Life Cycle Assessment of Supermarket Carrier Bags - Save The ...

use bag as prodegradant or non prodegradant. It was therefore assumed that, whilst thesingle use bag data represented all single use bag types, the reusable bag dataspecifically represented the use of LDPE bags. To adapt the LDPE bag data for otherreusable bag types, the number of items per litre was calculated (0.37 items per litre).The volume and weight of all other reusable bags considered was then measured (asshown in table B.4.4) and, based on the items per litre ratio, a number of items per bagtype was calculated. This was found to be 7.43 items for the paper bag, 7.3 items for thenon woven PP bag and 10.59 items for the cotton bag. The volume, weight and items perbag for every bag type are shown in table B.4.5.Table B.4.4 The volume and weight of all other reusable bag typesBag typeSupermarketsourceVolume(litres)Weight(grams)Gramsper litrePaper bag Supplier 20.10 55.200 2.75Non woven polyproylene (PP) bagCotton bagAsda 17.7 124.080 7.01Greengrocer 21.8 107.580 4.93Average 19.75 115.830 5.86Sainsbury 17.00 195.680 11.51Asda 32.10 229.050 7.14Co-op 33.40 78.660 2.36M&S 32.10 229.050 7.14Average 28.65 183.11 7.03Table B.4.5 The volume, weight and items per bag for all bag typesBag typeVolume(litres)Weight(grams)Items per bagHigh-density polyethylene (HDPE) bag 19.10 8.116 5.88High-density polyethylene (HDPE) bagwith a prodegradent additive19.10 8.266 5.88Starch polyester blend bag 19.10 16.491 5.88Paper bag 20.10 55.200 7.43Low-density polyethylene (LDPE) bag 21.52 34.945 7.96Non woven polyproylene (PP) bag 19.75 115.830 7.30Cotton bag 28.65 183.110 10.59The average volume, weight and ‘grams per litre’ ratio was also calculated for bin linersusing the same methods. Three liners were measured; a premium liner, a liner withhandles and a value liner. The liners selected had similar volumes to the carrier bagsinvestigated within this study and were smaller than conventional black bin liners usedfor household refuse. The calculated weights and volumes are shown in table B.4.6.83 Environment Agency Life Cycle Assessment of Supermarket Carrier Bags