Document ID: EPA-HQ-OW-2004-0002-0534
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
Deepwater
Horizon
Deepwater
Nautilus
Rig
Type
Semi
submersible
(
Dynamically
Positioned)
Total
Installed
Power
Generation
Capacity
56,323
HP
Number
of
Cooling
Water
Intake
Structures
(
CWISs)
8
Brief
description
of
each
CWIS
(
e.
g.,
sea
chest,
simple
pipe)
Sea
Chest
Rough
dimensions
of
each
CWIS
and
indicate
whether
onboard
CWIS
has
an
existing
flange
Sea
Chest
each
have
two
openings
sizes
24.4"
by
28.7"
There
is
an
existing
blank
flange
located
at
every
sea
chest
Screen
type
(
e.
g.,
strainer,
wedge
wire)
with
mesh
size
Single
Simplex
Strainers
,
stainless
steel
J­
basket,
mesh
10
Total
Design
Specifications
for
Daily
Maximum
Water
Intake
Volume
of
each
CWIS
4
inboard
strainers:
1,431,318
gal
(
34,079
bbls)
each
4
outboard
strainers:
2,557,380
gal
(
60,890
bbls)
each
Total
Daily
Water
Intake
Volume
of
each
CWIS
(
Set­
up/
Drilling)
4
inboard
strainers:
1,110,564
gal
(
26,422)
each
4
outboard
strainers:
1,110,564
gal
(
26,422)
each
Design
Specs
for
Through
Screen
Velocity
of
each
CWIS
(
i.
e.,
Q=
V*
A)
(
Set­
up/
Drilling)
0.54
ft/
sec
List
of
Purposes
of
Cooling
Water
Intakes
(
e.
g.,
cool
crude
oil,
produced
water,
power
generators,
drill
pipe
brakes)
Main
engines,
thrusters,
auxiliary
coolers
including
a/
c
units,
rig
air
compressors,
high
pressure
unit.

List
of
Purposes
of
Non­
cooling
Water
Intakes
(
e.
g.,
fire
water,
hotel
loads)
Water
makers,
fire
main,
ballast,
mud
pits.

Total
Volume
of
Water
Intake
for
Ballasting,
Duration
of
the
Ballast
intake,
and
the
Through
Screen
Velocity
of
the
Ballast
intake
5,879,244
gal
(
139,982
bbls)
of
water
intake
for
ballasting,
Duration
 
constantly
during
the
operation,
Through
screen
velocity
2.14
ft/
sec
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,
simplex
baskets,
cathodic
protection,
Chemically
treated
Weekly
basis
Is
the
Rig
equipped
with
a
Radiator
Cooling
System
for
the
Main
Engines?
No