Aviation Hydrant Isolation Valve type 355GF | Cla-Val

Cla-Val 355GF Hydrant Isolation Valve

The Cla-Val 355GF is an isolation valve designed for hydrant pit systems in aircraft refueling networks. It is installed directly below the hydrant pit valve and, when closed, enables removal of the pit valve for maintenance or replacement without depressurizing the remainder of the hydrant network.

Functional Role in Pit Assemblies

The 355GF serves as a local isolation point between the underground fuel main and the hydrant pit valve. It does not replace the deadman valve; it is intended for mechanical isolation during pit assembly maintenance procedures.

Typical applications include:

• aviation hydrant pits
• Jet A-1 / aviation fuel lines
• locations requiring pit valve removal with the network pressurized
• new pit assemblies in conjunction with Cla-Val 352GF

Construction and Connections

The valve features a 6” inlet x 4” outlet configuration with ANSI flanged connections. Inlet is 6” class 300, outlet is 4” class 150 ANSI. Overall height is approximately 6”, allowing direct replacement of existing adapter spools lacking isolation capability.

Key construction features:

• full-bore stainless steel ball valve
• operated via removable T-bar from pit box surface
• simple open/close position indicator
• integral inlet stone guard to protect pit valve
• fire safe qualification per API 607

Materials

• Body: ductile iron ASTM A536 65-45-12
• Ball / retainer / stem: AISI 316 stainless steel
• Strainer: AISI 303 stainless steel
• Seals: Teflon and Buna-N
• Corrosion protection: epoxy coating per MIL-C-4456

Operating Conditions

Operating temperature range is -40 to +180 °F (-40 to +80 °C). Valve selection should consider hydrant system pressures, flange class, pit geometry, and required assembly height.

FAQ

When is the 355GF used?
When hydrant pit valves must be removed without shutting down or depressurizing the entire hydrant system.

How is the valve operated?
Using a removable T-bar from the pit box surface; no entry into the pit is required.