Document ID: EPA-HQ-OW-2004-0002-0502
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2004-11-30T05:00Z

Cooling
Water
Intake
Structure
(
CWIS)
Information
Data
Required
Rig
Information
Rig
Name
ENSCO
81
ENSCO
82
Rig
Type
Jackup
Marathon
LeTourneau
116C
Total
Installed
Power
Generation
Capacity
6600
hp
Number
of
Cooling
Water
Intake
Structures
(
CWISs)
4
Brief
description
of
each
CWIS
(
e.
g.,
sea
chest,
simple
pipe)
Sea
chest,
raw
water
tower
deep
well
pumps
Rough
dimensions
of
each
CWIS
and
indicate
whether
onboard
CWIS
has
an
existing
flange
3
raw
water
tower
pumps,
2
stage
w/
75
hp
motors
pump
rated
1200
gpm
1
Sea
chest
used
only
while
under
tow
Screen
type
(
e.
g.,
strainer,
wedge
wire)
with
mesh
size
Basket
Strainers,
¼
"
Mesh
on
pump
itself
Total
Design
Specifications
for
Daily
Maximum
Water
Intake
Volume
of
each
CWIS
1,727,964
gals
(
41,142
bbls)

Total
Daily
Water
Intake
Volume
of
each
CWIS
(
Set­
up/
Drilling)
1,727,964
gals
(
41,142
bbls)

Design
Specs
for
Through
Screen
Velocity
of
each
CWIS
(
i.
e.,
Q=
V*
A)
(
Set­
up/
Drilling)
13.33
ft/
second
List
of
Purposes
of
Cooling
Water
Intakes
(
e.
g.,
cool
crude
oil,
produced
water,
power
generators,
drill
pipe
brakes)
Brake
water
cooling
List
of
Purposes
of
Non­
cooling
Water
Intakes
(
e.
g.,
fire
water,
hotel
loads)
Water
makers,
fire
main,
sanitary,
pre
load,
jet
spud
cans,
mud
pits,
shakers
Total
Volume
of
Water
Intake
for
Ballasting,
Duration
of
the
Ballast
intake,
and
the
Through
Screen
Velocity
of
the
Ballast
intake
2,677,500
gals
(
63,750
bbls)
Duration
=
time
on
location.
Through
Screen
Velocity
=
13.33
ft.
Per
second
Mitigation
Measures
for
reducing
Exotic
Species
Migration
through
Ballast
water
The
rig
does
not
carry
much
ballast
water
from
location
to
location.
It
is
taken
on
and
dumped
at
the
same
location.
Mitigation
Measures
for
reducing
Impingement
and
Entrainment
of
Aquatic
Organisms,
as
well
as
Bio­
fouling
Prevention
Measures
Sea
chest
screens,
and
baskets,
cathodic
protection
Is
the
Rig
equipped
with
a
Radiator
Cooling
System
for
the
Main
Engines?
Yes,
3
Radiators
for
the
engines