ASTM F1780-97(2002)
(Guide)Standard Guide for Estimating Oil Spill Recovery System Effectiveness
Standard Guide for Estimating Oil Spill Recovery System Effectiveness
ABSTRACT
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. 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. In evaluating the effectiveness of containment and recovery systems used in response to oil spills, many factors need to be considered of which skimmer performance is but one. The objective of this guide is to describe a range of factors that must be considered in estimating recovery system effectiveness. Response strategies will depend to some extent on the type of spill. The spill scenario should be defined as to whether it is an instantaneous or continuous release, whether or not the spill has ceased flowing, and whether the spill is contained or uncontained. The following oil slick properties must be specified for the spill scenario: spill volume; area; slick thickness; slick viscosity; and emulsification.
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.
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Designation: F1780 – 97 (Reapproved 2002)
Standard Guide for
Estimating Oil Spill Recovery System Effectiveness
This standard is issued under the fixed designation F1780; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
1.1 This guide covers the key factors to consider in estimat- 3.1 Definitions:
ing the effectiveness of containment and recovery systems that 3.1.1 advancing skimmer, n—a skimmer that is designed to
may be used to assist in the control of oil spills on water. be used to sweep out the spill area.
1.2 The purpose of this guide is to provide the user with 3.1.1.1 Discussion—he skimmer may be independent or
information on assessing the effective use of spill-cleanup may be attached to containment boom to increase sweep width.
equipment. It is intended for use by those involved in planning In some cases, the skimmer may not be attached to the boom
for and responding to oil spills. but is positioned in the pocket of the boom for skimming. As
1.3 Sections of this guide describe calculation procedures long as the skimmer operates while moving, it is considered to
for estimating recovery system effectiveness. It should be be an advancing skimmer. Some skimmers are used in both an
understood that any such calculations cannot be expected to advancing and stationary mode. These are classified according
predict system performance, but are intended to provide a to their application.
common basis for comparing system performance. 3.1.2 contained spills, n—a spill that is restricted from
1.4 One of the main reasons that the calculation procedures spreading by containment boom or natural means.
cannot be used to predict system performance is that the 3.1.3 oil slick encounter rate, n—the volume of oil slick per
analysis is sensitive to assumptions made on the properties of unit time actively encountered by the oil spill recovery system,
the oil slick, and particularly the changes in slick thickness and and therefore available for containment and recovery (m /h).
emulsification. It is emphasized that the purpose of this guide 3.1.4 oil spill recovery system, n—a combination of devices
is not to provide a standard method for estimating slick that operate together to recover spilled oil; the system would
property changes, but rather to provide a standard guide for include some or all of the following components: (1) contain-
using that information in comparing system performance. ment boom, (2) skimmer, (3) support vessels to deploy and
operate the boom and skimmer, (4) discharge/transfer pumps,
2. Referenced Documents
(5) oil/water separator, (6) temporary storage devices, and (7)
2.1 ASTM Standards:
shore based storage/disposal.
F625 Practice for Classifying Water Bodies for Spill Con- 3.1.5 recovery system effectiveness, n—the volume of oil
trol Systems
that is removed from the environment by a given recovery
F631 Guide for Collecting Skimmer Performance Data in system in a given recovery period.
Controlled Environments
3.1.6 recovery period, n—the time available for recovery
F808 Guide for Collecting Skimmer Performance Data in systems to carry out cleanup operations.
Uncontrolled Environments
3.1.7 response time, n—the time interval between the spill
F1523 Guide for Selection of Booms in Accordance With incident and the start of cleanup operations.
Water Body Classifications
3.1.8 stationary skimmer, n—a skimmer that is intended to
be used in a fixed location and is moved to new accumulations
of oil as skimming progresses.
This guide is under the jurisdiction of ASTM Committee F20 on Hazardous
3.1.8.1 Discussion—Some stationary skimmers are used in
Substances and Oil Spill Response and is the direct responsibility of Subcommittee
F20.12 on Removal. a containment boom system that moves to collect oil, then
Current edition approved Oct. 10, 2002. Published February 2003. Originally
pauses to permit the skimmer to recover the oil collected. Even
approved in 1997. Last previous edition approved in 1997 as F1780 – 97. DOI:
though this system moves periodically, the skimmer is still
10.1520/F1780-97R02.
ranked as a stationary skimmer because it operates when the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
system is at rest.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Withdrawn.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F1780 – 97 (2002)
3.1.9 uncontained spill, n—a spill that continues to spread
after the recovery effort begins.
4. Summary of Guide
4.1 In evaluating the effectiveness of containment and
recovery systems used in response to oil spills, many factors
need to be considered of which skimmer performance is but
one.Theobjectiveofthisguideistodescribearangeoffactors
that must be considered in estimating recovery system effec-
tiveness.
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
FIG. 1 Total Slick Area versus Time
the problem and thereby provide a focus for the evaluation
process. The spill should be defined in sufficient detail as to
5.2.3 Slick Thickness—Slickthicknessisusedinsubsequent
allow an unambiguous interpretation of its behavior in terms of
calculations of system encounter rate. Slick thickness is de-
the operating parameters of the countermeasures system. For
fined as the overall average thickness of the slick, and is
certain purposes it may be desirable to develop a set of
estimated by dividing the spill volume by the total spill area at
standard spill scenarios against which response system effec-
any given time. For this calculation, spill volume should take
tiveness would be measured in a quantifiable manner.
into account losses from the slick due to evaporation and
4.4 The performance characteristics must be identified for
natural dispersion, and increases to the slick volume due to
therecoverysystemanditsvariouscomponents.Ingeneral,the
emulsification. For uncontained spills, natural spreading forces
informationrequirementswillincludetheratesorcapacities,or
will cause the slick thickness to decline steadily during
both, the operating limitations, and the support requirements.
recovery operations, and may result in a discontinuous slick
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
ing an overall average slick thickness.
as being critical to the success of a spill response include:
5.2.4 Slick Viscosity—The viscosity of the spilled product is
contingency planning; communications plans; government ap-
used as a criteria to evaluate skimmer performance, as many
provals; logistics of supporting manpower and equipment in
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
systems. Many crude oils and refined products will tend to
5.2 Oil Slick Properties—The following oil slick properties
must be specified for the spill scenario. As some of these emulsify over the life of the spill depending on the properties
oftheoilandthelevelofwaveenergyinthespillenvironment.
properties may vary with time, it may be desirable to use
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. ontheoilproperties,spillsize,seaconditions,andtemperature.
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 standardratesofemulsificationforavarietyofoilproductsand
(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:
F1780 – 97 (2002)
TABLE 1 Example Data for Emulsified Water Content versus
example, for an environment that has waves less than 2 m for
Time for Crude Oil
80 % of the time, receives 14 h of daylight, and has visibility
12 h 1 day 2 days 3 days
greater than 500 m for 95 % of the time (note: all figures
% Water Content 30 50 65 75
should be specified for the time of year of interest), the
environmental applicability would be estimated as:
(0.80) 3 (14/24) 3 (0.95) = 44 %.
5.3.1 Temperature—Water temperature is important as a
5.4 Spill Location:
parameter for estimating oil slick properties as well as the rate
5.4.1 Spill location should be specified with respect to
of change of those properties due to weathering and emulsifi-
distanceofresponsebases,inordertoestimatetransittimesfor
cation. (It is assumed that the temperature of the oil slick is the
the recovery systems, and with respect to shoreline, in order to
same as the water on which the oil is floating.) Water
estimate the time available to respond prior to shoreline oiling.
temperature is defined as the temperature of the upper surface
Spill location may also be of importance when evaluating
layer and should be specified as °C.
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,
6.1 Containment System Operating Factors:
as a limiting factor for recovery operations. For the first
6.1.1 Encounter Rate—The encounter rate of the recovery
purpose, average wind speeds (km/h) should be specified. For
systemisaprimeconsiderationinevaluatingperformance.The
the purpose of establishing criteria for limiting recovery
encounter rate is simply the rate (m /h) at which the system
operations, exceedance statistics (significant wave height)
encounters the oil slick. The encounter rate includes three
should be specified for the spill location. Exceedance criteria
components: sweep width, encounter speed, and oil slick
should be expressed as the percentage of time that conditions
thickness.
will allow recovery operations with reference to the equipment
6.1.1.1 The sweep width (or swath) is the width intercepted
selected for the response and the environmental criteria listed
by a boom in collection mode, and is calculated by multiplying
in Practice F625. For example, for spills in open water, wave
the boom length by the gap ratio. Where the gap ratio is not
exceedance data should be specified as the percentage of time
specified, a value of ⁄3 should be used.
that waves are less than or equal to 2 m, which would represent
6.1.1.2 The encounter speed is the tow or current speed
the percentage of time that equipment specified for open water
relativetothecontainmentsystem.Ifnotspecified,amaximum
use would be applicable.
encounter speed of 0.5 m/s (1 knot) should be used.
5.3.3 Current—The presence of water currents may influ-
6.1.1.3 Encounter rate can be calculated as the product of
ence the selection of response strategies for a spill scenario,
these three factors, taking into account consistency of units.As
and may lead to a reduction in containment effectiveness in
well, simple nomograms (Fig. 2) can be used to estimate
certain applications. The water currents, in m/s, should be
encounter rates for a range of conditions.
specified for a given environment, with due regard to any local
6.1.2 Operating Limitations—Containment equipment must
variations.
be specified with regard to the environmental conditions of the
5.3.4 Visibility—Duetoconcernswithworkersafetyinpoor
given spill scenario. Guidance for selecting booms can be
visibility, as well as the inefficiencies related to the monitoring,
taken from Guide F1523, which lists minimum requirements
tracking, and containment of oil slicks during periods of poor
for boom dimensions and strength properties for calm, pro-
visibility, it is assumed in general that recovery operations are
tected, and open bodies of water. Other limitations on the
only possible wh
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