PVC or rubber suction hose: temperature, pressure and the Gulf summer

Two suction hoses of the same bore can sit side by side in a store at very different prices — a clear or grey PVC hose with a rigid helix, and a black rubber one with a steel wire. Both pull water. The choice between them usually comes down to two numbers on the listing, and in this region one of them is the temperature the hose will reach sitting in the sun.

/01Temperature is the first filter.

Every PVC suction hose in our range is listed from −10 to +55 °C. That is the medium and the hose, and it is a real limit: PVC softens as it warms, the helix loses its grip on the shape, and a hose that holds vacuum in the morning can flatten by afternoon. A dark hose lying on a site in a Gulf summer can exceed 55 °C on its surface without carrying anything warm at all. Our rubber water suction hoses — A210 and A216 — are rated to +70 °C, and down to −20 and −35 °C respectively.

/02Pressure falls with bore on PVC.

A PVC suction hose is rated per size, and the rating drops as the bore grows: our medium-duty PVC (IRRIBULK) is 3 to 8 bar across 1" to 6", our food and bulk PVC (PREMVIN) 2 to 12 bar across 1/2" to 6", and the PVC oil hose (BAKU) 3 to 9 bar across 1" to 6". All are built to a 3:1 safety factor. The rubber hoses hold a single rating across their range: 10 bar on A210 from 1" to 6", 16 bar on A216 from 2" to 8".

/03Handling decides the rest.

PVC hose is light, flexible enough to carry, often clear so the flow can be seen, and inexpensive — the right hose for irrigation, light dewatering and food and bulk transfer where it is handled with some care. Rubber is the hose for being dragged across rubble, driven over and left out: A210 and A216 have mandrel-wrapped SBR covers resistant to ozone and weather, A216 adds abrasion resistance, and both carry a steel helix inside textile plies. A216's double helix is built for the heavier suction work at large bores.

/04Vacuum and couplings.

Both kinds hold suction with a helix — rigid PVC on the PVC hoses, steel wire on the rubber. A210 prints its vacuum on the layline: 700 mmHg. Either way, the hose only holds suction if every joint is airtight, so match the coupling to the hose: cam and groove or Bauer halves clamped properly onto rubber, and fittings sized for the PVC hose's helix on PVC. A single loose clamp on a suction line is an air leak that reads as a weak pump.

The suction hose is half the system: on the discharge side most pumps feed lay flat hose. See why lay flat cannot go on the suction, and how TPU, NBR and PVC lay flat hose compare.