Visual Study of Prolapse
by Leif Zars
6/29/99
Assisted and Reviewed
by
Dr. Everett P. Bratcher
Dr. Vincent A. Caldarola
Dr. Gerhard A. Meyer
June 29, 1999
THE PROBLEM
Prolapse, frequently referred to as evisceration, is of serious concern to
the swimming pool industry. It generally is caused by a poorly designed main drain
system. Entrapping usually a child - and partially removing intestines via pump
suction.
This hazard can and must be prevented. There are several devices on the market
designed for this purpose, as well as the current trend to dual main drains.
THE QUESTI0N
The big question is "how much suction is too much?" Both
from the standpoint of how much can be safely tolerated by the human body, and how much
for how long?
Realizing that a very brief but still high amount of suction - if brief enough - can not
provide sufficient energy to move body tissue enough to cause damage. Things just wiggle a
slight distance and then return. And then too, a medium amount of suction over a prolonged
period of time may do more damage than a higher suction over a short period of time.
Therefore we must be interested in not only how much suction there is, but also how long
it lasts.
THE SEARCH
So, to what limits do we design to prevent this hazard? That is the
subject of this paper.
At the suggestion of the medical advisors young pigs were chosen as an acceptable model to
closely resemble the anatomy of a young child. Properly euthanized they were then
subjected to a series of tests that are documented on the following pages. Without muscle
tone the subjects were in a compliant state that led to results that are believed to be on
the conservative side.
TEST SERIES I
The first short series of tests were conducted to determine the effects of a gradually increasing amount of suction over a time span lasting minutes. Also in this series of tests was one in which full pump suction was applied instantaneously.
TEST SERIES II
The second series of tests were conducted utilizing a series of non-mechanical time delay devices (previously designed and tested main drain suction line vent configurations) calculated to interrupt the full pump suction after a predetermined time period. These time periods started out very briefly and increased in duration as the series progressed. To quantify the time/intensity period the unit "inch seconds" which is the amount of suction exceeding 4.438"Hg (the previously published number that was felt to be safe) over how many seconds was used. This is determined by the resultant area of the curve generated by the suction in the main drain sump during the test as discussed in my previous paper on this subject entitled "SUCTION ENTRAPMENT TESTS" dated 2/6/98.
EQUIPMENT
The basic test equipment used was an O.OLUX underwater B/W video camera mounted in the bottom of an 8" round main drain sump. This was connected to a standard 30 frame per second video tape recorder, which included a constant time hack in each frame. Audio was also recorded. This information was then correlated to the information gathered by the Monarch Paperless Data Recorder which recorded at the rate of 50 readings per second, and was driven by a Wika Tronic Pressure Transmitter also located within the sump. Suction was created by using a typical 1-1/2 HP self priming swimming pool pump flowing at between 60 and 64 GPM through 2" schedule 40 PVC pipe to the 8" round main drain sump with grate removed. Gallons per minute flow was measured by a Dynasonics Ultrasonic Flow Meter.
SUMMARY OF RESULTS
In Test Series I, Test #1 shows that even a relatively low constant vacuum
can cause significant visual prolapse.
Test #2 shows considerable prolapse when test subject was exposed to full pump suction
(193.27 inch seconds) without relief
Test Series II was designed to show the effects of limited suction periods - starting with
3.68-inch seconds and progressing to 47.53-inch seconds.
What we see in Test #5 is that with 4.59-inch seconds of suction we have very little
impact on the test subject. Even at 8.18-inch seconds (Test #7) we show little effect.
Similarly with Test #8 at 9.51 inch seconds.
With Test #11 at 11.09-inch seconds we begin to show more significant effects, although
there seems to be nothing of a lasting nature. Similarly in Test #12 at 11.07 inch
seconds.
In Test #12 it is very interesting to note the time lapse between the beginning of suction
and its release: 4:51:14:14 to 4:5115:02 or roughly 6/10ths of a second. And to reasonably
full return to original condition (4:51:15:09) roughly 8/10ths of a second from start. We
have a similar condition in test #12 with 13.41-inch seconds.
Test #15 is a rather lengthy series of photos following the sequence in 1/30' of a second
intervals. This test was at 15.83-inch seconds and displays a more aggressive action than
prior tests. Again, from start to first signs of relief is roughly 6/10ths of a second
(5:01:10:19 to 5:01:11:09). Also full visual recovery required almost one full second
(5:01:10:19 to 5:01:11:18).
The photo 9120 at the end of this series "relaxed" does seem to show some
residual damage.
From here on we go to higher and higher "inch seconds" of suction duration and
it appears we are encountering increasing amounts of damage.
CONCLUSIONS
In Test Series I, it appears that suction over a prolonged time period in
excess of 5.2"Hg tends to bring out intestinal material beyond a more or less flat
visual display of intestines.
Full pump suction removed several inches of intestines in a little over 1/2 second
(3:53:29:14 to 3:53:30:00)
In Test Series II it is apparent that prolapse is a function of time vs. strength of
suction. A much higher intermittent suction may be tolerated with a simple but effective
system to interrupt the suction following a sudden increase.
It appears that if we can stay below 11 -inch seconds of total exposure we should be able
to remain within the body's tolerance for temporary displacement.
Recognition
for
Physical Set Up and Support
Clint Heard
David Shooll
Jayson Riggs
Prolapse
Test Series I
CONSTANT SUCTION INCREASE TEST
Test #1
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
D305 3:45:07:00
0
Just beginning to seal drain sump
91CO 3:45:28:00
2.3
A little coming out
C383 3:46:49:00
5.2
More out
BO
3:47:00:00
7.5
1044 3:47:11:00
10
1332 3:47:19:00
11
Coming out good now
3025 3:47:31:00
13
Coming out good
Graph: Showing Time and Vacuum During Test
* Hours:Minutes:Seconds:1/30th Second
**(Tails were removed to improve visibility)
FULL FLOW INSTANT COVERAGE
Test #2
PHOTO TIME LINE
SUCTION "Hg
COMMENTS
D2F3 3:53:29:14
Beginning to come out
E083 3:53:29:16
1230 3:53:29:20
2240 3:53:30:00
40Al 3:53:30:12
5166 3:53:31:00
8195 3:53:36:20
9113 3:53:37:08
Maximum
PROLAPSE
TEST SERIES II
Test #3
General Conditions:
Suction Relief: 3/4" Vent to Main Drain Line
Effective Area of Suction Curve: 3.68 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE* SUCTION "Hg
COMMENTS**
None
(Drain inavertently blocked
During test.)
Graphs: 3.68 Inch Seconds
Test #4
General Conditions:
Suction Relief: 3/4" Vent to Main Drain Line
Effective Area of Suction Curve: 4.27 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
B232
Showing stubbed tail, anus and vagina.
Anus beginning to open, Tester's fingers
caught in drain, inconclusive test.
Graphs: 4.27 Inch Seconds
Test #5
General Conditions:
Suction Relief: 3/4" Vent to Main Drain Line
Effective Area of Suction Curve: 4.59 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
6lF2
4:23:21:00
Anus begins opening
8225
4:23:22:09
Maximum Opening
Graphs: 4.59 Inch Seconds
Test #6
General Conditions:
Suction Relief: 3/4" Vent with 2-90s & 4' of pipe to Main Drain Line
Effective Area of Suction Curve: 8.396 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
None 4:31:19:00
Drain Sealed
1151 4:31:20:10
Only Clear View, anus sealed
Graphs: 8.396 Inch Seconds
Test #7
General Conditions:
Suction Relief: 1/4" Vent with 2-90s & 4' of pipe to Main Drain Line
Effective Area of Suction Curve: 8.18 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
A364
4:35:18:19
Drain Sealed
C086
4:35:19:02
Good view
1313
4:35:19:24
2" Opening (Suction Bounce)
3022
4:35:20:00
Maximum Opening
Graphs: 8.18 Inch Seconds
Test #8
General Conditions:
Suction Relief: 3/4" Vent with 2-90s & 4' of pipe to Main Drain Line
Effective Area of Suction Curve: 9.51 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
8273
4:38:29:22
Drain Sealed
BOD3
4:38:30:00
Good view
B280
4:38:30:06
Maximum Opening
B392
4:38:30:08
Coming Down
C2AO
4:38:30:10
Closed
F314
4:38:31:07
Re Opened
1161
4:38:31:26
Max Re Opened
Graphs: 9.51 Inch Seconds
9.80 INCH SECONDS
General Conditions:
Suction Relief: 3/4" Vent with 2-90s & 4' of pipe to Main Drain
Line
Effective Area of Suction Curve: 9.80 Inch Seconds
Pump: 1-1/2HP Self Priming Suction
Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO
TIME LINE* SUCTION
"Hg COMMENTS**
4060
4:42:32:19
Drain Sealed
42A3
4:42:32:22
Opening
5295
4:42:33:06
Closed
6lF3
4:42:33:20
Bounced Open
7272
4:42:34:05
Full Open
B030
4:42:35:00
At Rest - Little bit left out.
Graphs: 9.80 Inch Seconds
Test #10
General Conditions:
Suction Relief: 3/4" Vent with 2-90s & 5'-6" of pipe to Main Drain Line
Effective
Area of Suction Curve: 11.18 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
None
Off Center - No Test
Graphs: 11.18 Inch Seconds
Test #11
General Conditions:
Suction Relief: 3/4" Vent with 2-90s & 5'-6" of pipe to Main Drain Line
Effective Area of Suction Curve: 11.09 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
9094
4:47:57:27
Drain Sealed
EOA2
4:47:58:00
Opening
E194
4:47:58:02
Growing
E243
4:47:58:03
Growing
FlD5
4:47:58:13
Coming Back
F330
4:47:58:16
Coming Back
114
4:47:58:20
Back Down
1322
4:47:59:00
Normal
3302
4:47:59:18
Open Again (Vacuum Bounce)
Graphs: 11.09 Inch Seconds
Test #12
General Conditions:
Suction Relief: 3/4" Vent with 2-90s & 5'-6" of pipe to Main Drain Line
Effective Area of Suction Curve: 11.07 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8"' Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
Al
4:51:14:14
Drain Sealed
lB2
4:51:14:16
260
4:51:14:18
2FO
4:51:14:20
1231
4:51:14:30
4192
4:51:15:00
2lD5
4:51:15:02
31FO
4:51:15:03
32C5
4:51:15:05
4035
4:51:15:08
4286
4:51:15:23
Suction Bounce
8031
4:51:16:02
Opening Agiain
8140
4:51:16:05
9062
4:51:16:07
B113
4:51:16:14
Little bit coming out
Graphs: 11.07 Inch Seconds
13.41 INCH SECONDS
Test #13
General Conditions:
Suction Relief: 3/4" Vent with 2-90s & 7'-6" of pipe to Main Drain Line
Effective Area of Suction Curve: 13.41 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
3324
4:54:47:13
Drain Seal
4001
4:54:47:14
40a2
4:54:47:15
5122
4:54:47:16
5273
4:54:47:17
Least Little Bit
5200
4:54:47:18
5361
4:54:47:19
3lCl
4:54:48:04
Closed - Some Out?
42Al
4:54:48:05
43A4
4:54:48:06
5133
4:54:48:07
Graphs: 13.41 Inch Seconds
Test #14
General Conditions:
Suction Relief: 1/4" Vent with 2-90s & 7'-6" of pipe to Main Drain Line
Effective Area of Suction Curve: 14.33 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
121
4:57:47:00
Maximum
Graphs: 14.33 Inch Seconds
1/30TH SECOND INTERVALS
Test #15
General Conditions:
Suction Relief: 3/4" Vent with 2-90s & 10' of pipe to Main Drain Line
Effective Area of Suction Curve: 15.83 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
8133
5:01:10:19
Drain Sealed
8213
5:01:10:20
8306
5:01:10:21
8392
5:01:10:22
9060
5:01:10:23
9105
5:01:10:24
9235
5:01:10:25
92A4
5:01:10:26
9371
5:01:10:27
A010
5:01:10:28
A080
5:01:10:29
A132
5:01:11:00
60D2
5:01:11:07
6153
5:01:11:08
6162
5:01:11:09
6283
5:01:11:10
62Bl
5:01:11:11
6320
5:01:11:12
6380
5:01:11:13
2090
5:01:11:14
2lFl
5:01:11:15
2274
5:01:11:16
2315
5:01:11:17
2395
5:01:11:18
70BO
5:01:11:19
7105
5:01:11:20
7175
5:01:11:21
71E5
5:01:11:22
7254
5:01:11:23
72DO
5:01:11:24
7341
5:01:11:25
8331
5:01:12:00
9210
5:01:13:00
Relaxed
Graphs: 15.83 Inch Seconds
Test #16
General Conditions:
Suction Relief: 3/4" Vent with 4-90s & 10'-6" of pipe to Main Drain Line
Effective Area of Suction Curve: 20.15 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
COC2
5:07:27:00
Full
Size
A336
5:07:30:00
Relaxed
Graphs: 20.15 Inch Seconds
Test #17
General Conditions:
Suction Relief: 3/4" Vent with 4-90s & 10'-6" of pipe to Main Drain Line
Effective Area of Suction Curve: 19.08 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE*
SUCITON "Hg
COMMENTS**
B296
5:10:25:01
Drain
Sealed
lC2
5:10:25:05
2A5
5:10:25:07
12C5
5:10:30:00
After
Torn
Graphs: 19.08 InchSeconds
Test #18
General Conditions:
Suction Relief: 3/4" Vent with 4-90s & 20'-6" of pipe to Main Drain Line
Effective Area of Suction Curve: 28.59 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8"' Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
E360
5:13:52:13
Drain
Sealed
FOF2
5:13:52:17
FlE5
5:13:52:21
1256
5:13:53:17
1033
5:13:53:25
5084
5:13:5?:??
At
End - Relaxed
Graphs: 28.59 Inch Seconds
Test #19
General Conditions:
Suction Relief: 3/4" Vent with 4-90s & 20'-6" of pipe to Main Drain Line
Effective Area of Suction Curve: 33.29 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
B285
5:19:01:00
Maximum
COF3
5:19:02:00
Relaxed
Graphs: 33.29 Inch Seconds
Test #20
General Conditions:
Suction Relief: 3/4" Vent with 4-90s & 20'-6" of pipe to Main Drain Line
Effective Area of Suction Curve: 36.54 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
3182
5:22:14:00
Placement
4140
5:22:18:00
Next
4384
5:22:19:00
Relaxed
Graphs: 36.54 Inch Seconds
Test #21
General Conditions:
Suction Relief: 3/4" Vent with 6-90s & 30'-6" of pipe to Main Drain Line
Effective Area of Suction Curve: 46.42 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
90B2
5:25:47:00
Near
max
7141
5:25:47:00
Maximum
A154
5:26:06:00
Removing
from Drain
Graphs: 46.42 Inch Seconds
Test #22
General Conditions:
Suction Relief: 3/4" Vent with 6-90s & 30'-6" of pipe to Main Drain Line
Effective Area of Suction Curve: 47.53 Inch Seconds
Pump: 1-1/2HP Self Priming
Suction Line: 2" PVC
Main Drain Sump: Hayward SP 1154-A 8" Round Without Grate
PHOTO TIME LINE*
SUCTION "Hg
COMMENTS**
F135
5:29:24:00
Close
to Maximum
1232
5:29:27:00
Relaxed
Graphs: 47.53 Inch Seconds
EQUIPMENT USED
FOR
SUCTION TESTS
VIDEO CAMERA IN MAIN DRAIN
CAMERA AND SENSOR IN MAIN DRAIN
WIKA TRONIC PRESSURE TRANSMITTER
MONARCH PAPERLESS DATA RECORDER
DYNASONICS ULTRASONIC FLOW METER