INFLUENCE OF TIlE WEIGHTS AND MEASURES ACT ON I'ACKAGING 43 It is obvious, therefore, that the maximum figure that can be declared assuming all factors to be under control is 85 c.c. and preferable that a safety factor should be allowed and 84 c.c. used. Metal tube, volumetrically filled Table V Factor Standard fill Container variation Accuracy of filling machines Processing losses Loss on storage (2 yr at 20 ø) Variation Not applicable _+0.5g none 0.$% -• 0.7 g Minimum t511 (Standard minus variation) 140 g 140 g 139.5 139.5 138.8 In this case a declared figure of 138 g is quite acceptable. Metal aerosol container with high product and low propellan! fill Table VI Factor Standard fill Container variation Accuracy of filling machint (concentrate) Accnracy of filling machine (propellant) Processing loss (spray testing) I•oss on storage Variation Not applicable 285 _+ 2 g 15+ lg 2g Minimum 'Standard minus 300 g 300 g 298 g 297 g fill variat i• m) 294 g 292 g In theory it should be possible to declare 292 g, but the manufacturer may feel that the filling weight tolerance is not perfectly under control and a safety factor of 1 or 2 g is advisable. These safety factors are at the manufacturer's discretion depending upon personal knowledge of his control techniques and it could well be felt by some manufacturers that this method of calculation is already a belt and braces job. The final minimum fill relates to a minimum size container, filled with the minimum quantity, subjected to the maximum processing loss and maximum storage period. It can be argued, therefore, that the number of packs thus involved is so small as to constitute its own safety factor.

44 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS These calculations quoted can all be made in reverse if it is desired to quote a given declaration and then determine the standard fill necessary. A word of warning, however, in the case of two part fills if the ratio of the two fills is critical: as an example, in the third case. if a declared fill of 292 g is desired with a ratio of 95:5 the initial individual fills will be 279.3 g and 14.7 g (Total 294 g at the filling stage). Adding the variations of 3 g for spray testing, 1 g on propellant and 2 g on concentrate filling still gives a total fill of 300 g, but the ratio then becomes 281.3:15.7 or 5.29}/0 of propel- lant instead of 5.0%. It is therefore necessary to re-allocate the total fill in the ratio of 95:5. I am merely suggesting these calculations as suitable ground for discus- sion, and I cannot accept any responsibility that they will always give protection against the Weights and Measures Act. CONSIDERATIONS TO DESIGN OF PACK AND PLANT In a competitive industry such as ours, the influence of the Weights and Measures Act on packaging can manifest itself in different ways. Some manufacturers may design their packs and plant in order to get the maxi- mum declared contents for the fill employed. This is probably used more in the standardised packs, such as tubes, aerosols, and standard or similar design bottles. A further effect of this principle may be seen in the choice of weight or volume for the declaration. In the case of a product of low specific gravity, such as a cologne or pre-shave it is possible to declare 70 c.c. as against 59 g. Conversely, if the gravity is high as in a toothpaste, 120 g may be declared compared to 80 c.c. These are, of course, equivalent figures, but does the customer think so? Other manufacturers may wish to ignore completely the effect of the declaration and go entirely for the competitive impact of the pack shape and design. This approach is more likely in the true cosmetic field where it may be felt that it is the appearance, perfume and name which is selling the product and not its quantity. Even so, why not declare the maximum possible figure by the use of efficient plant? In either of these approaches, it should be borne in mind that the spirit of the Weights and Measures Act implies that the declared contents should be as close as possible to the actual contents - a good point to remember. What therefore can be done to promote this in the design of packs and plant?