Netafim 1in Guardian Air/Vacuum Relief Air Vent

Netafim 1in Guardian Air Vent

Subsurface and surface drip systems are most at risk in the seconds after a valve closes or a pump stops. Water keeps moving downhill, and without an air path the pipe behind it is left under suction. That vacuum can draw soil through the drippers and, in severe cases, crush pipe or fittings. This Netafim vent gives the line a large air path at exactly those moments. Inside is a float that rises with the water. While the line fills, air streams out through an opening Netafim compares to a large standard vent. Once water reaches the float, it lifts and seals the outlet for normal running. When pressure drops or the line drains, the float falls away and air flows back in. Netafim states that this model remains open until air pressure reaches 5 psi, so it keeps venting during a fast fill. The large opening also softens water hammer that can split pipes and fittings. The housing is reinforced, UV protected composite with no metal parts, so there is nothing to rust and no spare parts to stock. It carries a 150 psi rating and a five year warranty from Netafim USA.

Sizing a 1 Inch Air Vacuum Relief Vent

Netafim sizes Guardian vents by the air intake a manifold needs at a vacuum of about 1.45 psi. On flat ground, the operating flow rate sets that need, since the water column keeps moving at that rate after a sudden shut-off. On sloping ground, use the higher of the controlled drainage rate or the flow during a pipe burst. In Netafim's own example, a four inch manifold on a 5 percent slope needed 300 GPM of air intake. The same zone running at 370 GPM called for one 1 inch Guardian. For short drip lines, Netafim suggests a 1 inch Guardian upstream of a 1 inch continuous acting air vent at the line end. Fit the vent after the manifold isolating valve, at high points and on risers at the manifold ends. Thread it into a 1 inch female tee or riser with sealing tape on the male threads. Stand it upright so the float can rise and fall freely. Keep the vent clear of mulch or soil that could block the air path. Inspect the seat at the start of each season and flush any grit away.

Key Features

• Two-Way Protection: Releases air while filling and admits air while draining.
• Float Operated: Seals under pressure, opens when pressure drops.
• Open to 5 psi: Keeps venting through a fast fill.
• Water Hammer Damping: Large opening protects pipe and fittings.
• Composite Body: Reinforced, UV protected, no metal parts.
• 150 psi Maximum: Rated operating pressure.
• 1 Inch NPT Male: Threads into a tee or riser.
• Five Year Warranty: From Netafim USA.

Technical Specifications