evaluated and listed as
conforming with both ANSI/NSF Standard 14 and ANSI/NSF Standard 61.
3. The pipe shall be marked with the nominal
size standard dimension ratio or schedule, type of material, either the
designation "PVC 1120" or "PVC 1220", the wording "well casing", designation
"ASTM F-480", manufacturers name or trademark, and the NSF-WC
designation.
I. Storage
1. The pipe and couplings shall be stored in
a manner to minimize exposure to ultraviolet radiation.
2. The pipe shall be stored in a manner to
prevent deformation, sagging or bending.
J. Assembly and Installation
1. Joining techniques, including procedures
for cutting, joint cleaning and priming, application of solvent cement,
assembly and hardening time for solvent cement joints, shall be in accordance
with the manufacturer's recommendations, and/or ASTM Standard D2855.
2. The well casing shall not be subjected to
excessive forces and it may not be driven, pushed or forced into the
formation.
3. PVC casing may be
used to any depth, provided that allowable head differential (AHD) and
hydraulic collapse pressure resistance (HCPR) are not exceeded. The well casing
diameter and SDR or schedule shall be selected based on Appendix "L" of AWWA
Standard A-100 and/or the manufacturer's recommendations for collapse pressure
under extreme conditions.
4. PVC
casing shall not be allowed to support the weight of the pump/motor (excluding
submersible and single-pipe jet pump) and its related piping. The pump/motor,
etc. shall be supported on a concrete base provided therefor.
5. Exposed PVC casings shall be protected
from ultra-violet degradation by appropriate coatings as recommended by the
manufacturer.
K. Height
of Casing. Well casing shall project at least one foot above ground level,
pump-house floor, or the top of concrete slab. For wells in areas subject to
flooding, refer to §319. A The ground surface or concrete slab around the well
shall be sloped to drain away from the well in all directions.
AUTHORITY NOTE:
Promulgated in accordance with
R.S.
38:3091-R.S.
38:309.8.
