BS-AU-168-1978.pdf

BRITISH STANDARD AUTOMOBILE SERIES BS AU 168:1978 Method for Determination of the windscreen fogging characteristics of organic trim materials in motor vehicles UDC 629.11.011.671:678.01:656.052.5 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 01:49:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS AU 168:1978 This British Standard, having been prepared under the direction of the Plastics Standards and Rubber Standards Committee, was published under the authority of the Executive Board on 31 October 1978 © BSI 02-2000 The following BSI references relate to the work on this standard: Committee reference PLC/RUC/8 Draft for comment 76/50118 DC ISBN 0 580 10327 7 Cooperating organizations The Plastics Standards Committee and Rubber Standards Committee, under whose direction this British Standard was prepared, consist of representatives from the following Government departments and scientific and industrial organizations: British Association of Synthetic Rubber Manufacturers British Plastics Federation* British Resin Manufacturers Association British Rubber Manufacturers Association* Chemical Industries Association* Department of Industry Chemicals and Textiles Department of Industry National Physical Laboratory Department of the Environment Building Research Establishment Electrical and Electronic and Insulation Association (BEAMA) Electrical Installation Equipment Manufacturers Association (BEAMA) Electrical Research Association Engineering Equipment Users Association Institution of Production Engineers Medical Sterile Products Association Ministry of Defence* Plastics and Rubber Institute Post Office Royal Institute of British Architects Rubber and Plastics Research Association of Great Britain Rubber Growers Association Society of Chemical Industry The Malaysian Rubber Producers Research Association* The Society of Motor Manufacturers and Traders Limited* The organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: Association of British Foam Laminators British Fire Services Association British Railways Board Chartered Institution of Building Services Department of the Environment (PSA) Department of the Environment Joint Fire Research Organization Department of the Environment and Fire Offices Committee Furniture Industry Research Association Leathercloth & Coated Fabrics Manufacturers Association London Transport Executive National Bedding Federation Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 01:49:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS AU 168:1978 © BSI 02-2000i Contents Page Cooperating organizationsInside front cover Forewordii 0Introduction1 1Scope and field of application1 2References1 3Reagents1 4Apparatus1 5Procedure2 6Temperature of test2 7Expression of results2 8Test report3 Figure 1 Diagram of windscreen fogging apparatus3 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 01:49:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS AU 168:1978 ii © BSI 02-2000 Foreword This British Standard has been prepared under the direction of the Plastics Standards Committee and the Rubber Standards Committee after consultation with the Automobile Standards Committee. The method measures the intensity of windscreen fogging which arises from the volatilization of ingredients of organic composite materials and their subsequent condensation and deposition on the inner side of motor-car glass windscreens. Such deposits reduce visibility and, in certain circumstances, can constitute a hazard to road safety. This standard provides a quality control method for comparing the intensity of fogging which may arise from the volatile ingredients in plastics and rubber materials used in the internal trim of motor vehicles, and hence a guide to the pre-selection of these materials as a contribution to the reduction of the potential hazard. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 3 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 01:49:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS AU 168:1978 © BSI 02-20001 0 Introduction Windscreen fog is the deposit of greasy material which accumulates on the insides of windscreens of cars under hot conditions. This is believed to be caused largely by the evaporation of slightly volatile ingredients from organic materials within the passenger compartment and their condensation on the cooler windscreen. These volatile ingredients may include high boiling solvents, plasticizers, stabilizers and other additives used in the manufacture of rubber, paint, PVC and other plastics materials. The effect of windscreen fog is most clearly observed when travelling towards the rising or setting sun or the headlights of other cars. A number of methods have been proposed for determining the fogging propensity of car trim materials. These methods are all based on heating the material in one part of a closed container, condensing the vapours evolved on a glass surface and measuring the opacity of the fog layer on the glass surface. The test material may be heated by lamps, air (oven) heat or a liquid bath. The method described here uses a thermostatically controlled liquid bath since it has been found easiest to control its temperature to the required degree of accuracy. Using this method the colour of the test material has no effect on the result, whereas with radiant heating the colour strongly affects surface temperature and hence the severity of fogging. The glass fog plate may be cooled by exposure to air at room temperature, by a jet of air or by a condenser through which water passes at a controlled temperature. The first method has been adopted here since it is the simplest and because the ambient air temperature has been shown not to be critical. The degree of fogging may be measured by loss of transmitted or reflected light. The latter method has been chosen as it is more sensitive and gives a wider range of readings. 1 Scope and field of application This British Standard specifies a method for measuring the degree of fogging by measurement of reflected light in the range of approximately 25 % reflectance for a heavily fogged plate to 100 % for a non-fogged plate. These figures correspond to fog numbers of 75 and 0 respectively. It is advisable not to make measurements close to either of these limits. The standard is suitable for measurements on car trim materials, foams and the liquid and solid raw materials used in the manufacture of these components. Tobacco smoke and traffic fumes drawn in by the car ventilation system may also contribute to windscreen fogging but are not covered by this test method. Under conditions of very heavy fogging, coalescence of droplets may occur, leading to good visibility through the glass and spuriously good test results. 2 References This standard makes reference to the following standards publications. BS 509, Acetone. BS 1995, Di-(2-ethylhexyl) phthalate1). BS 3978, Water for laboratory use. 3 Reagents The following reagents are required. 3.1 Acetone, complying with the requirements of BS 509. 3.2 Di-(2-ethylhexyl) phthalate, complying with the requirements of BS 1995. 3.3 Silicone oil, heat stabilized grade2). 3.4 Higher alkyl phthalate plasticizer. 3.5 Water, complying with the requirements of BS 3978. 4 Apparatus The following apparatus is required. 4.1 Thermostatically controlled oil bath, minimum dimensions 550 mm × 270 mm × 160 mm in depth, for use over the temperature range 60 °C to 120 °C. Fitted with a temperature over-ride cut-out to prevent overheating in the event of thermostat failure, a stainless steel false bottom and an efficient oil circulator to maintain the temperature throughout the bath to within ± 0.5 °C of the set temperature. 4.2 Six tall-form 1 litre beakers, of heat-resistant glass, without spout, height 190 mm, diameter 92 mm. The rim to be ground flat. 4.3 Six circular soft rubber gaskets, diameter 127 mm, hole diameter 76 mm, thickness 6 mm. 1) Contained in the publication BS 573, BS 574, BS 1995, BS 1996, BS 2535, BS 2536, BS 3647 “Specifications for plasticizer esters”. 2) Hopkin and Williams grade OC/550 is a suitable silicone oil. Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 01:49:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS AU 168:1978 2 © BSI 02-2000 4.4 Seven glass fogging plates, 115 mm square, made from 2 mm thick window glass. One plate is to be chosen to be retained as a standard plate and the remaining plates shall have a reflectance of within ± 1 % of that of the standard plate. 4.5 Heavy gauge glass, one sheet, 280 mm × 250 mm × 6 mm in thickness. 4.6 Aluminium sheet, minimum dimensions 490 mm × 280 mm × 2.5 mm in thickness, with six 99 mm diameter circular holes with 135 mm between centres. 4.7 Silicone rubber tubing, six pieces, length 317.5 mm, bore 10 mm, wall thickness 3 mm. 4.8 Reflectance meter, 60° specular glossmeter3). 5 Procedure 5.1 Preparation and assembly of test equipment 5.1.1 Wash the glass fogging plates (4.4), gaskets (4.3), beakers (4.2) and heavy gauge glass sheet (4.5) in acetone (3.1) followed by a solution of strong detergent and rinse thoroughly with water. Place the glass fogging plates in clean water, wipe dry and polish using a clean cloth. Dry the gaskets for 1 h at a temperature of 100 °C. Allow the beakers to drain and dry in air. 5.1.2 Stand the empty oil bath (4.1) on a level surface. Place the aluminium sheet (4.6) on top of the oil bath and fit the glass beakers through the holes in the sheet so that they rest on the false bottom. Adjust the height of the false bottom so that the beakers project 65 mm above the aluminium sheet. 5.1.3 Remove the beakers, fit the slit silicone rubber tubing (4.7) round the holes in the aluminium sheet (see Figure 1) and replace the beakers. Place the rubber gaskets on the beakers and the heavy gauge glass sheet over the beakers and gaskets. Fill up the oil bath with silicone oil (3.3) or higher alkyl phthalate plasticizer (3.4) until the depth above the false bottom is 63.5 mm. Then remove the beakers. 5.2 Preparation of test pieces. Cut, from the material to be tested, test pieces of 75 mm diameter and place each test piece in a beaker. Sufficient test pieces should be prepared to carry out three determinations. In the case of foams restrict the thickness to the top 10 mm. Place skinned foams and coated fabrics in the beakers with the face side uppermost. In the case of powders or liquids use a test portion of 3 ± 0.1 g. 5.3 Determination. Insert the beakers containing the test pieces, rubber gaskets and glass fogging plates into the oil bath, set at a temperature of 85 ± 0.5 °C, and cover the assembly with the heavy gauge glass sheet as described above. Leave the beakers in the bath for 16 h. Remove the glass fogging plates after this interval and store horizontally in a dust free atmosphere, fogged side uppermost, for 30 min. During this period switch on the reflectance meter (4.8) and allow it to heat up and stabilize. Calibrate the reflectance meter by placing the clean standard glass fogging plate on a matt black surface. Place the reflectance meter centrally on the glass and adjust the reading to 100. Before carrying out reflectance measurements examine the fogged plate. If droplet coalescence has occurred this should be reported and no further measurements made on the fogged plate. If not, place the fogged glass plates horizontally, one at a time, on the matt black surface. Place the reflectance meter so that the light beam is reflected from the centre of the fogged area and record the reading. Take four readings at right angles to each fogged plate, rotating the instrument after each reading on each fogging plate, and calculate the average value. 5.4 Control tests. Control tests may be carried out in parallel with those on the test pieces, using 3 ± 0.1 g of di-(2 ethylhexyl) phthalate (3.2) as a reference standard. This gives fog numbers averaging 51 at a test temperature of 85 °C. Coefficients of variation of fog numbers in interlaboratory comparisons are about 10 %. Carry out a blank test to evaluate the volatile constituents of the rubber gasket and apply any necessary correction to the average value for the reflectance of the test pieces. 6 Temperature of test The test shall normally be carried out at a temperature of 85 ± 0.5 °C. This temperature may, however, be varied to suit the material under test as agreed between the customer and the supplier. 7 Expression of results The degree of fogging shall be expressed as the fog number, which is derived by subtracting from 100 the average corrected percentage reflectance of the exposed test panels. 3) A glossmeter complying with ASTM D523-67 “Standard method of test for specular gloss” is suitable. Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 01:49:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS AU 168:1978 © BSI 02-20003 8 Test report The report shall include the following particulars. a) Complete identification of the material being tested. b) The test temperature. c) The result for each test plate. d) The mean of the results for each material. e) The number of this British Standard, i.e. BS AU 168. f) Any circumstances which may have affected the result. Figure 1 Diagram of windscreen fogging apparatus (not to scale) Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 01:49:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS AU 168:1978 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions British Standards are updated by amendment or revision. Users of British Standards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee respons