ISO 12775:1997 download free.Guidelines on types of glass of normal bulk-production composition and their test methods.
Various committees have been working for many years at national and international levels to produce agreed test methods for measuring the chemical and physical properties of glass as a material and glassware as finished articles, Because the international standardization part of the work has mostly been carried out under the aegis of the International Organization for Standardization, through its Technical Committee ISO/TC 48, Laboratory glassware and related apparatus, the aim of the work has always been slanted towards this type of ware. Even so, the test methods and classifications proposed to date are equally applicable to other kinds of glass and to glassware which is not necessarily used only for laboratory purposes.
It has been suggested that a collection of the information produced by the various committees would provide useful guidance to users and to manufacturers of glassware. ISO 12775 is, therefore, intended to give such guidance but it is strongly emphasized that a classification according to one test procedure is not necessarily related to classification by another test procedure.
Although not concerning normal bulk-production glass, Technical Committee ISO/TC 172, Optics and optical instruments, has established some International Standards for test procedures for optical glass, for example for acid resistance (ISO 8424) and for testing the resistance to attack by aqueous alkaline phosphate-containing detergent solutions (ISO 9689).
To make these guidelines complete, some test methods are also cited which do not have a classification (which is needed for most physical test methods) but that are sometimes of great interest for the glass user or glass manufacturer.
ISO 12775 establishes a survey of glass types and of methods for testing their chemical and physical properties to give, for example, consumers and producers of glass of normal bulk-production composition the possibility to compare the different types of glass and test methods and to decide which are of interest for a special demand or use. For this purpose, these comprehensive guidelines give a classification of the different glass types of normal bulk-production composition according to the chemical composition and indicate the different test methods and, where they exist, the classifications accordtng to chemical resistance.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of ISO 12775. At the time of publication, the editions indicated were valid. All standard are subject to revision, and parties to agreements based on ISO 12775 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of lEG and ISO maintain registers of currently valid International Standards.
ISO 695:1991, Glass — Resistance to attack by a boiling aqueous solution of mixed alkali — Method of test and classification.
ISO 718:1990, Laboratory glassware — Thermal shock and thermal shock endurance — Test methods.
ISO 719:1985. Glass — Hydrolytic resistance of glass grains at 98 °C — Method of test and classification.
ISO 720:1985, Glass — Hydrolytic resistance of glass grains at 121 °C — Method of test and classification.
Iso 1776:1985, Glass — Resistance to attack by hydrochloric acid at 100 °C — Flame emission or flame atomic absorption spectrometric method.
iSO 3585:1991, Borosilicate glass 3.3 — Properties.
ISO 48021:1988, Glassware — Hydrolytic resistance of the interior surfaces of glass containers — Part 1:
Determination by titration method and classification.
ISO 48022:1988, Glassware — Hydrolytic resistance of the interior surfaces of glass containers — Part 2:
Determination by flame spectrometry and classification.
ISO 4803:1978, Laboratory glassware — Borosilicate glass tubing.
150 7459:1984, Glass containers — Thermal shock resistance and thermal shock endurance — Test methods.
ISO 7991:1987, Glass — Determination of ccEfficient of mean linear thermal expansion.
3 Main types of glass of normal bulk-production composition
The main types of glass of normal bulk-production composition are classified in table 1.
NOTE — In many cases It is customary to divide glass Into different types according to the use or shape (laboratory glass, bottle glass, optical glass, flat glass, hollow glass) and in a general way this division is a kind of classification. Another possibility is a classification according to the chemical composition. This leads to the types listed in table 1, which of course cannot be absolutely pure concerning the composition ran9es.
4 ChemIcal properhes of glass and glass articles
4.1 General
The cheritical duribdity. o chen’ical resistance, of glass is a malarIal or of glass articles is the abilty of the exposed surfaces to withstand attack by acid, neutral or alkaline solutions. In general for silicate glasses this ibaty decreases wsh increasing alkalindy of the attacking medkm and test methods are available for measurIng these resistances.
4,2 Glass as a matenal and glass as-deliv.r.d
When properties of glass articles are considered. li mist be emphasized that tie surfac, of a finished glees article can have different properties than the glass *sed, caSed ‘glass as a umteflar. This glass as a material (I,.. the bulk glass) has, of course, the same propertie. as the glass of glass articles when their surface layers are reracved, for instance by grinding, or polishing, or acid etching with hydrolkiortc acid. But the properties of glen surfaces can be modified: for rietance, fire-polishing by pressing or blowing creates a sligiaty t*flerertt surface layer because of the avepofation of glass subetitueras at the glass.lomietg temperature. Also thu glass surface can be treated when the articles are finished: ion-exchange (salt melts, for Instance) can result na strengthening ehect or acid vapour (such as SOS) can reduce the alkali concentration in the surface of soda-lime glasses, and thus their surfaces show a better hydrolytic resistance; there are many other examples.
So when glass articles aie tasted, care shal be taken to define whether the surface is tested ‘as-debyared’ (.e. with the onginal surface layer) or ‘as a materiar, which is to b. achieved by acid etchdtg. gvwidlnolishlng or breaking. The qualitaties descriptions of the types of glass in table. 2 and 3 concern glass as a material ordy tables 4to6 concern non-treated gier’aiiElee except foe class IC 2 in ISO 4802 (in tables 4 and 5).
4.3 Test methods
4.31 HydrolytIc resistance (see ISO 719, ISO 720,1504802-1 and ISO 4802-2)
Grain tests, such as descrtied in ISO 719 and ISO 720, measure the resistance of glass as a rr*teriel to aback by neutral sokAlons (i.e waler) and this is caSed the ‘hydrolytic grien resistance’. These tests apply to glass as a malarial because the sample is broken and new bulk surfaces are produced.
The hydrolytIc resistance of ss containers is measured by a ‘whole article’ test in which the container is filled aSh water and the resistance of the ‘as-prockiced surface is measured
NOTE — The European Phaemaoopis uses the lithe type at lest to mews the pertonrisnor at containers and the lormw to iSslinguish tutw,an the resistances brcerted to glees by coropoelllon.l end surface treatment proceeees
Th. values ven in table 4 show the landing titration values reop Wed to neutralize 100 ml of extraction solution from venous capacities of containers, as given In ISO 4802.1.
NOTE — The values lot container dasees NC 1, 2 and 3 we Indeitcal to those pribueilied by the European Phemwcapla, wher, hey we caSed glass container tyPes. Swwe there ire trots container types, ISO 4802 Wudas also the container class MC B (a glees used eepeclaly toe ‘r,raliles’. L. drl*ing aropoules and h) end NC 0 (lot ‘dry substance.’),
Furthermore, a clasidicallon according to the direct delamination of th released alkali, different from the delenr.ination of the sum parameter of hydroxide lone by Ill ration (as doris by flame apectrom.tflC methods on the extract solution) is given In ISO 4602-2 (see table 5) A direct conversion from one system to ff4 other (tliratlon to flame-epectrometric values) is not dear nor eas5y achievable, but a corwersion factor between 2.5 and 3,0 wee proved by intertaboestory lest. to be true, so long as the values are near the limits between the container classes.
4.3.2 AcId resisfance (see ISO 1776)
The resistance 01 glass articles to attack by acid ,oklons (usually 6 molfi hydrochloric acid) can be measurd by the procedure described In ISO 1776. In thl procedure lh glass sample ‘S prepared in the fOrn of a piece, of 30 cm’ 1040cm’ surface ares. When the are. of the cut edges does not exceed 10% of thu total surfac. ares, the pieces can be regarded as tasted as’dellv.red. When the area of the edges Is greater then 10 %, the rest of the original surfaces shall be removed for the acid resistance lest in accordance with ISO 1776 by acid etching and then 1h test results rater to glass as a rneteflal. The etching procedure shall be applied whin thicker samples at
suites. audi as from glass plant. pipeline or tatings. are to be tested m accordance wtih ISO 1776
4.3.3 Alkali resistance (see ISO 696)
The resistance of glass articles to alkabw attack – measured m accordance with ISO 696. Pieces with surfaces of lOan’ to 15cm’ each (20 cm’ to 30cm’ Ii total) are submitted to attack by a bodang alkaline mixture, and the loss ii mesa Is determined. Because of the strength of the attack, distinction concerning the new cut edges is not necessary.
42.4 Othar chemical test methods
For optical glass, 11i test methods are specified in ISO 8424 (acId res4tanc., SP). In ISO 9689 (phosphate resistance, PR) and ISO 10629 (alkali resistance. AR). Since this type of glass is not of general Interest, International Standards for the teat methods are given lot lfllOrfT*llOfl only.
4.4 ClassificatIons of glass and glass articles according to their chemical properties
4.4.1 Prhcipt. of classWicatbns
In the classification tables wlech follow, the class nurr has an additional abbimnation to designate the type of
ISO lest procedrure. For instance, the grain teats can be dlsllngutsh.d by the class designations: ISO 719 by HG8
(hyd%f Ic resistance of glass grains raccor&g to the boding weter test method. at 96 ‘C) and ISO 720 by I4GA
(byd%lic resistance of Ø accordr-ig to the autoclave test method. at 121 ‘C). For th container test, the
designation of ISO 4802 is HC ()oIytic resistance onleiner class). The $ia9 resistance class is ISO 695. class A.
It ahouki be emphasized that because the test conditions are ddterent. class HGB 2 of ISO 719 is not the same as class HGA 2 of ISO 720. Furthermore, neither of them is ,elated to class HC 2 of ISO 4802. or class A2 of ISO 895, which is class 2 in the -]-•. resistance table
4.4.2 ClassificatIon table andl’or limit values
4.42.1 For the hydrolytic resistance of glass grains at 98 ‘C according to ISO 719, and at 121 ‘C according to ISO 720. see table 2 and tl 3. mejwly.