- Chemical Resistance
- Safety Data Sheets (SDS)
- Material Properties
- PRO Systems
- PE Pressure Pipe
- PE Pipe Selection
- MAOP for PE Pipes
- Temperature Influences
- Selection of Wall Thickness for Special Applications
- Hydraulic Design for PE Pipes
- Surge and Fatigue
- Slurry Flow
- Pneumatic Flow
- Expansion and Contraction
- External Pressure Resistance
- Allowable Bending Radius
- Thrust Block Support
- Conductivity, Vibration and Heat Sources
- Polyethylene Jointing
- Handling and Storage
- Trench Preparation for Buried Pipes
- Relining and Sliplining
- Pipeline Detection
- Above Ground Installation
- Accommodation of Thermal Movement by Deflection Legs
- Service Connections for PE Pipes
- Concrete Encasement
- Fire Rating
- Testing and Commissioning
- PVC Pressure Pipe
- PVC Pressure Pipe Standards
- Pressure Considerations
- PVC Temperature Considerations
- Mine Subsidence
- Water Hammer
- Thrust Support
- Air and Scour Valves
- Soil and Traffic Loads
- Bending Loads
- PVC Pipe Jointing
- Jointing Components with Ductile Iron Flanged Joints
- Service Connections for PVC Pipe
- PVC Pipe Handling and Storage
- Below Ground Installation
- Above Ground Installation for PVC Pipe
- Testing and Commissioning for PVC Pressure Pipe
- Detecting Buried Pipes
- FLUFF – Friction Loss in Uniform Fluid Flow
- Technical Notes
PVC Pipe Jointing
During manufacture pipes are cut to standard length by cut-off saws. These saws have carbide-tipped circular blades which produce a neat cut without burrs.
However, pipes may be cut on site with a variety of cutting tools. These are:
- Proprietary cutting tools – These tools can cut, deburr and chamfer the pipe in one operation. They are the best tools for cutting pipe.
- A portable petrol-driven ‘quick cut saw – This is quick and easy to use . However, care must be taken and some deburring will be required
- Air-driven tools – This produces a neat, clean cut. It does, however require a compressor.
- A hand saw and mitre box – This saw produces a square cut but requires more deburring. It takes comparatively more time and effort and requires a stand.
The use of roller cutters is not recommended.
Vinidex recommends Vinidex solvent cements and priming fluid for use with Vinidex PVC pipes and fittings, thus ensuring a complete quality system. Vinidex premium solvent cements and priming fluid are specially formulated for PVC pipes and fittings and should not be used with other thermoplastic materials.
The following procedure should be strictly observed for best results. The steps and precautions will allow easy and efficient assembly of joints. Users may refer to AS/NZS 2032 – Installation of PVC pipe systems, for further guidance.
Incorrect procedure and short cuts will lead to poor quality joints and possible system failure.
Sockets on Vinidex pressure pipes and fittings for solvent cement jointing are tapered, ensuring the right level of interference. This may not apply to all pipes and fittings, particularly from other countries which may have a low interference joint requiring a gap filling solvent cement.
Vinidex offers three types of solvent cements formulated specifically for pressure and non-pressure applications. They are colour coded, along with the primer, in accordance with AS/NZS 3879:
- Type ‘P’ for pressure, including potable water installations, designed to develop high shear strengths with an interference fit (green solvent, green print & lid)
- Type ‘N’ for non-pressure applications, designed for the higher gap filling properties needed for clearance fits (blue solvent, blue label & lid)
- Type ‘G’” gap filling for parallel or low interference pressure and non pressure joints (clear)
- Priming fluid for use with all solvent cements (red priming fluid, red label & lid)
Always use the correct solvent cement for the application.
Solvent cement jointing is a ‘chemical welding’, not a gluing process. The priming fluid cleans, degreases and removes the glazed surface thus preparing and softening the surface of the pipe so that the solvent cement bonds the PVC. The solvent cement softens, swells and dissolves the spigot and socket surfaces. These surfaces form a bond into one solid material as they cure.
Note: PVC-O pipes are not suitable for solvent cement jointing.
Make sure that the end of each pipe is square in its socket and in the same alignment and grade as the preceding pipes or fittings.
Create a 0.5mm chamfer, as a sharp edge on the spigot will wipe off the solvent and reduce the interface area. Remove all swarf and burrs so that filings cannot later become dislodged and jam taps and valves.
Do not attempt to joint pipes at an angle. Curved lines should be jointed without stress, and then curved after the joint is cured. Support the spigot clear of the ground when jointing, this will avoid contamination with soil or sand.
An unsatisfactory solvent cement joint cannot be re-executed, nor can previously cemented spigots and sockets be re-used. To affect repairs, cut out the joint and remake or use mechanical repair fittings.
The correct amount of solvent is a uniform self-levelling layer without runs, achieved by experience and judgement. Too much solvent will form pools and continue to attack and weaken the pipe. Too little solvent will require you to brush out excessively, the solvent will quickly evaporate with vigorous brushing.
Take care not to spill solvent cement onto pipes or fittings. Accidental spillage should be wiped off immediately.
Vinidex Type P and N solvent cements satisfy the long term pressure test procedure of AS/NZS 3879 requiring an open time of 3 minutes. Open time is the time from the beginning of solvent application until the jointing of the parts.
In the field, allowable open time can vary considerably because weather conditions can influence the drying time of solvent cements. Each joint should be completed immediately.
High temperature and air movement will radically increase the loss of solvents, and solvent cement jointing should not be performed when the temperature is more than 35°C. Some form of protection should be provided when jointing in windy and dusty conditions.
When jointing under wet and very cold conditions, make sure that the mating surfaces are dry and free from ice, as moisture may prevent the solvent cement from obtaining its maximum strength.
Keep the containers stored below 30°C. The solvent cement lids should be tightly sealed when not in use to prevent evaporation of the solvent. Do not use solvent cement that has gone cloudy or has started to gel in the can. Do not use solvent cement after the ‘use by’ date shown on the can, the chemical constituents can change over a long period, even in a sealed can.
Forced ventilation should be used in confined spaces. Do not bring a naked flame within the vicinity of solvent cement operations. Spillage onto the skin should be washed off immediately with soap and water. Should the solvent cement get in the eyes, wash them with clean water for at least 15 minutes and seek medical advice.
If poisoning occurs, contact a doctor or Poisons Information Centre.If swallowed, do not induce vomiting – give a glass of water.
For further safety information, refer to Material Safety Data Sheet available from Vinidex.
If poisoning occurs, contact a doctor or Poisons Information Centre. If swallowed, and more than 15 minutes from a hospital, induce vomiting preferably using Ipecac Syrup APF.
For further safety information, refer to Material Safety Data Sheet available from Vinidex.
The following table provides an indication as to the number of joints that are made per 500ml container of priming fluid and solvent cement.
Average number of joints per 500ml.
|Size of pipe DN (mm)||Priming fluid||Solvent cement|
Jointing rings are supplied with the pipe, together with a lubricant suitable for the purpose. Other lubricants may not be suitable for potable water contact and may affect the ring. They should not be substituted without specific knowledge of these effects.
The ring provides a fluid seal in the socket of a pipe or fitting and is compressed when the spigot is passed into the socket. Check the label on the pipe socket. Series 1, Series 2, sewer rings or rings from other manufacturers cannot be interchanged. Sewer rings may contain a root inhibitor and must not be used for potable water lines. These rings can be easily identified by their two coloured dots; pressure rings have only one coloured dot.
Vinidex PVC pipes for rubber ring jointing are supplied with a chamfered end. However, if a pipe which has been cut in the field is to be used for making a rubber ring joint, the spigot end must be chamfered. Special chamfering tools are available for this purpose, but in the absence of this equipment a body file can be used provided it does not leave any sharp edges which may cut the rubber ring. The chamfer length and angle should be the same as that on an as-manufactured pipe. Do not make an excessively sharp edge at the rim of the bore and do not chip or break this edge.
When a pipe is cut, a witness mark should be penciled in on the spigot end. Care should be taken to mark the correct position using the factory marked spigot end as an example.
Chamfer lengths and witness mark positions for Vinidex Reiber rubber ring jointed pipes can be found below:
- Rieber Ring Jointing Dimensions for Series 1 Vinidex PVC-U
- Rieber Ring Jointing Dimensions for Series 1 Vinidex Hydro PVC-M
- Rieber Ring Jointing Dimensions for Series 2 Vinidex Hydro PVC-M
- Pipes may be jointed out of the trench but it is preferable that connections be made in the trench to prevent possible “pulling” of the joint.
- Clean the socket, especially the ring groove. Do not use rag with lubricant on it.
- Check that the spigot end, if cut in the field, has a chamfer of approximately 12° to 15°. Check the “NOTICE TO PIPE INSTALLERS” label on the pipe socket for the type of joint and specific jointing instructions. Note that some Vinidex pipes incorporate a Rieber joint with a non-removable rubber ring that is pre-installed in the factory. This ring must not be removed in the field. For all other rubber ring joint types, clean and dry the ring groove and insert the rubber ring into the groove as shown on the label.
- Run your finger around the lead-in angle of the rubber ring to check that it is correctly seated, not twisted, and that it is evenly distributed around the ring groove.
- Clean the spigot end of the pipe as far back as the witness mark.
- Apply Vinidex jointing lubricant to the spigot end as far back as the witness mark and especially to the chamfered section.
Note. Keep the rubber ring and ring groove free of jointing lubricant until the joint is actually being made.
- Align the spigot with the socket and apply a firm, even thrust to push the spigot into the socket. It is possible to joint 100 mm and 150 mm diameter pipes by hand. However, larger diameter pipes such as 200 mm and above may require the use of a bar and timber block as illustrated. Alternatively, a commercially available pipe puller may be used to joint the pipes
- Brace the socket end of the line so that previously jointed pipes are prevented from closing up
- Inspect each joint to ensure that the witness mark is just visible at the face of each socket.
- Pipe joints must not be pushed home to the bottom of the socket. They must go no further than the witness mark. This is to allow for possible expansion of the pipe. Polydex PVC and cast iron fittings use the same rubber ring as Polydex pipe and jointing procedures are identical.
- If a pipe joint is homed too far, it may be withdrawn immediately, but once the lubricant is dry (which takes only a few minutes in hot weather) mechanical aids are required to pull the joint apart.
- With mechanical assistance, rubber ring joints can be recovered and re-made years after the original joint was made. New rubber rings should be used and care should be taken to ensure that there is no damage to pipe or socket.
If the joint is likely to be dismantled in the future the task is much easier if silicone lubricant is used.
Hint. If excessive force is required to make a joint, this may mean that the rubber ring has been displaced. To check placement of the ring without having to dismantle the joint, a feeler gauge can be inserted between the socket and pipe to check even placement of the ring.
To simplify the jointing process it is suggested that the initial joint made with the coupling is carried out before the pipe is placed in the trench.
- Clean the socket of the coupling and spigot of the pipe.
- Apply Vinidex jointing lubricant to the spigot of the pipe as far back as the witness mark and especially to the chamfered section.Align the spigot with the coupling and apply a firm even thrust to push the spigot into the coupling. For this joint, ensure that the spigot is inserted until the witness mark is no longer visible. It is possible to joint the 150mm pipe by hand. It may be found helpful to brace the coupling against a solid vertical surface.The second joint is made with the coupling of the pipe already in the trench.
- Use the same technique as before but only insert the spigot into the coupling sufficiently to leave one witness mark visible at the face of the coupling. This is necessary to allow for possible expansion of the pipe after installation.
If a joint is inserted too far, it may be withdrawn immediately, but once the lubricant is dry (which only takes a few minutes in hot weather) mechanical aids are required to pull the joint apart.
Ensure the coupling to be jointed is supported to prevent closing of preceding couplings.
The diagram below indicates the correct pipe positions in the coupling.
Vinidex Superlink ductile iron fittings have been designed with deep sockets to be suitable for PVC pressure pipes in all situations.
The depth of sockets on pipes and fittings must be sufficient to accommodate the axial movements due to the combined effect of a number of factors, such as thermal contraction and Poisson contraction which occurs when a pipe is pressurised. The Poisson effect is more significant for PVC-M and PVC-O pipes because of their higher operating stress. Vinidex SuperLink ductile iron fittings have socket lengths adequate for all situations and are recommended for use with PVC pipe.
A variety of other cast/ductile iron, bronze, aluminium, steel ABS and PVC fittings may be used with Vinidex PVC pipes. In most cases the fittings have sockets that are shorter than pipe sockets. When the socket is too short for the spigot to be inserted to the witness mark, the pipe should be fully homed and special precautions should be taken during construction to ensure that no contraction of the pipe will be taken up at these joints, i.e. it should be taken up at other joints.
The main functions of a flanged joint is to create a demountable joint, to connect valves and vessels where strength in tension is required, or to joint to other materials.
The three types of flanges available are:
1. Full-faced PVC socketed flanges.
2. PVC socketed stub flanges with loose PVC or metal backing rings.
3. Tapered cores with either metal or PVC flanges.
Flange joints require gaskets to seal them. In high stress situations, metal backing plates or flat washers are also required to spread the force and prevent damage to the flange. Bolts should not be over tightened. Epoxy-coated aluminium or ductile iron flange adaptors are also available.
For normal water supply purposes, the cutting of threads on PVC pipes is not an acceptable practice. A moulded threaded adaptor should be used.
When making threaded joints the following points should be observed:-
1. A thread sealant is recommended and the only acceptable material is PTFE (TEFLON) tape. Hemp, grease or solvent cement should never be used.
Test the ‘fit’ of the joint, particularly when connecting to other materials or to other manufacturers’ fittings. Judge the amount of tape accordingly. Under no circumstances should the thread bottom against a stop on either the male or female fitting.
2. Hand tighten initially. Usually a further two more turns are sufficient to effect a seal. Tighten only just enough to seal, plus half a turn more.
Note. Over tightening will over stress the fitting. Avoid using serrated grip tools particularly on the plain barrel of fittings or pipes.
3. If a threaded connection is made to a metal fitting, it is preferable that the male thread be PVC. For female PVC fittings special care should be taken to avoid overstressing.
GOLDEN RULE – DO NOT OVERTIGHTEN
There are various types of compression joints available for use with PVC pipes. In principle all of these effect a seal by mechanical compression of a rubber ring by means of threaded caps or bolted end plates. Because immediate pressurisation is possible such joints are generally preferred for repair work.
They are also used frequently for final connections in difficult situations where slight misalignment cannot be avoided.
When making compression joints the manufacturers’ recommendations should be followed. Over-tightening should be avoided. It may be found advantageous to use a lubricant on the rubber ring.
A wide range of adaptors to joint PVC pipes and fittings to pipes and fittings of other materials is available.