ASTM F2491-05(2010)e1
(Guide)Standard Guide for Determining Load Ratios for Technical Rescue Systems and Equipment
Standard Guide for Determining Load Ratios for Technical Rescue Systems and Equipment
SIGNIFICANCE AND USE
This guide may be used to provide a consistent method for determining load ratios for technical rescue equipment and systems.
Use of this guide will help to maintain clearer, more consistent calculation and reporting of load ratios.
It should be acknowledged that, while component load ratios are fairly straightforward to calculate, they are of limited value for estimating system load ratios. System load ratios are usually desired for field applications, but are more difficult to calculate accurately.
SCOPE
1.1 This guide covers the general concept of determining load ratios for technical rescue equipment and systems.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 In the event of any conflict between the text of this guide and any references cited, the text of this guide takes preference.
1.4 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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´1
Designation: F2491 − 05(Reapproved 2010)
Standard Guide for
Determining Load Ratios for Technical Rescue Systems and
Equipment
This standard is issued under the fixed designation F2491; 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.
´ NOTE—Editorial changes were made in 1.2, 2.1.6, 5.1, and 5.3.1 in December 2010.
1. Scope 2.1.6 system safety factor, n—the ratio of the load at which
something in the system will fail and the load that is planned
1.1 This guide covers the general concept of determining
to be applied to the system.
load ratios for technical rescue equipment and systems.
2.1.7 user, n—a person, agency, or representative who has
1.2 The values stated in SI units are to be regarded as
authority to make safety-related decisions for rescue applica-
standard. No other units of measurement are included in this
tions as discussed herein.
standard.
1.3 Intheeventofanyconflictbetweenthetextofthisguide
3. Significance and Use
and any references cited, the text of this guide takes preference.
3.1 This guide may be used to provide a consistent method
1.4 This standard may involve hazardous materials,
for determining load ratios for technical rescue equipment and
operations, and equipment. This standard does not purport to
systems.
address all of the safety concerns, if any, associated with its
3.2 Use of this guide will help to maintain clearer, more
use. It is the responsibility of the user of this standard to
consistent calculation and reporting of load ratios.
establish appropriate safety and health practices and deter-
mine the applicability of regulatory limitations prior to use.
3.3 It should be acknowledged that, while component load
ratios are fairly straightforward to calculate, they are of limited
2. Terminology
value for estimating system load ratios. System load ratios are
usually desired for field applications, but are more difficult to
2.1 Definitions of Terms Specific to This Standard:
calculate accurately.
2.1.1 component, n—an individual piece of equipment in its
usable form, but unconnected and unencumbered by other
4. Load Ratio
pieces of equipment in a system.
2.1.2 force multiplying situation, n—a situation where the
4.1 Load ratio refers to the ratio between the breaking
rigging causes a force on a component to be greater than strength of the item and the load that the item is intended to
caused by the load.
suspend.
2.1.3 load ratio, n—ratio between a specified breaking
4.2 Various load ratios may be used for different reasons for
strength and an anticipated load.
a particular piece of equipment.
2.1.4 strength reduction situation, n—a situation where the 4.2.1 A manufacturer may or may not have a specified
rigging of the system causes a component to not perform at its design factor, representing the ratio between the breaking
minimum breaking strength.An example would be a carabiner strength of the product and the working load (that is, the load
with tri-axial forces. that the product is designed to carry on a normal basis).
4.2.2 Users of equipment may specify a load ratio for
2.1.5 system, n—a group of components integrally con-
equipment that will help them to maintain system safety factors
nected for the purpose of accomplishing work.
that are acceptable within their own scope.
4.2.3 The load ratio specified by an equipment user shall be
no lower than that specified by the manufacturer, if the
This guide is under the jurisdiction of ASTM Committee F32 on Search and
manufacturer specifies this information.
Rescue and is the direct responsibility of Subcommittee F32.01 on Equipment,
Testing, and Maintenance.
4.3 Load ratio is applicable only to the component, and does
Current edition approved Dec. 1, 2010. Published March 2011. Originally
not address how this component affects or is affected by other
approved in 2005. Last previous edition approved in 2005
...
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