S.I. No. 390/1953:

STANDARD SPECIFICATION (WALLPAPER BASE) ORDER, 1953

STANDARD SPECIFICATION (WALLPAPER BASE) ORDER, 1953

I, SEAN F. LEMASS, Minister for Industry and Commerce, in exercise of the power conferred on me by subsection (3) of section 20 of the Industrial Research and Standards Act, 1946 (No. 25 of 1946), hereby order as follows :--

1. This Order may be cited as the Standard Specification (Wallpaper Base) Order, 1953.

2.--(1) The specification set forth in the Schedule to this Order is hereby declared to be the standard specification for Wallpaper Base.

(2) The said standard specification may be cited as Irish Standard 55 : 1953 or as I.S. 55 : 1953.

SCHEDULE

SCOPE

1. This specification covers the requirements of base paper for the manufacture of wallpaper.

DESCRIPTION

2. The wallpaper base shall be a comparatively high-bulking paper, designed to have good opacity and to be as non-curling as possible so that it will lie flat when paste or coating is applied. It shall be well sized to resist excessive moisture penetration. The surface, although of very low finish, shall be suitable for taking good impressions.

FURNISH

3. The wallpaper base shall contain not less than 20 per cent. unbleached sulphite fibre.

WIDTH

4. The wallpaper base shall be 22 in. or 20 in. in width subject to a tolerance of plus or minus 0·5 per cent. The measurements shall be made on paper, air-conditioned as described in Clause 15.

DIAMETER AND WEIGHT OF REELS

5. The reels of wallpaper base shall be hard-wound to a diameter of 28 in. to 30 in. and shall weigh from 2 ¾ to 3 cwt.

COLOUR, FREEDOM FROM DEFECTS, AND FINISH

6. The colour of wallpaper base shall be as agreed between the purchaser and the vendor. The colour and shade shall be uniform through-out.

The wallpaper base shall be free from cracks, creases, holes, and tears, and from objectionable specks and dirt. The reels shall be firmly wound and free from slack-edge, breaks and gum joints.

The surface shall be finished so as to be capable of taking good impressions and of retaining such impressions when coloured.

FORMATION

7. The distribution of the fibres and other solid components of the sheet shall be such that the sheet has a uniform appearance when viewed by transmitted light.

SUBSTANCE

8. The substance of wallpaper base, taken as the weight in ounces per roll of Long Elephant size (22 inches by 12 yards) shall be :

13, 16, 18, 20, 22, 24, 26, 28 or 32 oz.

The substance shall be subject to a tolerance of plus or minus 5 per cent.

The equivalent substances, expressed in pounds per ream of 500 sheets of Double Crown size (20 in. by 30 in.), and in grams per square metre, shall be taken as the values set out below :

13 oz. - 25·6 lb. D. C. 500s - 60 g. per sq. m.

16 " - 31·6 " " " " - 74 g. " " "

18 " - 35·5 " " " " - 83 g. " " "

20 " - 39·5 " " " " - 92 g. " " "

22 " - 43·4 " " " " - 102 g. " " "

24 " - 47·3 " " " " - 111 g. " " "

26 " - 51·3 " " " " - 120 g. " " "

28 " - 55·2 " " " " - 129 g. " " "

32 " - 63·1 " " " " - 148 g. " " "

The substance of wallpaper base shall be determined as described in Appendix A.

THICKNESS AND BULK

9. The thickness of wallpaper base, when determined as described in Appendix B, shall be not less than the values set out in Table 1 for the substance of the paper.

The bulk of wallpaper base shall be not less than 1·75.

Bulk is defined as the ratio of the volume of paper measured at 65 ± 2 per cent relative humidity and 20°C. ± 1±7°C. to the volume of an equal weight of water at 4°C. The bulk of wallpaper base shall be taken as 5·49 times the thickness of the paper in thousandths of an inch divided by the substance in ounces per roll Long Elephant. The equivalent value of the bulk when the substance is expressed in lb. D. C. 500s shall be taken as 10·84 times the thickness in thousandths of an inch divided by the substance.

TABLE 1

THICKNESS, BURSTING STRENGTH, AND ASH CONTENT

BURSTING STRENGTH

10. The bursting strength in pounds per square inch, when determined as described in Appendix C, shall be not less than the value set out for the substance of the paper in Table 1.

LOADING

11. The loading content of wallpaper base shall be such that the ash content, when determined as described in Appendix D, shall not exceed the value set out for the substance of the paper in Table 1.

SIZING

12. The sizing of wallpaper base shall be such that the water absorption of the paper, when determined as described in Appendix E, shall not exceed 30 grams per square metre.

MARKING

13. The wrappers of the reels of wallpaper base shall be clearly marked with the manufacturer's name or mark, the words " WALLPAPER BASE ", the substance, and the weight of the reel.

SAMPLING

14. For the purpose of testing conformity of wallpaper base with the requirements of this specification not less than 10 per cent. of the total number of reels comprising a lot of paper shall be sampled but in lots of over 60 reels 5 per cent. shall be sampled. The samples shall be taken at random so as to be representative of the lot.

Sample sheets shall be taken from the first unharmed layer of each reel. Test pieces shall be taken from these sample sheets and shall be not less than 10 in. by 10 in. in size.

Test pieces shall be so cut that their edges are exactly parallel to the machine and cross directions of the paper. They shall be kept flat, free from wrinkles or folds and shall be protected from exposure to liquids, direct sunlight or other harmful influences.

CONDITIONS FOR TESTING

15. Tests on wallpaper base shall be carried out in a room maintained at a temperature of 20°C. ± 1·7°C. and a relative humidity of 65 ± 2·0 per cent. Arrangements shall be provided for circulating the air in the room so that its temperature and relative humidity shall be uniform.

The wallpaper base to be tested shall be dried at a temperature of 55°C. to 60°C. over a saturated solution of calcium chloride and then suspended so that the atmosphere of the room has access to all the surface of the paper. Before testing, the paper shall be weighed at intervals of one half-hour until the weight is found to be constant.

The relative humidity of the atmosphere of the room shall be determined by means of wet-and-dry bulb thermometers placed in an air current having a velocity of at least three metres per second. The thermometers shall be graduated to the nearest 0·5°C. and shall be matched to within 0·25°C. throughout their range. They shall be compared with a certified thermometer before using and the necessary corrections applied.

APPENDIX A

Determination of Substance

Ten test pieces shall be tested. Each test piece shall be weighed either on a beam scales or on an automatic scales. The scales shall be sensitive to at least 0·25 per cent. of the load applied and shall be protected from air currents. If an automatic scales is used, it shall be checked before use both with increasing and decreasing loads made up of accurate weights.

The weight in oz. per roll, 22 in. wide and 12 yd. long shall be determined for each test piece and the average weight per roll of the ten test pieces shall be calculated to two places of decimals. This average weight shall be taken as the substance of the paper.

APPENDIX B

Determination of Thickness

The apparatus used for this test shall be a micrometer with an instrumental error not exceeding ± 0·0002 in. The apparatus shall contain two horizontal plain parallel circular faces, the lower face being fixed and the upper capable of moving in a direction perpendicular to the fixed face. The moveable face shall have an area of 0·25 ± 0·01 sq. in. and the fixed face shall have an area equal to or greater than that of the upper face. The faces shall be concentric and shall remain parallel to within 0·0001 in. when moved over the range of travel of the upper face. The upper face shall exert a downward pressure of 7·5 ± 0·5 lb. per sq. in. on a sheet of paper placed between the faces.

Ten test pieces shall be tested. Each test piece shall be inserted in the micrometer and its thickness measured to the nearest 0·0002 in. at five evenly spaced places, but in each case the faces of the micrometer shall not overhang the edge of the paper. The arithmetic mean of the fifty results to the nearest 0·0001 in. shall be taken as the thickness of the wallpaper base.

APPENDIX C

Determination of Bursting Strength

Twenty test pieces shall be tested.

The apparatus required for this test shall consist of an arrangement whereby pressure is applied by means of a rubber diaphragm to a circular area of paper. The periphery of the paper is held rigidly and the paper is allowed to bulge under the pressure until it bursts, the pressure at which it bursts being measured by a pressure gauge.

The diaphragm shall be such that it does not materially affect the bursting pressure. It shall be made of pure vulcanised rubber free from loading and shall be 0·4 mm. in thickness.

The surfaces of the clamps for clamping the test sample shall be parallel to each other and their apertures shall register when in contact. The diameter of the apertures shall be 1·2 in. ± 0·004 in. and the lower edge of the upper aperture shall be slightly radiused so that when bursting occurs the rupture is not peripheral due to shearing.

The diaphragm shall be arranged so that the portion of it which comes in contact with the test area of the paper is in the same plane as the upper surface of the lower clamping ring.

Either of two pressure gauges, reading from 0 to 50 lb. per sq. in. or from 0 to 150 lb. per sq. in., shall be used depending on the bursting strength of the paper. The pressure gauge shall be calibrated before use so that its readings are accurate to within ± 1 per cent. During calibration the pressure gauge shall be placed in a similar position to that in which it is fixed on the apparatus.

The application of pressure to the diaphragm shall be controlled so that the rate of increase of pressure is 10 lb. per sq. in. per second.

The test piece shall be clamped in position so that the full clamping area is utilised. The pressure of the clamps on the paper shall be firm enough to prevent slipping, but not so great as to damage the paper causing the burst to occur around the periphery of the test area. Slipping may be detected by the presence of creases after bursting and may be due either to insufficient clamping pressure or to non-uniform clamping pressure.

Immediately the paper has burst, the pressure indicated on the gauge shall be read and the instrument returned to the zero position.

Twenty test pieces shall be tested, half of them having the wire-side of the paper uppermost in the apparatus and the other half the top-side uppermost. If a reading differs by more than 25 per cent. from the mean or if the test sample shows creases due to slipping during testing, the reading shall be rejected and another sample tested. The arithmetic mean of the readings in lb. per sq. in. shall be calculated and shall be taken as the bursting strength of the paper.

APPENDIX D

Determination of Ash Content

The crucible used in this determination shall have a well-fitting lid, shall be of platinum, alundum, porcelain or silica, and shall not change in weight under the conditions of ignition used in the determination. An analytical balance and weights having an overall accuracy of 0·1 mg. shall be used. The furnace used in carrying out the ignition shall be operated at a temperature of 850°C. ± 50°C. An electric muffle furnace is preferable to a gas fired muffle but a gas burner may be used.

From a test piece of paper taken in accordance with Clause 14 and conditioned in accordance with Clause 15, small pieces shall be cut from various parts in such a way that the pieces are representative of the test piece. The total quantity of pieces shall weigh not less than 1 gram or shall be sufficient to yield a content of ash of not less than 0·01 g.

The crucible and lid shall be heated in the furnace, cooled in a desiccator and weighed to the nearest 0·1 mg. The pieces of paper shall be placed in the crucible and weighed to the nearest 0·5 mg. The crucible and contents shall be ignited in a furnace, care being taken to cover the crucible during the early stages of ignition to avoid loss of small particles. The ignition shall be started at a low temperature and shall gradually be raised to a temperature of 850° ± 50°C. as the volatile matter is driven off. When the maximum temperature has been reached the crucible cover shall be raised gently and placed slightly to one side so as to allow combustion to continue to completion which condition is indicated by the absence of black particles in the ash.

When combustion is complete the crucible lid shall be replaced and the crucible removed and placed in a desiccator until cool. The crucible and contents shall then be weighed to the nearest 0·5 mg. and the process of ignition and weighing shall be repeated until the weight is constant.

A second determination shall be carried out under the same conditions. The content of ash shall be determined in each case as a percentage of the weight of the conditioned paper. The average of the values obtained shall be taken as the ash content of the paper.

APPENDIX E

Determination of Water Absorption

The apparatus shall consist of a metal cylinder of 100 sq. cm. internal cross-sectional area, height about 5 cm. and thickness about 6 mm. with means for clamping it on to the surface of the paper to be tested. The lower edge of the cylinder which comes in contact with the paper shall be machined smooth.

Six test pieces shall be tested. A test piece shall be weighed to the nearest 1 mg. and placed on a rubber backing sheet with the surface to be tested uppermost. The cylinder shall be placed on the test piece and clamped sufficiently firmly to prevent any leakage of water between it and the paper. The apparatus shall be mounted on a level bench. One hundred ml. of water shall be poured into the cylinder and a stop watch immediately started. During the test the temperature of the water shall be maintained at 20°C. ± 0·5°C. After 45 seconds the water shall be poured off care being taken to prevent it getting on to the remaining surface of the test piece. At the end of exactly 60 seconds from the commencement of the test the cylinder shall be quickly but carefully removed and surplus water removed from the sample by means of blotting paper, light pressure being used in the blotting. The presence of a highly reflecting area on the surface shows that excess water remains and if so it shall be removed by further blotting. The test piece shall be weighed to the nearest 1. mg. immediately after blotting. The increase in weight of the paper shall be expressed in centigrams.

Three test pieces shall be tested with the felt side of the paper uppermost and three with the wire side uppermost.

The average of the values obtained shall be taken to be the water absorption in grams per square metre.

GIVEN under my Official Seal this 14th day of December, 1953.

SEAN F. LEMASS,

Minister for Industry and Commerce.