Pipes & Fittings - Supadiverta - syphonic rainwater diverter

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Pipes and fittings - so many choices.
.......... one more reason Supadiverta is such a great choice!

Supadiverta diverts to PVC pressure pipe, PVC DWV pipe, poly pipe or a combination of all three.
References to 1st, 2nd and 3rd priority outlets refers to the outlet’s order of use, the lowest middle flush outlet having 1st priority use and the tallest outlet having 3rd priority use.
The middle (1st) outlet is usually but not exclusively reserved for first flush and continuous sediment extraction.
PVC pressure pipe sizes are nominal and the internal diameters are larger.
The term faucet refers to a fitting with a female thread, usually at one end only.
The fittings shown are the ones most commonly used with Supadiverta. Other available fittings may provide solutions for less common usage.
PVC PIPE AND FITTINGS have low friction loss.
PVC DWV (Drain Waste Vent) PIPE AND FITTINGS are cheaper than pressure pipe and commonly used when diverting long distances. Note that DWV pipe internal diameters are smaller than the pressure pipe equivalent sizes.
POLY PIPE AND FITTINGS are cheaper and there are a range of fittings and accessories. 19mm and 25mm low density poly pipe is mainly used by gardeners.
AS/NZS 2032 Installation of PVC pipe systems specifies that PVC pressure pipes installed in direct sunlight must be either painted with light coloured water-based paints or otherwise protected.

PVC VALVE SOCKETS A 20mm x 3/4" BSP male threaded valve socket screws into a SUPADIVERTA 3/4" BSP female threaded outlet and a (nominal) 20mm PVC class 12 pipe slips into the valve socket’s tapered end. The use of PVC solvent cement is strongly discouraged for this connection. SUPADIVERTA outlets and PVC valve sockets are tapered, Teflon tape must not be used.
The vertical drops connect to either individual horizontal  pipes or to a shared pipe.

If using 19mm poly pipe drops, the poly fitting used is a 19mm x 3/4" BSP male threaded poly director.
PHOTO 1: Two 20mm PVC vertical drops divert to a 25mm x 20mm reducing elbow and a 25mm x 20mm reducing tee. The elbow and tee are joined by a 25mm PVC pipe (not shown) cut to size.
Supadiverta is designed to use 20mm vertical drops but larger 25mm class 12 PVC vertical drops can be used with 25mm x ¾” BSP male threaded valve sockets provided that a 25mm air purger is fitted into the top of the 25mm pipe. If a 25mm PVC vertical drop is not fitted with the purger, the drop can take a long time to prime which delays transition to full flow.

This combination is used for larger roof areas or in high intensity rainfall areas.

Do not use the greater volume 25mm class 9 pressure pipe as a vertical drop.

PHOTO 2: A larger 25mm vertical drop is shown diverting to a 25mm plain elbow.
Inside supadiverta

PHOTO 3: 25mm and 20mm PVC drops are shown diverting to 40mm fittings. A 40mm x 25mm bush adapts the 25mm drop to the 40mm elbow.

(Two tees are used when two Supadivertas connect to a shared horizontal pipe).

PHOTO 4: Tees, elbows and bushes come in a range of sizes. Tees and elbows are also available as faucet fittings.
Two 45 degree elbows used to raise or lower a pipe’s height have less turbulence and friction loss than two 90 degree elbows.
A plain tee can be used to make an effective sediment trap in a horizontal pipe. See photos 13 & 14.
A reducing tee can be fitted to a horizontal pipe to fit a connection that attaches to drip hoses for garden watering. See photos 8, 9 and 10.
Bushes fit into PVC fittings, allowing different pipe sizes to connect.
Joins two PVC pipes. Reducing joiners are also available for joining different size pipes.

Joins a PVC pipe to a male threaded fitting.

Fits into PVC fitting and connects to a male threaded fitting.

Very useful and also available in some reducing and increasing sizes.
19mm directors and 19mm poly pipe can be used as vertical drops, mainly for garden applications and are often used with PVC faucet couplings to connect PVC pipe to polypipe and some hoses.
Directors can also connect reinforced pond hose between a PVC pressure pipe and a water tank bottom inlet to serve as a flexible coupling. See PHOTO 10.

Popular with pool owners and gardeners. See PHOTOs 8 and 9.

INLINE TAP Available for 13mm, 19mm and 25 mm poly pipe.
Commonly used when a 19mm poly pipe is fitted to the flush outlet to collect sediment. The tap must be fitted to a horizontal length of poly pipe and not to a vertical drop as the trapped sediment will make the tap difficult to open and close. See PHOTO 7

Connects to a PVC faucet fitting and snap fits to a hose connector. See PHOTO 10

Joins a hose to a sprinkler adaptor.

Connects two hoses. Also available as a reducing fitting to connect different size hoses.

PHOTO 6: PVC and poly plain & reducing joiners.

PHOTO 7: 45 degree elbows are fitted near the bottom of the drops to allow the horizontal pipe to clear the downpipe.

Note that the horizontal pipe and fittings are shown above ground for clarity. The pipes are usually buried.

Photo 9: Neat and compact.
PHOTO 8: Reducing tees can be fitted anywhere along a horizontal pipe’s length to connect to drip hoses.
The plain reducing tee is connected to a 20mm PVC valve by a short PVC pipe. Another short PVC pipe then connects the valve to a faucet socket.
This allows a 20mm BSP male threaded fitting to be screwed to the faucet socket. The sprinkler adaptor shown allows a hose to be connected.

PHOTO 11: Connecting a PVC pressure pipe to a tank’s ball or gate valve is easy.
Screw a director into each end of a UV stabilised reinforced pond hose and then screw one director into the tank inlet and the other to a faucet socket. The faucet socket then slips over the PVC pipe.
The pond hose serves as a flexible coupling and eliminates elbows.
The tank inlet should be a minimum of 100mm above the bottom of the tank at its lowest point and within a 75 degree arc from the pump’s draw outlet.

PHOTO 12: Neat and tidy.

PHOTO 10: Fitting an elbow allows the pipes to run parallel.

A DIY sediment trap fitted to a horizontal pipe will remove a large percentage of the bed load.
Bed load travels slowly along a straight length of pipe. By fitting an inverted tee to a straight non turbulent section of pipe and connecting the tee to an elbow, a lot of sediment will fall down the tee. Larger tee branches are more effective.
There are several combinations of fittings that can be used after the bush.
Water harvested to tanks will be much cleaner and the fitting is also popular with pool owners.

PHOTO 13: DIY sediment trap. (One version).
Fit a plain tee (branch facing downwards) to the horizontal pipe.
Fit two 45 degree or a 90 degree elbow as shown and reduce the elbow outlet with a bush.
Connect the bush to a faucet socket and a director as depicted.
Connect a 19mm or 25mm poly pipe and fit an inline tap to the end.
The smaller poly pipe will flush the captured sediment at high velocity when the tap is opened.

PHOTO 14: Very compact when fitted.
The poly pipe can be any length. This simple trap works well and the pipe will not block because water has already passed through the Supadiverta 750 micron filter and discharges at a high flow rate.


Selection depends on the total roof area harvested, the regions rainfall pattern and the intended use. For example, there would be little point in connecting a drop to a large horizontal pipe if the drop was supplying a drip hose that required no more than 4 litres per minute.
If plumbing to tanks, it is best to base calculations on a one metre head as this generally represents a half full tank.
The pipe length and all fittings cause friction/flow loss.

CLASS 12 pressure pipes are sold at hardware stores and irrigation outlets. Always compare prices.
CLASS 9 pressure pipes have the same outside diameter but their thinner walls give a greater internal volume. Rated at 900 kPa but are not available in 20mm.
Both pipes use the same pressure fittings and depending on size, class 9 pipes are up to 40% cheaper but are not as widely available.
Our DVD shows two 2,000 litre tanks in Melbourne metro supplied by a 32mm pressure pipe diverted to by two Supadivertas harvesting a combined roof area of 84 square metres.
40mm pressure pipe is usually about 30% dearer than 32mm pressure pipe but some fittings can be cheaper.
Higher volume class 9 pressure pipe generates higher flow rates than class 12 pipe.

The tanks are buried 80mm and sit on a compacted sand base.
A buried 32mm PVC pipe diverts to the two foreground 25mm & 32mm inlets.
The rear tap attaches to a garden hose to top up the pool.

What is underground?
A 32mm poly director connects to a faucet adaptor and a 32mm reinforced pond hose. A second 32mm director (not shown) connects to the other end of the pond hose and to the elbow fitted to the tank’s inlet. The faucet adaptor is then fitted last to a plain tee fitted to the buried 32mm pipe.
Note that the pond hose is not cut to length.

Very cheap and easy to fit.
A 19mm drop connected to a 25mm poly pipe has good flow rates. For example, a single 19mm drop with a 1 metre head connected to a 13 metre length of 19mm poly pipe connected to a tank bottom inlet will flow at 15 lpm but the same drop will flow at 25 lpm if connected to a 25 mm poly pipe. The poly pipe lengths do not include friction losses through fittings given as pipe length.
A 25mm x 20mm BSP director and 25mm poly pipe is sometimes fitted to a 2nd priority outlet but purging can sometimes be slow.
A 25mm poly pipe drop with a 2 metre head connected to a 25 metre length of 25mm poly pipe will free drain to a pool at 38 lpm. In real life, the heavy rain required to produce this flow rate would normally mean that the pool would not need additional topping up.

Rural poly is rarely used and the fittings are expensive.


Friction losses in pipe fittings are added to the pipe length to represent their equivalent friction loss as metres of pipe. For example, a 5 metre length of 40 mm PVC pipe fitted with two 90 degree elbows will have a total friction loss of the 5 metre pipe plus 2 x 1.3 metres for the two elbows, a total pipe length of 7.6 metres.
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