NBSIR 73-132

State of the Art on Durability

Testing of Building Components and

Materials

Larry W. Masters, Winthrop C. Wolfe, Walter J. Ross iter, Jr., James R. Shaver

Center for Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D. C. 20234

March 1973

Interim Report for FY 1973

Prepared for Office of Research and Technology

Department of Housing and Urban Development

Washington, D. C. 20410

NBSIR 73-132

STATE OF THE ART REPORT ON DURABILITY

TESTING OF BUILDING COMPONENTS AND

MATERIALS

Larry W. Masters, Winthrop C. Wolfe, Walter J. Rossiter, Jr., James R. Shaver

Center for Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D. C. 20234

March 1973

Interim Report for FY 1973

Prepared for Office of Research and Technology

Department of Housing and Urban Development

Washington, D. C. 20410

U. S. DEPARTMENT OF COMMERCE, Frederick B. Dent, Secretary

NATIONAL BUREAU OF STANDARDS, Richard W. Roberts, Director

TABLE OF CONTENTS

Page

1.0 INTRODUCTION 1

1.1 Scope 3

1.2 Sources of Information 3

2.0 NATURE OF AGING OR DETERIORATION 4

2.1 Rate of Aging 4

2.2 Environmental Factors Affecting Performance 6

2.2.1 Effect of Moisture 7

2.2.2 Effect of Temperature 8

2.2.3 Effect of Ultraviolet Radiation 9

2.3 Classification of Climates 10

2.4 Mechanical or Stress Factors 10

3.0 ESTIMATING THE DURABILITY OF BUILDING MATERIALS

AND COMPONENTS BY MEASUREMENT OF PROPERTIES 11

3.1 Properties Used to Determine Durability 11

3.1.1 Visual Inspection and Appearance Properties. . . 12

3.1.2 Other Physical Properties. .... 12

3.1.3 Chemical Properties 13

4.0 NON- DESTRUCTIVE EVALUATIVE TECHNIQUES FOR

ESTIMATING DURABILITY 14

4.1 Pulsed Acoustic Energy Testing 14

4.2 Resonance Testing 16

4.3 Acoustic Emission 17

4.4 Scanning Electron Microscope Technique 19

i
TABLE OF CONTENTS - continued

Page

5.0 OUTDOOR EXPOSURE (NATURAL WEATHERING) TECHNIQUES 19

6.0 ACCELERATED AGING TECHNIQUES USING LABORATORY EQUIPMENT . . . 21

6.1 Accelerated Aging Procedures Without Applied Stress . . 23

6.1.1 Devices to Intensify Sunlight 23

6.1.2 Light Exposure Apparatus 24

6.1.3 Light and Water Exposure Apparatus 24

6.1.4 Environmental Chambers 26

6.1.5 Continuous and Cyclic Testing 27

6.2 Accelerated Aging Tests With Applied Stress 28

6.2.1 Dead Load Testing 29

6.2.2 Progressive Load Testing 32

6.2.3 Crack Propagation 33

6.2.4 Cyclic Load Testing 35

7.0 PREDICTING DURABILITY , . 37

7.1 The Difficulties of Predicting Durability 37

7.1.1 Correlating Natural and Accelerated Aging. ... 37

7.1.2 Test Specimen Size 38

7.2 Rate Process Method for Predicting Durability 39

7.3 Mathematical Correlation Method 42

8.0 CONCLUSIONS 45

9.0 SUMMARY OF RECOMMENDATION 47

ii
GLOSSARY

Aging (1) Change in physical or chemical properties with the passage

of time. The effect of exposure to an environment for an

interval of time on systems, components and materials.

(2) The process of exposing systems, components, and materials

to an environment for an interval of time.

Weathering Changes occurring in systems, components, and materials

due to actual exposure to climate and to other environmental

factors

.

Deterioration The loss of appearance and/or functional service with

time; used interchangeably with aging.

Durability (1) Resistance to deterioration

(2) Service life or period during which a system,

component or material remains above a minimum

acceptable performance level.

Predictive testing Short-term testing of components or materials

designed to predict the long-term performance (durability) of

the components or materials.

Climate Mean physical state of the atmosphere and solar radiation in a

given area over a period of time or total weather behavior in

genera 1

.

Environment The sum of all weathering, stress and physical, chemical

or mechanical incompatibility factors to which a housing system,

component or material is exposed.

iii
GLOSSARY - continued

Weather The state of the atmosphere and solar radiation at a given

time in a given area. The state of the atmosphere is defined by

weather elements, the most important of which are clouds,

precipitation, temperature, humidity, wind, pressure, and

visibility

.

Building Material The matter of which a building component is comprised

such as brick, concrete, lumber, etc.

Building Component A part of a building formed by combining building

materials such as a wall.

Building System A structure or building composed of various components

and materials which have been combined in such a way as to

provide a shelter for man or his property.

Sandwich construction A construction in which a core material is bonded

on two sides by adhesion to facings (or skins) resulting in a

composite structure which can be used as the walls, roof .or floor

in housing systems.

Structural component Component which is designed to carry a load or

weight of the building or stresses to which the building is

subjected in service, such as wind or snow loads.

Non- structural component Component which does not have a structural

function or in which the primary function is decorative or

protective rather than structural.
ABSTRACT

This report is a summary of the present knowledge pertaining to

durability predictions for building components and materials which are

subjected to the effects of outdoor exposure. The various chapters of

the report include discussions of the nature of aging, the measurement

of properties to predict durability, non-destructive evaluation

techniques, outdoor exposure techniques, accelerated aging techniques,

techniques for applying testing data to durability predictions and

difficulties which arise in predicting durability. Conclusions and

recommendations are also included.

An appendix, which summarizes ASTM Standards for durability testing

of building components and materials, is included.

v

1.0 INTRODUCTION

The term "aging", when used in relation to materials, components and

systems, refers to a change, with time, in some chemical or physical property which generally results in a decreased performance capability.

Factors which affect the rate and extent of aging include climatic

exposure, applied stresses (either sustained or cyclic), faulty construction or installation, inappropriate usage, and physical abuse.

The prediction of the rates and effects of aging is necessary in

order to estimate maintenance costs and frequency of repair and replacement; in short, prediction is aimed at the proper types of usage of

materials, components and systems in specific exposure environments.

Past research efforts have attempted to fulfill this need for predictive ability by developing laboratory based testing procedures. These

attempts have either sought to provide quality control or to accelerate

natural aging processes. The intent of the quality control type of procedure is to provide a means of comparing two or more similar materials

by relating comparable changes in their properties resulting from shortterm exposures. These procedures (or tests) do not in themselves produce

estimates of long-term performance, but rather are used as the basis for

estimating the performance of new or untried materials.

The goal of accelerated aging is to produce, in a much shorter time,

the changes in a component or material that would occur in real time of

extended duration. Thus, an acclerated aging procedure which fulfills

its goal would permit short-term test results to be extrapolated to longterm performance.

1
Since existing testing and exposure procedures seldom yield results

which can be correlated to long-term performance, durability predictions

also include a judgmental factor which is based upon a knowledge of

materials' behavior. This approach of predicting durability is inadequat

particularly so for new or innovative housing components and materials

for which experience is not yet available.

Durability is usually defined at the building component or materials

level because it is difficult, if not impossible, to either define or

test for the durability of a building system. The durability of a total

building system is difficult to define because each component or material

comprising the system may have different durability requirements. For

example, an exterior paint may be called durable if it performs five

years whereas roofing shingles may be required to perform twenty years

to be classified as durable. It is also difficult to determine the

durability of a system by testing because each component and material com

prising the system performs a specific function and must be evaluated in

that particular performance function. For example, an exterior coating

provides protection to the materials it covers and, at the same time,

provides an esthetically pleasing appearance. Durability tests for this

material must determine if the paint performs these function by testing

for such properties as fading, chalking, embritt lement , etc. under environmental conditions to which it will be exposed. The function of a

material such as a joint sealant is to seal the joints in buildings to

prevent the penetration of exterior environmental factors to the interior

of the system. To perform this function, the sealant must resist degradation by such climato logical factors as solar radiation, moisture, and
temperature changes and in addition, it must expand and contract with the

movement of its adjoining materials. Tests for sealants must, therefore,

reflect these performance requirements. Durability test procedures are,

for this reason, designed for specific components or materials because it

is not practical with present knowledge to either define or test for

durability of total building systems.

1 . 1 Scope

This report is a review and summary of current technology and

methodologies related to the predictive testing of building components

and materials. A preliminary discussion of the nature of aging of building

components and materials is followed by a review of methods used to measure changes in properties or deterioration. Methods for natural and

accelerated aging are described and a discussion of how accelerated aging

tests can be used to predict durability is presented. Research recommendations are also included. An appendix listing ASTM test methods for outdoor and accelerated aging is included.

The content of this report is limited to the consideration of the

deterioration of exterior building components and materials; it is not

addressed to the deterioration of other interior finishes or surfaces.

Where possible, the report distinguishes between tests designed for

structural and non- structural components and materials. Of the factors

listed previously as affecting aging, this report will be concerned only

with weathering and applied stresses.

1 . 2 Sources of Information

This report is based on a review of published literature in appropriate fields, ASTM Standards, and a survey of research laboratories that

3
are active in durability testing. The authors contacted approximately 70

manufacturers of building components and materials by written correspondence and visited twenty-two of those contacted. The authors are in close

contact with government laboratories knowledgeable in durability testing.

In addition, liaison has been established with appropriate ASTM Committees,

such as the Committee on Simulated Service and Performance Testing,

Committee D- 14 on Adhesives, E-6, on Performance of Building Constructions,

and E-7 on Non- Destructive Testing.

2.0 NATURE OF AGING OR DETERIORATION

2 • 1 Rate of Aging

Durability testing consists of measuring the rate at which a critical

property or characteristic of a material or component changes with time

(ages) in an attempt to estimate when that property will fall below an

acceptable performance level under either specific or general exposure

conditions. The aging rate is determined by the nature of the material

in question such as its strength, hardness, flexibility, etc., its compatibility with the adjoining materials, and by such factors as exposure,

climate, use and maintenance.

The durability of a material may be hypothetically classified by one

of four modes of performance over a specified period of time, as illustrated by Figure 1. In this figure, the y axis is a measured value of a

property of a material which is essential to its performance, e.g. the

shear strength of an adhesive, the transparency of a plastic glazing material,

or the extensibility of a joint sealant. The x axis is divided into

arbitrary units of time. In using this technique as a measure of durability, a predetermined level of performance for the particular property
must be identified above which the material conforms to the criteria.

This level is indicated as the "acceptable performance level."

Curve A in Figure 1 illustrates a material which is very stable with

respect to the selected property, so that essentially no change occurs

with time and the material is always above the acceptable performance

level. Properties such as tensile and flexural strength of structural

steel will not change appreciable with time, provided the steel is protected from corrosion or is not exposed outdoors.

Curve B illustrates a material which undergoes a rapid initial increase in the value of a desirable property. Then the material adjusts

to its environment and the increase in value is gradual as the value

approaches the acceptable performance level. Probably the best example of

this is the curing of concrete, which reaches about 75 percent of its

ultimate compressive strength in 7 to 28 days, depending on the type of

portland cement used.

Curve C illustrates a material the performance properties of which

degrade linearly with time. If the slope of the line is known, durability

can be predicted. Gray and Cadoff [1]—^ found that a plot of color change

versus outdoor exposure time in months was approximately linear for rigid

polyvinyl chloride (PVC) polymers.

Curve D illustrates a common type of durability curve. After an

initial decrease in property value, it tends to level off until some

point in time where a sudden break occurs and the property drops below

~^ Figures in brackets refer to literature references at the end of

this report

.

5
the acceptable performance level. Obviously this represents a material

the durability of which is extremely hard to predict accurately. This is

particularly true of materials such as sealants and adhesives.

2 . 2 Environmental Factors Affecting Performance

The performance capabilities of a building component or material may

be degraded by 1) chemical factors, 2) physical factors, and 3) microbiological attack.

Building materials such as adhesives, asphalt roofing and siding,

coatings, plastics, sealants, etc., are composed of organic compounds.

Organic compounds in general are susceptible to chemical reaction with

such elements and compounds as oxygen and water, and these reactions can

lead to aging. Physical factors may also lead to changes which result in

aging, such as the warping in plastics brought about by mechanical stress.

An example of the third possible mechanism for degradation, microbiological

deterioration, is fungi, which can cause damage to building materials

composed of organic compounds.

Accelerated aging tests are designed to yield results which can be

extrapolated to some in-use time. These tests are normally designed to

incorporate environmental (primarily climatic) factors that are considered

to be important in the degradation process. Environmental factors which

may, to varying degrees, be causes of degradation are moisture, temperature, ultraviolet radiation, oxygen, wind, sand, dust, ozone, pollutants,

salt, acids, alkalies, mildew, rot organisms, bacteria, etc. The principal factors are probably moisture, temperature, and ultraviolet radiation,

with the other factors having somewhat lesser effects. Individual factors

may assume greater importance in specific climatic or geographical areas.
For example, salt spray is an important factor near an ocean as are wind

and sand in desert areas and chemical pollutants in industrial areas.

2.2.1 Effect of Moisture

Moisture may lead to the degradation of building materials as a

result of its role in reactions based upon hydrolysis. Organic polymers

in building materials often contain hydrolyzable groups such as esters,

amides, nitriles and acetals. However, in many instances, the physical

nature of absorbed moisture is more important as a degradative influence.

For example, moisture absorbed in a glass-fiber reinforced polyester

(GRP) material may not be detrimental in chemical deterioration but when

freezing and thawing occurs, the resultant expansion and contraction

cycling may result in a mechanical separation of the GRP fibers. Surfaceadhered moisture has been shown [2] to significantly reduce the ability of

an adhesive joint to support a sustained load. Several of the laboratories

visited during this study have indicated that moisture vapor has a greater

deteriorating effect on adhesive joints than water soaking.

Vapor penetration in sandwich construction can cause delamination

of the skin material by weakening the adhesive joint. Moisture may also

result in chemical corrosion of the skin material or deterioration of the

core material.

Since moisture is an important factor in aging, many test methods

include exposure to moisture, as in humidity chambers and light and water

exposure apparatus. These test methods will be discussed in Chapter 6.0,

Accelerated Aging Methods.

7
2.2.2 Effect of Temperature

The temperature changes to which building components are subjected

through normal seasonal changes result in substantial movements of these

components. The expansion and contraction observed with temperature

changes are, of course, material dependent. Restraint of component movement can result in increased stresses in a housing system. To illustrate

this, consider a sandwich-type construction with a paper honeycomb core

and steel skins. Differential expansion and contraction between the paper

honeycomb and the skin can result in increased stresses on the adhesive

bond. Movement of the materials in the sandwich panel also results in

stresses upon the adhesive or sealant material used to join or seal

individual panels.

Data published by the National Oceanic and Atmospheric Administration

(NOAA) in Climatological Data - National Summary , show that normal daily

temperature variations of 25-35°F are not uncommon in most parts of the

United States. Also, recorded temperature extremes are often very large.

For example, Havre, Montana, has experienced temperatures varying from a

high of 111°F to a low of -57°F -- a difference of 168°Fl The average

temperature variation in Havre due to seasonal changes is 56°F from a

high of 70°F to a low of 14°F.

Cullen[3] notes that a roof exposed to solar radiation absorbs heat,

resulting in a surface temperature higher than that of the ambient air,

and states that surface temperatures on outer housing components as high

as 165°F are not unusual. Cullen also states that, by radiative cooling,

the temperature of a roof surface at night can drop below the ambient

air temperature

.

8
The temperature changes observed in building components and materials

may therefore be quite large on a daily basis and even more so on an

annual basis.

2.2.3 Effect of Ultraviolet Radiation

Such materials as coatings and sealants, as well as those composed of

plastics, are affected considerably by sunlight, which causes deterioration

in appearance and very often in function. Exposure to ultraviolet radiation causes many coatings to fade, chalk, or crack. Such failures are

not only unsightly but may result in loss of serviceability, since the

function of non-structural components such as coatings is largely to

protect other components. The protective function may be severely

hindered by degradation.

2 The solar constant, which is approximately 1.92 cal/min cm , is the

energy falling on one sq . cm. area at normal incidence, outside the

earth's atmosphere, at the mean distance of the earth from the sun.

Energy distribution is irregular in various parts of the spectrum, with

47o of the total energy falling in the ultraviolet (0.20 to 0.38 micrometers), 437o in the visible (0.38 to 0.75 micrometers), and 53% in the

infrared (0.75 - 25 micrometers). The energy of the solar radiation decreases as the wavelength increases so that the ultraviolet range is the

primary zone of photochemical action. In this range, radiation energy is

sufficient to break the chemical bonds [4] in the polymers of plastics,

paints and associated materials and is therefore considered to be the

primary portion of the sun's energy spectrum which causes materials

degradation.

9
2 .3 Classification of Climates

Although there are many different generic types of climate in the

United States, existing accelerated aging procedures have not been

designed for the most part to account for climatic variations. To better

understand the importance of specific climatic conditions on the deterior

ation of building materials, it is necessary to distinguish and identify

types of climates. Trewartha [5] has developed a scheme in which six

major divisions of climate are defined, varying from tropical and desert

climates to polar climates; all divisions are found in the United States.

A detailed discussion of Trewartha' s classifications and the importance

of climatological considerations in developing tests for durability will

be presented in a report to be submitted as the second output of this

study

.

The value of any accelerated aging procedure depends on the correlation developed between the accelerated test results and natural aging in

the specific environment of ultimate exposure. Obviously, the varying

weathering factors which are important to the aging of building component

and materials in specific climates must be defined, as new procedures

for accelerated aging are developed, these factors must be incorporated.

Studies are needed, therefore, to define these factors and to determine

how they may be feasibly considered in accelerated aging techniques.

2 .4 Mechanical or Stress Factors

Structural materials and components are subjected to various types

of loads in-service, and the presence of these loads can be an important

factor in their aging. In general, the structural component must support

a given load due to the dead weight of the structure. The actual load

10
will change from time to time as the live loads applied to the structure

change, with large increases occurring when wind and snow loads are

applied

.

Most durability tests for structural materials do not require an

applied load during the test, although quite often the change in the loadcarrying capacity of the material is used as a measure of durability. For

certain materials, such as adhesives, the effect of load is included in

the durability test by requiring that a dead load be applied during the

test. This, however, does not account for the fluctuating or cyclic

nature of the load in the actual structure.

3.0 ESTIMATING THE DURABILITY OF BUILDING MATERIALS

AND COMPONENTS BY MEASUREMENT OF PROPERTIES

A product being evaluated to predict its durability is first subjected

to an exposure condition, whether outdoors or in the laboratory, and then

is studied to determine what changes may have taken place as a result of

that exposure. The quantification of those changes constitutes the basis

for estimating the durability of building components and materials. The

properties of the material or component which are studied must effectively

indicate deterioration or aging and it is therefore important to distinguish between those properties relating to appearance and those intrinsic

to the serviceability of the component. It is a prerequisite that the

tests or evaluative techniques do, in fact, measure the extent of changes

in the selected properties.

3 . 1 Properties Used to Determine Durability

The choice of the property or properties to be studied to determine

durability depends largely on the component or material to be evaluated.

Protection of structural components is the most important function of

11
non- structural components. Second in importance is the control of the

interior environment, and third is the appearance of the building.

A detailed discussion of properties used for predicting the durability of various components and materials is not included in this report

because it would be too voluminous. The following discussion will

briefly summarize the importance of changes detected by visual inspection

and those detected by measurement of physical and chemical properties.

Additional information on the measurement of properties may be obtained

in review papers by Fenner[6] or Supnik [7] or in texts such as those

by Greathouse and Wessel [5] or Brown [8].

3.1.1 Visual Inspection and Appearance Properties

Changes in appearance, which can be characterized by visual inspection,

are usually not important to the durability of structural components

unless such changes are indications of deterioration.

Climatic conditions initially affect the surface of materials exposed

outdoors and therefore durability is often estimated by measuring only

changes in surface appearance. Surface appearance changes include fading,

discoloration, chalking, cracking, and dirt retention.

3.1.2 Other Physical Properties

Properties other than appearance which may be important parameters

in evaluating the durability of non-structural components include hardness, softening point, gloss retention, permeability, and water solubility

and others. For example, thermal coefficient of expansion is one of the

most important properties of elastomeric sealants. Also of importance

for sealants is adhesion to the building components on either side of the

filled joints. Impact resistance is important for cladding and roofing.

12
Strength and stiffness are the primary concern in evaluating the durability of structural components. Strength properties relevant to durability

are compressive, shear, and tensile strength. Stiffness may be character

ized by flexure or racking tests.

3.1.3 Chemical Properties

In addition to measuring physical properties, it is also possible to

measure chemical properties and attempt to relate them to durability.

Aging is normally attributed, at least in some materials, to a chemical

degradation mechanism, so that by measuring the rate of the degradation

reaction one can attempt to extrapolate the results to predict long-term

degradation.

The application of chemical techniques to measuring rate of degradation is illustrated by the references cited below. Gray and Wright [9]

developed a colorimetric method for measuring polyester degradation due

to accelerated and natural weathering. Wallder [10] described a method

using multiple internal reflection spectroscopy in the infrared region to

detect and measure the carbonyl molecules which are products of polyethylene oxidation. He found the aging period necessary to detect meaningful

changes to be short -- on the order of 40 hours outdoor exposure. A

method [11] was developed for detecting hydroperoxide groups, which

served to indicate chemical degradation, during the early stages of

polyethylene oxidation.

The chemical degradation approach has been useful in areas of product development and in the study of stability additives for building

materials. Most building materials are composed of many different

chemical compounds. The various chemical compositions of building

13
materials, therefore, leads to many different types of degradation

mechanisms. Thus the prediction of durability by chemical means would

require many different chemical methods to adequately cover all types of

materials. For this reason, measurement of chemical properties has not

been given as much attention in solving durability evaluation problems

as measurement of physical properties.

4.0 NON- DESTRUCTIVE EVALUATIVE TECHNIQUES

FOR ESTIMATING DURABILITY

Most accelerated aging tests are destructive since the test specimen

is degraded to the point of failure as part of the evaluative process.

Destructive tests are disadvantageous in that only one test result per

specimen is obtainable and the specimen is not usable after the test.

Destructive tests present a particular liability in the testing of large

scale components. For these reasons, testing laboratories are considerin

non-destructive test techniques in durability testing. Non-destructive

testing techniques have also been used as a means of detecting incipient

changes in building materials which indicate deterioration. If such

changes could be detected and measured in the early stages of deterioration, it might not be necessary to accelerate the exposure with accompany

ing problems as discussed in this report.

Non-destructive techniques discussed in this chapter are pulsed

acoustic energy testing, resonance testing, acoustic emission and

scanning electron microscopy.

4 . 1 Pulsed Acoustic Energy Testing

The process of sending pulsed acoustic energy signals through a

material to evaluate it non-destructive ly is commonly referred to by

most authors as ultrasonic testing. The pulsed signal is monitored after

14
transmission through the material or after reflection back to the origin

of the signal. Instrumentation has been developed which utilizes either

separate transmitter and receiver crystals or single crystal units which

serve as both transmitter and receiver. The signal may be analyzed for

velocity of travel through the material, by quantitative determination

of the relative intensities of transmitted and received signals, or by

both methods. Changes in velocity or intensity of the energy signals

indicate changes in the material.

The transmission principle of pulsed non-destructive testing involves

the use of separate transmitter and receiver crystals. In one form of

this application the two crystals are aligned geometrically on opposite

sides of the material so that the pulsed acoustic energy signal from the

transmitter energizes the receiver. The quantitative difference between

the transmitted and received signals or the velocity of the signal as

the crystals are moved over the surface of the material may be used to

evaluate the quality of the material. A tentative ASTM Method,

C-597-68T [12] has been developed for determining the longitudinal

pulse velocity through concrete.

Another technique frequently used in pulsed acoustic energy testing

is the pulse-echo technique. This technique consists of transmitting

pulsed energy signals through the material and utilizes the same transducer for transmitting and detecting the signal. The signal reflected

back to the origin is measured in this technique. The primary advantage

of the pulse-echo technique over the transmission technique is that there

is no problem with geometrically aligning the transmitter and receiver

crystals

.

15
Dietz [13] has used the transmission technique to study glassreinforced plastics and found the velocity of transmission of the ultrasonic pulses to be directly proportional to the ratio of glass to resin.

Zurbrick [14,15] studied pulsed acoustic energy and # -radiometric nondestructive tests in relation to glass fabric-reinforced laminates. In

these studies, he illustrated the relation between elastic moduli and

longitudinal wave velocity for various resin systems. Pulsed acoustic

energy techniques have been applied to the evaluation of sandwich- type

structures [16,17]. The pulsed tester, which measures the elastic

modulus of the adherend, was used in these studies to detect voids in

the adhesive or flaws in the adherends or core. Smith and Cagle [18]

determined correlation between pulsed energy signal results and lap shear

strength of bonds with aluminum substrates.

The primary use of pulsed acoustic energy tests thus far has been in

quality control type tests, and the technique seems to work well in this

application. Studies are being conducted to relate these test results to

properties that would be useful in evaluating materials, such as strength.

Certainly much work is needed in this area of non-destructive testing

before it can be used for durability predictions.

4.2 Resonance Testing

The resonant frequency is a fundamental physical property of a specimen at which the specimen vibrates. It is dependent upon the mechanical

properties, shape, and size of the specimen. The resonant frequency may

be determined by exciting the specimen with manual energy such as that of

a hammer blow, or electronically by the transmission of variable frequency

energy. Methods determining the resonant frequency are often referred

16
to as "sonic test methods." The determination of the resonant frequency

provides a non-destructive means of determining the mechanical and

elastic properties of many materials used in the construction field.

Sufficient data can be generated with the measurement of the flexural,

longitudinal, and shear resonant frequencies to determine Young's Modulus,

shear modulus, and Poisson's Ratio.

The resonant frequency method has been used for studying the deterioration of concrete specimens subjected to repeated cycles of freezing

and thawing. ASTM Standard Method C-666-71 [12] describes techniques

for conducting these studies.

Dynamic mechanical testing using a torsion pendulum apparatus has

been used to measure the shear modulus and the mechanical damping properties of boron fiber reinforced composites [19] and correlations have been

obtained between the elastic shear modulus of the matrix materials and

properties of the composite such as torsion shear modulus, ultimate

flexural strength, and flexural modulus. Klapprott [20] obtained straight

line inverse relationships between the elastic shear modulus and the

tensile shear strength of adhesive joints.

These relationships may be very useful in determining strength

properties of housing components non-destructive ly but much development

work is needed in this area.

4 . 3 Acoustic Emission

Deformation of materials results in sound emissions of various

intensity levels and attempts are being made to utilize these sound

emissions to non-destructively detect flaws in materials and components.

Acoustic emission is the term applied to the "low- level sounds" emitted

17
by a material when it is deformed. Liptai and Harris [21] presented

examples of sound emissions which are of such a "high level" that they

are audible to the unaided ear. Such examples are the creaking of timber

or the sounds produced by rocks when subjected to loads near failure.

Acoustic emission is an attempt to utilize sound emissions in predicting failure by detecting the low level emissions with sophisticated

instrumentation. The detection systems normally use piezoelectric

transducers to detect the emission and the signal is then amplified and

processed by analysis circuitry. The analysis circuitry allows a quantitative display of the acoustic energy release. The total energy and

the rate of release can be obtained concerning the integrity of the

structure. A major advantage of the detection system is that the signals

can be simultaneously analyzed by a digital computer so that the location

of structural flaws can be determined.

The application of acoustic emission to the evaluation of structural

integrity has been described by Hutton and Parry [22]. The authors described the use of the method to evaluate the structural integrity of

fiberglas rocket chambers, metallic structures, welding processes, carbon

steel pipe, laminated wood, ceramic materials, and underground structures.

It would appear that such a non-destructive test offers promise for use

in durability testing, because of its applicability to evaluating

structural integrity. If the method is developed to the extent that the

acoustic emissions can be quantified in a manner yielding durability

predictions, it could be a major asset to durability testing of

structural systems.

18
4 .4 Scanning Electron Microscope Technique

Scanning electron microscopy (SEM) is a technique by which surfaces

can be scanned, viewed, and photographed with a magnification factor up

to several hundred thousand. Its application to weathering studies is

based on the early visual detection of changes on the surface which are

the result of degradation due to aging. Early detection of changes, indicative of degradation, would permit shorter exposure periods. Blaga [23]

applied scanning electron microscopy to the detection of surface change

of glass-fiber reinforced polyester sheets which were exposed at four

outdoor weathering sites in Canada. He found the degradation on the side

exposed to solar radiation to be much greater than that on the protected

side and developed a chronological sequence for the degradation. Such

studies possess the potential for supplying basic data as to the physical

mechanism of degradation and may lead to techniques for reducing the

aging breakdown. Their direct application to durability testing and prediction has not yet been accomplished. Much more work is needed in this

area to determine the ultimate usefulness of the method in durability

testing

.

5.0 OUTDOOR EXPOSURE (NATURAL WEATHERING) TECHNIQUES

Outdoor weathering is used for durability testing because of the

difficulty in simulating environmental conditions, particularly sunlight,

in laboratory tests. The National Bureau of Standards maintains outdoor

exposure sites at seven locations: Alaska, Washington, Nevada, New Jersey,

Maryland (2), and Puerto Rico. Other laboratories have established their

own outdoor weathering facilities as well, but there are also commercial

exposure stations in southern Florida (subtropical environment) and in

19
New Mexico and Arizona (desert environment) . Test areas in Florida and

Arizona are most commonly used for outdoor weathering in the United

States because of the availability of the maximum amount of solar

radiation [24]. Commercial weathering stations in their periodic reports

supply basic environmental data, such as rainfall, average relative

humidity, and ultraviolet exposure. This type of data is not usually

collected by laboratories maintaining their own weathering stations.

Most outdoor exposure tests in this country follow closely the

recommendations of ASTM D 1435 [25] with regard to sample position, that

is, maintaining the specimen at a 45° angle to the horizontal, facing

south, and unrestrained. Also suggested in ASTM D 1435 is recording

weather data such as average daily temperature, average daily relative

humidity, daily rainfall, and total daily solar radiation in langleys

2 (cal/cm ) in the plane of the samples.

It is difficult to correlate outdoor weathering test results between

various exposure sites because of the variation in climatic conditions

and the lack of sufficient measurements of important environmental

parameters

.

The major problem with outdoor exposure methods is the time required

to obtain test results. Several years of exposure are often required to

achieve detectable changes in properties. It is not always practicable

or economically feasible to wait for lengthy tests except for long range

research purposes.

As new building technology is developed, it is necessary to evaluate their durability before they are used in construction in order to

prevent possible costly or catastrophic failures. Manufacturers cannot

20
afford to wait for several years of outdoor exposure tests before introducing new products to the building market.

A summary of outdoor aging methods in ASTM Standards appears in

Table I of the Appendix. The tables in the Appendix which refer to outdoor weathering are as follows:

I. Outdoor Weathering Methods in ASTM Standards (1971)

III. Summary of Exposure Conditions and Procedures in ASTM

Standards for Outdoor Weathering (1971)

V. Criteria for Outdoor and Accelerated Weathering Methods

6.0 ACCELERATED AGING TECHNIQUES USING LABORATORY EQUIPMENT

In order to overcome the problems of lengthy outdoor testing,

methods have been developed to accelerate the aging process. This

approach has raised a number of technical problems:

1) How can a laboratory method be devised to simulate outdoor

weathering but accelerate its effect on building components?

2) What climatic factors cause the aging of building components,

how can these factors be measured, and with what degree of

accuracy?

3) What climatic factors can be accelerated and to what extent?

4) What is the chemical mechanism of aging and can this

mechanism be easily accelerated?

5) By what criteria can the test results be evaluated?

6) Does the specimen size affect the test results?

7) Should systems, components, or materials be tested and how

can we interrelate the results?

In devising a laboratory method to simulate, yet accelerate, the

aging process, there is the question of the effect of acceleration on the

mechanism of aging. If it is possible to accelerate the effects of aging

caused by outdoor exposure, there are still the questions of whether the
accelerated aging method can be related to outdoor exposure, whether the

mechanism is the same, and whether there is the same relationship between

time of exposure and change in whatever properties are measured. In both

outdoor exposure and accelerated aging, criteria must be selected and

these must be properties of the building components which are relevant

to its service life or durability.

It is difficult at best to separate the individual effects of various

environmental factors on the deterioration of building components. These

factors are best considered in combination. Durability tests must be

designed for the environment in which the product in question is to be

used. However, there are a variety of environments in the United States,

as previously discussed, and some thought has been given to the idea of

developing durability tests to reflect the environments of various

geographic areas of the country. In fact, ASTM Standard Specification

for Brick, C 62-66 [26], has different requirements according to the

geographic area. Such areas are indicated on a map of the United States

and indicates where brick will be subjected to severe, moderate, or

negligible weathering. Efforts are needed to apply classifications of

this type to other building components and materials.

A summary of accelerated aging methods in ASTM Standards is presented in Table II of the Appendix. The tables in the Appendix which

refer to accelerated aging are as follows:

II. Accelerated Aging and Weathering Methods in ASTM Standards (1971).

IV. Summary of Exposure Conditions and Procedures in ASTM Standards

for Accelerated Weathering (1971).

V. Criteria for Outdoor and Accelerated Weathering Methods.

22
6 . 1 Accelerated Aging Procedures without Applied Stress

Most accelerated aging methods are used without the application of

stress to the test specimen. While these methods are appropriate for

non-structural building components, they are commonly used with structural

components as well. They may involve continuous exposure to a given set

of conditions, thermal cycling, humidity manipulation, water spray, etc.

Tests are designed to determine the resistance of the material or component to such environmental conditions as temperature, moisture,

oxidation, pollutants, solvents, acid, alkali, dust, sand, wind, salt,

rot organisms, and bacteria.

6.1.1 Devices to Intensify Sunlight

One method for accelerating aging is outdoor exposure with a device

to intensify the sunlight on the specimens, as EMMA [27] (Equatorial

Mount with Mirrors for Acceleration) . This type of device may be combined with water spray as in EMMAQUA r 28 ] . EMMA is reported to accelerate

outdoor aging by a factor of 6 to 10.

In one study \29] there was little correlation between data obtained

from outdoor exposure of polypropylene and polyethylene using EMMA and

data from accelerated aging tests with a light and water exposure apparatus.

Some commercial laboratories do not use EMMA or EMMAQUA on a routine

basis because of the high cost, lack of reproducibility, and lack of

correlation with outdoor exposure tests based on natural weathering, in

which EMMA and EMMAQUA are not used. The authors know of one laboratory

which uses EMMAQUA for screening materials for production control.

Another commercial laboratory has found good correlation between

EMMAQUA tests and natural weathering tests and reports that the accelerating factor of EMMAQUA is about 4.

23
6.1.2 Light Exposure Apparatus

Commercial light exposure apparatus is used to accelerate the effect

of ultraviolet light under controlled conditions. Carbon arc lamps are

commonly used but models with xenon arc lamps are available. Environmental conditions are usually continuous and are not cycled. Light

exposure apparatus is not used as frequently as light and water exposure

apparatus for testing building components and materials and is not considered as reliable for predicting durability. Building components and

materials tested by both types of equipment include organic coatings,

plastics, roofing, sealants, cladding, etc. Sample size is limited by

the design of these devices to several inches in length and width.

6.1.3 Light and Water Exposure Apparatus

Devices to provide both light and water exposure combine ultraviolet

radiation, water spray, and temperature, to simulate the effects obtained

by continued outdoor exposure. Environmental factors may be cycled to

simulate periods of sunlight, darkness, and rainfall. Types of apparatus

differ mainly in the ultraviolet lamp used. Such lamps may be ultraviolet

carbon arcs, sunshine carbon arcs, xenon, fluorescent lamps, or mercury

arcs. The xenon arc spectrum is generally considered to most nearly

simulate that of sunlight in the 300-720 mu range. Carbon arcs exhibit

spikes in the spectral curve in the range of 350-400 mu, resulting in

significantly more energy in that region than sunlight. Corex filters

are used to reduce the spectral spikes in the sunshine carbon arc.

Mercury arcs and daylight fluorescent tubes also exhibit spikes in the

spectral curve and do not closely simulate sunlight.

24
The "dew cycle" [30] is frequently used in light and water exposure

apparatus. This consists of irradiating the sample with unfiltered light

from a carbon arc while spraying the backs of the specimens with cold

water to induce the deposition of dew on the exposed face. Other cycles

used include boiling water, immersion in vapor, and water soaking alternating with exposure in the light and water apparatus.

A fluorescent sunlamp-blacklamp [31] has been reported to yield

accelerated aging results which correlate well with Florida and Arizona

weathering of rigid polyvinyl chloride films [32]. The xenon arc light

source has been used to accurately predict outdoor weathering of plastics

[33]. However, the appropriate environmental factors for outdoor

weathering must be measured. Another study [34] showed xenon arc

weathering to compare favorably with outdoor weathering of plastics

especially when the samples were sprayed periodically with water. Other

studies with light and water exposure apparatus [29] have shown the

accelerated test results to give a very conservative estimate of the

outdoor durability of polyethylene. Studies to compare the light sources

for artificial weathering have been reported [35,36].

Private discussions with other investigators indicate mixed feelings

toward the usefulness of light and water exposure apparatus. With regard

to studies using a twin carbon arc device, Jordan et al [37] state that

the apparatus can be used effectively to screen the relative outdoor

performance of certain copolymers, but that it should not be used by

itself to predict absolute long-term outdoor performance. This same conclusion has been expressed by many investigators working in laboratories

throughout the country. Most workers feel that it is a useful tool to

screen materials and to compare the relative durability of similar materials.

25
One problem which adds to the confusion as to whether or not light

and water exposure apparatus is useful is that very often accelerated

aging reports do not specify the light source and other test conditions.

It is important to specify these factors in discussions and publications.

6.1.4 Environmental Chambers

Environmental chambers used in accelerated weathering vary from

small commercial humidity cabinets to large rooms accommodating a fullscale house. Such chambers are widely used in testing laboratories to

simulate outdoor weathering or the influence of drastic environmental

differences between the interior and exterior of buildings. The larger

chambers or rooms can often be cycled through various environments to

more closely simulate the actual effect of outdoor weathering, but such

facilities are few in number. Some of the smaller testing facilities do

have environmental rooms large enough to test a full-scale wall or

ceiling system, however. The primary environmental factors controlled

in these chambers are moisture and temperature.

Testing full-scale systems under controlled environments is considered to be the most meaningful test for some of the newer building

components such as sandwich panels. One can test panels in such a way

as to simulate interior-exterior environmental differences and evaluate

these effects under a sustained load. But no direct correlation between

these test results and in-service performance exists. Test results must

be related to durability by the evaluator's judgment and intercompar ison

with other systems.

Full-scale testing raises the question of specimen size. Results of

tests of large specimens do not usually correlate with small-specimen
tests. It would be desirable to test new housing systems as an entire

unit in order to predict their durability. However, this is not feasible

from the standpoint of time and cost so the results of small-specimen

tests must be heavily augmented with judgment.

Chambers for ASTM Standard Method C-481-62 (sandwich constructions)

r 38 ] have been built to accommodate 4x8 ft. panels, although most

laboratories use specimens not more than 1 x 3 ft. in size. Very little

correlation has been found between results of tests with large and small

specimens but most laboratories feel that the larger the test specimen

the more meaningful the results. Apparently, larger specimens exhibit

more twisting and prompter indication of warping from thermal expansion

differentials than do small specimens.

6.1.5 Continuous and Cyclic Testing

Exposure conditions may be held constant or cycled.

The use of various environmental conditions in a cyclic mode is

basically sound, since the component is subjected to this type of environmental change in service. The problem is to accelerate the aging

process by accentuating cyclic conditions. Experience of other laboratories indicates that increasing the severity of the conditions may not

necessarily accelerate aging. Several testing laboratories have tried

shortening the cycle time, thus increasing the frequency of cycling

and this technique has had some success with specific sealant materials.

Cyclic tests are used to simulate alternating environmental exposures. ASTM Methods C-481-62 and D- 1037-64 [38] are procedures for

laboratory aging of sandwich constructions and wood-base fiber or

particle panel materials, respectively. Both incorporate cycles of

water soaking, steam or hot water spray, freezing, and oven drying.
An ASTM cyclic aging test for adhesives, D- 1183-70 [38] provides

different test cycles of temperature and moisture exposures for interior

and exterior service. Cyclic aging of plastics is described by ASTM

D-756-56 [25] and includes seven different procedures for various types

of specimens. Each procedure in this test contains variations in the

severity of temperature and moisture conditions.

Industrial laboratories often develop tests for their own materials,

some of which involve cyclic exposure. Some of these cyclic tests are

reported to yield reproducible results for specific materials applications.

Exposure conditions used in cycles include outdoor exposure, light and

water exposure apparatus, boiling water immersion, room temperature

water immersion, dry heat, freezing, etc. In an unpublished procedure,

a cycle of 4 hours water soaking and 20 hours exposure in a xenon arc

light and water apparatus is used to evaluate coatings.

6 . 2 Accelerated Aging Tests with Applied Stress

The primary objective in developing weathering methods having an

applied stress factor is to provide a means of evaluating structural components. Short-term test techniques provide a measure of the component

strength under a limited set of conditions. The data are usually meaningless for engineering design purposes because the component strength

decreases with aging. The parameter of true interest is the stress level

the component will sustain for a predetermined time - the lifetime of

the housing system.

Lewis [39] has proposed a model for the rheological response of a

structural adhesive material to a static stress. This model is presented

in Table 2. The model defines the types of damage at various levels of

28
relative stress. The relative stress is the ratio of applied static

stress to short-term bond strength. This type of model illustrates that

the design strength must be much less than the strength obtained from

short-term tests. For engineering purposes, the ultimate design strength

based upon this model for adhesives should be less than 25 percent of the

short-term strength. Although this model was developed for a specific

material, the concept behind it (that the design strength must be less

than the short-term test strength) applies to most structural components.

Such models are useful in developing criteria and illustrating the distinction between short-term test results and strength retention with time.

The test methods to be described in this section are dead load

(sustained load) testing, progressive load testing, crack propagation,

and cyclic load (fatigue) testing. Sustained loading and progressive

loading are more advanced in their application to durability testing than

crack propagation and cyclic load testing. The scientific literature

contains numerous articles describing the development of each of these

methods and illustrating their applicability to durability testing. Some

of these articles will be cited in the discussion of each of the methods.

6.2.1 Dead Load Testing

Dead load testing consists of applying a sustained load to a material

and measuring either the time to failure or the change of a certain property with time. This approach has been used for years to simulate the

effect of long-term loading. The material can be exposed to various

environmental conditions while under the sustained stress in order to

more closely simulate natural weathering conditions. The large environmental chambers mentioned earlier are very useful in this regard. For

29
example, structural sandwich type panels can be built into a chamber and

a sustained load placed on them to simulate the effect of various conditions on a wall construction. Structural beams of concrete are also

frequently tested by sustained load tests.

More often, however, smaller specimens are evaluated by dead load

testing. The smaller specimen approach is common for 1" x 6" dogbone

samples of roofing or plastics and for evaluating adhesive bonded lapjoints. Various sustained loads may be applied to individual test

specimens to obtain stress-rupture curves. Such a curve is a plot of

one of the strength parameters versus time and is normally plotted on a

semi- log or log- log scale. Studies such as those by Cass and Fenner

[40, 41, 42] show a subsequent flattening of the curve so that for many

materials the curve can be extrapolated to obtain long term predictions of

performance from short-term data. The value obtained by extrapolation is

called the endurance limit, which is defined as the stress level a

material can withstand indefinitely. Practical limitations require that

the endurance limit be determined for a finite time and this time has

arbitrarily been taken in practice as 10,000 hours. A typical stressrupture curve is shown in Figure 2. Acrylic and methacrylate based

plastics have been evaluated by dead load testing using a cantilever

flexure test [43] with outdoor exposure. Other publications describe

studies of compressive, flexural, or tension loads on plastics under

actual environmental conditions [44, 45, 46, 47]. Procedures developed

under the auspices of ASTM provide methods for measuring the time-tofailure of plastics [25] and creep properties of adhesives [38].

30
The application of the dead load can be accomplished by using a testing

machine, by hanging weights from the specimen or by the use of spring

loaded devices such as that proposed by Sharpe [2]. Carter [48] has

proposed an outdoor weathering rack in which lap-shear joints can be

stressed up to 3000 psi. This device can accommodate up to 90 specimens

1" (2.5 cm) in width and 5 1/2" (14 cm) long. Wegman [49] has used both

the Sharpe [2] jig with artificial environments and a stressed outdoor

weathering frame in evaluating the durability of adhesive bonded joints,

and both were found promising for durability testing. Other spring- loaded

fixtures have been devised which permit periodic corrections for creep,

thereby maintaining constant loads on the specimens. The use of suspended weights is also a popular method of applying a sustained load.

In the laboratories surveyed by the authors, several dead load

fixtures based on suspended weights have been built. The current trend

is to build the fixture so that test specimens can be enclosed in an

environmental chamber. The dead load fixtures are designed so that test

specimens are placed in series. One fixture when loaded might well

accommodate several test specimens. This approach raises the question

of stress distribution among the various specimens. For this reason,

the single specimen fixtures may be more desirable than multi-specimen

fixtures.

Sustained loading can be a very useful tool in evaluating materials

durability. The basic principle behind dead load fixtures can be applied

to many different building materials for which sustained stress might be

a factor. The major drawback in most cases with the dead load approach

is the relatively long time required to obtain meaningful curves which

can be extrapolated to yield an endurance limit.

31
6.2.2 Progressive Load Testing

Progressive loading is a means by which one can determine the endurance limit of a stressed material in a much shorter time than that

required by the stress-rupture curve, described above for dead load

testing

.

E. Marcel Prot [50] in 1948 proposed a method of accelerating the

cyclic fatigue testing of materials. Prot showed mathematically that

by progressively increasing the load on a specimen until failure occurs,

one should be able to predict the stress level a specimen is capable of

withstanding without rupture for an infinite time. This stress level

should be nearly the same as the endurance limit as determined from the

stress-rupture curve described by sustained loading. The Prot method

consists of subjecting the specimen to progressively increasing loading

rates to achieve failure. The failing loads are applied to mathematical

equations so that one can obtain a graph which can be related to the

endurance limit.

Boiler [51] applied a modified Prot equation to the determination

of the endurance limit of glass- reinforced plastic laminates. He concluded that the endurance limits from both the Prot and sustained load

methods were in good agreement at 10,000 hours duration by the sustained

load methods. Boiler further stated, "The Prot method of test, which can

be conducted on one material at one condition within 1 week, compared

with 4 years by the Wohler (sustained load) method, is a substantial

time saver and hence is a good, quick estimate of long-term strength

characteristics ."

32
Loveless, Dee ley, and Swanson [50] developed a hyperbolic equation

relating rupture stress and time to break, based on Prot's work. The

equation developed was:

(SR

- E) t B = k

Where S = stress at rupture R

E = endurance limit

t = time to break

K = material constant

They found it more meaningful to relate the endurance limit to the

slope of the curve because of the substantial extrapolation involved,

whereas Boiler had related the endurance limit to the intercept after

extrapolation. They also found their equation to be useful in predicting

reliable measures of long-term strength.

Lewis, Kinmonth, and Kreahling [53] found the Prot method, as modified by Loveless, Deeley, and Swanson, to give a reasonable estimate of

the long-term endurance strength of an adhesive joint.

Several of the laboratories surveyed are working on the progressive

loading method. All those contacted expressed optimism in developing the

method to reliably predict endurance limits for building materials. It

is felt, however, that much more work is needed in refining the method.

6.2.3 Crack Propagation

Fracture mechanics is a concept which makes it possible to measure

quantitatively a material's resistance to fast crack extension in the

presence of a flaw. Slow-moving cracks indicate high toughness while

rapid extension of a crack is associated with low toughness.

33
Mostovoy and Ripling [54,55] have used the principles of fracture

mechanics to evaluate the speed of crack propagation in epoxy bond systems.

A contoured double cantilever beam adhesive specimen, a uniform double

cantilever beam specimen, and a tensile specimen were used. The adherend,

which is the material bonded by the adhesive, was aluminum.

In more recent work, Ripling, Mostovoy, and Corten [56] reviewed the

basic concepts of fracture mechanics and emphasized those aspects that

are applicable to the evaluation of structural adhesives. One major

advantage of the method is that all adherend parameters are extraneous

to the value of fracture toughness, which is measured because the test

is designed so that no energy is lost to them during the course of crack

extension. This permits comparison of a given adhesive with different

adherends, which is impossible with tests such as peel and shear.

Gurney and Amling [57] presented a general theory of crack propagation

and applied it to the normal separation of two bonded elastic strips.

The work of tearing may be computed from a plot of load and deflection

as the crack spreads if the adhered beams are sufficiently strong to

resist bending.

Attempts are currently being made to utilize crack propagation in

predicting adhesive durability. Thick adherends are used to prepare

the contoured double cantilever beam specimen. The adherends on one

end of the specimen are separated in a testing machine by the application

of a certain load. The specimen is clamped in a manner to hold the

stressed position and then placed in various environments. The crack

which was initiated by the stress application grows and releases some

portion of the applied load. A plot of crack length versus the number

34
of days in the artificial environment is made and the curve eventually

reaches some point in time at which the crack growth rate is constant.

The constant growth rate at a particular stress can be used to determine

the length of time necessary to rupture the bond.

This approach is new and results are, therefore, sparse. However,

the results to date, reported by a laboratory surveyed by the authors,

appear to be encouraging.

In its present state of the art the crack propagation method is

being developed for adhesive bond evaluation; but if perfected, it may

well be applicable to other load bearing housing materials.

6.2.4 Cyclic Load Testing

The sustained load that a loadbearing building material withstands

is not in reality a constant load. Rather the load varies constantly

with environmental changes. An example is a sandwich type construction

with a paper honeycomb core and stressed steel facings. The steel facing

exposed to sunlight may well reach surface temperatures of 160°F or higher

which would result in expansion of the steel. Contraction of the steel

would occur in cold weather. The differences in thermal expansion

coefficients between the core and skin materials would result in differential movement between the two, thus producing a stress in the bond.

This movement would place additional stresses on the composition of the

sandwich panel. The effect cyclic loading has on materials is called

fatigue. Test methods are currently under development and evaluation to

simulate more closely this type of cyclic loading. Many of the laboratories surveyed definitely feel this is a feasible approach to take in

developing durability tests for loadbearing components.

35
The technique would involve varying the load on the material around

some predetermined load level. The predetermined load level and the

amount of variation must be chosen experimentally - perhaps based upon

the design load of the structure or the endurance limit from a stressrupture type curve. One must also determine experimentally the rate of

loading cycling. Various environmental factors such as temperature,

moisture, ultraviolet irradiation, etc. could be included in the test

method by developing a test apparatus so that the specimens could be

enclosed in an environmental chamber. Test facilities to incorporate all

these factors have been recently built in a few laboratories. Hearle [58]

published a review of fatigue in fibers and plastics in which he described

a fatigue test apparatus used in his studies. This apparatus was not

adapted for environmental aging, however.

Fatigue testing of materials has been shown in a few of the laboratories surveyed to yield faster rupture than sustained loading at the

same levels of applied stress.

Little [59] surveyed the three kinds of fatigue tests and included

advantages and disadvantages for each. He based the discussion on the

P-S-N surface model and described the three fundamental fatigue variables

as

:

S = fully reversed stress amplitude, or fully reversed strain amplitude

N = number of stress or strain cycles imposed

P = proportion failed prior to N stress or strain cycles.

Any two of these variables can be plotted against each other when the

third is fixed. He defined the three basic fatigue tests as S-N

(preliminary tests), P-N (life tests), and P-S (strength tests).

36
7.0 PREDICTING DURABILITY

The durability of housing materials is predicted largely on the basis

of results of the testing and evaluative techniques described previously.

The results of these accelerated aging tests or other short-term tests are

compared with the results of similar materials which are known by experience to be sufficiently durable. The evaluator then applied a judgmental factor, based upon experience, to yield the durability prediction.

The judgmental factor, then, is the key to durability predictions. The

judgmental factor is a necessary part of durability prediction because

short-term test procedure results do not yield quantitative durability

measurements. There is a need, therefore, to develop better durability

test procedures for all housing materials and components so that the

need to reply on the judgmental factor can be minimized.

7 . 1 The Difficulties of Predicting Durability

7.1.1 Correlating Natural and Accelerated Aging

Many attempts have been made to establish valid performance tests

for durability by correlating the results of accelerated aging procedures

with data from outdoor exposure tests. Although some correlations have

been established for specific materials, there is no general relationship

between accelerated aging and outdoor exposure. The following are possible

reasons for this lack of correlations:

(1) The conditions used in the accelerated aging procedure may not

accurately simulate environmental conditions in service or conditions of the outdoor exposure.

(2) Conditions which cause deterioration in service or in outdoor

exposure may not be known or if they are known they may not

be accelerated or even present in the accelerated aging test.

37
(3) There may be a lack of knowledge or lack of adequate measure- ments of climatological and other environmental factors present

in the outdoor exposure.

(4) There may be a lack of precision of control and measurement

of conditions of accelerated aging test.

(5) There may be a lack of precision of measurement of the physical

property change following the outdoor exposure or accelerated

aging test

.

7.1.2 Test Specimen Size

One of the major problems in durability testing is that of test

specimen size. A consistent correlation between test results obtained

with large and small specimens has not been established. The choice of

specimen size is a particularly difficult problem in evaluating housing

systems. For example, in sandwich type constructions, the stresses

induced on the system by various environmental cycles may be considerably

different in 4- by 8- ft. factory produced panels and 6- by 6-inch laboratory specimens. Obviously, it is much more desirable to test small

specimens because of ease of handling and cost. Also, the lack of adequate test facilities in many laboratories prohibits testing a full

4- by 8- ft. panel, an entire wall or ceiling system, or an entire housing

system.

Whenever possible, tests are based on the quantitative measurement

of some property of the material or building component. Techniques of

this type can yield results which can be plotted and extrapolated.

However, extrapolations are subject to large errors, since the variance

in data from physical property measurements is likely to be on the order

of 10 to 20 percent.

The time, cost, and facilities required to test enough large speciments for statistical handling of data is extremely high but replication

38
is necessary to obtain meaningful results because of the lack of precision

of test methods. For a durability test to become widely accepted in the

housing industry, it must be designed for specimens which are of a convenient size. However, the results from small test specimens are useful

only if they can be related to the entire building system. It is therefore

necessary to correlate results from large and small specimens in establishing a test method, using the minimum number of large specimens necessary

to validate the method. If small specimens are used, the precision of

data can be improved by increasing the number of replicates but this is

impracticable with large specimens.

7 .2 Rate Process Method for Predicting Durability

Predicting durability from accelerated aging tests involves extrapolation of data from short-term tests to long-term service life. One

procedure which involves extrapolation of short-term data is called the

rate process method which is based on the Arrhenius equation [60]

normally expressed as:

d In k = E/RT2

, where

k = reaction rate constant

T = absolute temperature

E = activation energy

R = gas constant

The Arrhenius equation mathematically expresses that most chemical

reactions proceed at a faster rate as the temperature is increased. When

applied to durability testing, the rate of deterioration of the material

(which is normally observed by a change in a physical property) is considered to be a rate of chemical decomposition. To apply the rate

39
process method, the rates of deterioration are determined at exposure

temperatures higher than those encountered in actual use. Assuming that

the activation energy, E, is constant, a plot of rate versus inverse

temperature produces a straight line and the line can be extrapolated to

the lower temperature (in-use temperature) . The rate of deterioration of

the material at the lower temperature is thus determined. There are

possible sources of error of which one should be aware when applying the

rate process method. First, the activation energy may not be constant

and this means a linear extrapolation will be erroneous. A larger source

of error can arise from the fact that the chemical mechanism of the

deterioration may involve more than one pathway. The relative rates of

the different pathways may change considerably as the temperature is

raised. Thus, the mode of deterioration at the higher temperature may

not be the same as that at the lower temperature. That is, the normal

path of in-service aging is not observed in the acceleration. In these

two cases, the rate process method should not be used for predicting the

service life of the material.

Although in durability testing one is normally concerned with changes

in physical properties, Goldfein [61] states that if processes such as

creep and rupture are defined as the separation and breaking apart of

molecules, they may be treated as chemical reactions. This assumption,

of course, makes it possible to apply the Arrhenius rate process to many

types of tests which result in rupture of the material. Goldfein applied

the rate process to stress-rupture, creep, chemical degradation, and

thermal degradation. His derivations were similar to the empirically

derived Larson-Miller [62] stress-time-temperature equation which was

40
applied. to stress-rupture and creep in glass-reinforced plastics. Raphael

[63] found that by using an Arrhenius plot, an accelerated aging test

could be based on temperature as the sole accelerating means for plastics.

Gillespie [64,65] has applied the rate process method to predicting

durability of adhesive bonded wood joints. He postulated that moisture

is the rate controlling influence in degradation of adhesive bonded joints

and that temperature primarily accelerates the moisture attack. The procedure used involved exposing specimens to various environmental conditions

for different intervals of time before measuring shear strength. By

increasing the temperature and the concentration of other environmental

factors, the rate at which a factor degrades a bond may be accelerated

for laboratory evaluations. The data were plotted as the log of shear

strength versus time for each temperature studied. The linear response

was expressed mathematically by the Arrhenius rate equation in which the

slope of the line is a constant, K, describing the rate of loss. The log

of K was then plotted versus 1/T, where T was the absolute temperature.

Gillespie found this plot to yield straight line responses which could be

extrapolated to determine the bond strength half- life, the time required

for the bond to lose one half its initial strength.

McAbee, et al [66] applied the rate equation of Coleman and Knox

[67] to constant loading data to evaluate the feasibility of the rate

process method for predicting adhesive bond durability. The data used in

that work were obtained by sustained loading and measuring the time to

failure using shear and tensile testing. They found the mathematical

relations developed by them fit the data quite well.

41
The rate process method has been shown in the above reference to be

applicable to durability predictions for plastics and adhesives joints.

The method should also be applicable to other materials as well. The

durability data obtained from the rate process method would seem to be

reasonably reliable, even with the extensive extrapolation involved.

Additional studies are needed with the rate process method to determine

its applicability to other building materials and to fatigue type tests.

7 . 3 Mathematical Correlation Method

The mathematical correlation method, in which the rate of change of

a material's property is expressed mathematically, represents another

attempt to correlate accelerated aging test results with those of natural

outdoor aging and service life. An empirical equation is used in attempting to predict the long-term behavior of the material after short-term

aging. Thus, for a class of materials, the mathematical equations for

indoor and outdoor exposures and the relationship between them are found.

Then, for a new material of the same class its long term outdoor exposure

lifetime is predicted based on its accelerated test data.

This approach uses statistical analysis of data to obtain the

mathematical relationship. Before a statistical correlation can be obtained, a mathematical model must be chosen which corresponds to the

actual physical mechanism by which the material deteriorates. For

example, if the material ages linearly with time, one should not attempt

to fit the data to an exponential model. Also the model equation must

account for variations in aging due to climatic conditions. Thus, the

model must contain terms which relate the exposure (aging) of the material

to the exposure site (local climate). Such terms in the model equations

42
have been named "exposure parameters" [68] . They are constants for a

given exposure condition.

The mathematical approach to predicting the durability of plastics

was first described by Kamal [68]. He artificially weathered three

commercial plastics specimens under sixteen different exposure conditions.

A xenon arc light source was used in all exposures. The variants in

exposure conditions were temperature and water spray cycle. Kamal

determined that for a given exposure, the change of a specimen property

could be described by the equation:

LnP = b

Q

+ b

x (t-250) + b

2 (1-0.710) where

P = a property of the material

t = time of exposure in hours

2

I = intensity of light source in joules/hr/cm

bg, b^, b^ = exposure parameters

0.710 = average relative intensity of the light during exposures

The exposure parameters b^ and bp were related to the following three

variables: 1) temperature, 2) the length of time of the wet portion of

the cycle, and 3) the percent time that the specimen was wet during the

cycle. The experiment was not designed to determine b^.

With the assumption that average relative outdoor intensity varies

little from 0.710, the above equation reduces to:

LnP = b

Q

+ ]> 1 (t-250)

Kamal determined the primary environmental parameters at his outdoor

exposure site and related this information to the mathematical equation

developed by accelerated weathering. He then used the simplified

equation to predict the length of time necessary for outdoor weathering

43
to induce the same property changes for the same three commercial plastics.

Another example of the use of the mathematical approach is the work

of Clark [69]. In that project, twenty plastics specimens were weathered

outdoors at three different exposure sites. Clark determined that the

change in ultimate elongation with time for fifteen of the twenty specimens

could be described by the following equation:

Y = b^ exp [- (t + b

2

) b4l + b

5 where

b

3

Y = ultimate elongation

t = time

b^, b^, b^, b^, b<. = exposure parameters.

Although there are numerous reports in the literature discussing the

reliability of correlating indoor and outdoor exposures, there are too

few reports describing the mathematical approach. There does not appear

to be enough experimental evidence to judge the approach. The real value

of this method would appear to be its ability to relate the model and the

degradation of the material to the climatic conditions of the exposure

site. In other words, by finding the model for deterioration and by

knowing the primary weather parameters at the exposure site, a prediction

of the durability of a material can be made. Of course, the reliability

of such a prediction is only as good as the statistics involved in determining the model. However, even with good statistics, the approach still

must be subjected to much more experimentation and possible refinement.

Studies have not been published to show the relationship between

natural weathering and tests such as dead load, fatigue, crack propagation, rate process, and progressive load testing.

44
8.0 CONCLUSIONS

1. Of all the attributes required of building systems, components, and

materials, durability is probably the most important and the most

difficult to define and specify.

2. For the purpose of evaluation, durability must be specified at the

component or materials level because each component or material

may be required to have a different service life or life-cost.

3. At the present state of the art, it is virtually impossible to

predict durability precisely with short-term testing.

4. Durability is predicted at present by a combination of testing,

in-service performance, and scientific and engineering judgment and

the current techniques of durability prediction are acceptable for

some building components and materials, especially for those for

which much experience has been obtained by in-service performance.

5. The current techniques of durability prediction are not acceptable

for new or innovative components and materials that have not been

used extensively in the past; hence, there is an immediate need

for predictive techniques for these components and materials.

6. Criteria for judging the performance of building components and

materials following durability tests are needed.

7. Evaluative techniques to provide durability data must be designed

for specific building components and materials because

(a) each component or material performs a different function and

must be tested for that function.

(b) each component or material is affected differently by the

various environmental parameters.

45
8. Climatological and other environmental parameters and interactions

affecting durability need to be better defined and understood as

well as measured more meaningfully.

9. The phenomenon of aging is not well understood and studies are

needed in this area

(a) in devising techniques to accelerate aging mechanisms in such

a way as to better quantify durability.

(b) in devising and improving other predictive tests, such as

non-destructive testing and detecting deterioration in its

early stages.

(c) in testing building components subjected to stresses in service.

10. Studies are needed to better correlate natural outdoor weathering

or aging and accelerated aging.

11. Studies are needed to determine the relationship between the aging

of small specimens and full-scale components.

46
9.0 SUMMARY OF RECOMMENDATIONS

The recommendations for research efforts to improve the state-of-theart of durability testing of building components and materials are as

follows for:

1. ENVIRONMENTAL FACTORS

a. Define environmental factors (including weathering, stress

and incompatibility) which are important in aging of building components and materials leading to a decreased performance capability.

b. Classify climates in various geographic areas of the

United States according to the deteriorating effect

exhibited by the factors in those climates on building

components and materials.

c. Develop a scheme by which the environmental factors of

importance for specific building components and materials

may be incorporated into durability test procedures.

d. Determine the best technique of accelerating the aging

effect of specific environmental factors.

2. EVALUATIVE TECHNIQUES AND ACCELERATED AGING PROCEDURES

a. Evaluate existing non-destructive evaluative techniques

such as pulsed acoustic energy testing, resonance testing,

acoustic emission and scanning electron microscopy to

determine if these techniques can be applied to the durability testing of building components and materials.

47
b. Evaluate existing procedures of accelerated aging and develop

new procedures as needed which:

1) Incorporate environmental factors of importance and

2) Yield meaningful results which can be related

quantitatively to durability in the actual application

of the building component or material.

c. Determine the feasibility and necessity of quantitatively

measuring environmental factors which are used in the

accelerated aging procedure.

d. Determine the physical and chemical properties most useful

as indicators of deterioration for specific building components and materials.

OUTDOOR (NATURAL) AGING

a. Select test sites for outdoor exposure which are representative of the various climatological divisions defined

previous ly

.

b. Determine which environmental factors should be measured

during the exposure and how such measured values can best

be utilized in the durability testing of building components

and materials.

CORRELATING ACCELERATED AND NATURAL AGING

a. Correlate on a quantitative basis the results of accelerated

test procedures and the results of natural aging.

48
TEST SPECIMEN SIZE

a. Determine the relationship between

1) The results of accelerated aging tests of specific

materials ana the natural aging of the material in

conjunction with other materials (a component)

.

2) The results of accelerated aging tests of small

laboratory size components and the natural aging

of full size components.

PERFORMANCE CRITERIA

a. Develop performance criteria by which the results of existing and newly developed durability test procedures can be

evaluated

.

GENERAL METHODOLOGY FOR DURABILITY TESTING

a. A research effort is needed to devise a methodology for

predicting durability which will be of general application

to building components and materials.

b. The research effort should reflect the content of

recommendations 1 through 6 listed above and should

utilize a specific housing component and/or group of

materials to demonstrate the use of the general methodology.

49
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"~

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53
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54
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APPENDIX

Accelerated aging and durability test procedures and evaluative

techniques are included in the following:

(1) Published standards

(a) Issued by standards-making organizations such as the

American Society for Testing and Materials (ASTM) , American

National Standards Institute (ANSI), and the International

Standards Organization (ISO).

(b) United States Government standards, such as Federal and

Military Specifications.

(c) State standards, as those issued by the State University

of New York.

(d) Standards issued by foreign governments and other bodies

outside the United States.

(2) Industrial practice, as discussed elsewhere in this report

(3) Research on test methods

(a) Published proposed test methods

(b) Published research on test methods or on the deterioration

of materials and building components

(d) Information on current research, as discussed elsewhere in

this report

.

The most comprehensive and best organized body of standard test

methods is to be found in the Annual ASTM Standards and many other standards are based on these. Some of the ASTM Standards are test methods,

some are procedures for exposure of specimens, and some are specifications

for materials or components. The Standards are developed by technical

committees from industry, government, universities, and consumer organizations. The set of Annual ASTM Standards is a very good summary of the

state-of-the-art of test methods, covering durability, performance, and

quality control. The 1971 Annual ASTM Standards consists of 33 parts,
each a separate volume, of which Part 33 is the Index. The Index does not

cover detail on durability tests such that the investigator can readily

ascertain the state-of-the-art of durability testing. Therefore, we have

prepared a set of five tables to complete our report on the state-of-theart. The tables are as follows:

I Outdoor Weathering Methods in ASTM Standards (1971)

II Accelerated Aging and Weathering Methods in ASTM Standards (1971)

III Summary of Exposure Conditions and Procedures in ASTM Standards

for Outdoor Weathering Methods (1971)

IV Summary of Exposure Conditions and Procedures in ASTM Standards

for Accelerated Weathering Methods

V Criteria for Outdoor and Accelerated Weathering Methods and

Evaluative Techniques in ASTM Standards (1971)

Methods listed are from the 1971 ASTM Standards. Where 1972 Standards

were available, any necessary corrections were made from the later edition.

Table I, Outdoor Weathering Methods in ASTM Standards (1971), consists

of three parts. Part A contains a listing of ASTM Standard Methods for

outdoor weathering in numerical order, cites the part number of the ASTM

Standard in which the method is found, and identifies the specific

material covered by the method. Part B lists all outdoor weathering

methods according to the type of material covered by the method. Following the number of the Standard Method, the ASTM part number is indicated

in parentheses. Part C lists all outdoor weathering methods according

to subject matter, classified as:

1) Atmospheres, Definitions

2) Climatological data, instrumentation

3) Exposure type
4) Positioning and Mounting of specimens

5) Rack, fence, exposure cabinet design

Table II, Accelerated Aging and Weathering Methods in ASTM

Standards (1971), also contains three parts. Part A contains a numerical

listing of ASTM Standard Methods for accelerated aging, cites the part

number of the ASTM Standard in which the method is found, and identifies

the specific materials covered by the method. Part B lists all accelerated

aging methods according to the type of material covered by the method.

Following the number of the Standard Method, the ASTM part number is

indicated in parentheses. Part C lists all accelerated aging methods

according to type of exposure.

Table III, Summary of Exposure Conditions and Procedures in ASTM

Standards for Outdoor Weathering Methods (1971), contains the test method

number, ASTM part number, test title, and a description of exposure

details for ASTM test methods for outdoor weathering.

Table IV, Summary of Exposure Conditions and Procedures in ASTM

Standards for Accelerated Weathering Methods, contains the test method

number, ASTM part number, test title, and a description of exposure

details for ASTM test methods for accelerated aging.

Table V is a list of criteria used in ASTM Standards to determine

the effects of outdoor or accelerated weathering, methods used to measure

these effects, and evaluative techniques used in ASTM Standards. The

criteria are listed under ASTM Standards, arranged in order. Evaluative

techniques include predictive tests not involving outdoor exposure or

accelerated aging.
In using the tables, it should be borne in mind that ASTM Standards

(1) are mainly but not entirely for test methods. Some Standards

cover specifications for materials and components.

(2) do not always cover complete test methods. Some Standards

cover procedures for outdoor exposure or accelerated aging.

Other Standards cover criteria and evaluative techniques for

changes following exposure. These evaluative techniques may

consist of visual or microscopic examination. Most techniques

involve physical testing and some involve chemical tests.

It is also important to know that most test methods for durability

consist of three steps:

(1) Exposure (outdoor or accelerated)

(2) Identify properties which indicate a change

(3) Tests to evaluate these properties

However, some tests predict durability by non-destructive methods for

detecting or measuring flaws which might cause failure. Other tests predict durability after short periods of exposure by detecting or measuring

incipient changes which precede failure.

The following information is available from the tables:

Outdoor exposure conditions and methods Table I

Detail on the same Table III

Accelerated aging, exposure conditions and methods.. Table ]jl

Detail on the same Table IV

Criteria and evaluative techniques (tests) for

specimens after exposure (outdoor or accelerated)... Table V

Index of outdoor exposure methods Table I

A-4
Index of accelerated aging methods f Table II

Building components and materials covered by

ASTM Standards

for outdoor weathering Table I

for accelerated aging Talbe II

A5
Table I OUTDOOR WEATHERING METHODS IN ASTM STANDARDS (1971)

PART A - Listing in Numerical Order

TEST NUMBER (ASTM PART NUMBER) (BUILDING MATERIAL)

B 537 (7) (chromium plated steel and zinc die castings)

C 62 (12) (brick)

C 216(12) (brick)

C 488(14) (finishes for thermal insulation)

D 518(28) (soft rubber)

D 904(16) (adhesives)

D 1006(21) (organic coatings on wood)

D 1014(21) (organic coatings on steel)

D 1435(27) (plastics)

D 1641(21) (varnishes)

D 1654(21) (organic coatings on steel)

D 1828(16) (adhesive bonded joints and structures)

D 2830(20)

(21) (organic coatings on wood)

D 2918(16) (adhesive joints)

D 2919(16) (adhesive joints)

G 7 (30) (nonmetallic materials)

G 11 (21)

(30) (pipeline coatings)

G 24 (24)

(30) (various materials)

A6
Table I (continued)

PART B - Listed by Building Material

BUILDING MATERIAL: TEST NUMBER (ASTM PART NUMBER)

Adhesives: D 904 (16)

Adhesive bonded joints and structures: D 1828 (16), D 2918 (16),

D 2919 (16)

Brick: C 62 (12), C 216 (12)

Chromium plated steel: B 537 (7)

Nonmetallic materials: G 7 (30)

Organic coatings: C 488 (14), D 1006 (21), D 1014 (21), D 1641 (21),

D 1654 (21), D 2830 (20,21), G 11 (21,30)

on metal: D 1014 (21), D 1654 (21), G 11 (21,30)

on pipelines: G 11 (21, 30)

on thermal insulation: C 488 (14)

on wood: D 1006 (21), D 2830 (20, 21)

Varnishes: D 1654 (21)

Plastics: D 1435 (27)

Rubber: D 518 (28)

Various materials: G 24 (24,30)

Varnishes: See Organic coatings.

Zinc based die castings: B 537 (7)
Table I (continued)

PART C - Listed by Subject Matter

Atmospheres, Definitions

C 62

C 216 Areas in the United States defined by Weathering Index

(See Climatological data, instrumentation).

D 1435 As defined by National Oceanic and Atmospheric Administration (NOAA)

D 1828 Rural- pure (ASTM site: State College, Pennsylvania)

Industrial-sulfurous gases present (Pittsburgh, Pennsylvania)

Marine- seacoast where chlorides are deposited on specimens

(Kure Beach, North Carolina)

Tropical or southern Florida under conditions of heat and

high humidity (Freeport , Texas)

(S 7 Tropical or subtropical, inland

Tropical or subtropical, salt atmosphere

Temperature, inland

Temperature, salt atmosphere

Desert

Arctic or subarctic

Industrial, low pH

Industrial, high pH

Industrial, N0

2

, SC> 2

, or (> 3

(Definitions of above are under study by ASTM Committee G-3).

A8
Table I, Part C (continued)

Climatological data, instrumentation

C 62

C 216 Areas in the United States defined and indicated in a map

according to Weathering Index, which is, for any locality, the

product of average annual number of freezing cycle days and

average annual winter rainfall in inches. Areas in the map

include those with:

Severe index, over 500

Moderate index, 100 - 500

Negligible, less than 100

D 1435 Report shall include:

Sunlight energy data if available, as integrated incident

2 expressed in langleys (g-cal/cm )

Description of climate and summary of data at site from NOAA

Rainfall

Percentage of possible sunshine

Temperature average and extremes

Humidity average and extremes

D 1828 Report shall include:

Average monthly relative humidity

Average monthly temperature

Total monthly rainfall

Average daily solar radiation, if available

Total solar radiation on specimens, if available

.Air pollution data, if available

References to instrumentation which meets NOAA requirements

A9
Table I, Part C (continued)

G 7 Report shall include:

Daily maximum, minimum, mean temperatures

Daily maximum, minimum, mean percent relative humidities

Daily hours of rain and dew (wetness)

Daily total inches of rainfall

Daily irradiation: total langleys, spectral langleys (wavelength band specified), ultraviolet sun-hours (solar

2 irradiation above an intensity of 0.823 cal/cm min.)

1 langley = 1 g-cal/cm2 = 11.62 W/m2 m 41,840 J/m2

G 24 Report shall include;

Date and location, including approximate latitude

Maximum, minimum, mean daily air temperatures and relative humidity,

humidities

Exposure type

Direct (to all prevailing atmospheric conditions): B 537, C 488,

D 518, D 1006, D 1014, D 1435, D 1641, D 1828, D 2830, G 11

Window (in cabinet under glass) : G 24

Sunlight Exposure Method : Specimens exposed in glass-covered

cabinet between 9:00 a.m. and 3:00 p.m. (standard time) on

clear, sunny days. At all other times, specimens are removed

from the cabinet and stored in a dark and dry storage area

at normal room temperature.

Daylight Exposure Method : Same as for Sunlight Exposure Method

except that the specimens are left in the exposure cabinet

continuously 24 hrs. a day and are removed only for inspection.

A- 10
Table I, Part C (continued)

Window (under glass, not in cabinet): D 904

Direct or Window : G 7

Positioning and mounting of specimens

C 488 45 degrees from horizontal, facing south

D 518 45 degrees facing south

D 904 45 degrees facing south

D 1006 Vertically facing both south and north on test fences. If dust

collection and mildew resistance are nof pertinent, north

vertical exposure may be eliminated.

D 1014 45 degrees facing south

45 degrees facing north

Vertical facing south

Vertical facing north

D 1435 45 degrees facing equator

90 degrees facing equator

Horizontal

D 1641 45 degrees facing south

D 1828 45 degrees facing south

D 2830 90 degrees on test fences as in D 1006

G 7 Most common: 45 degrees from horizontal facing equator

Others

:

Vertical facing south and north

Horizontal

Angle from horizontal equal to latitude of location in

degrees, facing equator

Normal service position

A-ll
Table I, Part C (continued)

Angle of 30 degrees from horizontal, facing equator

Angle of 5 degrees from horizontal, facing equator

G 11 Horizontal

G 24 Angle from horizontal equal to approximate latitude of location

in degrees, facing equator.

Rack, fence, exposure cabinet design

Exposure cabinet : G 24

Racks ; D 1435, D 1828, G 7, G 11

Test fences, racks ; D 1006

A- 12
Table II ACCELERATED AGING AND WEATHERING

METHODS IN ASTM STANDARDS (1971)

PART A t Listed in Numerical Order

TEST (ASTM PART NUMBER) (BUILDING MATERIAL)

B 117 (7, 21, 31) (metals, coatings on metals)

B 287 (7, 21, 31) (metals, coatings on metals)

B 368 (7, 21) (chromium alloy plate on steel and zinc base die castings)

C 62 (12) (brick)

C 67 (12) (brick)

C 88 (10) (concrete aggregates)

C 216 (12) (brick)

C 217 (12) (natural slate)

C 481 (16) (sandwich constructions)

C 510 (14) (joint sealants)

C 666 (10) (concrete)

C 669 (14) (sealants used in back bedding and face glazing)

C 671 (10) (concrete)

C 682 (10) (concrete aggregates)

D 518 (28) (soft rubber)

D 529 (11) (bituminous materials)

D 545 (10, 11) (preformed expansion joint fillers for concrete)

D 750 (28) (vulcanized rubber)

D 756 (27) (plastics)

D 822 (21) (organic coatings)

D 904 (16) (adhesives)

D 1037 (16) (wood based hardboard, particleboard)

D 1101 (16) (adhesive joints in structural laminated wood)

A- 13
Table II, Part A (continued)

D 1148 (28) (vulcanized rubber)

D 1149 (28) (vulcanized rubber)

D 1151 (16) (adhesive bonds)

D 1167 (11, 21) (asphalt emulsion coatings on built-up roofs)

D 1183 (16) (adhesives)

D 1499 (27) (plastics)

D 1501 (27) (plastics)

D 1565 (28) (vinyl foam)

D 1654 (21) (organic coatings on metal)

D 1735 (21) (organic coatings)

D 1754 (11) (asphalt)

D 1870 (27, 28) (polymers)

D 2126 (28) (rigid cellular plastics)

D 2246 (21) (coated metal)

D 2247 (21) (coated metal)

D 2248 (21) (organic coatings)

D 2249 (14, 21) (sealants used in glazing and bedding)

D 2366 (21) (exterior house paints on wood)

D 2445 (26) (propylene plastics)

D 2559 (16) (adhesives)

D 2565 (27) (plastics)

D 2803 (21) (organic coatings on metal)

D 2831 (20, 21) (latex paints on masonry and asbestos-cement shingles)

D 2898 (16) ( fire-retardant treatment of wood)

D 2918 (16) (adhesive joints)

A- 14
Table II, Part A (continued)

D 2919 (16) (adhesive joints)

G 23 (24, 27, 30) (nonmetallic materials)

G 25 (24, 30) (nonmetallic materials)

G 26 (30) (nonmetallic materials)

G 27 (30) (nonmetallic materials)

PART B - Listed by Building Material

BUILDING MATERIAL: TEST NUMBER (ASTM PART NUMBER)

Adhesives: D 904 (16), D 1183 (16), D 2559 (16)

Adhesive bonded joints and structures: D 1101 (16), D 1151 (16),

D 2918 (16), D 2919 (16)

Asphalt: D 1754 (11)

Asphalt emulsion coatings on built-up roofs: D 1167 (11, 21)

Bituminous materials: D 529 (11)

Brick: C 62 (12), C 216 (12)

Chromium alloy plate on steel: B 368 (7, 21)

Concrete: C 666 (10), C 671 (10)

Concrete aggregates: C 88 (10), C 682 (10)

Concrete expansion joint fillers: See Preformed expansion joint

fillers for concrete

Fire-retardant treatment of wood: D 2898 (16)

Hardboard : See Wood based hardboard and particle board

Joint sealants: C 510 (14)

Natural slate: C 217 (12)

Nonmetallic materials: G 23 (24, 27, 30), G 25 (24, 30), G 26 (30),

G 27 (30)

A- 15
Table II, Part B (continued)

Organic coatings: B 117 (7, 21, 31), B 287 (7, 21, 32), D 822 (21),

D 1654 (21), D 1735 (21), D 2246 (21), D 2247 (21), D 2248 (21),

D 2366 (21), D 2803 (21), D 2831 (20,21)

on asbestos- cement shingles: D 2831 (20, 21)

on metal: B 117 (7, 21, 31), B 287 (7, 21, 31), D 1654 (21),

D 2246 (21), D 2247 (21), D 2803 (21)

on wood: D 2366 (21)

Part icleboard : See Wood based hardboard and particleboard

.

Plastics: D 756 (27), D 1499 (27), D 1501 (27), D 2126 (26), D 2445 (26),

D 2565 (27). See Polymers.

Polymers: D 1870 (27, 28). See Plastics.

Preformed expansion joint fillers for concrete: D 545 (10, 11)

Rubber: D 518 (28), D 750 (28), D 1148 (28), D 1149 (28)

Sandwich constructions: C 481 (16)

Sealants: See Joint sealants.

Sealants used in glazing and bedding: C 669 (14), D 2249 (14, 21)

Slate, natural: See Natural slate.

Vinyl foam: D 1565 (28)

Wood: See Fire-retardant treatment of wood.

Wood based hardboard and particleboard: D 1037 (16)

Zinc based die castings: B 368 (7, 21)

A- 16
Table II (continued

PART C - Listed by Type of Exposure

Light exposure apparatus

Carbon-arc type : G 25, D 904

Xenon-arc type : G 27

Light and water exposure apparatus

Carbon-arc type ; C 510, C 669, D 529, D 750, D 822, D 1499,

D 2249, G 23

Xenon-arc type : D 2565, G 26

Fog chamber : D 1735

Humidity chamber : D 2247

Humidity chamber and cold box - cycling : D 2246

Salt-spray cabinets : B 117, B 287, B 368, D 2803

Various exposure conditions : C 62, C 67, C 88, C 216, C 217, C 481,

C 510, C 666, C 669, C 671, C 682, D 518,

D 545, D 756, D 1037, D 1101, D 1148,

D 1149, D 1151, D 1167, D 1183, D 1501,

D 1565, D 1654, D 1754, D 1870, D 2126,

D 2248, D 2366, D 2445, D 2559, D 2803,

i D 2831, D 2898, D 2918, D 2919

A- 17
Table III SUMMARY OF EXPOSURE CONDITIONS AND PROCEDURES IN ASTM

STANDARDS FOR OUTDOOR WEATHERING METHODS (1971)

The following ASTM Standards are included in this table: B 537,

C 216, C 488, D 1006, D 1014, D 1435, D 1641, D 1828, D 2830,

G 7, G 11, and G 24.

TEST NUMBER (ASTM PART NUMBER) TEST TITLE AND EXPOSURE DETAILS

B 537 (7) Standard Recommended Practice for Rating of Electroplated

Panels Subjected to Atmospheric Exposure

Direct exposure

C 216 (12) Standard Specifications for Facing Brick (Solid Masonry Units

Made from Clay or Shale)

C 488 (14) Standard Method for Conducting Exterior Exposure Tests of

Finishes for Thermal Insulation

Direct exposure. Specimens mounted 45 degrees from horizontal, facing south.

D 518 (28) Standard Method of Test for Surface Cracking Resistance of

Stretched Rubber Compounds

Direct exposure. Specimens mounted at 45 degrees facing south.

For accelerated weathering method, see Table V.

D 904 (16) Standard Recommended Practice for Determining the Effect of

Artificial (Carbon-Arc Type) and Natural Light on the

Permanence of Adhesives

Window exposure not in cabinet. Specimens mounted at 45

degrees, facing south, protected with transparent shield

which transmits solar radiation.

For accelerated weathering method, see Table V.

A- 18
Table III - continued

D 1006 (21) Recommended Practice for Conducting Exterior Exposure Tests

Paints on Wood

Direct exposure. Specimens mounted vertically facing both

south and north on test fences. If dust collection and

mildew resistance are not pertinent, north vertical exposure

may be eliminated. Descriptiqn of test fences and racks.

D 1014 (21) Standard Method of Conducting Exterior Exposure Tests of

Paints on Steel

Direct exposure.

Specimens may be mounted as follows:

45 degrees facing south

45 degrees facing north

Vertical facing south

Vertical facing north

D 1435 (27) Standard Recommended Practice fpr Outdoor Weathering of

Plastics

Direct exposure.

Specimens may be mounted as follows:

45 degrees facing equator

90 degrees facing equator

Horizontal

Description of racks.

D 1641 (21) Standard Method of Test for Exterior Durability of Varnishes

Direct exposure. Specimens mounted 45 degrees facing south.

A- 19
Table III - continued

D 1828 (16) Standard Recommended Practice for Atmospheric Exposure of

Adhesive-Bonded Joints and Structures

Direct exposure. Specimens mounted 45 degrees facing south

Description of racks

D 2830 (20,21) Standard Method of Test for Durability and Compatibility of

Factory- Primed Wood Products with Representative Finish Coats

Direct exposure.

90 degrees from horizontal on test fences as in D 1006

G 7 (30) Tentative Recommended Practice for Atmosphereic Environmental

Exposure Testing of Nonmetallic Materials

Direct or window exposure.

Specimens usually mounted 45 degrees to horizontal facing

equator. May also be mounted as follows:

Vertical facing south and north

Horizontal

Angle from horizontal equal to latitude of location in

degrees, facing equator

Normal service position

Angle of 30 degrees from horizontal, facing equator

Angle of 5 degrees from horizontal, facing equator

Description of racks

A-20
Table III - continued

G 11 (21, 30) Tentative Method of Test for Effects of Outdoor Weathering

on Pipeline Coatings

Direct Exposure.

Specimens mounted horizontally

Description of racks

G 24 (24, 30) Standard Recommended Practice for Conducting Natural Light

(Sunlight and Daylight) Exposures Under Glass

Window exposure

Angle from horizontal equal to approximate latitude of location

in degrees, facing equator

Description of exposure cabinet

A-21
Table IV SUMMARY OF EXPOSURE CONDITIONS AND PROCEDURES IN ASTM

STANDARDS FOR ACCELERATED WEATHERING METHODS

The following ASTM Standards are included in this table: B 117,

B 287, B 368, C 62, C 67, C 88, C 217, C 481, C 510, C 666, C 669,

C 671, C 682, D 518, D 529, D 545, D 750, D 756, D 822, D 904,

D 1037, D 1101, D 1148, D 1149, D 1151, D 1167, D 1183, D 1499,

D 1501, D 1565, D 1654, D 1735, D 1754, D 1870, D 2126, D 2246,

D 2247, D 2248, D 2249, D 2366, D 2445, D 2559, D 2565, D 2803,

D 2831, D 2898, D 2918, D 2919, G 23, G 25, G 26, and G 27.

TEST NUMBER (ASTM PART NUMBER) TEST TITLE AND EXPOSURE DETAILS

B 117 (7, 21, 31) Standard Method of Salt Spray (Fog) Testing

(for organic coatings on metal)

(Specimens mounted between 15 and 30 degrees from vertical, such

as to permit free settling of fog on surface; preferably parallel

to horizontal flow of fog.

Salt solution: 5 ± 1 parts by weight NaCl in 95 parts distilled

water; pH of salt solution shall be 6.5 to 7.2 when atomized

at 35°C (95°F)

.

Exposure zone of salt chamber at 35° (+1.1 or -1.7)°C.

Period as agreed on. Recommended periods 16, 24, 48, 96, 200,

240, 500, or 720 hours.

B 287 (7, 21, 31) Standard Method of Acetic Acid - Salt Spray (Fog) testing

(for organic coatings on metal)

Specimens as in B 117

Salt solution: 5±1 parts by weight NaCl in 95 parts distilled

water; pH of solution shall be adjusted with acetic acid to

3.1-3.3 as measured on a sample of the collected spray and

measured at 25°C (77°F) .

Temperature of exposure zone and periods of exposure as in B 117.

A-22
Table IV - continued

B 368 (7, 21) Standard Method of Test for Copper-Accelerated Acetic Acid -

Salt Spray (Fog) Testing (CASS Test)

(for chromium alloy plate on steel and zinc base die castings)

Specimens 15+2 degrees from vertical, preferably parallel to

horizontal flow of fog

Solution sprayed: 5 parts NaCl in 95 parts distilled water; 1 g

CuCl *2H 0 per 3.8 liters salt solution; pH of the solution shall

be adjusted with acetic acid to 3.1-3.3 as measured on a sample

of the collected spray and measured at 25°C (77°F)

.

Exposure zone of CASS Test Chamber at 47±1°C.

Recommended exposure periods: 6, 16, 22, 48, 96, 192, 240, 504,

or 720 hours.

Exposure zone of CASS Test Chamber at 49±1°C.

Recommended exposure periods: 6, 16, 22, 48, 96, 192, 240, 504 4

or 720 hours

C 62 (12) Standard Specifications for Building Brick (Solid Masonry

Units Made from Clay or Shale)

See C 67

C 67 (12) Standard Methods of Sampling and Testing Brick

Exposure to Freezing and Thawing:

Specimens are half bricks with approximately plane and parallel

ends. Specimens are dried, cooled, and weighed before and

after exposure.

A-23
Table IV - continued

1. Submerge specimens in thawing tank in water at 75±10°F.

(24±5.5°C) for 4 hours.

2. Stand specimens on edge in 1/2 inch of water in a pan and

place pan in freezing chamber (temperature not over 16°F

or -9°C) for 20 hours.

3. Remove from freezing chamber and immerse in thawing tank

as in Step 1 for 4 hours.

4. Repeat Steps 2 and 3 in succession five times.

5. Store in drying room at 75±15°F (24±8°C) for 40 hours.

6. Repeat Step 1.

7. Repeat Step 4.

Continue exposure for 50 cycles or until specimen is broken or

has lost more than 3 percent of its original weight.

C 217 (12) Standard Method of Test for Weather Resistance of Natural

Slate Specimens soaked for 7 days in 1 percent solution of sulfuric

acid, using fresh acid each day.

C 481 (16) Standard Method of Test for Laboratory Aging of Sandwich

Constructions

Description of two aging cycles:

Cycle A:

1. Totally immerse specimen horizontally in water at 49±2°C

(120±3°F) for 1 hour.

2. Spray with steam and water vapor at 93±3°C (200±5°F)

for 3 hours.

3. Store at -12±3°C (10±5°F) for 20 hours.

A- 24
Table IV - continued

4. Heat at 99±2°C (210±3°F) in dry air for 3 hours.

5. Repeat Step 2.

6. Heat in dry air at 99±2°C (210±30°F) for 18 hours.

Cycle B:

1. Totally immerse specimen horizontally in water at

49±3°C (120±5°F) for 1 hour.

2. Spray with hot water at 71±3°C ( 160+5 °F) for 3 hours.

3. Store at -40±3°C (-40±5°F) for 20 hours.

4. Heat in dry air at 71±3°C (160±5°F) for 3 hours.

5. Repeat Step 2.

6. Heat in dry air at 71±3°C (160±5°F) for 18 hours.

C 510 (14) Standard Method of Test for Staining and Color Change of Oneor Two-Part Joint Sealants

a) Expose for 100 hours in light and water exposure apparatus,

Type A, conforming to ASTM G 23. Specimen temperature

140±5°F (60±3°C). Water temperature 75±4°F (24±2.4°C).

b) Expose other samples at 73.4±20°F (23±1.1°C) and 50±10

percent relative humidity for 14 days. Immerse in distilled

water for 1 minute once a day (5 days per week)

.

C 666 (10) Standard Method of Test for Resistance of Concrete to

Rapid Freezing and Thawing

Prepare concrete specimens as in C 192 and store in saturated

lime water.

A- 25
Table IV - continued

Subject specimens to freezing and thawing cycles. Alternately

lower temperature from 40 to 0°F (4.4 to -17.8°C) in not less than

2 nor more than 4 hours. Continue for 300 cycles or until relative

dynamic modulus of elasticity reaches 60 percent of the initial

modulus, whichever occurs first, unless other limits are specified.

C 669 (14) Standard Specification for Glazing Compounds for Back

Bedding and Face Glazing of Metal Sash

Specimens prepared and exposed as in D 2249.

D 518 (28) Standard Method of Test for Surface Cracking Resistance

of Stretched Rubber Compounds

(for soft rubber)

Continuous exposure of rubber test specimens, held under stain,

to weather and sunlight at 45 degrees facing south or to airozone mixtures as in D 1149.

D 529 (11) Recommended Practice for Accelerated Weathering Test of

Bituminous Materials

(modification of G 23 with optional cold air exposure in Daily

Cycle B)

Daily Cycle A:

1. Light only (140±5°F) (60±3°C) black panel

temperature for 51 mins.

2. Light with spray (spray water 45±5°F or

7±3°C at nozzle) for 9 mins

.

Total, 22 periods 60 mins.

A- 26
Table IV - continued

Daily Cycle B:

1. Water spray only (70±5°F) (2l±3°C) for 1 hour

2. Light exposure only (140±5°F) (60±3°C) for 1 1/2 hours

3. Water spray only (70±5°F) (2l±3°C) for 2 hours

4. Light only (140±5°F) (60±3°C) for 16 1/2 hours

5. Cold (refrigerator) (0±10°F) (-18±6°C) for 1 3/4 hours

TOTAL 22 3/4 hours

D 545 (10, 11) Standard Methods of Testing Preformed Expansion Joint

Fillers for Concrete (Nonextruding and Resilient Types)

Cycle in Section 7 (Accelerated Weathering Test):

1. Expose 7 days at 165°F (74°C).

2. Immerse in water at room temperature for 24 hours.

3. Place specimens on edge in pan; immerse in water to depth

of 2 inches (50 mm) (1/2 height of specimens). Place in

freezing chamber at +14 to -4°F (-10 to -20°C) until

water is frozen to solid ice.

4. Partially immerse pan in water at 65-100°F (18-38°C)

until ice has melted entirely.

Repeat cycle 10 times.

Remove from water and allow to stand in air at room temperature

for 48 hours.

A-27
Table IV - continued

D 750 (28) Recommended Practice for Operating Light- and WaterExposure Apparatus (Carbon-Arc Type) for Artificial Weathering

Testing of Rubber Compounds.

(for vulcanized rubber) (modification of G 23)

Rubber specimens exposed either with or without elongation.

D 756 (27) Standard Methods of Test for Resistance of Plastics to

Accelerated Service Conditions

Seven test procedures which prescribe conditions for different

types of exposure: six cover exposure at graduated levels of

temperature and extremes of humidity; the seventh covers alternate exposure to high and low temperatures.

A- 28
Table IV - continued

Procedure Cycle or Exposure

A 24 hrs

.

at 60°C (140°F), 88 percent relative humidity

24 hrs

.

at 60°C (140°F) in oven

B 72 hrs

.

at 60°C (140°F) in oven

C 24 hrs

.

at 70°C (158°F), 70-75 percent relative humidity

24 hrs

.

at 70°C (158°F) in oven

D 24 hrs

.

at 80°C (176°F) over water

24 hrs

.

at 80°C (176°F) in oven

E 24 hrs

.

at 80°C (176°F), 70-75 percent relative humidity

24 hrs

.

at -40°C (-40°F) or -57°C (-20.6°F) as specified

24 hrs . at 80°C (176°F) in oven

24 hrs

.

at -40°C (-40°F) or -57°C (-70.6°F) as specified

F 24 hrs

.

at 38°C (100. 4°F), 100 percent relative humidity

24 hrs

.

at 60°C (140°F) in oven

G 24 hrs

.

at 49°C (120. 2°F), 100 percent relative humidity

24 hrs

.

at 49°C (120. 2°F) in oven

D 822 (21) Recommended Practice for Operating Light- and Water-Exposure

Apparatus (Carbon- Arc Type) for Testing Paint, Varnish, Lacquer,

and Related Products

(for organic coatings) (modification of G 23)

Exposure apparatus, as in G 23, specified in Table I for

various panel sizes.

Duration of exposure may be mutually agreed on or may be the

number of hours required to produce a mutually agreed on change

in the test specimens or in a standard sample.

A-29
Table IV - continued

D 904 (16) Standard Recommended Practice for Determining the Effect

of Artificial (Carbon-Arc Type) and Natural Light on the

Permanence of Adhesives (See Table IV for outdoor exposure).

Specimens exposed to carbon-arc, air temperature 35-50°C, for 10

hours or until significant change is observed. Specimens mounted

vertically or at an angle not over 30 degrees such that the light

from the arc has a normal incidence on the specimens.

D 1Q37 (16) Standard Methods of Evaluating the Properties of Wood-Based

Fiber and Particle Panel Materials

(for wood-based hardboard, particleboard)

Accelerated aging cycle, Sections 118-123:

1. Immerse in water at 120±3°F (49±2°C) for 1 hour

2. Spray with steam and water vapor at 200±5°F

(93±3°C) for 3 hours

3. Store at 10±5°F (-12±3°C) for 20 hours

4. Heat at 210±3°F (99±2°C) in dry air for 3 hours

5. Repeat Step 2 3 hours

6. Heat in dry air at 210±3°F (99±2°C) for 18 hours

TOTAL 48 hours

A- 30
Table IV - continued

D 1101 (16) Standard Method of Test for Integrity of Glue Joints

in Structural Laminated Wood Products for Exterior Use

1. Impregnate specimens with water in an autoclave by means

of two vacuum-pressure cycles (specimen immersed in water)

:

1.1 Vacuum applied 20-25 in. (508-635 mm) Hg

for 15 minutes

1.2 Pressure applied 150±5 psi (1034±34 kN/m2

) for 2 hours

Total time, 2 cycles, approximately 4 1/2 hours

2. Dry in circulating air oven at 80-85°F (27-29°C), 25-30

percent relative humidity, circulation at a rate of

500±50 ft. (150±15 m)/min 91 1/2 hours

Repeat Steps 1 and 2 for total of 8 days

D 1148 (28) Standard Method of Test for Discoloration of Vulcanized

Rubber: Organic Finish Coated or Light Colored

Exposure to ultraviolet light source: calibrated sunlamp in

test chamber.

D 1149 (28) Standard Method of Test for Accelerated Ozone Cracking

of Vulcanized Rubber

Specimens under tensile strain exposed to various air-ozone

mixtures in a chamber at various temperatures from ambient to

70°C (158°F)

D 1151 (16) Standard Method of Test for Effect of Moisture and Temperature on Adhesive Bonds

Test specimens preconditioned for 70 days at 50±2 percent relativ

humidity and 23±1°C (73 .4±1 . 8°F) , then subjected to designated

exposure conditions as in Table 1 for prescribed time.
Table IV - continued

Table 1. Standard Test Exposures (D 1151)

Test Exposure Temperature

Number deg. C. deg. F. Moisture Conditions

1 -57 -70 as conditioned

2 -34 -30 as conditioned

3 -34 -30 presoaked^

4 0 32 as conditioned

5 23 73.4 50 percent relative humidity

6 23 73.4 immersed in water

7 38 100 88 percent relative humidity

8 63 145 oven, uncontrolled humidity

9 63 145

c over water

10 63 145 immersed in water

11 70 158 oven, uncontrolled humidity

12 70 158

c over water

13 82 180 oven, uncontrolled humidity

14 82 180

c over water

15 100 212 oven, uncontrolled humidity

16 100 212 immersed in water

17 105 221 oven, uncontrolled humidity

18 149 300 oven, uncontrolled humidity

19 204 400 oven, uncontrolled humidity

20 260 500 oven, uncontrolled humidity

21 316 600 oven, uncontrolled humidity

see footnotes, next page

A-32
Table IV - continued

The tolerance for test temperature shall be ±1°C or ±1.8°F up to

82°C or 180°F and ±1 percent for temperatures above 82°C or 180°F.

Presoaking shall consist of submerging specimens in water and apply

ing vacuum at 50 cm (20 in) of mercury until weight equilibrium is

reached

.

The relative humidity will ordinarily be 95 to 100 percent.

Specimens are tested

(a) under conditions at which they are exposed;

(b) immediately after conditioning for 4 hrs. at 50±2

percent relative humidity and 23±1°C (73 .4±1 .8°F)

;

(c) immediately after conditioning for 7 days at 50±2

percent relative humidity and 23±1°C (73 .4±1 .8°F)

.

A- 33
D 1167 (11, 21) Standard Methods of Testing Asphalt-Base Emulsions for

Use as Protective Coatings for Built-Up Roofs

Heat Test , Section 12:

Dry asphalt coated steel panels in horizontal position for

48 hours at 70-80°F (2l-27°C), 50 percent relative humidity.

Heat in oven at 2l2±3°F (100±5°C) for 24 hours.

Water Resistance , Section 14:

Dry asphalt coated brass panels in forced draft air

circulating oven for 24 hours at 140±5°F (60±30°C)

.

Completely immerse panels in water in glass containers at

70-80°F (21-27°C) for 24 hours.

D 1183 Standard Methods of Test for Resistance of Adhesives to Cyclic

Laboratory Aging Conditions.

Cyclic exposure to high and low temperatures, high and low

relative humidities as defined in Table 1.

A- 34
Cycles

:

Table IV - continued

Table 1. Test Procedures

Procedure Name

Interior

Interior

Exterior

,

land and air

Exterior

Marine

Period

hrs .

24

24

72

48

48

48

8

64

48

48

8

64

48

48

8

64

Temperature

deg. C . deg. F ,

23±1.1

48.5±3

23+1.1

48.5±3

60±3

38.5±2

-18±2

38.5±2

71+3

23+1 a

-57±3

38.5±2

73.4±2

120±5

73.4±2

120±5

140±5

100±3.5

0±3.5

100±3.5

160±5

73.4±2

-70±5

100±3.5

71+3 160±5

23+1.1 73.4±2

-57±3 -70±5

23±1.1 73.4±2

Relative Humidity

percent

85 to 90

less than 25

85 to 90

less than 25

less than 25

85 to 90

about 100

85 to 90

less than 10

immersed in water

about 100

about 100

less than 10

immersed in substitute

ocean water

about 100

immersed in substitute

ocean water

A- 35
Table IV - continued

D 1499 (27) Standard Recommended Practice for Operating Light- and

Water-Exposure Apparatus (Carbon-Arc Type) for Exposure of

Plastics (modification of G 23)

Black panel temperature (spray off) 63±5°C (145±9°F) but lower

temperature may be used if specimens are temperature sensitive.

If water spray is not required, proceed as in G 25.

D 1501 (27) Standard Recommended Practice for Exposure of Plastics

to Fluorescent Sunlamp.

Definition of three exposure conditions for plastics:

Procedure A. Exposure to fluorescent sunlamp at ambient

temperature

Procedure B. Exposure to fluorescent sunlamp in heated air

at 50-60°C (131-140°F)

Procedure C. Exposure to fluorescent sunlamp at 55-60°C

(131-140°F) with interruptions for exposure in

fog chamber. Cycle as follows:

1. Fog chamber 2 hours

2. Heat and light as in Procedure B.... 2 hours

3. Fog chamber.. 2 hours

4. Heat and light as in Procedure B.... 18 hours

Total 24 hours

for total of 240 hours

Turntable and fog chamber recommended: Figures 3,

4, ASTM Recommended Practice D 795 (discontinued)

A- 36
Table IV - continued

D 1565 (28) Standard Specification for Flexible Foams Made from

Polymers or Copolymers of Vinyl Chloride

Air oven aging test, sections 22-27: Exposure of specimens in

forced-ventilation oven for 22 hours at 100°C (2l2°F)

D 1654 (21) Standard Method of Evaluation of Painted or Coated

Specimens Subjected to Corrosive Environments

Scribe the specimen with a special tool vertically, near the

center, penetrating the coating. For flat specimens, begin the

scribe at approximately 1/2 inch from one edge and continue to

1/2 inch from the opposite edge.

Expose the specimen as in B 117, B 287, D 1014, or by any other

method as mutually agreed.

Treat as in Method A or B:

Method A: Rinse with a gentle stream of water at 100±10°F

(38±5°C) and clean with an air blast as prescribed.

Method B: Rinse with a gentle stream of water at 100±10°F

(38±5°C) and scrape with a tool as prescribed.

D 1735 (21) Standard Method for Water Fog Testing of Organic Coatings

Specimens 15 degrees from vertical and parallel to horizontal

flow of fog. Exposure zone of fog chamber 100±2°F unless otherwise specified. Recommended exposure periods intervals of 24

hours to the total of 96, 192, 504, or 1008 hours.

D 1754 (11) Standard Method of Test for Effect of Heat and Air on

Asphaltic Materials (Thin-Film Oven Test)

Heating 1/8 inch film of asphlatic specimen in oven at 163°C

(325°F) for 5 hours.

A-37
Table IV - continued

D 1870 (27, 28) Standard Method of Test for Elevated Temperature

Aging Using a Tubular Oven

(for polymers)

Specimens heated at specified temperature in tubular oven and

changes in physical properties measured.

D 2126 (26) Standard Method of Test for Resistance of Rigid Cellular

Plastics to Simulated Service Conditions

Specimens conditioned and exposed to one of seven conditions of

temperature and relative humidity:

Procedure Temperature Relative Humidity

deg . C deg . F percent

A 23±1 73.4±1.8 50±2

B -29±3 -20.2±5.4

C 38±1 100.4+1.8 90 - 100

D 60±1 140±1.8 90 - 100

E 7011 158±1.8

F 7011 15811.8 90 - 100

G 10011 21211.8

A- 38
Table IV - continued

D 2246 (21) Standard Method for Testing Finishes on Primed Metallic

Substrates for Resistance to Humidity - Thermal Cycle Cracking

Specimens in rack 0 to 30 degrees from vertical

Cycle as follows:

1. Humidity cabinet, 100°F (38°C)

,

100 percent relative humidity 24±l/2 hours

2. Cold box, -10±3°F (-23±2°C) 20±l/2 hours

3. Room temperature , 4±l/2 hours

TOTAL 48 hours

Run for 15 cycles or as mutually agreed on.

D 2247 (21) Standard Method for Testing Coated Metal Specimens at

100 Percent Relative Humidity

Specimens placed in humidity chamber in such a way as to permit

condensation on surfaces. Temperature of saturated air 38±1°C

(100±2°F) . Test may be used as a continuous humidity test or

as part of a cycle.

D 2248 (21) Standard Method of Test for Detergent Resistance of

Organic Finishes

(for organic coatings)

Test for resistance to detergent of organic coatings on metal

panels by suspending the specimens vertically and immersing at

least half of the surface area in a standardized detergent

solution at 74±1°C (165±2°F), the solution being replaced every

168 hours. Period of test not prescribed.

A-39
Table IV - continued

D 2249 (14, 21) Standard Method of Predicting the Effect of Weathering

on Face Glazing and Bedding Compounds on Metal Sash

(for sealants used in glazing and bedding) (modification of G 23)

Specimens knifed and pressed into a special aluminum and glass

assembly to simulate face glazing and bedding.

One of the Units of Type D through G of G 23 used for exposure,

with addition of 102-18 cycling cam and black panel thermometer

accessories

.

Specimens exposed vertically with surface of sealant facing

light source, at black panel temperature of 60±3°C (140±5°F),

with 102-18 cycling cam.

Specimens examined after each 100 hour exposure to a maximum of

300 hours.

D 2366 (21) Standard Method for Accelerated Testing of Moisture

Blister Resistance of Exterior House Paints on Wood

Expose specimens in a blister box or cabinet containing water at

a specified temperature; air temperature 100±2°F (38±1°C), 95-100

percent relative humidity. Exterior air temperature 77±2°F

(25±1°C); relative humidity 50±5 percent.

D 2445 (26) Standard Method of Test fo - Thermal Oxidative Stability

of Propylene Plastics

Exposure time determined for pellets of plastic to become

embrittled in an oxygen atmosphere at 150°C (302°F)

A-40
Table IV - continued

D 2559 (16) Standard Specification for Adhesives for Structural

Laminated Wood Products for Use Under Exterior (Wet Use)

Exposure Conditions

Section 13:

Test for resistance to delaminat ion during accelerated exposure

1. Impregnate specimens with water in an autoclave by mean

of two vacuum- pressure cycles (specimen immersed in water)

1.1 Vacuum of at least 635 mm (25 in) Hg applied

for 5 min.

1.2 Pressure of 5.27±0.141 kg/cm2 (75±2 psi)

applied for 1 hour.

Total time, 2 cycles, approximately 2 1/6 hours

2. Dry in an oven at 65±2°C (150±3.6°F),

relative humidity 15 percent or less, for 21-22 hours

3. Subject specimens to steam at 100°C (212°F) for 1 1/2 hours

4. Add water, apply a pressure of 5.27±0.141

2 kg/cm (75±2 psi) for 40 mins

.

Repeat Steps 1 and 2; total test period 3 days

D 2565 (27) Standard Recommended Practice for Operating Xenon-Arc Type

(Water-Cooled) Light and Water-Exposure Apparatus for Exposure

of Plastics

(modification of G 26)

Water-cooled xenon-arc, Types A, AH, B, BH in G 26

Details on lamps, filters, operating procedures for equipment but

otherwise not on exposure conditions.

A-41
Table IV - continued

D 2803 (21) Standard Method of Test for Filiform Corrosion Resistance

of Organic Coatings on Metal

(Filiform corrosion is a special type which occurs under coatings

on metal and is characterized by a thread-like structure and

directional growth. This usually occurs between 21 and 35°C

(70-95°F) and 60 to 95 percent relative humidity.)

Test procedure ;

1. Scribe specimens as mutually agreed on. Recommended

procedure: D 1654.

2. Expose specimens in a salt-spray cabinet as in B 117

for at least 4 hours but not more than 24 hours.

3. Remove specimens from the cabinet and rinse thoroughly

with distilled or demineralized water.

4. Place the wet specimen in a humidity cabinet at 25±1.7°C

(77±3°F) and 85±2 percent relative humidity unless

otherwise specified.

5. Inspect the specimens at intervals of approximately 168 hours.

The normal test period is 6 weeks (1008 hours) but other

periods may be used as mutually agreed.

D 2831 (20, 21) Standard Method of Test for Evaluating the Ability of

a Latex Paint to Resist Efflorescence from the Substrate, Parts

20, 21.

Prepare test specimens from asbestos cement shingle blanks and

latex paint as prescribed.

A-42
Table IV - continued

Test procedure ;

1. Fill container with tap water so that the water level is

1 to 1 1/2 inch (2.5-3.5 cm) below the surface of the

panels when in place.

2. Regulate temperature of water to 40±3°C (104±5°F).

3. Place panels on pan over the water, painted side down,

and expose for 16-17 hours.

4. Turn panels over; dry 1-2 hours or more, flat, with

painted side up.

D 2898 (16) Tentative Methods of Test for Durability of Fire-Retardant

Treatment of Wood

Description of apparatus, test specimens, exposure cycles

(Methods A and B)

Method A (cycle)

:

1. Water spray at 35-60°F (2-16°C) 96 hours

2. Drying in moving air stream at

135 = 140°F (57-80°G) 72 hours

TOTAL 1 week

Method B (cycle) : Ultraviolet light from sunlamps is evenly

distributed over the specimen surface,

1. Water spray at not over 90°F (32°C) 4 hours

2. Drying at 150±5°F (63±3°C) 4 hours

3. Repeat water spray as in Step 1.. 4 hours

4. Repeat drying as in Step 2 4 hours

5 . Rest 8 hours

TOTAL 24 hours

Repeat for total of 1,000 hours

A-43
Table IV - continued

D 2918 (16) Standard Recommended Practice for Determining Durability

of Adhesive Joints Stressed in Peel

Clamp upper end of test panel to frame and attach desired weight

to lower end. Force on ahdesive should be a multiple of 450g

(1.0 lb). Suggested stress 25, 50, 75 percent of normal peel

strength as measured by D 1876.

Expose specimen to one of Standard Test Environments in Table 1.

Test at least 3 specimens under each set of conditions (test

environment and stress)

Table 1. Standard Test Environments

Test Environment , Number Temperature Moisture Conditions

1 23°C (73.4°F) immersed in distilled or deionized water

2 23°C (73.4°F) 50 percent relative humidity

3 23°C (73.4°F) 15 percent relative humidity

4 35°C (75°F) 90 percent relative humidity

5 35°C (95°F) 100 percent relative humidity

6 50°C (122°F) 90 percent relative humidity

7 50°C (122°F) 100 percent relative humidity

8 35°C (95°F) 5 percent salt fog

9 Ambient (outdoors) Ambient (outdoors)

10 Other (specify) Other (including aqueous

solutions or nonaqueous liquid

(specify)

a. The tolerance for the test temperature shall be ±1°C or ±1.8°F

for environments 1 to 8.

b. The moisture conditions may be provided by controlling the relative

humidity of a box, room, or other chamber by any convenient means.

A-44
Table IV - continued

D 2919 (16) Standard Recommended Practice for Determining Durability of

Adhesive Joints Stressed in Shear by Tension Loading.

Prepare lap- shear adhesive joints as in D 1002 except that the

dimensions shall be as in Figure 2, D 2919.

Test six specimens to destruction as in D 1002 at 23.0±1°C

(73.4±1.8°F) and 50±2 percent relative humidity.

Place at least six specimens in the fixture, Figure 1, D 2919,

and apply the desired stress by means of the springs and grip

bolts, not to exceed the initial failing stress.

Expose to one of the standard test environments as in Table 1

(same as Table 1, D 2918)

.

G 23 (24, 27, 30) Standard Recommended Practice for Operating Light- and

Water-Exposure Apparatus (Carbon-Arc Type) for Exposure of Nonmetallic Materials (formerly E 42)

Description of apparatus and operating procedures for carbon-arc

exposure apparatus without specifications for exposure conditions

except as noted.

Specimens generally mounted vertically but may be mounted

horizontally if vertical mount is impracticable.

Water strikes specimens as a fine spray, evenly distributed, at

a temperature of 15±5°C (60±90°F); pH of water 6.0-8.0.

Types of light and water exposure apparatus described (12): A,

AH, B, C, D, DH, E, EH, F, G, H, HH. Types AH, DH, EH, HH have

automatic humidity control. Types A, AH, D, DH, E, EH, H, and

HH have automatic temperature control.

A-45
Table IV - continued

G 25 (24, 30) Standard Recommended Practice for Operating Enclosed

Carbon-Arc Type Apparatus for Light Exposure of Nonmetallic

Materials

Description of apparatus and operating procedure for carbon-arc

light exposure apparatus without specifications for exposure

conditions except as noted.

Exposure intended to simulate G 24 Sunlight Exposure (Method A)

or Daylight Exposure (Method B)

.

Specimens mounted vertically unless vertical mount is impracticable.

Temperature measurement and control based on black panel

thermometer unit.

Two Types of exposure are described:

Method A. Continuous exposure to light and

Method B. Alternate exposure to light and darkness

In Method A, the relative humidity is adjusted to 30±5 percent at the

exit of air from the chamber, unless otherwise specified. Black

panel temperature is adjusted to 63±3°C (145±5°F). Controls are

adjusted so that 20 hours continuous operation produces 18±2

standard fading hours as determined by color standards. In Method

B, the relative humidity is adjusted to 35±5 percent during the

light-on period and to 90+5 percent during the light-off period.

Black panel temperature at equilibrium during the light-on peripd

shall be 63±3°C ( 145+5 °F)

.

Unless otherwise specified, controls shall be adjusted for a cycle

of 1 hour darkness and 3 hours light.

A-46
Table IV - continued

Apparatus is calibrated in terms of standard fading hours by

means of color standards.

G 26 (30) Standard Recommended Practice for Operating Light- and WaterExposure Apparatus (Xenon-Arc Type) for exposure of Nonmetallic

Materials

(formerly E 239)

Description of apparatus and operating procedures for xenon-arc

light and water exposure apparatus without specifications for

exposure conditions except as noted.

Specimens mounted vertically.

Temperature measurement and control based on black panel

thermometer unit.

Water strikes specimens as a fine spray, evenly distributed, at

a temperature of 60.8±9°F (16±5°C); pH of water 6.0-8.0

Types of light and water exposure apparatus described (6)

:

A, AH, B, BH, C, D

Types A, AH, B, BH are water-cooled.

Types C and D are air-cooled.

Types A, AH, C, D have automatic humidity control.

Types A, AH, B, BH, D have automatic temperature control.

All types have automatic cycle control.

A-47
Table IV - continued

G 27 (30) Standard Recommended Practice for Operating Xenon-Arc Type

Apparatus for Light Exposure of Nonmetallic Materials

Description of apparatus and operating procedure for xenon-arc

exposure apparatus without specification for exposure conditions

except as noted.

Exposure intended to simulate G 24 Sunlight Exposure (Method A)

or Daylight Exposure (Method B)

.

Specimens mounted vertically.

Temperature measurement and control based on black panel

thermometer unit

.

Apparatus may use water-cooled or air-cooled xenon-arc.

Type types of exposures (Methods A and B) are described as in

G 25 with the same conditions. However, the apparatus is not

calibrated in terms of standard fading hours but color standards

are used as references with test specimens.

A-48
Table V - CRITERIA FOR OUTDOOR AND ACCELERATED WEATHERING METHODS

AND EVALUATIVE TECHNIQUES IN ASTM STANDARDS (1971)

B 117 (7, 21, 31) (for organic coatings on metal)

Extent of corrosion

. . b Visual examination

B 287 (7, 21, 31) (for organic coatings on metal)

Extent of corrosion

. b Visual examination

B 368 (7, 21) (for chromium alloy plate on steel and zinc base die castin

cL Extent of corrosion

Visual examination

B 537 (7) (for chromium plated steel and zinc die castings)

£L Extent of corrosion

Visual examination with numerical rating :

"Protection number": Ability of coating to protect the substrate

from corrosion:

R = 3(2 - logA) , where

R = rating

A = percentage of total area covered by defects as

determined by comparison with "dot charts"

"Appearance number": Numerical rating based on degree to

which surface coating defects affect appearance, as

determined by comparison with reference photographs

See footnotes next page

A-49
Table V - continued

a. Criterion

b. Evaluative technique or test

c. Predictive test not based on exposure. In most cases, criteria for

durability are properties, changes in which are measured following

outdoor exposure or accelerated aging. In some cases, however, predictive tests are applied to components or materials without exposure.

C 62 (12) (for brick) (See also C 67)

a b Weathering Index and Map '

Compressive strength*

5

Dimensional tolerances3

. b Visual examination

C 67 (12) (for brick)

Loss of weight as percentage of original weight

Number of cycles causing breakage

Modulus of rupture (Flexure Test)

Compressive strength

Absorption

Five-hour boiling test

Initial rate of absorption (Suction)

Efflorescence

A-50
Table V - continued

C 88° (10) Standard Method of Test for Soundness of Aggregate by Use

of Sodium Sulfate or Magnesium Sulfate

(for concrete aggregates)

1. Immerse sieved specimens of aggregate (fine or coarse) in

special solutions of sodium or magnesium sulfate for 16-18

hours, so that the solution covers the specimens to a depth

of at least 1/2 inch, at 70±2°F (2l±l°C)

2. Drain specimens for 15±5 minutes.

3. Dry in an oven at 230±9°F (110±5°C) to constant weight.

Repeat immersion and drying for required number of cycles.

Quantitative examination: Loss of aggregate by breaking into fine

particles as determined by sieve test.

Qualitative examination: Number of particles coarser than 3/4 inch

showing "distress", such as disintegration, splitting, crumbling,

cracking, and flaking.

C 216 (12) See C 67

C 217 (12) (for natural slate)

Softening

Depth of softening determined by Shear/Scratch Tester or by

Hand Scraping Tool^.

C 481 (16) (for sandwich constructions)

Measurement of properties before and after aging:

Shear test, C 273

Compressive strength, C 364

Delamination strength, C 363

A-51
Table V - continued

Tension test, C 297

Flatwise flexure test, C 393

Climbing Drum Peel Test, D 1781

C 488 (14) (for finishes for thermal insulation)

Blistering, chalking, crazing, cracking, discoloration, flaking,

and shrinkage3.

Visual observation^

C 510 (14) (for joint sealants)

a b Change in color of sealant as compared with control specimen '

C 666 (10) (for concrete)

Durability Factor

3

, DF = PN/M, where

DF = durability factor of test specimen

P = relative dynamic modulus of elasticity at N cycles, percent

N = number of cycles at which P reaches the specified minimum

value for discontinuing the test or the specified number of

cycles at which the exposure is to be terminated, whichever

is less

M = specified number of cycles at which the exposure is to be

terminated

Relative dynamic modulus of elasticity, determined as in C 215 :

P = (n n 2 /n2

) x 100, where

c 1 P^ = relative dynamic modulus of elasticity after c cycles of

freezing and thawing, percent

n = fundamental transverse frequency at 0 cycles of freezing

and thawing

n-^ = fundamental transverse frequency after c cycles of freezing

and thawing
Table V - continued

C 669 (14) (for sealants used in back bedding and face glazing)

a b

Changes not greater than illustrated by photographs in D 2249 ' :

Surface cracking and peeling, No. 5, Plate No. 1; Deep-bead

cracking, No. 5, Plate No. 2; Loss of adhesion, Nos . 4,5,

Plate No. 3; Wrinkling, Nos. 4,5, Plate No. 4; Oil exudation,

No. 5, Plate No. 5.

C 671° (10) Tentative Method of Test for Critical Dilation of Concrete

Specimens Subjected to Freezing

Prepare concrete specimens as in C 192, fitted with gage studs as

in C 490, and position specimens in strain frame.

Test cycle: Cool specimens in water- saturated kerosene from 35 to

15°F (1.7 to -9.4°C) at the rate of 5±1°F (2.8±0.5°C), followed by

immediate return of the specimen? to the 35°F water bath, where they

shall remain until the next cycle. One test cycle shall be carried

out every 2 weeks. Test shall be continued until the critical

dilation is exceeded.

C 682 (10) Tentative Recommended Practice for Evaluation of Frost

Resistance of Coarse Aggregates in Air-Entrained Concrete by

Critical Dilation Procedures

Coarse aggregates are sampled, graded, and conditioned, and used

to prepare concrete specimens, fitted with gage studs 3s in

C 671 and moded as in Method C of C 192. Tests are conducted as

in Method C of C 6 71.

Mean value for test period of frost immunity or total test

period for which critical diluation does not occur.

Critical dilation is that during the last test cycle before

the dilation begins to increase sharply.

A-53
Table V - continued

Dilation is determined by measuring the vertical distance from a

straight- line projection of the prefreezing length - time

contraction curve (at constant cooling rate) and the maximum

deviation of the strain trace from it. The curves are obtained

from specimen length changes and cooling bath temperatures during

the cooling cycle.

D 518 (28) (for soft rubber)

3, Appearance of first minute surface cracks by visual observation,

using 7X magnification^5

a b

Percent elongation of tapered specimens '

D 529 (11) (for bituminous materials)

Visual examination of the samples compared with unexposed

i a ,b samples , or

Si Failure Endpoint as in D 1670: Number of cracks in film as

determined by high-voltage spark and counting grid*

5

.

D 545 (10, 11) (for preformed expansion joint fillers for concrete)

b a Visual examination for evidence of disintegration (Section 7).

D 750 (28) (for vulcanized rubber)

b a Visual examination for the degree and number of cracks and for

evidence of crazing

a b Tensile strength and ultimate elongation, D 412 '

(Specimen preparation for tests, D 15)

A-54
Table V - continued

D 756 (27) (for plastics)

Noticeable changes in surfaces, outline, general appearance

including changes in color, surface irregularities, odor, splits

as in D 883

a ' b

a b

Changes in weight and dimensions '

D 822 (21) (for organic coatings)

Visual examination for:

Blistering, D 714

a

Chalking, D 65

9

a

Checking, D 660

a

Cracking, D 661

Erosion, D 662

a

Flaking (Scaling), D 772a

Rusting, D 610

a

ab Change in color, E 308, D 2244

a b Change in reflectance, E 97 '

a b Change in specular gloss, D 523 '

D 904 (16) (for adhesives)

Visual change in appearance

3 '*5

a b Results of physical and chemical tests '

D 1006 (21) (for organic coatings on wood)

a b Recording on standard form as in D 1150 '

A-55
Table V - continued

D 1014 (21) (for organic coatings on steel)

Visual examination^ for

Blistering, D 714

a

Chalking, D 65

9

a

Rusting, D 610

a

D 1037 (16) (for wood-based hardboard, particleboard)

b a Visual inspection for de lamination or other disintegration

a b

Measurement of cupping and twisting '

Changes3 ' bin

Static bending

Lateral nail resistance

Nail withdrawal

Water absorption

Nail Head Pull-Through

D 1101 (16) (for adhesive joints in structural laminated wood)

a b

Percentage delamination ' = Length of open glue joint area

on end-grain surface x \qq

Total length of end-grain joints

D 1148 (28) (for vulcanized rubber)

Change in color or test specimen in relation to original sample

as expressed by numerical rating of degree of discoloration^

D 1149 (28) (for vulcanized rubber)

Cracking3

Time to first observed cracking, using 7X magnification, except

for triangular specimens of Method D 1171, where the magnification

shall be 2X

A-56
Table V - continued

D 1151 (16) (for adhesive bonds)

Various strength properties measured before and after exposure 3

Performance A = (A/C) x 100

a

Performance B = (B/C) x 100 , where

A = average strength after exposure

B = average strength after exposure

C = original strength after conditioning

D 1167 (11, 21) (for asphalt emulsion coatings on built-up roofs)

Heat Test \ Section 12:

Examine coating for sagging, slipping, blistering .

Record extent of sagging or slipping past reference line in

decimals of inch, and the presence or absence of blisters.

Water Resistance^, Section 14:

Examine for blistering and re-emulsification as evidenced

by asphalt particles in the water .

D 1183 (16) (for adhesives)

Change in appearance

3 '

a b Change in strength properties as ' :

Cleavage strength of bond, D 1062

Impact strength of bond, D 950

Peel or stripping strength of bond, D 903

Flexural strength of assemblies, D 1184

Shear by tension loading, D 906, D 1002

Tensile properties of bond, D 897

Tensile properties of cross- lap specimens, D 1344

A-57
Table V - continued

D 1435 (27) (for plastics)

Appearance Properties

COLOR

a

Color difference13

, D 1535, D 1729, D 2244, E 308

Yellowness , D 1925, E 313

GEOMETRIC DISTRIBUTION3

Gloss , D 523, D 2457

Haze

b

, D 1003

Transparency^ , D 1746

Electrical Properties

High-voltage, low-current arc resistance, D 495^

Dielectric breakdown, dielectric strength, D 149^

Mechanical Properties

Dimensional change, D 1042, D 1204^

Impact, D 256

Indentation hardness, D 785, D 2240

b

Stiffness, D 747

b

Tear resistance, D 1004, D 1938

Tensile and elongation properties, D 638, D 882, D 1708,

D 1923, D 2289

b

.

D 1499 (27) (for plastics)

Evaluation covered in ASTM methods or specifications for specific

materials

.

A-58
Table V - continued

D 1501 (27) (for plastics)

a b

Color change (none, slight, appreciable, extreme) '

b a Surface changes (as chalking , dulling) by visual observation

a b

Deep-seated changes (as checking, crazing, warping, discoloration) '

a b

Physical and chemical tests to determine extent of degradation '

D 1565 (28) (for vinyl foam)

Percentage change in indentation- load deflection or compressiona b

load deflection '

D 1641 (21) (for varnishes)

b a General appearance and visual observation or checking ,

cracking , discoloration , dulling , recoatability

D 1654 (21) (for organic coatings on metal)

Si EL 9i 8L Loss of adhesion , extent of blistering , corrosion , and rust

are evaluated by measuring the distance between the scribed

mark and the edge of the unaffected area of the finish . Numerical

ratings are based on these measurements.

Rating Schedule No. 1: Report maximum and minimum creepage from

the scribe and use numerical rating .

Rating Schedule No. 2: Rate by percentage failure as corrosion

spots, blisters. Recommend use of counting grid. Photographic

reference standards may be used as in D 610, D 714^.

D 1735 (21) (for organic coatings)

Si Visual observation

Blistering, D 714

Rusting, D 610

A-59
a ,b

Table V - continued

D 1754 (11) (for asphalt)

a b Reduction of penetration as in D 5

'

ci b

Loss of weight '

D 1828 (16) (for adhesive bonded joints and structures)

a b General appearance dimensions (including warpage) '

a,b Change in properties

D 1870 (27, 28) (for polymers)

a b

Change in physical properties in percent '

D 2126 (26) (for rigid cellular plastics)

Change in appearance

Percentage change in weight, dimensions, and other properties

D 2246 (21) (for coated metal)

a b Cracking by visual observation , using a grid, and counting

number of grid squares within which one or more cracks is visible.

D 2247 (21) (for coated metal)

Degradation of finish as observed visually*

5

:

Blistering, D 714

a

3. Corrosion, D 1654

Rusting, D 610

a

Loss of adhesion, D 2l97a ' b

a b

Change in Indentation Hardness, D 1474 '

a b Change in Specular Gloss, D 523 '

D 2248 (21) Not prescribed but the usual coatings tests are applicable

(D 523, D 610, D 714, D 1474, D 1654, D 2197, D 2248)

A-60
Table V - continued

D 2249 (14, 21) (for sealants used in glazing and bedding)

ci b 3. Visual estimation , using numerical scale , of loss of adhesion ,

surface cracking and peeling3

, deep bead cracking

3

, wrinkling3

,

and oil exudation .

P 2366 (21) (for exterior house paints on wood)

Evaluate degree of blistering and percentage of test area on

a b which blisters occur after 1, 2, 4, 7, and 14 days by D 714 .

Percentage of panel area on which blisters have formed may be

determined by means of a counting grid*

3

;

Area blistered, percent = Number of squares covering blisters x 100

Total number pf squares over

1 test area

D 2445 (26) (for propylene plastics)

ci Pellets tested for brittleness by lightly applying a light compressive force manually and observing whether they crush easily

to powder form . The specimen has failed if at least 8 of the

first 10 pellets tested are completely embrittled.

D 2559 (16) (for adhesives)

a b Section 13: De lamination on end-grain surfaces '

:

Percentage de lamination = Length of open glue joint area iqq

Total length of bond line

D 2565 (27) (for plastics)

a a,b Appearance

D 2803 (21) (for organic coatings on metal)

ci Note filiform corrosion as threads initiating at the scribe .

Description or photograph may be used for reporting .

A-61
Table V - continued

D 2830 (20, 21) (for organic coatings on wood)

b Si SL Si Visual examination for appearance , mildew , and film failure

a b

Test for adhesion between the primer and top coat ':

Cut a small X to penetrate the substrate slightly.

Apply cellophane tape to cross the X; press; remove quickly.

D 2831 (20, 21) (for latex paints on asbestos cement shingles)

b a Visual observation of efflorescence , rated as none, slight,

moderate, or severe

D 2898 (16) (for fire-retardant treatment of wood)

Fire tests as in E 84, E 286, D 108

a ' b

D 2918 (16) (for adhesive joints)

a b

Rate of peel of adhesive from joint '

Plot distance peeled versus time and divide the curve into six

equal parts. If the peel rate varies less than a factor of 2 over

all six parts of the curve, obtain the average peel rate (slope of

the curve) for the specimen. To assess durability, compare peel

rates under different levels of stress and environment and plot

log peel versus stress.

D 2919 (16) (for adhesive joints)

Maximum, minimum, average length of time to failure of stressed

a,b specimens exposed to environment

G 7 (30) (for nonmetallic materials)

One or more of the following may be pertinent:

a b

Appearance, electrical and mechanical properties, D 1435 '

Appearance, visual observation of checking, cracking, disco lora b ation, dulling, and recoatability , D 1641 '

A-62
Table V - continued

Visual observation^ of

Blistering, D 714

a

Chalking, D 659a

Checking, D 660

a

Color Change, G 24a

Cracking, D 661

Erosion, D 662

a

Flaking (scaling), D 772

&

Rusting, D 610a

Number of cracks in film as determined by high-voltage spark

and counting grid, D 1670^.

G 11 (21, 30) (for pipeline coatings)

b ci cl cl Visual observation of blistering , checking , cracking , a , . _ , .,a,b corrosion , undercutting from intentional scribe

G 23 (24, 27, 30)

Evaluation covered in ASTM methods or specifications for

specific materials.

G 24 (24, 36)

Evaluation covered in ASTM methods or specifications for specific

materials

.

G 25 (24, 30) (for nonmetallic materials)

Evaluation covered in ASTM methods or specification for specific

materials

.

A-63
Table V - continued

G 26 (30)

Evaluation covered in ASTM methods or specifications ' for specific

materials

.

G 27 (30)

Evaluation covered in ASTM methods or specifications for specific

materials

.

A-64
FCrtM NBS-114A (1-71) u

' dept. of comm. 1. PUBLICATION OR REPORT NO. 2. Gov't Accession

BIBLIOGRAPHIC DATA No* SHEET NBSIR 73-132

3. Recipient's Accession No.

4. TITLE AND SUBTITLE

State-of-the-Art Report on Durability Testing of Building

Pfimnnnpnf q and Mafpf*! ale

5. Publication Date

6. Performing Organization Code

7. author(s) Larry W. Masters, Winthrop C. Wolfe, Walter J.

Rossiter, Jr., and James R. Shaver

8. Performing Organization

NRSTR 73-132

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Proiect/Ta<;k/Work Unit Nn

4618490

11. Contract/Grant No.

12. Sponsoring Organization Name and Address

Department of Housing and Urban Development

451 7th St., S. W.

Washington, D. C. 204 10

13. Type of Report & Period

Coveted Interim Report for

FY 1973

1

t Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summaty of most significant information. If document includes a significant

bibliography or literature survey, mention it here.) This report is a summary of the present knowledge pertaining to durability

predictions for building components and materials which are subjected to the

effects of outdoor exposure. The various chapters of the report include

discussions of the nature of aging, the measurement of properties to predict

durability, non-destructive evaluation techniques, outdoor exposure techniques,

accelerated aging techniques, techniques for applying testing data to durability

predictions and difficulties which arise in predicting durability. Conclusions

and recommendations are also included.

An appendix, which summarizes ASTM Standards for durability testing of building

components and materials, is included.

i

17. KEY WORDS (Alphabetical order, separated by semicolons) Accelerated aging; aging of buildings;

building components; climate; criteria; deterioration; durability; materials;

mechanisms; non-destructive testing; testing.

18. AVAILABILITY STATEMENT 19. SECURITY CLASS 21. NO. OF PAGES

(THIS REPORT)

5<1 UNLIMITED.

UNCL ASSIFIED

1 1 FOR OFFICIAL DISTRIBUTION. DO NOT RELEASE 20. SECURITY CLASS 22. Price

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