Control systems Safety valves
4
Correction Factor (Ks) for Superheated Steam (continued)
Satured Steam Temperature
Set Pressure
Temperature
°C
290 300 320 330 340 350 360 370 380 390 400
bar g psi g °C °F
°F
560 580 600 620 640 660 680 700 720 740 750
1.0 15 122 250 0.90 0.89 0.88 0.87 0.86 0.86 0.85 0.84 0.83 0.83 0.82
1.5 20 128 259 0.90 0.89 0.88 0.87 0.86 0.86 0.85 0.84 0.83 0.83 0.82
2.0 30 134 274 0.90 0.89 0.88 0.87 0.86 0.86 0.85 0.84 0.84 0.83 0.82
3.0 45 144 292 0.90 0.89 0.88 0.87 0.87 0.86 0.85 0.84 0.84 0.83 0.82
4.0 60 152 308 0.90 0.89 0.88 0.87 0.87 0.86 0.85 0.84 0.84 0.83 0.82
4.7 27
5.0 70 160 316 0.90 0.89 0.88 0.87 0.87 0.86 0.85 0.84 0.84 0.83 0.82
5.5 80 162 324 0.90 0.89 0.89 0.88 0.87 0.86 0.85 0.84 0.84 0.83 0.82
7.0 100 171 338 0.91 0.90 0.89 0.88 0.87 0.86 0.85 0.85 0.84 0.83 0.82
8.5 120 178 350 0.91 0.90 0.89 0.88 0.87 0.86 0.85 0.85 0.84 0.83 0.82
9.5 140 182 361 0.91 0.90 0.89 0.88 0.87 0.86 0.85 0.85 0.84 0.83 0.82
12 175 192 378 0.91 0.90 0.89 0.88 0.87 0.86 0.86 0.85 0.84 0.83 0.82
14 205 198 390 0.91 0.91 0.89 0.88 0.87 0.86 0.86 0.85 0.84 0.84 0.83
16 230 205 400 0.92 0.91 0.90 0.89 0.87 0.87 0.86 0.85 0.84 0.84 0.83
18 260 210 410 0.92 0.91 0.90 0.89 0.88 0.87 0.86 0.85 0.85 0.84 0.83
21 305 217 423 0.93 0.91 0.90 0.89 0.88 0.87 0.86 0.86 0.85 0.84 0.83
For superheated steam capacity, multiply saturated steam capacity by the correction factor (Ks).
How to order The following information is required for the correct sizing and selection of SV44H Safety Valves: 1) Fluid 2) Required Capacity (Flow) 3) Operating Pressure and Set Pressure 4) Operating Temperature and Relieving Temperature
5) Back pressure 6) Overpressure 7) Molecular Weight (Gases)
Spirax Sarco provides on its website the PSV Calc software for the calculation, sizing, and selection of Safety and Relief Valves.
TI-P710-01 CTLS Issue 1
Page 13 of 13
SV44H Carbon Steel Safety Valve
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