12. Some useful facts about water and ice
Properties of water and ice
Properties  Metric Units  Remarks 
Pure water  
Density at 15°C  1 kg/l 1 t/m³ 
Pure
water becomes denser as the temperature falls, until at
4°C it is at its densest, ie 1 kg/l. For practical icemaking calculations, the density of water can safely be assumed to be 1 kg.1 
Specific heat  1.0 kcal/kg°C  
Latent heat of fusion  80 kcal/kg  
Thermal conductivity (at 10°C) 
0.5 kcal/mh°C  
Freezing point  0°C  
Boiling point  100°C 
Sea water  
Density  1.027 kg/l  At 0°C and salinity of 3.5%. 
1.027 t/m³  
Specific heat  0.94 kcal/kg°C  At 0°C 
0.93 kcal/kg°C  At 20°C  
Latent heat of fusion  7780 kcal/kg  Approximate values at salinities of up to 3.5%. Indeterminate owing to presence of salts. 
Freezing point at salinity of:  Salinity varies
from sea to sea but for practical purposes the world
average of 3.5% is sufficiently accurate. 

1.0%  0.6°C  
2.0%  1.2°C  
3.0%  1.6°C  
3.5%  1.9°C  
4.0%  2.2°C 
Ice  
Density  
Freshwater ice  0.92 kg/l  At 0°C 
0.92 t/m³  
Seawater ice  0.860.92 t/m³  Depending on salinity and amount of trapped air. 
Specific heat:  For calculating the amount of ice to use on fish, a value of 0.5 is sufficiently accurate. Specific heat of seawater ice can be very much higher near to melting point.  
0°C  0.49  
20°C  0.46  
Latent heat of melting  80 kcal/kg  
Thermal conductivity:  kcal/mh°C  
0°C  1.91  
10°C  1.99  
20°C  2.08  
Melting point  0°C  Melting point of seawater ice is indeterminate, since salt content is rarely uniform throughout the ice, but should on average be about 2°C. 
Stowage rates  m³/t  
Block ice in blocks  1.4  
Crushed block ice  1.41.5  
Flake ice  2.22.3  
Tube ice  1.62.0  
Plate ice  1.71.8 