ASTM F1780-97
(Guide)Standard Guide for Estimating Oil Spill Recovery System Effectiveness
Standard Guide for Estimating Oil Spill Recovery System Effectiveness
SCOPE
1.1 This guide covers the key factors to consider in estimating the effectiveness of containment and recovery systems that may be used to assist in the control of oil spills on water.
1.2 The purpose of this guide is to provide the user with information on assessing the effective use of spill-cleanup equipment. It is intended for use by those involved in planning for and responding to oil spills.
1.3 Sections of this guide describe calculation procedures for estimating recovery system effectiveness. It should be understood that any such calculations cannot be expected to predict system performance, but are intended to provide a common basis for comparing system performance.
1.4 One of the main reasons that the calculation procedures cannot be used to predict system performance is that the analysis is sensitive to assumptions made on the properties of the oil slick, and particularly the changes in slick thickness and emulsification. It is emphasized that the purpose of this guide is not to provide a standard method for estimating slick property changes, but rather to provide a standard guide for using that information in comparing system performance.
General Information
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Standards Content (Sample)
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Designation: F 1780 – 97
Standard Guide for
Estimating Oil Spill Recovery System Effectiveness
This standard is issued under the fixed designation F 1780; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope In some cases, the skimmer may not be attached to the boom
but is positioned in the pocket of the boom for skimming. As
1.1 This guide covers the key factors to consider in estimat-
long as the skimmer operates while moving, it is considered to
ing the effectiveness of containment and recovery systems that
be an advancing skimmer. Some skimmers are used in both an
may be used to assist in the control of oil spills on water.
advancing and stationary mode. These are classified according
1.2 The purpose of this guide is to provide the user with
to their application.
information on assessing the effective use of spill-cleanup
3.1.3 contained spills, n—a spill that is restricted from
equipment. It is intended for use by those involved in planning
spreading by containment boom or natural means.
for and responding to oil spills.
3.1.4 oil slick encounter rate, n—the volume of oil slick per
1.3 Sections of this guide describe calculation procedures
unit time actively encountered by the oil spill recovery system,
for estimating recovery system effectiveness. It should be
and therefore available for containment and recovery (m /h).
understood that any such calculations cannot be expected to
3.1.5 oil spill recovery system, n—a combination of devices
predict system performance, but are intended to provide a
that operate together to recover spilled oil; the system would
common basis for comparing system performance.
include some or all of the following components: (1) contain-
1.4 One of the main reasons that the calculation procedures
ment boom, (2) skimmer, (3) support vessels to deploy and
cannot be used to predict system performance is that the
operate the boom and skimmer, (4) discharge/transfer pumps,
analysis is sensitive to assumptions made on the properties of
(5) oil/water separator, (6) temporary storage devices, and (7)
the oil slick, and particularly the changes in slick thickness and
shore based storage/disposal.
emulsification. It is emphasized that the purpose of this guide
3.1.6 recovery system effectiveness, n—the volume of oil
is not to provide a standard method for estimating slick
that is removed from the environment by a given recovery
property changes, but rather to provide a standard guide for
system in a given recovery period.
using that information in comparing system performance.
3.1.7 recovery period, n—the time available for recovery
2. Referenced Documents systems to carry out cleanup operations.
3.1.8 response time, n—the time interval between the spill
2.1 ASTM Standards:
incident and the start of cleanup operations.
F 625 Practice for Classifying Water Bodies for Spill Con-
3.1.9 stationary skimmer, n—a skimmer that is intended to
trol Systems
be used in a fixed location and is moved to new accumulations
F 631 Guide for Collecting Skimmer Performance Data in
of oil as skimming progresses.
Controlled Environments
3.1.10 Discussion—Some stationary skimmers are used in a
F 808 Guide for Collecting Skimmer Performance Data in
containment boom system that moves to collect oil, then
Uncontrolled Environments
pauses to permit the skimmer to recover the oil collected. Even
F 1523 Guide for the Selection of Booms According to
though this system moves periodically, the skimmer is still
Water Body Classifications
ranked as a stationary skimmer because it operates when the
3. Terminology
system is at rest.
3.1.11 uncontained spill, n—a spill that continues to spread
3.1 Definitions:
after the recovery effort begins.
3.1.1 advancing skimmer, n—a skimmer that is designed to
be used to sweep out the spill area.
4. Summary of Guide
3.1.2 Discussion—The skimmer may be independent or
4.1 In evaluating the effectiveness of containment and
may be attached to containment boom to increase sweep width.
recovery systems used in response to oil spills, many factors
need to be considered of which skimmer performance is but
This guide is under the jurisdiction of ASTM Committee F-20 on Hazardous
one. The objective of this guide is to describe a range of factors
Substances and Oil Spill Responseand is the direct responsibility of Subcommittee
F20.12 on Removal. that must be considered in estimating recovery system effec-
Current edition approved Feb. 10, 1997. Published April 1997.
tiveness.
Annual Book of ASTM Standards, Vol 11.04.
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
F 1780
4.2 In order to evaluate a recovery system, there are two
general types of information required, a set of information to
describe the spill scenario against which the system will be
measured, and a set of information to describe the performance
characteristics of the recovery system.
4.3 Information on the spill is required to adequately define
the problem and thereby provide a focus for the evaluation
process. The spill should be defined in sufficient detail as to
allow an unambiguous interpretation of its behavior in terms of
the operating parameters of the countermeasures system. For
certain purposes it may be desirable to develop a set of
standard spill scenarios against which response system effec-
tiveness would be measured in a quantifiable manner.
4.4 The performance characteristics must be identified for
the recovery system and its various components. In general, the
information requirements will include the rates or capacities, or
FIG. 1 Total Slick Area versus Time
both, the operating limitations, and the support requirements.
4.5 This guide covers equipment-related factors that will
composed of windows and patches separated by sheen or open
affect recovery-system effectiveness. Additional important fac-
water, or both. These factors should be considered in estimat-
tors that are not covered in this guide but should be considered
as being critical to the success of a spill response include: ing an overall average slick thickness.
5.2.4 Slick Viscosity—The viscosity of the spilled product is
contingency planning; communications plans; government ap-
provals; logistics of supporting manpower and equipment in used as a criteria to evaluate skimmer performance, as many
skimming and pumping units will perform less effectively as
the field; and training and exercising of manpower.
viscosity increases. The viscosity of the spilled product will
5. Spill-related Information
generally increase through the recovery period as the oil is
5.1 Spill Type:
subjected to weathering and emulsification processes. The
5.1.1 Response strategies will depend to some extent on the
viscosity should be specified as mm /s (cSt).
type of spill. The spill scenario should be defined as to whether
5.2.5 Emulsification—Emulsification is important as a spill
it is an instantaneous or continuous release, whether or not the
process not only for its effect on oil viscosity but also because
spill has ceased flowing, and whether the spill is contained or
an emulsified oil represents a greater total volume of spill
uncontained.
product that must be handled by skimming and pumping
5.2 Oil Slick Properties—The following oil slick properties
systems. Many crude oils and refined products will tend to
must be specified for the spill scenario. As some of these
emulsify over the life of the spill depending on the properties
properties may vary with time, it may be desirable to use
of the oil and the level of wave energy in the spill environment.
computer-based behavior models to produce spill property
The degree of emulsification should be specified as the
information for the time period of interest. For certain appli-
emulsified water content expressed as a percentage.
cations it may be useful to produce standard sets of spill
5.2.5.1 It is recognized that emulsification rates for oil
property information that describe spills of interest as a
spilled in the marine environment will vary greatly depending
function of time.
on the oil properties, spill size, sea conditions, and temperature.
5.2.1 Spill Volume—The total volume of oil spilled should
As noted in 1.4, it is not the intent of this guide to provide
be specified (m ). For spills that have not ceased, a spill rate
standard rates of emulsification for a variety of oil products and
(m /h) should also be specified.
environmental conditions. For the purposes of comparing
5.2.2 Spill Area—The total spill area must be estimated in
system performance, the data in Table 1 is provided as an
order to calculate estimates of slick thickness. For uncontained
example of emulsification data for crude oil over a period of
spills, the total spill area will increase over time; estimates can
several days. Users of this guide are encouraged to use
be made using computer-based behavior models. Alternatively,
alternative data that suits their particular oils and environmen-
a simplified spreading model (Fig. 1: example spreading
tal conditions.
curves) can be used for first-order estimates.
5.3 Spill Environment:
5.2.3 Slick Thickness—Slick thickness is used in subsequent
5.3.1 Temperature—Water temperature is important as a
calculations of system encounter rate. Slick thickness is de-
parameter for estimating oil slick properties as well as the rate
fined as the overall average thickness of the slick, and is
of change of those properties due to weathering and emulsifi-
estimated by dividing the spill volume by the total spill area at
cation. (It is assumed that the temperature of the oil slick is the
any given time. For this calculation, spill volume should take
into account losses from the slick due to evaporation and
TABLE 1 Example Data for Emulsified Water Content versus
natural dispersion, and increases to the slick volume due to
Time for Crude Oil
emulsification. For uncontained spills, natural spreading forces
12 h 1 day 2 days 3 days
will cause the slick thickness to decline steadily during
% Water Content 30 50 65 75
recovery operations, and may result in a discontinuous slick
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
F 1780
same as the water on which the oil is floating.) Water the recovery systems, and with respect to shoreline, in order to
temperature is defined as the temperature of the upper surface estimate the time available to respond prior to shoreline oiling.
layer and should be specified as °C. Spill location may also be of importance when evaluating
recovery systems that include the shuttling of recovered oil
5.3.1.1 Air temperature may be important as a parameter for
between the recovery site and temporary storage locations, in
modifying or limiting the performance of skimming and
which case transit times may have to be deducted from the
pumping equipment, and should be specified as °C.
on-site availability of storage systems.
5.3.2 Wind/Waves—The wind and wave environment is
important to the analysis for two reasons; first, as a parameter
6. Recovery System Information
in estimating the behavior changes of the oil slick, and second,
as a limiting factor for recovery operations. For the first
6.1 Containment System Operating Factors:
purpose, average wind speeds (km/h) should be specified. For
6.1.1 Encounter Rate—The encounter rate of the recovery
the purpose of establishing criteria for limiting recovery
system is a prime consideration in evaluating performance. The
operations, exceedance statistics (significant wave height)
encounter rate is simply the rate (m /h) at which the system
should be specified for the spill location. Exceedance criteria
encounters the oil slick. The encounter rate includes three
should be expressed as the percentage of time that conditions
components: sweep width, encounter speed, and oil slick
will allow recovery operations with reference to the equipment
thickness.
selected for the response and the environmental criteria listed
6.1.1.1 The sweep width (or swath) is the width intercepted
in Practice F 625. For example, for spills in open water, wave
by a boom in collection mode, and is calculated by multiplying
exceedance data should be specified as the percentage of time
the boom length by the gap ratio. Where the gap ratio is not
that waves are less than or equal to 2 m, which would represent 1
specified, a value of ⁄3 should be used.
the percentage of time that equipment specified for open water
6.1.1.2 The encounter speed is the tow or current speed
use would be applicable.
relative to the containment system. If not specified, a maximum
5.3.3 Current—The presence of water currents may influ-
encounter speed of 0.5 m/s (1 knot) should be used.
ence the selection of response strategies for a spill scenario,
6.1.1.3 Encounter rate can be calculated as the product of
and may lead to a reduction in containment effectiveness in
these three factors, taking into account consistency of units. As
certain applications. The water currents, in m/s, should be
well, simple nomograms (Fig. 2) can be used to estimate
specified for a given environment, with due regard to any local
encounter rates for a range of conditions.
variations.
6.1.2 Operating Limitations—Containment equipment must
5.3.4 Visibility—Due to concerns with worker safety in poor
be specified with regard to the environmental conditions of the
visibility, as well as the inefficiencies related to the monitoring,
given spill scenario. Guidance for selecting booms can be
tracking, and containment of oil slicks during periods of poor
taken from Guide F 1523, which lists minimum requirements
visibility, it is assumed in general that recovery operations are
for boom dimensions and strength properties for calm, pro-
only possible when there is daylight and visibility of greater
tected, and open bodies of water. Other limitations on the
than 500 m (0.25 n.miles). Both of these factors should be
specified boom, such as minimum water depths and maximum
expressed as the percentage of time that conditions exist that
tow speeds should also be listed.
would allow effective operations.
6.1.2.1 The applicability of a boom to a given spill scenario
5.3.4.1 It may be possible
...
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