· Whereas on a normal day 62% of fluid is lost as urine, 18% as sweat, 16% as respiration and 4% as faeces, on a hot day sweat increases to 30% at the expense of urine. This reduction in urine output is more pronounced and more important for design in the under-developed markets.
· Disposable diaper sales decrease in hot sunny weather due mothers preferring to use washables when they can be line dried – at least in markets where disposables penetration is lower than in the USA.
· Most new diaper producers define their absorbency for a medium size and then adjust the capacity for other sizes in proportion to baby’s weight. However, a 2kg baby produces about 200mls urine/day and a 26kg baby produces 1650 ml/day from a much larger bladder. Mls/kg/hour of urine should be considered and this goes down as baby grows.
· Diapers are worn for 4.5 hours on average before changing but this increases to 6.5 hours as baby grows and varies dramatically with culture. Japan and Korea change much more frequently.
· Probability of diaper leakage decreases as the amount of urine absorbed increases. This is because leakage failure is usually occurs on first urination through the cuffs due to poor construction.
