Park Place-CS 910404April 4, 1991
Mr. Larry Davis
Development Construction Inspector
City of Coppell
732 Deforest Rd.
P.O. Box 478
Coppell, Tx 75019
Re;' ~ace~
Ai~lts
Dear Larry,
C.W. Young Construction Co. retained us Thursday, April 8th 1991,
to perform line acceptance testing in the Park Place Addition. The
line segment tested was in Woodcrest Lane, (an 8" sanitary sewer)
line "C" from station #8 + 31 to 13 + 06. The criteria used for
acceptance testing on SDR35 was the current North Texas Council of
Governments set of standard specifications, located in division 6
on pages 332 and 333.
The line segment was approximately 475' in length with service
lines capped at the property line. Our test procedure was to pump
the line to 4 psig and allow the air to stabilize. The line was
bled back to 3.5 psig and the time noted to begin the test. The
C.O.G. standard for 475' of 8" SDR 35 is 4:26 minutes allowed time
for a drop in pressure from 3.5 to 2.5. If a pressure drop of 1
psig occurs in less than 4:26 minutes, the line would not meet the
standard, if a pressure drop is less than 1 psig in 4:26 minutes
the line meet the test criteria established by C.O.G. and meets the
standard.
continued
515 N, Kealy Street 19350 FM 1093
(214) 436-4568 Lewisville,Texas 75057 · Richmond,Texas 77469 (713) 579-0074
Municipal and Utility Contractor's Services
page 2
In testing this line segment, we noted a pressure drop of 1/4 pound
during the 4:26 period of allowable loss. This amount of loss
falls we]] within the C.O.G. guidelines. It is clear that the line
has met the standards required and will perform as designed.
If I can be of any further assistance,
don't hesitate
to call.
c.c.C.W. Young
c.c. Howard Pafford, City of Coppell
GTS/nl
515 N. Kealy Street 19350 FM 1093
(214) 436-4568 tewisville,Texas 75057 · Richmond,Texas 77469 (7t3) 579-0074
equilibr/um with the temperature of the pipe walls. The pressure w/ii
normaily drop slightly until equilibrium is obtained. During this period
all assessable plugs should be checked with soap solution to detect any
plug leakage. 5) Determine the rate of ulr loss by either the constant
pressure method or the time pressure drop method. For the constant
pressure method, air is supplied to the pipe test section at a rate suffi-
cient to maintain a gauge pressure of 3.0 psi. The rate of air flow in cubic
feet per minute is read directly by means ufa retometer. The rate of air
flow must be corrected for pressure and temperature under standard
conditions. 6) Upon completion of the test, the bleeder valve is opened
and ail air is allowed to escape. Plugs should not be removed until afl air
pressure in the test section has been released. Also no one should be
allowed in the trench or manhole while the test is being conducted.
(C) Constant Pressure Method: 1) Air is supplied to the pipe test
section at a rate sufficient to mainta/n a gauge pressure of 3.0 psi. The
rate of air flow ' -
m cubic feet per minute is read directly by the means ufa
retometer. The rate of air flow shall be corrected for pressure and tern-
under standard conditions. 2) The requirements for air loss
under the "Constant Pressure" method shaft be considered satisfied if
the air loss does not exceed a rate of 0.003 cfm per square foot of internal
pipe surface area with a total rate of air loss not greater than 2.0 cubic
feet per minute, based on a wetted pipe.
(D) Time Pressure Drop Method: 1) Air is slowly introduced into
the section of plpPsi~O e air pressure is raised to ap-
' owed to stabilize for a period of
two minutes. The air supply is disconnected and the test pressure
allowed to decrease to 3.5 psig. The time required for the test pressure
to drop from 3.5 psig to 2.5 psig is determined, and this time interval is
then compared · ·
to the required time to determine ff the rate of ah' Ions is
within the allowable. 2) Minimum holding times required per pipe diame-
ter · re shown in the table "Duration Requirements for Air Testing.'
(Note: Test times are independent of the line length once the minimum
holding time has been reeched.)
(4) Individuai Joint Test Method. Afl concrete sewer main 36* ~ ~
larger in dhuneter shall be 100% air tested at each
The method of testing shaft be described in Item 6.7.2.(/).
j ~ u,mu oe au' tested until the p~pe has been b~kffi{~l..{
shah be performed ss pipe inst~l!ption progresses. At no ~
installation exceed 100 feet fi'om the lnst joint tested. Iftbe
pass the joint air test, necessary ropaire as recommended I
manufacturer may be made ff approved by the ow~z~ m~l tim
tested. Failure to pass the air test after r
for rejection.
At'DST t987
TABLE -- DURAT1ON REQUIREMENTS FOR AIR TESTING
SPECIIqCAT1ON TIME REQUIRED FOR LOSS OF PRESSURE FROM 3.5 PSIG
TO ?-5 PSIG FOR SIZE AND LENGTH OF FqPE INDICATION FOR Q=0.{X)3
4 1:53 597 1:53 1:53 1:53 1:53 1:53 1:53 1:53 - 1:53
6 2:50 398 2:50 2:50 2:50 2:50 2:50 2:50 2:50-- 2:50
8 3:47 298 3:47 3:37 3:47 3:47 3:48 4:26 4:26
10 4:43 239 4:43 4:43 4:43 4:57 5:56. 5:56
12 5:40 199 5:40 5:40 5:42 7:08 7:08
15 7:05 159 7:05 7:05 8:54 8:54
18 8:30 133 8:30 9:37 9:37
21 9:95 114 9:55 13:05 13:05
24 11:20 99 11:24 11:24
27 12:45 88 14:25 14:25
30 14:10 80 17:48 17:48
33 15:35 72 21:33 .21:33
36 17.'00 66 25:39 25:39
"This tatYm is based on T = 0.0850 DK/Q
D = p~pe diameter, in.
L = ~ of pipe be~rtcj tested, ff.
~ '"Te~ New Sewer Pipe Installation' by Roy E. Ramseier.
This document is part of the ASTM
Standards process and is for ASTM
committee use only. It shall not
be reproduced, in whole or in part,
outside of the ASTM committee
activities except with the approval
of the chairman of the committee
having jurisdiction or the President
of the Society.
Proposed Draft: A
Date: 06-01-90
SUBCOMMITTEE: F17.62
PROJECT NO: 62-90-03
Subcommittee Letter Ballot
Standard Test Method for
Low-Pressure Air Test of Plastic Pipe Sewer Line
1. Scope
1.1 This test method defines procedures for testing plastic pipe
sewer lines, using low-pressure air to demonstrate the structural
integrity of the installed line.
1.2 This test method shall be performed on lines after
connection laterals, if any, have been plugged and braced adequately
to withstand the test pressure, and after the trenches have been
backfilled for a sufficient time, not less than 30 days, to generate
a significant portion of the ultimate trench load on the pipe line.
The time between completion of the backfill operation and
low-pressure air testing shall be determined by the approving
authority.
1.3 This test method may also be used as a preliminary test,
which enables the installer to demonstrate the condition of the line
prior to backfill and further construction activities.
1.4 This test method is suitable for testing gravity-flow sewer
pipe constructed of plastic pipe and fittings.
1.5 Thermoplastic pipe,
pipe and reinforced plastic
test method.
reinforced thermosetting resin (RTRP)
mortar (RTMP) pipe are covered by the
1.6 This
and equipment.
safety problems
standard may involve hazardous materials, operations,
This standard does not purport to address all of the
associated with its use. It is the responsibility of
the user of this standard to establish appropriate safety and health
practices and determine the applicability of regulatory limitations
prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D618 Methods of Conditioning Plastics and Electrical Insulating
2
Materials for Testing
2
D695 Test Method of Compressive Properties of Rigid Plastics
2,3
D833 Definitions of Terms Relating to Plastics
2,3
D1600 Abbreviations of Terms Relating to Plastics
D2122 Method of Determining Dimensions of Thermoplastic Pipe and
3
Fittings
F405 Specification for Corrugated Polyethylene (PE) Tubing and
3
Fittings
3
F412 Definitions of Terms Relating to Plastic Piping Systems
2
3. Significance and Use
3.1 The low-pressure air test provides for the detection of
damaged installed pipe or improper jointing and is a test which
determines the rate at which air under pressure escapes from an
isolated section of sewer.
3.2 The rate of air loss is intended to indicate the presence or
absence of installed pipe damage.
3.3 Whether or not the joints have been properly installed.
3.4 The test is not intended to indicate water leakage limits
and cannot be used as a measure of leakage under service conditions
for infiltration or exfiltrations.
4. S~mmary of Test Method
4.1
pressure,
test if
The section of the line to be tested is plu§ged. Air, at low
is introduced into the plugged line. The line passes the
the rate of air loss, as measured by pressure drop, does not
exceed a specified amount in a specified time. This may be determined
by the use of Table I, or calculated by use of the formulas in
Section 9.1.
5. Hazards
5.1
through lack
overpressuri zed
important that
The low pressure air test may be dangerous to personnel if,
of understanding or carelessness, a line is
or plugs are installed improperly. It is extremely
the various plugs be installed so as to prevent the
sudden expulsion of a poorly installed or partially inflated plug. As
an example of the hazard, a force of 250 lbf (1112 N) is exerted on
an 8-in. (200-mm) plug by an internal pressure of 5 psi (34 kPa).
Observe the following safety precautions:
5.1.1 No one shall be allowed in the manholes during testing
because of the hazards.
5.1.2 Install all plugs securely.
5.1.3 When lines are to be tested, it will be necessary that the
plugs be braced as an added safety factor.
5.1.4 Do not overpressurize the lines.
5.1.5 Do not exceed 9 psig internal pressure at any time.
6. Preparation of the Line
6.1 The section of sewer line to be tested shall be flushed and
cleaned prior to conducting the low pressure air test. This serves to
eliminate debris, as well as, wet the pipe and produce the most
consistent results.
?. Procedures
7.1
inflatable
branches, laterals,
will be plugged to
Isolate the section of sewer line to be tested by means of
stoppers or other suitable test plugs. The ends of all
tees, wyes and stubs to be included in the test
prevent air leakage. All plugs will be securely
braced
O~e of the plugs
connecting a hose
hose to the inlet
to prevent possible blow-out due to the internal air pressure.
should have an inlet tap, or other provision for
to a portable air control source. Connect the air
tap and portable air control source. The air
equipment will consist of necessary valves and pressure gauges to
control air source. The air equipment will consist of necessary
valves and pressure gauges to control the rate at which air flows
into the test section and to enable monitoring of the air pressure
within the test section. Add air slowly to the test section until the
pressure inside the pipe is raised to 4.0 psig. After the pressure of
4.0 psig is obtained, regulate the air supply so that the pressure is
maintained between 3.5 to 4.0 psig for a period of two minutes. This
allows the air temperature to stabilize in equilibrium with the
temperature of the pipe walls. The pressure will normally drop
slightly until equilibri~m is obtained. During this period all
assessable plugs should be checked with soap solution to detect any
plug leakage.
7.2 Determine the
rate of air loss by either the constant
pressure method or the time pressure drop method.
5
7.2.1 Constant Pressure Method: Air is supplied to the pipe test
section at a rate sufficient to maintain a gauge pressure of 3.0 psi.
The rate of air flow in cubic feet per minute is read directly by the
means of a rotometer. The rate of air flow shall be Corrected for
pressure and temperature under standard conditions. The requirements
for air loss under the "Constant Pressure" method shall be considered
satisfied if the air loss does not exceed a rate of 0.0015 cfm per
square foot of internal pipe surface area. Air is supplied to the
pipe test section at a rate sufficient to maintain a gauge pressure
of 3.00 psig. The rate of air flow in cubic feet per minute is read
directly by means of a rotometer.
7.2.2 Time Pressure Drop Method: 1) Air is slowly introduced
into the section of pipe to be tested, until the air pressure is
raised to approximately 4.0 psig. The air shall be allowed to
stabilize for a period of two minutes. The air supply is disconnected
and the test pressure allowed to decrease to 3.5 psig. The time
required for the test pressure to drop from 3.5 psig to 2.5 psig is
determined, end this time interval is then compared to the required
time to determine if the rate of air loss is within the allowable.
2) Minimum holding times required per pipe diameter are shown in the
Table 1.
all
air
should be
conducted.
7.3 Upon completion of the test, the bleeder valve is opened and
air is allowed to escape. Plugs should not be removed until all
pressure in the test section has been released. Also, no one
allowed in the trench or manhole while the test is being
6
8. Apparatus
8.1 Pings mechanical or pneumatic type designed to resist
internal test pressure without bracing or blocking.
8.2
with a
pressure
pressure
pressure
psi.
Air Compressor - a properly calibrated pOrtable air source
singular control panel containing a main shut off valve,
re~ulatinq valve, a 9 psig pressure relief valve input
gauge, and a continuous monitoring pressure gauge having
range from 0 to at least 10 psi and an accuracy of + 0.04
9. ?e~t Time
9.1 Test time criteria - No test section shall be accepted if
air loss is more than 0.0015 cubic feet per minute per square foot.
Calculate all test time by the following formula.
? ~ 0.085 PK / (;
T=
8hottest time in seconds allowed for air pressure to drop
1.0 psig.
K = 0.000419 DL but not less than 1.0
Q = 0.0015 cubic feet/minute/square feet of internal surface
D = Normal pipe diameter in inches.
L = Length of pipe being tested in feet.
Table I contains the specified minimum times required for 1.00 psig
pressure drop from a starting pressure of 3.5 psig to 2.5 psig.
7
9.2
in Table
excessive
falls the
determine
If pressure drops 1.0 psig before the appropriate time shown
I has elapsed, the air loss rate shall be considered
~nd the section of pipe has failed the test. If the line
test then segmented testing may be utilized solely to
the location of leaks. Once leaks are located and repaired,
the completed pipe installation
meet the requirements of this test.
9.3
diameter
of 1.0
shall be retested and required to
Efficient testing of long sections and or sections of larger
pipes, a time pressure drop of 0.5 psig may be used in lieu
psig timed pressure drop. If a 0.5 psig pressure drop is used
the appropriate required test time shall be exactly half as long as
shown on Table I. Table II is provided for convience.
9.4 It is not necessary to hold the test for the entire period
of time in Table I or Table II when it is clearly evident that the
rate of air loss is less than the allowable, and is authorized by the
approving authority.
APPENDIX (NON
X.i.1 In order to demonstrate the technique of applying this test
method the following examples have been prepared. The examples have
been designed to illustrate the use of Tables and the formula.
X.l.l.2 A manhole to manhole reach of nominal 12 inch pipe is 350
feet long. No lateral connections exist in the reach. What is the
required test time for a 0.5 psig pressure drop?
Solution: The required test time can be read directly form Table
II. For 350 feet of 12 inch pipe, the required test time is 9:58
(9 minutes and 58 seconds).
X.l.l.3 A 350 foot section of nominal 12 inch pipe is ready for
testing. A total of 128 feet of 4 inch lateral sewer pipe is
connected to the 350 foot section and will be included in the test.
What will be their required test time for a 0.5 psig pressure drop?
Solution: Lateral sewers may be disregarded when selecting test
times Ieee Section 9.4). Therefore, the required test time will
be the same as for Example A, i.e., 9 minutes and 58 seconds.
**NOTE: If the lateral sewers had not been disregarded, the
required test time would be 10 minutes and 22 seconds, i.e., only
24 seconds longer.
X.l.l.4 Wh~t should the required test time be for a 1.0 psig
pressure drop in 327 feet of nominal 8 inch diameter pipe between two
manholes?
Solution: The exact test time is easily calculated by using
Table I. Table ! is used because a 1.0 psig pressure drop is
specified. Since 327 feet exceeds the 298 foot length associated
with the minimum test time for an 8 inch pipeline, the forth
column in Table I shall be used to quickly calculate the required
test time as follows:
T = 1.520 L = 1.52 x 327 = 497 seconds
Therefore, the required test time for a 1.0 psig pressure drop is
497 seconds or 8 minutes and 17 seconds.
X.l.l.5 A manhole
feet long. What is
drop?
to manhole reach of nominal 24 inch pipe is 82
the required test time for a 0.5 psig pressure
Solution: Table II must be used because a 0.5 peig pressure drop
is specified. Since 82 feet is less than the 99 foot length
associated with the minimum test time for a 24 inch Pipeline, the
minimum test time shall apply. Thus, the required test time for a
0.5 psig pressure drop must be 11:20 (11 minutes and 20 seconds).
X.l.l.6
readied
lateral
the 15
and
A 412 foot section of nominal 15 inch sewer pipe has been
for air testing. A total of 374 feet of nominal 6 inch
piping and 148 feet of nominal 4 inch later piping branch off
inch sewer line. All laterals have been capped and/or plugged
will be tested together with the 15 inch main line. The specified
pressure drop which will be timed in 0.5 peig. What is the
appropriate test time for this piDe network?
Solution: All.lateral sewer sizes and lengths may be disregarded
since their influence is generally not significant enough to
warrant computation. Table II must be used for a 0.5 psig
pressure drop. The fourth column in the table provides the
appropriate formula for calculating the required test time
because 412 feet is longer than the third column value of 159
feet.
T = 2.671L = 2.671 x 412 = 1,100 seconds
The required test time is 1,100 seconds or 18 minutes and 20
seconds.
Xl.l.7 A manhole to manhole reach of nominal 8 inch pipe is only 100
feet long. A total of 300 feet of nominal 4 inch lateral piping is
connected to the 100 foot section end will be included in air testing
the section and will be included in air testing the section. What
will be the required test time for a 1.0 psig pressure drop?
Solution: The required test time can be read directly from Table
l, since lateral sewers need not be considered. Thus, for 100
feet of 8 inch pipe, the required holding time is 7:34 (7 minutes
and 34 seconds). However, should the section fail to meet this
test, the required holding time must be recalculated taking into
account the connected laterals. This recalculation is required
because the total internal pipe surface area is less than 625
square feet.
Total Area :
12
: 3.14 ~8 x 100) : (4 x 300~
12
: 524 square feet
Thus using the equation provided in Section 9.4, the required test
ti~e should be recomputed as follows:
K = 0.000419 (8 x 100) + (4 x 300)
--> K 1.0
K will always be 1.0 when the total area is less than
= 0.838
0.838 < 1.0
** NOTE:
625 square feet.
T= 0.085 ~.~8A x 100)+ (4~4 x 300)9
L (8 loo) _- 300)_j
1.O
0.0015
T = 317 seconds
The required test time is actually only 317 seconds or 5 minutes and
17 seconds for a 1.0 psig pressure drop. Therefore, if the section is
able to meet this test time, it shall be passed.
** NOTE: - For a
holding time would
seconds.
specified 0.5 psig pressure drop, the test
be only half as long, i.e., 2 minutes and 38