| (a) For a collection system pipe that will transport
wastewater by gravity flow, the design must specify an infiltration
and exfiltration test or a low-pressure air test. The test must conform
to the following requirements:
(1) Low Pressure Air Test.
(A) A low pressure air test must follow the procedures
described in American Society for Testing and Materials (ASTM) C 828,
ASTM C 924, or ASTM F 1417 or other procedure approved in writing
by the executive director. The testing times listed in Table C.4.
in Figure: 30 TAC §217.57(a)(1)(C) or Equation C.3 in Figure:
30 TAC §217.57(a)(1)(B)(ii) must be used, regardless of the testing
procedure.
(B) For sections of collection system pipe with an
average inside diameter less than 36 inches, the following procedure
applies, unless a pipe is to be tested as required by paragraph (2)
of this subsection.
(i) A pipe must be pressurized to 3.5 pounds per square
inch (psi) gauge. If groundwater is present, then a pipe must be pressurized
to 3.5 psi gauge greater than the pressure exerted by groundwater
above the pipe.
(ii) Once the pressure is stabilized, the minimum time
allowable for the pressure to drop from 3.5 psi gauge to 2.5 psi gauge
is computed from the following equation:
Attached Graphic
(C) Since a K value of less than 1.0 may not be used,
the minimum testing time for each pipe diameter is shown in the following
table:
Attached Graphic
(D) An owner may stop a test if no pressure loss has
occurred during the first 25% of the calculated testing time.
(E) If any pressure loss or leakage has occurred during
the first 25% of a testing period, then the test must continue for
the entire test duration as outlined above or until failure of the
test.
(F) Collection system pipes with a 27 inch or larger
average inside diameter may be air tested at each joint instead of
following the procedure outlined in this section.
(G) A testing procedure for a pipe with an inside diameter
greater than 33 inches must be approved in writing by the executive
director.
(2) Infiltration/Exfiltration Test.
(A) The total exfiltration, as determined by a hydrostatic
head test, must not exceed 10 gallons per inch of diameter per mile
of pipe per 24 hours at a minimum test head of 2.0 feet above the
crown of a pipe at an upstream manhole, or at least two feet above
the existing groundwater level, whichever is greater.
(B) An owner shall use an infiltration test in lieu
of an exfiltration test when pipes are installed below the groundwater
level.
(C) If the quantity of infiltration or exfiltration
exceeds the maximum quantity specified, an owner shall take remedial
action in order to reduce the infiltration or exfiltration to an amount
within the limits specified by Equation C.3. in Figure: 30 TAC §217.57(a)(1)(B)(ii)
before putting the system into service. An owner shall retest a pipe
following a remedial action according to the requirements of this
chapter.
(b) If a gravity collection system pipe is composed
of flexible pipe, deflection testing is also required.
(1) For a collection system pipe with an inside diameter
less than 27 inches, deflection measurement requires a rigid mandrel.
(A) Mandrel Sizing.
(i) A rigid mandrel must have an outside diameter not
less than 95% of the base inside diameter or average inside diameter
of a pipe, as specified in the appropriate standard by the ASTM, American
Water Works Association, UNI-BELL, or American National Standards
Institute.
(ii) If the mandrel diameter is not specified in the
standard used in clause (i) of this subparagraph, the mandrel must
have an outside diameter equal to 95% of the inside diameter of a
pipe. In this case, the inside diameter of the pipe, for the purpose
of determining the outside diameter of the mandrel, must equal the
average outside diameter minus two minimum wall thicknesses for outside
diameter controlled pipe and the average inside diameter for inside
diameter controlled pipe.
(iii) All mandrel dimensions must meet the standard
used in clause (i) of this subparagraph.
(B) Mandrel Design.
(i) A mandrel must be constructed of a metal or a rigid
plastic material that can withstand 200 psi without being deformed.
Adjustable or flexible mandrels are prohibited.
(ii) A mandrel must have an odd number of runners or
legs.
(iii) A mandrel must have nine or more runners or legs.
(iv) The length of the mandrel's barrel section must
equal at least 75% of the inside diameter of the collection system
pipe.
(v) Each mandrel size must use a separate proving ring.
(C) Method Options.
(i) An owner may not use television inspection as a
substitute for a deflection test.
(ii) If requested, the executive director may approve,
in writing, the use of a deflectometer or a mandrel with removable
legs or runners on a case-by-case basis.
(D) Trenchless Testing. The executive director may
exempt pipe sections installed by trenchless technologies from mandrel
testing in writing on a case-by-case basis.
(2) For a gravity collection system pipe with an inside
diameter of 27 inches and greater, other test methods approved in
writing by the executive director may be used to determine vertical
deflection.
(3) A deflection test method must be accurate to within
plus or minus 0.2% deflection.
(4) An owner shall not conduct a deflection test until
at least 30 days after the final backfill.
(5) Collection system pipe deflection must not exceed
5%.
(6) If a pipe section fails a deflection test, an owner
shall correct the problem immediately, and then must conduct a second
test after the final backfill has been in place at least 30 days.
(7) An owner shall not use any mechanical pulling devices
during deflection testing.
(8) An owner shall include a certification in the notice
of completion required in §217.14 of this title (relating to
Completion Notice), that the collection system passed the deflection
tests.
(c) An owner of a collection system must inspect the
structural integrity of the collection system under the direction
of an engineer during the construction and testing phases of the project.
|
