The Rothwell scale, or Rothwell system, or Rothwell method, applied to incontinence care products, is a scale that shows how absorbent a particular incontinence pad or adult diaper is, and how much liquid it can absorb and hold before it is likely to leak due to overfill.
The system provides a quick reference for assessing how much liquid can be held by a sheet, pad or diaper, and therefore how appropriate it will be for a particular individual in any given circumstance. The scale is based on the total absorbency test ISO 11948–1. The scale runs from 1 to 22, with 1 indicating the least liquid absorbed, measured in grams, and 22 the most liquid absorbed. The scale also applies a prefix to show what type of product is being referred to, with pads and sheets having an “I” prefix, and all in one diapers using a D prefix.
Scale Absorbency Scale Absorbency I1 0g to 49g D14 1300g to 1699g I2 50g to 99g D15 1700g to 2099g I3 100g to 199g D16 2100g to 2499g I4 200g to 299g D17 2500g to 2899g I5 300g to 449g D18 2900g to 3299g I6 450g to 599g D19 3300g to 3699g I7 600g to 799g D20 3700g to 4099g I8 800g to 999g D21 4100g to 4499g I9 1000g to 1249g D22 4500g to 4899g I10 1250g to 1499g I11 1500g to 1799g I12 1800g to 2099g I13 2100g to 2499g I14 2500g to 2899g I15 2900g to 3299g
References M Fader, A Cottenden, K Getliffe, H Gage, S Clarke-O’Neill, K Jamieson, N Green, P Williams, R Brooks and J Malone-Lee, "Absorbent products for urinary/faecal incontinence: a comparative evaluation of key product designs", Health Technology Assessment, vol. 12, no. 29, 2008. A.M Cottenden, J.G Rothwell, H Leander, C Grau, R.J Brooks, "An investigation of the repeatability and reproducibility of ISO 11948-1 (the Rothwell method) for measuring the absorption capacity of incontinence pads", Medical Engineering & Physics, vol. 24, iss. 2, pp. 159–163, March 2002. ISO 11948-1:1996, "Urine-absorbing aids -- Part 1: Whole-product testing", International Organization for Standardization, 1996