Technical Information

Introduction

High Integrity Jointing, Quick and Easy

Solvent welding is an easy system which produces a permanent joint of power identical to, or exceeding, the pipe itself.

No specific equipment, tools or hot works permits are necessary.

Limescale and Corrosion Resistant

Limescale and Corrosion can be a troublesome problem for any metal-based pipework system.

The smooth bore lining used by Pieces prevents limescale build up during the life of the system, sustaining constant flow rates.

In addition, Pieces pipework is exceptionally corrosion resistant with a full range of common chemicals which means no expensive system replacement and less maintenance fees.

PVC-U Product Information

Size Ranges from ½” – 12”

Temperature Ranges 0⁰ to + 60⁰

Pressure Rating up to Class E

Product Features

Compact and simple to fit

Limescale and corrosion resistant

Fully solvent welded system

Excellent chemical resistance properties

Technical Information

Fittings

The calculation of pressure drop in fittings is more complex but calculations can be made for equivalent lengths of straight pipe using the formula A= B x C where:

A = equivalent pipe length (metres)

B = fittings constant (see table below

C = fitting internal diameter (mm)

To calculate the total pressure drop in the system, the equivalent straight pipe lengths for fittings is then added to the total straight pipe length to obtain the total drop.

Fittings Constant

90⁰ elbow 0.03

90⁰ tee – straight through 0.01

90⁰ tee – side branch 0.06

90⁰ bend 0.01

45⁰ elbow 0.01

45⁰ bend 0.01

Reducing bush (per size reduction) 0.01

Butterfly valves 0.13

Diaphragm valves 0.23

Check valves 0.05

The values are included as a guide to aid calculation of overall system performance and should not be used in isolation.

Flow Calculations

Pressure drop due to friction in pipes conveying water can be determined using the Flow Nomogram on page ?       NO CLUE HOW TO DO THIS?  SORRY

The pressure drop at a given flow rate can be determined as follows:

  1. Obtain the internal diameter of the pipe to be used (can be found in the pipe dimensional section on page ?
  2. Mark this diameter on Scale A.
  3. Mark the required flow rate in litres per second on Scale B.
  4. Draw a straight line connecting the points on Scales A and B and extend this to Scales C and D.
  5. The velocity of flow in metres per second is determined from the intersection with Scale C.
  6. The frictional head loss in metres per 100 metres of pipe can then be read off Scale D.
 
 

Pipe Routing

Systems mounted above ground ought to be designed such that there are enough modifications to accommodate growth or contraction.

The support technique shown below guarantees the pipework is able to move pivotally without twisting.

Make full use of the pipe pliability whilst ensuring the clips are not direct to variation in direction.

Catering for Pipe Movement

Frameworks introduced above ground ought to be outlined to guarantee that there are adequate changes in heading to suit extension and contraction.

The back strategy portrayed afterward will guarantee that the pipework can pivotally without twisting.

If adequate changes in course are not accessible inside the plan of the framework, elective strategies of catering for pipe development can be considered such as extension loops or adaptable rubber elbows.

Pipe Supports and Clips

Pipe bolsters and clips ought to give sidelong restriction and permit free, unhindered, hub pipe development.  Standard ‘drop rods’ may not give adequate sidelong limitation and the pipe may begin to twist.

Support Centres

Where the substance have a particular gravity more noteworthy than 1 the separate must be diminished by partitioning the suggested middle separate by the particular gravity.

For vertical channels, bolster centres by be expanded by 50%.

The prescribed distance between underpins and channels filled with water is given within the table shown below.

PVC-U Support Distances

   
           

Metric

Imperial

20⁰C

30⁰C

40⁰C

50⁰C

20

1/2

0.90

0.85

0.85

0.80

25

3/4

1.00

0.95

0.90

0.90

32

1

1.10

1.05

1.00

1.00

40

1 1/4

1.30

1.25

1.20

1.15

50

1 1/2

1.50

1.45

1.40

1.35

63

2

1.60

1.55

1.50

1.45

75

2  1/2

1.80

1.75

1.70

1.60

90

3

2.10

2.05

1.95

1.90

110

4

2.40

2.30

2.25

2.10

125

2.50

2.40

2.35

2.20

140

5

2.70

2.60

2.55

2.40

160

6

2.90

2.80

2.70

2.60

200

3.20

3.10

3.00

2.90

225

8

3.45

3.30

3.25

3.10

250

3.60

3.45

3.40

3.25

280

10

3.80

3.65

3.55

3.40

315

12

4.10

3.95

3.85

3.70

Buried Pipes

Proposals covering fundamental prerequisites for installations underneath ground may be abridged as follows:

Commonly trenches ought to not be less than a metre profound.  Trenches ought to be straight sided, approximately 300mm more extensive than the pipe distance across to permit appropriate solidification of pressing materials.  Trench bottoms need to be as level as possible.

Ensure all flotsam and jetsam, rubble and sharp-edged items are cleared away.

On the other hand shingle/grit can be laid approximately 100mm profound on the floor of the trench.  Sand may be utilized but underground water is obligated to wash away leaving the pipe unsupported.

Pipes may be jointed above ground but it is imperative they not be moved for at least 2hours before being moved into place.

Once pipes are in correct position they need to be consealed with shingle/grit to a depth of 100mm over the crown of the pipe.  The shingle/grit must be amplified sideways to both trench dividers and requires compacting, ideally this had best be done before testing is carried out leaving the joints uncovered.

Before the pipes are re-covered check area thoroughly for risk of rubble, sharp-edged items getting into the trench.

Pressure testing may now be done and when complete will require back filling, cover the pipe joints with shingle/grit.

Below shows an example of the guidance’s given above.

Example to be inserted here?

Technical Information – How To……

Instructions for Jointing

The dissolvable cement works by chemically softening the exterior of the pipe and the interior of the fitting.  Joint astuteness is enormously decreased in case these surfaces are not completely spotless and correctly made ready.

  1. The pipe must be cut square and clean.  If a saw is used be aware this will generate shavings which could result in getting into the pipework structure.
  1. Bevel the pipe, roughly 3mm to 5mm depending upon pipe measure with either a deburring tool or rough file.  This anticipates the dissolvable cement layer being scratched from the surface of the fitting once joint is constructed.
  1. Clearly score the pipe a known distance from the end and clear of the area to be scraped.  This is required for ensuring the pipe infiltration into the attachment after construction.
  1. With a clean abrasive cloth completely smooth the end of the pipe to the size of the fitting socket.
  1. Meticulously scrape clean the inside of the fitting socket.
  1. Wipe the now smooth area of the pipe and fittings with a paper towel which has been dipped in pipe cleaning fluid or a lint free clean cloth.
  1. With a clean brush apply the dissolvable cement to the pipe and fitting with lengthwise strokes.  The scraped ranges need to be totally secured with the cement.  The sum required will shift with pipe distance across and the fit between pipe and fitting but ought to be such for all cases that the cement is still fluid when pipe and fitting are constructed.  It is vital to apply cement rapidly, to permit construction without considerable force being needed.
  1. Directly after applying the cement push the pipe straight into the fitting without rotating.  Depending on size of pipe and fitting you need to hold onto them for range of time for different sizes.  3/8” hold for few seconds but 8” and over up to 1 minute.  Implementation of the right sum of cement will result in a tidy globule of cement at the edge of the fitting and the pipe.  Avoid putting too much coating in the pipes and fittings especially small sizes as this can diminish the wall.  Extra care must be taken when working in cold conditions to ensure the joints are free from ice and dampness.  Additional curing time must be permitted to compensate for the low temperature.   
  1. Remove the surplus cement from the outside of the joint.    The drying time for joints will change with fit, quantity of dissolvable cement connected, surrounding air temperature and working pressure.  It is advised when possible the joints are left to dry for 24 hours before the test pressure is applied (up to 8”/225mm).  Be that as it may, it is perceived there will be times when joints will required for use within a few hours of being made.  A basic but safe working guide, where contents temperature will not exceed 20⁰C, is 1 hour per bar for systems up to 4”.  For bigger sizes increase time to 1½ hours per bar.  No matter what joints should be allowed to cure for a minimum of 4 hours.
  1. Ensure the pipe has been fully inserted by using the score made earlier.
  1. Once assembled leave the joint for a minimum of 10 minutes, this increases to 4 hours for bigger sizes and do not twist or bend the joint during this time.  The following joints may be done without waiting but do not impact pressure to the newly made joints in the system.  Make certain there is enough drying time before pressurization of the system.
  1. Put the lids back on the containers.


WARNINGS

Do NOT apply near exposed flame.

Do NOT smoke anywhere in the area using.

Do NOT joint in wet or rain conditions.

Do NOT apply in small compact spaces.

Do NOT use soiled brushes or cloths.

Do NOT use same brushes for multiple cements.

Do NOT water down or thin solvent cement.  See the instructions on the tin.

Note

To reach the correct speed of implementation on sizes 5”/140mm and over the cement should be applied to both pipe and fitting at the same time by two people.

Drying Times

Size Range

Up to 2½”       75mm

3″ –  4″               90mm – 125mm

5″ & 6″             140mm & 160mm

8″                    200mm & 225mm

10″ & 12″           250mm & 315mm

 
             

Drying Time

           

PVC-U

1 hr / bar

1 hr/ bar

1½ hrs / bar

2 hrs / bar

30 hrs minimum

 
             

* The drying period must never be less than 1 hr

   
             

A demonstration of the number of joints to be made per litre of cement is shown below:

Size Joints per Litre      PVC-U

mmInch

16 – 32 3/8 – 1 300

40 – 63 1¼ – 2 120

75 – 110 2½ – 4 50

125 – 140 5 15

160 – 225 6 – 8 8

250 – 315 10 – 12 3

Testing

The following testing method is recommended to be completed once the suitable minimum drying

time has been allowed for the joints.

The pipes should be placed into sections ready for testing.

Fill each section with cold water ensuring there are no air pockets.  Do not pressurise yet.

Carefully check for any leaks.  If no leaks present make sure you check for and eliminate any

remaining air.  The pressure may now be increased up to 3 bar but NO further at this moment.

Allow at least 10 minutes before checking for any pressure break down and repairing any leaks if

required.  If the pressure remains continuous then slowly increase the hydrostatic pressure to

1½ times the minimal operating pressure.

Leave the pressurised pipe section no more than 1 hour and the pressure should remain the same.