Engineering Specifications of Floating Ball Valves
The engineering specifications of Metals Valve’s floating ball valve series includes the selection of seat & sealing materials’ selection, flow coefficient, as well as its torque values. Metals Valve supplies soft seated floating type ball valves in cast steel, forged steel and stainless steel materials.

Aluminium bronze ball valve, floating type, 4″ 150LB, PTFE soft seat, lever operated. Body & Trim: UNS C95800.
1. Seat material selection of floating ball valves(soft seated).

The pressure-temperature ratings of seating and sealing materials including PTFE, Nylon, PEEK, BUNA, Viton and HSN.
Properties | PTFE | NYLON | PEEK | PCTFE | DEVLON |
Temperature ℉ | -328~428 | -58~248 | -148~500 | -328~302 | -148~302 |
Temperature ℃ | -200~220 | -50~120 | -100~260 | -200~150 | -100~150 |
Pressure Ratings(LB) | 150~600 | 150~1500 | 150~2500 | 150~1500 | 150~1500 |
Hardness | 58 | 72 | 88 | 85 | 78 |
Tensile Strength(MPa) | 14~34 | 55.2 | 134 | 35.9 | 79.9 |
Yield Strength(MPa) | 350 | 250 | 2.2 | 150 | 5.4 |
Specific Gravity(g/cm3) | 2.17 | 1.02 | 1.44 | 2.12 | 1.14 |
Water Absorption(24hr %) | 0.00 | 1.00 | 0.06 | 0.00 | 0.10 |
Water Saturation | <0.01 | 1.60 | 0.20 | <0.01 | 3.00 |
Different soft seating materials can be respectively chosen in terms of specific applications: PTFE mainly for chemical & cryogenic service, NYLON for high pressure & hydrocarbon service, PEEK for high pressure & high temperature service, PCTFE for cryogenic service, DEVLON for high pressure & hydrocarbon applications.
2. Sealing materials selection
Properties | NBR | HNBR | VITON | FFKM | EPDM |
Temperature ℉ | -22~230 | -40~302 | -4~392 | -4~620 | -58~302 |
Temperature ℃ | -30~110 | -40~150 | -20~200 | -20~327 | -50~150 |
Specific Density(g/cm3) | 1.31 | 1.34 | 1.85 | 2.00 | 0.87 |
Hardness(shore A) | 75 | 75 | 75 | 75 | 75 |
Generally, all body/ bonnet seals are furnished in graphite. The sealing materials listed within this table are mainly used for stem and seat O-rings.
3. Flow Coefficient(Cv) and Operating Torque of floating ball valves
- Flow Coefficient
- Operating Torque 01
- Operating Torque 02
Flow Coefficient
Size | 150LB | 300LB | 600LB | 900LB | 1500LB |
1/2" | 25 | 25 | 20 | 16 | 16 |
3/4" | 56 | 56 | 48 | 34 | 34 |
1" | 95 | 95 | 64 | 55 | 55 |
1-1/2" | 308 | 308 | 308 | 165 | 165 |
2" | 500 | 430 | 370 | 320 | 320 |
3" | 1360 | 1100 | 1020 | 920 | - |
4" | 2500 | 2000 | 1850 | - | - |
6" | 5300 | 5250 | - | - | - |
8" | 10750 | 10100 | - | - | - |
10" | 17500 | 16820 | - | - | - |
12" | 26750 | 25950 | - | - | - |
The flow coefficient Cv of the floating ball valve denoting flow rate of water(gallons/minutes):
(1) All sizes are in full port and fully open position.
(2) Pressure ratings shall be in accordance with ASME B16.34.
Operating Torque 01
Size | 150LB | 300LB | 400LB | 600LB |
inch | N.m | Ft/lbs | N.m | Ft/lbs | N.m | Ft/lbs | N.m | Ft/lbs |
1/4" | 5 | 3.69 | 6 | 4.43 | 8 | 5.90 | 12 | 8.86 |
3/8" | 5 | 3.69 | 6 | 4.43 | 8 | 5.90 | 12 | 8.86 |
1/2" | 6 | 4.43 | 9 | 6.64 | 11 | 8.12 | 16 | 11.81 |
3/4" | 10 | 7.38 | 12 | 8.86 | 14 | 10.33 | 20 | 14.76 |
1" | 15 | 11.07 | 20 | 14.76 | 29 | 21.40 | 422 | 31.00 |
1-1/4" | 32 | 23.62 | 48 | 35.42 | 45 | 33.21 | 60 | 44.28 |
1-1/2" | 40 | 29.52 | 60 | 44.28 | 62 | 45.76 | 90 | 66.42 |
2" | 50 | 36.90 | 70 | 51.66 | 90 | 66.42 | 130 | 95.94 |
2-1/2" | 80 | 59.04 | 90 | 66.42 | 104 | 76.75 | 150 | 110.70 |
3" | 90 | 66.42 | 120 | 88.56 | 138 | 101.84 | 200 | 147.60 |
4" | 180 | 132.84 | 230 | 169.74 | 255 | 188.19 | 370 | 273.06 |
5" | 340 | 250.92 | 420 | 309.96 | - | - | - | - |
6" | 840 | 619.92 | 930 | 686.34 | - | - | - | - |
8" | 1100 | 811.80 | 1930 | 1424.34 | - | - | - | - |
10" | 2000 | 1476.00 | 4500 | 3321 | - | - | - | - |
12" | 3200 | 2361.60 | - | - | - | - | - | - |
The torque values of floating ball valves 150LB ~ 600 LB:
1. The torque is calculated based on room temperature, with PTFE seats for 150LB~300LB and Nylon for 600LB~1500LB.
2. In cryogenic service, the torque shall be increased by about 2~2.5 times.
3. Torque values listed are used for selection of actuators. Recommended safety factory: 1.3~1.5.
4. The torque may vary in different fluid or with different trim materials.
Operating Torque 02
Size | 800LB | 900LB | 1500LB | 2500LB |
inch | N.m | Ft/lbs | N.m | Ft/lbs | N.m | Ft/lbs | N.m | Ft/lbs |
1/4" | 15 | 11.07 | 15 | 11.07 | 22 | 5.90 | 32 | 23.62 |
3/8" | 15 | 11.07 | 15 | 11.07 | 22 | 5.90 | 32 | 23.62 |
1/2" | 19 | 14.02 | 20 | 14.76 | 32 | 8.12 | 56 | 41.33 |
3/4" | 33 | 24.35 | 35 | 25.83 | 45 | 10.33 | 100 | 73.80 |
1" | 65 | 47.97 | 70 | 51.66 | 120 | 21.40 | 190 | 140.22 |
1-1/4" | 90 | 66.42 | 100 | 73.80 | 170 | 33.21 | 310 | 228.78 |
1-1/2" | 130 | 95.94 | 140 | 103.32 | 189 | 45.76 | 360 | 265.68 |
2" | 187 | 138.01 | 200 | 147.60 | 420 | 66.42 | - | - |
2-1/2" | 280 | 206.64 | 320 | 236.16 | - | - | - | - |
3" | 403 | 297.41 | 431 | 318.08 | - | - | - | - |
The torque values of floating ball valves 800LB ~ 2500 LB:
1. The torque is calculated based on room temperature, with PTFE seats for 150LB~300LB and Nylon for 600LB~1500LB.
2. In cryogenic service, the torque shall be increased by about 2~2.5 times.
3. Torque values listed are used for selection of actuators. Recommended safety factory: 1.3~1.5.
4. The torque may vary in different fluid or with different trim materials.
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