The standard BS 718 : 1991 is generally aligned with ISO 387 and ISO 649. The specification includes five series and three sub-series of Hydrometers, of which the most widely used are listed. They are calibrated using the accepted units of density: grams per milliliter (g/ml).
BS718:1991 Density Hydrometers Series S50
Range Span 0.050g/ml
Length = 190mm
Divisioned in 0.002 g/ml
adjusted at 20°
Hydrometer Range Surface Product No 0.60 to 0.65 Low 10/300/0 0.65 to 0.70 10/301/0 0.70 to 0.75 10/302/0 0.75 to 0.80 10/303/0 0.80 to 0.85 10/304/0 0.85 to 0.90 10/305/0 0.90 to 0.95 10/306/0 0.95 to 1.00 10/307/0 1.00 to 1.05 Medium 10/308/0 1.05 to 1.10 10/309/0 1.10 to 1.15 10/310/0 1.15 to 1.20 10/311/0 1.20 to 1.25 10/312/0 1.25 to 1.30 10/313/0 1.30 to 1.35 10/314/0 1.35 to 1.40 10/315/0 1.40 to 1.45 10/316/0 1.45 to 1.50 10/317/0 1.50 to 1.55 10/318/0 1.55 to 1.60 10/319/0 1.60 to 1.65 10/320/0 1.65 to 1.70 10/321/0 1.70 to 1.75 10/322/0 1.75 to 1.80 10/323/0 1.80 to 1.85 10/324/0 1.85 to 1.90 10/325/0 1.90 to 1.95 10/326/0 1.95 to 2.00 10/327/0
g/ml
Tension
BS718:1991 Density Hydrometers Series M50
Range Span 0.050g/ml
Length = 270mm
Divisioned in 0.001 g/ml
adjusted at 20°C°
Hydrometer Range Surface Product No 0.60 to 0.65 Low 10/330/0 0.65 to 0.70 10/331/0 0.70 to 0.75 10/332/0 0.75 to 0.80 10/333/0 0.80 to 0.85 10/334/0 0.85 to 0.90 10/335/0 0.90 to 0.95 10/336/0 0.95 to 1.00 10/337/0 1.00 to 1.05 Medium 10/338/0 1.05 to 1.10 10/339/0 1.10 to 1.15 10/340/0 1.15 to 1.20 10/341/0 1.20 to 1.25 10/342/0 1.25 to 1.30 10/343/0 1.30 to 1.35 10/344/0 1.35 to 1.40 10/345/0 1.40 to 1.45 10/346/0 1.45 to 1.50 10/347/0 1.50 to 1.55 10/348/0 1.55 to 1.60 10/349/0 1.60 to 1.65 10/350/0 1.65 to 1.70 10/351/0 1.70 to 1.75 10/352/0 1.75 to 1.80 10/353/0 1.80 to 1.85 10/354/0 1.85 to 1.90 10/355/0 1.90 to 1.95 10/356/0 1.95 to 2.00 10/357/0
g/ml
Tension
BS718:1991 Density Hydrometers Series L50
Range Span 0.050g/ml
Length = 330mm
Divisioned in 0.0005 g/ml
adjusted at 20°C
Hydrometer Range Surface Product No 0.60 to 0.65 g/ml Low 10/360/0 0.65 to 0.70 g/ml 10/361/0 0.70 to 0.75 g/ml 10/362/0 0.75 to 0.80 g/ml 10/363/0 0.80 to 0.85 g/ml 10/364/0 0.85 to 0.90 g/ml 10/365/0 0.90 to 0.95 g/ml 10/366/0 0.95 to 1.00 g/ml 10/367/0 1.00 to 1.05 g/ml Medium 10/368/0 1.05 to 1.10 g/ml 10/369/0 1.10 to 1.15 g/ml 10/370/0 1.15 to 1.20 g/ml 10/371/0 1.20 to 1.25 g/ml 10/372/0 1.25 to 1.30 g/ml 10/373/0 1.30 to 1.35 g/ml 10/374/0 1.35 to 1.40 g/ml 10/375/0 1.40 to 1.45 g/ml 10/376/0 1.45 to 1.50 g/ml 10/377/0 1.50 to 1.55 g/ml 10/378/0 1.55 to 1.60 g/ml 10/379/0 1.60 to 1.65 g/ml 10/380/0 1.65 to 1.70 g/ml 10/381/0 1.70 to 1.75 g/ml 10/382/0 1.75 to 1.80 g/ml 10/383/0 1.80 to 1.85 g/ml 10/384/0 1.85 to 1.90 g/ml 10/385/0 1.90 to 1.95 g/ml 10/386/0 1.95 to 2.00 g/ml 10/387/0
g/ml
Tension
BS718:1991 Density Hydrometers Series M100
Range Span 0.100g/ml
Length = 250mm
Divisioned in 0.002 g/ml
adjusted at 20°C
Hydrometer Range Surface Product No 0.60 to 0.70 Low 10/400/0 0.70 to 0.80 10/401/0 0.80 to 0.90 10/402/0 0.90 to 1.00 10/403/0 1.00 to 1.10 Medium 10/404/0 1.10 to 1.20 10/405/0 1.20 to 1.30 10/406/0 1.30 to 1.40 10/407/0 1.40 to 1.50 10/408/0 1.50 to 1.60 10/409/0 1.60 to 1.70 10/410/0 1.75 to 1.80 10/411/0 1.80 to 1.90 10/412/0 1.90 to 2.00 10/413/0
g/ml
Tension
BS718:1991 Density Hydrometers Sub-series M50 SP
This sub-series has a greater accuracy than the standard M50 Series and is only available over a limited range of density. This sub-series is commonly used in the Petroleum industry and corresponds to IP 160
Range Span 0.050g/ml
Length = 270mm
Divisioned in 0.001 g/ml
adjusted at 15°C
Hydrometer Range Surface Product No Low 10/450/0 10/451/0 10/452/0 10/453/0 10/454/0 10/455/0 10/456/0 10/457/0 10/458/0 10/459/0
g/ml
Tension
0.60 to 0.65
0.65 to 0.70
0.70 to 0.75
0.75 to 0.80
0.80 to 0.85
0.85 to 0.90
0.90 to 0.95
0.95 to 1.00
1.00 to 1.05
1.05 to 1.10