Document ID: EPA-HQ-OW-2004-0002-0539
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:
Transocean
Marianas
Rig
Type:
Semi­
submersible
Total
Installed
Power
Generation
Capacity
23,800
HP
(
6
x
3600
BHP
&
1
x
2200
BHP)

Number
of
Cooling
Water
Intake
Structures
(
CWISs)
2
Brief
description
of
each
CWIS
(
e.
g.,
sea
chest,
simple
pipe)
Sea
Chests
Rough
dimensions
of
each
CWIS
and
indicate
whether
onboard
CWIS
has
an
existing
flange
18
inch
pipe
w/
18"
gate
valve
Screen
type
(
e.
g.,
strainer,
wedge
wire)
with
mesh
size
Simplex
Basket
Strainers
w/
¼
"
perforations
Total
Design
Specifications
for
Daily
Maximum
Water
Intake
Volume
of
each
CWIS
Total
Daily
Water
Intake
Volume
of
each
CWIS
(
Set­
up/
Drilling)
2,447,570
gals
(
58,285
bbls)

Design
Specs
for
Through
Screen
Velocity
of
each
CWIS
(
i.
e.,
Q=
V*
A)
(
Set­
up/
Drilling)
0.76
fps
List
of
Purposes
of
Cooling
Water
Intakes
(
e.
g.,
cool
crude
oil,
produced
water,
power
generators,
drill
pipe
brakes)
Winch
cooling,
Plate
heat
exchangers
for
fresh
water
cooling
system,
7
engine
shell
and
tube
heat
exchangers
List
of
Purposes
of
Non­
cooling
Water
Intakes
(
e.
g.,
fire
water,
hotel
loads)
Water
Makers,
Fire
Main,
Ballast,
Sanitary,
Pits,

Total
Volume
of
Water
Intake
for
Ballasting,
Duration
of
the
Ballast
intake,
and
the
Through
Screen
Velocity
of
the
Ballast
intake
227,556
gal
(
5416
bbls)
Total
/
20
day
duration
Through
Screen
Velocity
=
11.38
fps
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
Is
the
Rig
equipped
with
a
Radiator
Cooling
System
for
the
Main
Engines?
No