106 Meat refrigeration Air speed 3.0 0.75 Fig 6.5 Weight loss during 18 h chilling at an air temperature of 0C at different velocities and relative humidities( source: James and Bailey, 1990) operated as a storage chill, for example over weekends, the need to operate it low air velocities to reduce weight loss and subsequent surface dis- colouration is even more important 6. 2.1.2.3 Relative humidity Relative humidity has a greater effect on weight loss than either air tem perature(see previously) or velocity(Fig. 6.5). Reducing relative humidity from 95 to 80% increased evaporative weight loss over an 18h chilling cycle ato° by nearly0.% 6.2. 1.2.4 Side weight Percentage evaporative weight loss decreases as side weight increases (Table 6.3), the effect being marked at very low side weights(<100kg),but far less so at and above the average side weight for the UK (135 kg) 6.2.1.2.5 Fat cover It is clear from Fig 6.5 that fat cover has a substantial effect on evapora tive weight loss during an 18h chilling period. In the worst circumstances a very lean side with little or no fat cover can lose almost 1% more than sides of similar weight with a thick even covering of fatoperated as a storage chill, for example over weekends, the need to operate at low air velocities to reduce weight loss and subsequent surface dis￾colouration is even more important. 6.2.1.2.3 Relative humidity Relative humidity has a greater effect on weight loss than either air tem￾perature (see previously) or velocity (Fig. 6.5). Reducing relative humidity from 95 to 80% increased evaporative weight loss over an 18 h chilling cycle at 0 °C by nearly 0.5%. 6.2.1.2.4 Side weight Percentage evaporative weight loss decreases as side weight increases (Table 6.3), the effect being marked at very low side weights (<100 kg), but far less so at and above the average side weight for the UK (135 kg). 6.2.1.2.5 Fat cover It is clear from Fig. 6.5 that fat cover has a substantial effect on evapora￾tive weight loss during an 18h chilling period. In the worst circumstances a very lean side with little or no fat cover can lose almost 1% more than sides of similar weight with a thick even covering of fat. 106 Meat refrigeration 3.0 1.5 75 80 85 90 95 0.75 Air speed m s–1 Relative humidity (%) 2.0 2.5 Weight loss (%) Fig. 6.5 Weight loss during 18 h chilling at an air temperature of 0 °C at different velocities and relative humidities (source: James and Bailey, 1990)