High Point Vent and Low Point Drain Pit Assemblies

Liquip hydrant pit assemblies are a vital part of any hydrant pit system as they are critical for the operation, function and safety of the airport fuel hydrant system.

It is a requirement for Aviation fuel hydrant pipelines to include dedicated low drains and high point vents. JIG2 states that low point drains are flushed at a high velocity once a week to ensure removal of water and sediment.

The Liquip HLV150-300 sample vent and drain model is designed to be installed on the riser flange inside the hydrant pit box. This vent comprises a stainless steel 6 inch ASME B16.5 class 300LB raised face base flange and is fitted with two manually operated 1½” (40mm) stainless steel fire safe ball valves.

At the top of the assembly there is a flanged stainless-steel tank unit which features a pressure relief valve in the poppet which is set at 1,600 kPa. This tank unit provides a leakproof connection when coupled to the mating hose unit. 

As our high and low point assemblies are designed and made in house at our Australian factory, variations to suit various flange sizes are easily accommodated.  

  • Compact and robust stainless steel construction.
  • Twin ball valve design for safer operation.
  • Ball valves are fire safe for extra security.
  • Ball valves have an allowance to lock them out.
  • 2” stainless steel tank unit (adaptor).
  • SS316/316L base flange is 6” 300# to allow installation into standard hydrant pit boxes e.g. Liquip’s HPA series.
  • Vent height fits in Liquip’s HPA series hydrant pit boxes.
    Dust cap supplied as standard.
  • ¼” BSPT threaded hole on sump flange for optional bleed valve. (This is blanked as standard).
  • SS fasteners and Klinger C4430 gaskets supplied with vent.
  • Australian designed and globally supported.

Base flange 6” ASME B15.5 Class 300# raised face, type 316/316L stainless steel. 

Ball Valves
1½” (40mm) stainless steel CF3M floating full bore ball valve, fire safe to API607. Teflon seals, flanged PN 16 to EN 1092-1.

Tank Unit
2” tank unit to NATO STANAG 3756, stainless steel, flanged DN40 PN 16. Poppet includes a relief valve set at 1,600 kPa.

According to EN1514-1, non-metallic Klinger C4430 flat gaskets, inside bolt circle DN40 PN 16.

Design Temperature
-20°C to +80°C.

Working Pressure
16 BAR (1,600 kPa).

As per site maintenance schedule. 

Mounting to hydrant pit base flange - 6” ASME 300#. 
SS B8M Studs and Nuts included.
There is also a 6” ASME 300# gasket included, which gets installed between the hydrant pit sump and hydrant flange connection.

During operation the bottom valve is typically installed as always open and for maintenance it is closed.

The HLV150-300 is typically controlled using the top valve.

**Warning** the upper valve must always be closed when coupling or uncoupling the tank unit. Please refer to site procedures for additional guidance.

HLV150-300*: Hydrant pit sump high low valve DN150 300# to 2” STANAG 3756.

*When using this assembly for low point sampling, an extension pipe must be welded into the base of the flange and must reach into the sump. This is not included but the base flange is bored to 50mm diameter into which an extension pipe can be socket welded.


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