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Q: Residual Stress in Glass Products ( Answered 4 out of 5 stars,   2 Comments )
Subject: Residual Stress in Glass Products
Category: Science
Asked by: yborice-ga
List Price: $200.00
Posted: 02 May 2006 10:25 PDT
Expires: 01 Jun 2006 10:25 PDT
Question ID: 724742
I know that residual stress is a property of glass that is reduced to
acceptable levels by annealing. What I don't know, but need to learn
is what maximum level of residual stress is considered in the industry
to be acceptable for unstressed glass containers used for consumer
products. I also need to know whether there is a published industry
'standard' that establishes  this maximimum safe, acceptable level

Request for Question Clarification by guillermo-ga on 02 May 2006 12:02 PDT
Hello yborice-ga,

I found where the standards are published, but also that they charge a
fee for them. However, the closest to your requirement that I found
there is the standard for glass to be used in laboratory paraphernalia
-- this one, for example, is charged $29 and is downloadable. Would
you accept this information as an answer? Please let me know. Thank


Clarification of Question by yborice-ga on 07 May 2006 13:07 PDT
Dear Guillermo-ga:


If the information you located is ASTM E671 - 98 (2004) Standard
Specifications for Maximum Permissible Thermal Residual Stress in
Annealed Glass Laboratory Apparatus, we already have this information.
 E671 relates solely to the residual stress found in laboratory
apparatus and fails to address what maximum level of residual stress
is considered in the industry to be acceptable for glass containers
used for consumer products.    Got anything like that?
Subject: Re: Residual Stress in Glass Products
Answered By: leapinglizard-ga on 07 May 2006 17:27 PDT
Rated:4 out of 5 stars
Dear yborice,

After a thorough search, I have located the proposed Israeli national
standards for residual stress in glass containers. These standards
ought to be representative of manufacturing norms in other highly
industrialized countries. I did not find any other national standards
published online. However, see further below for an ISO document that
you may find useful.

I should mention that the proposed Israeli standard cites the American
stress measurement standard ASTM C148-00, "Standard Test Methods for
Polariscopic Examination of Glass Containers".

    These test methods describe the determination of relative
    optical retardation associated with the state of anneal of
    glass containers.

ANSI webstore: Standard Test Methods for Polariscopic Examination of
Glass Containers - ASTM C148-00

As you may know, the temper of glass is a measure of the residual stress
after annealing, which is also referred to in the literature as residual
strain, thermal stress, and other such variations.

    Temper -- The degree of residual stress in annealed glass as
    measured using polarized light techniques.

SKS Bottle: Glass Glossary: Temper [page 8 of PDF document]

The proposed Israeli national standard uses the ASTM measuring methods
to derive a number called T_R, the Real Temper, and specifies that it
must not be higher than 4. The document includes, in section 2.4.2, a
table showing the relationship between the Apparent Temper, T_A, and the
analyzer rotation measurement obtained from polarimetric examination. In
section 2.4.1., T_R is obtained from T_A by the equation

  T_R  =  T_A * 4.06 / T

in which T is the thickness in millimeters of the container's side wall
at its base. Note that in the idiosyncratic English of the Israeli
document, residual strain is termed "remaining effort". I have made
several amendments to clarify the text.

    2.4 Remaining internal effort (temper number ^2)

        [Herein] are examined the internal pressures that remain
        in the container after the temper process, using one
        of the two methods described in the document of the
        American Society for Tests and Materials ASTM C 148,
        with the changes detailed hereunder:

        2.4.1 Polariscopic examination

            For T_A values up to [and including] 3[,] T_A = T_R

            For T_A values higher than 3 are calculated the
            T_R values according to the formula:

                T_R  =  (T_A * 4.06) / T


                [T] -- Thickness of the side wall measured
                [at] the base of the container (mm)

                T_R -- Real Temper [Number] ^2

                T_A -- Apparent Temper [Number] ^2

            The T_R values [shall] not be higher than 4.

    {^2 Temper Number: Number that expresses the remaining effort
    in the tempered glass}

        2.4.2 Polarimetric examination

            In the polarimetric examination are obtained
            values defined in the aforementioned document as
            analyzer rotation. These values are [translated]
            to T_A values as detailed in table 6 and [are
            used to calculate] the T_R -- Real Temper as
            detailed in paragraph 2.4.1 .

            The T_R values [shall] not be higher than 4.

            Table 6 -- Transition from analyzer rotation to
            apparent temper

            Analyzer rotation       Apparent temper [number] (T_A)
            -----------------       ------------------------------
            From 0.0 up to 7.2       1
            From 7.3 up to 14.5      2
            From 14.6 up to 21.7     3
            From 21.8 up to 29.0     4
            From 29.1 up to 36.2     5
            From 36.3 up to 43.4     6
            From 43.5 up to 50.7     7
            From 50.8 up to 57.9     8
            From 58.0 up to 65.1     9
            From 65.2 up to 72.4    10

European Commission: Enterprise and Industry: Glass containers for food
and beverages; Amendment No. 1; Israeli standard IS 172  [Word document]

I have furthermore located the ISO standard that I believe is most
pertinent to your situation. This standard is issued by TC 63, the
Technical Committee for Glass Containers, and is numbered ISO 9058:1992,
with the title "Glass containers -- Tolerances". I do not know whether the
prescribed manufacturing tolerances include a maximum residual stress,
but I bring this document to your attention in the hope that you will
have some use for it. If not, I trust the Israeli national standard will
suffice as a guideline.

International Organization for Standardization: ISO 9058:1992, Glass
containers -- Tolerances

International Organization for Standardization: Technical Committee TC
63, Glass containers

It has been an interesting challenge to answer your question. If you have
any concerns about the accuracy or completeness of my research, please
advise me through a Clarification Request and allow me the opportunity
to fully meet your needs before you rate this answer.



Search strategy:

glass container maximum stress

container annealing standard

glass residual strain maximum standard

glass bottle residual strain stress maximum standard

glass container mechanical performance standard 
yborice-ga rated this answer:4 out of 5 stars and gave an additional tip of: $50.00
Thanks for this information. It looks like there just are no standards
exactly on the money. Having an authoritative answer of 'none' is
almost as valuable as if there had been one to find. Thanks!

Subject: Re: Residual Stress in Glass Products
From: guillermo-ga on 08 May 2006 04:57 PDT
Hello Yborice-ga,

Yes, the information I had is exactly the one you mentioned and
already have, so it would not make a satisfactory answer -- thanks for
your reply.

Other researchers have been trying your question and gave it up. Even
Leapinglizard's answer shows that there is no US domestic standard
available for consumer products' containers, while offering the
Israeli's (a good idea, IMHO) and opening the possibility of an ISO's.
Hopefully, either that or the Israeli standard provided will be useful
for you. Good luck!


Subject: Re: Residual Stress in Glass Products
From: leapinglizard-ga on 10 May 2006 08:12 PDT
Thank you for the generous tip. It is much appreciated.


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