Inox-val 2 Piece Ball Valves - 709G FF 7/1-709N FF NPT Series | Valpres

Valpres 709G-FF / 709N-FF Two-Piece Ball Valve

The Valpres 709G-FF and 709N-FF series are two-piece stainless steel full-port ball valves for on/off isolation in high-pressure threaded piping systems. The 709G-FF version uses ISO 7 Rp female threads, while the 709N-FF version uses NPT female threads.

Technical Data

• Valve type: two-piece ball valve, full port
• Sizes: 1/4" to 2"
• Pressure rating: PN138
• Vacuum service: down to 10^-3 torr
• Temperature range: -20°C to +160°C
• Body material: ASTM A351 CF8M stainless steel
• Ball material: ASTM A479 316 / 316L
• Stem material: ASTM A479 316 / 316L
• Seats: PTFE
• Stem sealing: PTFE and carbographite packing
• Stem design: anti-static

Standards and Certifications

Fire-safe execution is available according to ISO 10497:2010. For regulated plant areas, confirm the required pressure test, leakage class, material certificates, and fire-safe documentation at procurement stage.

Suitable Media and Services

• Natural gas and fuel gases, subject to local code approval
• Compressed air and inert gases
• Low and medium pressure steam within the seat temperature limit
• Industrial gases
• Chemical liquids compatible with 316 stainless steel and PTFE
• Vacuum and utility isolation duties

Variant Comparison

Actuation and Operation

The standard configuration is manual quarter-turn operation. If remote operation is required, verify actuator compatibility, mounting arrangement, torque margin, and duty cycle before specifying pneumatic or electric actuation.

Selection Notes

• Use full-port construction where low pressure drop or pigging/cleaning access is relevant.
• Check PTFE seat compatibility with temperature, pressure, and chemical service.
• For steam, consider thermal cycling, packing adjustment access, and isolation practice.
• For gas or fuel service, confirm fire-safe requirement and leakage test documentation.
• Do not mix ISO Rp and NPT threads; thread form compatibility is part of pressure boundary integrity.

FAQ

What is the main difference between 709G-FF and 709N-FF?

The valve construction is the same in application terms; the difference is the female thread standard: ISO 7 Rp for 709G-FF and NPT for 709N-FF.

Can this valve be used on steam?

Yes, within the stated temperature range and provided that PTFE seat limits, pressure conditions, and plant isolation requirements are acceptable.

Is it suitable for corrosive fluids?

Only where the fluid is compatible with ASTM A351 CF8M / 316 stainless steel and PTFE. Chlorides, concentration, temperature, and cleaning chemicals must be reviewed.

When should the fire-safe version be specified?

Specify fire-safe execution for fuel gas, hydrocarbons, or hazardous services where loss of soft-seat sealing during fire exposure must be addressed by ISO 10497:2010 compliance.