Investigating openability of rigid plastic containers with peelable lids : the link between human strength and grip and opening forces

As society ages there is a growing need to understand issues surrounding declining user capabilities. One such area has been accessibility of packaging by older people. To date much of the current research in this area has focused on measuring strength of older people and analysing the force needed to open various pack formats and has largely concentrated on accessibility of jam or sauce jars. However, a survey by 'Yours' magazine indicated that problems with thin film pack forms and peelable packaging was also an issue for older people. Hence the authors undertook a small-scale study to understand the issues surrounding accessing a rigid plastic container with a peelable lid. To that end the authors built a bespoke measuring device to measure container peeling forces, measured finger friction between pack and finger and undertook an observational analysis on 60 users accessing packaging of this type. Results indicated that the force needed to open containers of this type is lower than measured user forces including older people and it is therefore likely that the issues surrounding accessibility of this type of pack format are related to dexterity not strength. However, the authors also showed that this can be affected by context of use in that oily fingers could reduce the friction coefficient between finger and pack such that older people may not have sufficient strength to open packs of this type.