ASTM C1850-17(2021)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:C1850 −17 (Reapproved 2021)
Standard Guide for
Improved Laboratory Accelerated Tests to Predict the
Weathering and for Use in Developing Protocols to Predict
the Design Life of Building Sealant Systems
This standard is issued under the fixed designation C1850; 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 3.2.2 building sealant system component—a part of a build-
ing sealant system that may include a combination of building
1.1 This guide describes the steps for developing improved
materials, such as cladding, substrates or the sealant.
laboratory accelerated weathering tests for predicting the
3.2.3 building sealant system material—a material that may
natural weathering effects on building sealant systems and for
be used in a building sealant system.
using those tests in development of methods for design life
prediction of the systems.
3.2.4 critical performance characteristic(s)—a property, or
group of properties, of a building sealant system that must be
1.2 This guide outlines a systematic approach to develop-
maintained above a certain minimum level.
ment of laboratory accelerated weathering tests of building
sealant systems including the identification of needed
3.2.5 degradation mechanism—the chemical reactions in-
information, the development of accelerated tests, the applica-
duced in a building component or material by one or more
tion of data, and the reporting of results.
degradation factors resulting in changes in one or more of the
critical performance characteristics.
1.3 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3.2.6 incompatibility factor—any of the group of degrada-
ization established in the Decision on Principles for the
tion factors that result from detrimental chemical and physical
Development of International Standards, Guides and Recom-
interactions between building components or materials.
mendations issued by the World Trade Organization Technical
3.2.7 in-service test—a test in which building components
Barriers to Trade (TBT) Committee.
ormaterialsareexposedtodegradationfactorsunderin-service
conditions.
2. Referenced Documents
2 3.2.8 performance criterion—a quantitative statement of a
2.1 ASTM Standards:
level of properties for a selected characteristic of a component
C717 Terminology of Building Seals and Sealants
or material needed to ensure compliance with a functional
G113 Terminology Relating to Natural andArtificial Weath-
requirement.
ering Tests of Nonmetallic Materials
3.2.9 property measurement test—a test for measuring one
3. Terminology
or more properties of building components or materials.
3.1 Definitions—For definitions of terms used in this guide,
3.2.10 load stress factor—anydegradationfactorsthatresult
refer to Terminologies C717 and G113.
fromexternallyappliedsustainedorperiodicmechanicalloads.
3.2 Definitions of Terms Specific to This Standard:
3.2.11 use factor—any factor that affects the material as a
3.2.1 biological degradation factor—degradation factors di-
result of the design of the system, installation and maintenance
rectly associated with living organisms, including
procedures, normal wear and tear, and user abuse. (Example:
microorganisms, fungi, and bacteria.
abrasion of foot traffic.)
3.2.12 weathering factors—any degradation factors associ-
ThisguideisunderthejurisdictionofASTMCommitteeC24onBuildingSeals
ated with the natural environment, including radiation,
and Sealants and is the direct responsibility of Subcommittee C24.20 on General
temperature, rain and other forms of water, freezing and
Test Methods.
thawing.
Current edition approved May 1, 2021. Published May 2021. Originally
approved in 2017. Last previous edition approved in 2017 as C1850–17. DOI:
4. Significance and Use
10.1520/C1850-17R21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4.1 This guide is intended to serve as a reference of
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
recommended methodology for users developing relevant,
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. reliable and valid tests for predicting natural weathering effects
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1850−17 (2021)
and for use in developing methods to determine design life of on sealants and for use in development of methods for
building sealant systems through the use of accelerated test estimating design life (see Fig. 1 for a flow chart).
protocols. The proposed standard corrects for some of the
6. Scope
deficiencies of existing laboratory accelerated tests of sealants.
6.1 The scope describes the intentions of the test and the
4.2 The development of accelerated weathering tests ca-
degradation factors that should be included.
pable of being used in protocols to reliably and accurately
predict the long-term in-service performance of building seal-
I–Problem Definition
ant systems have limitations due to:
4.2.1 The external factors that affect functional properties,
7. Definition of In-Service Performance Characteristic
whicharenumerousandrequireefforttoquantify,sothatmany
Requirements and Criteria
existing accelerated procedures do not include all factors of
7.1 The critical performance characteristic criteria define
importance, and
the minimum acceptable levels of in-service functional prop-
4.2.2 The sealant specimens are often tested in configura-
erties stated in terms of absolute values or changes from the
tions different from those used in-service.
initial test.
5. Procedure
8. Characterization of the Sealant
5.1 This guide describes a recommended sequence of steps
for users to follow for developing laboratory accelerated 8.1 Characterize the sealant system in terms of composition,
weathering tests for predicting the effects of natural weathering critical performance characteristics, and physical properties the
FIG. 1Recommended Steps for Developing Improved Artificial Accelerated Weathering Tests to Predict Natural Weathering Effects and
for Use in Developing Protocols for Predicting Design Life
C1850−17 (2021)
TABLE 1 Degradation Factors Affecting the Design Life of
changes of which will serve as degradation indicators, the
Sealant Systems
range and type of degradation factors to which the sealant
Weathering Factors
responds, and all possible types of degradation and mecha-
Radiation Solar Nuclear Thermal
nisms by which the degradation factors induce changes in the
Temperature Cycles
critical performance properties.
Water
Solid (such as snow, ice)
8.1.1 Critical Performance Characteristics and Properties:
Liquid (such as rain, condensation, standing water)
8.1.1.1 Properties used as measures of degradation must be
Vapor (such as high relative humidity)
the same as or directly linked to the critical performance Mechanical Movements
Normal Air Constituents Oxygen and ozone Carbon dioxide
characteristic. Fig. 2 provides a matrix for use in identifying
Air Contaminants
properties that indicate degradation.
Gases (such as oxides of nitrogen and sulfur)
8.1.1.2 The Vertical Axis of the Matrix—An alphabetical Mists (such as aerosols, salt, acids, and alkalies dissolved in water)
Particulates (such as sand, dust, dirt)
letter is used in the matrix to designate individual building
Freeze-thaw
elements and interfaces as part of a building sealant system.
Wind
For example, a wall element may include an exterior coating Biological Factors Microorganisms Fungi
Bacteria
(A), an exterior substrate (B), a structural member (C),
Strain
insulation (D), an interior substrate (E), and an interior coating
Static strain of seasonal cycles
(F). The interfaces between each pair of materials can then be Dynamic strain of daily cycles
Stress Factors, sustained or periodic
designated, for example, A-B, B-C, A-C, etc.
Physical action of water, as rain, hail, sleet, and snow
8.1.1.3 Consider the characteristics of the sealant and
Physical action of wind
interfaces with other building components in the evaluation. Combination of physical action of water and wind
Movement due to other factors
Fig. 2 lists changes in properties that may be useful as
Incompatibility Factors
measures of degradation. These include both visual changes
Chemical
Physical
(chalking, crazing, cracking, checking, flaking, scaling, blister-
Use Factors
ing) and instrumentally measurable changes (color, gloss,
Design of system
tensile modulus, etc.).
Installation and maintenance procedures
8.1.2 Type and Range of Degradation Factors: Normal wear and tear
Abuse by the user
8.1.2.1 Identify the type of degradation factors to which the
sealant will be exposed in-service and their range. A list of
common degradation factors is presented in Table 1.This list is
not exhaustive and other possible important factors should be
sought in each specific case. thermal expansion coefficients of rigidly connected dissimilar
8.1.2.2 Quantitative information on weathering factors is materials that can be estimated.
available from published weather and climatological data. 8.1.2.5 Use factors include the design of the system, instal-
These data will usually be sufficient to indicate the ranges of lation and maintenance procedures, normal wear and tear and
intensities to which the component or material will be exposed
abuse.
in-service. 8.1.2.6 Biological, incompatibility, and use factors and their
8.1.2.3 Stress factors consist of sustained stress, developed range of in-service intensity can be difficult to quantify but
from seasonal changes, and periodic stress, such as daily upper limits of common in-service conditions can usually be
temperature or moisture variation. The intensities of stress estimated from a technical assessment and engineering judg-
factors can be estimated. ment. Consider each of the degradation factors that the sealant
8.1.2.4 Chemical andPhysicalIncompatibilitybetweenDis- may experience in-service within the given building system in
similar Materials—This includes stress caused by the different designing the assessment protocol.
FIG. 2Example of a Matrix for Identifying Observable Changes of Sealants
C1850−17 (2021)
8.1.3 Postulation of Types of Degradation—This step of the warm, moist locations; chemical incompatibility may only be
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