Performing Pressure Tests in Pexgol Water Supply Lines and Dewatering
Test purpose: final check to make sure there are no leakages in the fittings.
1.1 Make sure the underground pipes are already covered, leaving only the fittings uncovered It is recommended to fill up the pipeline with water at the maximum working pressure on the day before the test
1.2 On the day of the test, inspect the pipeline visually,especially around the fittings.
1.3 Temporarily cover metal fittings (flanged couplings, branch-off saddles) to prevent excessive heat buildup due to exposure to sunlight.
1.4 For installation above the ground, test pressures in the table 92.1. Take into consideration that the pipe might be heated due to exposure to sunlight.
1.5 Take into consideration changes in the pipeline topography (which could create higher local pressure due to a water column); reduce the test pressure accordingly.
Test puPressure testing:
1.1 Bring the pressure to the level of the test pressure (see table 92.1) and then close the feeding line.
1.2 As the pipe is flexible and tends to expand its diameter under pressure, the line pressure is expected to decrease.
1.3 Increase the line pressure again, up to the test pressure.
1.4 With each cycle of pressure reduction and increase, the pressure is expected to decrease less.
After 3-4 cycles, open the valve and close it immediately, rapidly lowering the pressure to approx. 75% of the test pressure by letting water out of the line.
1.1 After closing the valve, the pressure is expected to increase as a result of the tendency of the pipe to decrease its volume.
1.2 If the pressure decreases instead of increasing, investigate the reason for pressure loss, for example, leakages at the fittings.
Table No. 92.1: Pressure test
Instructions for Welding Electrofusion Fittings
Electrofusion fittings can be used to connect Pexgol cross-linked polyethylene pipes.
The pipes and fitting are connected by means of fusion welding creating a leak-proof seal.
A sealing ring is not needed.
During the electrofusion process a current is transported through a heating wire.
The surrounding material around the wire is melted and welds the pipe to the fitting.
Electrofusion system is one of Pexgol’s connector systems, providing all connection technologies for Pexgol pipes.
Electrofusion fittings are the main means of connection in municipal water and industrial distribution systems.
Fittings are tested and have a lifetime of 50 years, according to the European standards a working pressures of 16 atm in water networks.
Lightweight and small volume welding connectors.
Economical use especially for big diameters in water transportation.
Connectors are offered in diameters ranging from 20mm to 630 mm as well as in a wide variety: couplers, elbows, end plugs, Tees, saddles, tapping saddles (for connecting new outlets to “live line”).
The entire electrofusion process is executed and fully monitored by the computerized control box ensuring safe, reliable connections.
Installation instructions for electrofusion fittings: Installation performed only by trained workers who have received a valid certificate showing that they have been trained by a person authorized by Pexgol.
Type of electrofusion fittings: Use only electrofusion fittings approved for fusion with Pexgol cross-linked polyethylene pipes.
Wall thickness defined as follows:
25 – 75 mm pipes, minimum S.D.R. 11
90 – 355 mm pipes, minimum S.D.R. 16.2
PN 16 electrofusion fittings are suitable for working together with Pexgol pipes which are rated up to pressures of P.N. 15 in water or 10 bars in gas (only PE spigot connectors are produced in two levels, P.N. 10 and P.N. 16).
Rounding the pipe
For a quality fusion and for easy insertion, rounding the pipe is compulsory. This is achieved by using rounding tools which are placed on the pipe end. The tools maintain a rounded pipe during the welding process.
Support of the fitting during the welding process:
When welding pipes in diameters 90 mm and higher, the pipe should be inserted into the fitting by means of spanners (come-alongs) which allow controlled insertion and ensure the coupler does not move during the welding process.
Please note the cooling time that appears on a sticker on each fitting.
Do not disassemble spanners and rounding devices until the cooling time has elapsed.
When the fusion process is completed, note the hour and add the cooling time. The result is the disassemble time. Mark this time on the fitting and do not disassemble it earlier than this time!
Pexgol electrofusion fittings are allowed for use at the following temperatures: In case of higher pressures please consult the Pexgol Field Service.
Preparing the fittings for welding: Preparation and welding can be conducted at ambient temperature. If the weather is windy (with dust) or rain or other sources of humidity, the welding area should be protected by a cover or welding should be halted until the weather conditions are suitable.
Preparation (cleaning and scrubbing) must be done close to the welding time. Do not prepare pipes and fittings for welding if you plan to weld at a later stage.
Scraping and peeling of the pipe: universal or hand scraper must be in perfect working condition with a sharp blade. The blade in the universal scraper should be replaced when no longer sharp. The blade of the hand scraper should be sharpened from time to time using a fine iron file.
The thickness of the scraped layer should be as follows:
• Diameter: 20 - 25 mm, 0.15 - 0.20 mm
• Diameter: 32 - 75 mm, 0.15 - 0.25 mm
• Diameter: 90 - 355 mm, 0.20 - 0.30 mm
A. Marking the pipe for cutting
The pipe must be free of dirt and dust.
Use a plastic marking tape long enough to go around the pipe circumference.
Mark the welding location around the pipe with a marker.
B. Cutting the pipe
1. Use a cutting tool for plastic pipes up to diameter 160 mm. From diameter 180 mm and higher use a JigSaw cutter, with a suitable plastic saw.
C. Rounding of the pipe and scraping the oxidized layer
Round the pipe prior to scraping it.
Place the rounding device on the pipe so that the distance from the pipe to the rounder is equal to the depth insertion of the pipe into the fitting plus 4 centimeters.
Note: To ensure perfect, symmetric roundness of the pipe, make sure that the rounding device is placed in such a way that the screws will be on the flattened sides of the pipe (on the narrow axis of the oval) and fasten them until perfect roundness of the pipe is reached.
Use the universal rotational scraper according to the instructions.
D. Pipe Preparation
The pipe must be marked to prepare insertion of the fitting.
Move the rounding device until the marking of the full insertion.
It is absolutely necessary to clean entire welding surface. This is performed with a special cleaning solution of 95% ethanol (or equivalent) and new clean paper wipers to ensure that no fibers are left on the surface.
E. Installing the fitting onto the pipe
Remove the fitting from its original packaging, only when you are ready to start the welding process. Clean the inner side of the fitting with the special cleaning solution. Clean the pipe surface again.
Install the fitting onto the prepared pipe and make sure that the pipe is fully inserted into the fitting up to the end. The fitting should fit easily into the pipe.
F. Preparation of the opposite pipe end for insertion
Clean, mark and place the rounding device as described.
Pull the pipe into the fitting by means of 2 spanners from each side
until the rounder and the coupler meet.
Make sure to insert the pipe straight and precisely along the axis of the fitting by guiding both spanners. Make sure that there are no “angles” between the pipe’s axis and the fitting’s axis.
Please follow carefully installation instructions for the electrofusion control box.
Connect the terminals from the control box to the fitting. Make sure to connect “black to black” and “red to red”, and make sure that the electric cable is loose, not pulled tight.
Operate the control box and start the welding process.
H. Cooling time
At the end of the fusion carefully remove the black and red terminals from the fitting.
The correct cooling time is shown on the barcode label on each fitting. Mark on the coupler the exact hour when the coupler can be removed (adding the correct cooling time to the exact hour when the fusion was completed).
Dismantle the clamps and rounding equipment only at the end of the cooling time.
Since pressure testing requires lower temperatures of the joint, we recommend waiting twice the cooling time after fusion before pressurizing the pipe and waiting 3 times the cooling time after fusion before beginning pressure testing.
Welding of Saddles
A. Pipe must be marked
The pipe must be free of dirt and dust.
Place the lower part of the saddle on the place intended for fusion, mark the location of the outlet by marking a line all around the pipe. Use the lower part of the saddle for marking in order to avoid dirtying the upper part prior to welding.
Mark 3 lines on each side of the line at a distance of 30 mm from each other.
Remove the lower part and scrape the marked area with a manual scraper
until all lines are scraped (except for the center line).
Note: The manual scraper should be very sharp! Sharpen it by rotating the knife from time to time (4 positions) and by sharpening it with a fine iron file.
Use a manual scraper and scrape using two hands to achieve best results.
B. Pipe preparation and mounting of the saddle
Clean the pipe with a special cleaning solution for PE cleaning (ethanol) as any other fluid may damage the joint. To apply the solution, use clean wipes.
Clean the inner side of the upper saddle and install it to the pipe.
Close the saddle screws so that the upper and lower parts meet.
Fasten the screws.
Note: The hole should be drilled only after the welding is completed.
Please follow carefully installation instructions of the welding device.
Connect the terminals from the generator to the saddle “red to red”, “black to black”.
Operate the generator and start welding process.
D. Cooling time and drilling of hole
At the end of the fusion carefully remove the black and red terminals from the fitting.
Mark on the coupler the exact hour when the coupler can be removed (adding the correct cooling time to the exact hour when the fusion was completed).
Dismantle the clamps and rerounding equipment only at the end ofthe cooling time. After cooling, drill the outlet hole using a hole saw tool.
Installation Instructions for Saddles
Note: the following data for installing Golan brass saddles, electrofusion saddles and Krausz stainless steel saddles to Pexgol pipes.
Install all saddles onto the pipe prior to drilling the outlet hole.
Table No. 98.1: Dimensions of drills for outlet hole in brass saddles
• Saddles up to 63 mm – 11 mm wrench
• Saddles 75 mm and 90 mm – 14 mm wrench • Tighten the saddles until the two halves meet.
Table No. 98.2: Dimensions of drills for outlet hole in stainless steel saddles
Install electrofusion saddles of all manufacturers (Plasson, Friatec, GF/Wavin) and Plasson mechanical saddles according to the manufacturer’s instructions.
Connecting Pexgol Pipes with Flared Ends
The flared-end connection is suitable for both hot and cold media. Special fixpoint clamps should be used before and after the flared ends (see pages 57 & 73). Flange material is carbon steel A37. Other carbon steel or stainless steel grades can be ordered.
In case of sub zero temperatures, special restraining techniques should be employed to prevent pulling out of the flared end from the flanges.
No gasket is needed when connecting two Pexgol pipes with flared ends and flanges or when connecting a Pexgol pipe with a flared end to a flanged fitting.
Tighten the bolts evenly around the flange until all the bolts are all tight.
If torque wrenches are applied , use the recommended values in the following table. Tighten the bolts evenly using 75% of the recommended torque values and then tighten to the final value.
No retorquing is necessary in the flared ends of Pexgol pipes.
Table No. 99.1: Tightening torque values for Pexgol flared ends
Repair Instructions for Pexgol Pipe
1. Small hole (up to 5 cm diameter)
1.1 Uncover the pipe, 2 meters along the pipe and 0.5 meter below the pipe.
1.2 Carefully clean the soil from the pipe and make sure no scratches extend beyond the repair area.
1.3 Use a repair fitting, supplied by Golan or use a branch-off saddle.
1.4 In case of vertical installation (dewatering line), the fitting must be protected by a fixpoint bridge.
2. Large hole requiring (replacing a pipe section)
2.1 Uncover the pipe, 3 meters along the pipe and 0.5 meters below the pipe.
2.2 Cut out the section of the pipe with the hole and replace with a new section.
2.3 In most cases, the maximum length of the section to be replaced does not exceed 1 meter in length.
2.4 The new section will be connected by:
- Two electrofusion repair couplers Four Golan flanged couplings
- Two Plasson mechanical couplers (for pipes up to 160 mm
Only technicians trained by Golan’s field service personnel are authorized to perform the repair.
If necessary, can stop water flow using common squeeze-off techniques.
In case of a vertical installation (dewatering line), the pipe must be secured by a fixpoint bridge prior o cutting the pipe.
Follow the instructions according to the size of the hole in the pipe.
Instructions for Underground Installation of Pexgol Pipes
For all Pexgol pipe classes, the minimum recommended depth of the trench is 60 cm, to prevent mechanical damage to the pipe. If the pipe is to be covered only to prevent solar heating, the designer may reduce this depth.
In cold areas the installation depth may be increased by the designer to prevent freezing of the transported fluids.
For the maximum allowed installation depth for each pipe class, please contact the application engineer.
If required, the width can be increased to allow more comfortable work in the trench. The minimum recommendation depth of the trench is 60 cm, to prevent mechanical damage of the pipe.
For a route change, for example a 90° angle, it is recommended to dig the trench with a suitable radius.
See Natural bending radius in page 78.
The following table shows the minimum required trench width for Pexgol pipes.
Table No. 101.1: Trench width
Backfilling of the Trench
The excellent scratch resistance of the Pexgol pipes enables laying the pipes in trenches with no sand bedding; if sand bedding is required by the pipe designer, fill the trench with sand 10 cm above the pipe.
Backfilling the trench using the earth originally removed from the trench is allowed (in accordance with ISO 14531, Part 4); if corrosive soil is used to cover Pexgol pipes that are connected with metal fittings, cover the fittings with sand, not with the corrosive soil.
No compacting is required for any class of Pexgol pipes regardless of the depth of the trench.
Installation below a road or a pavement can be done without any protective sleeves. In this case, controlled compacting of the soil/ground, according to the designer’s instructions, should be applied when covering the pipe to prevent the ground sinking.
It is recommended to insulate hot water underground Pexgol pipes to reduce energy losses.
Above Ground Installation Guidelines
Above-ground installation of Pexgol pipes is advantageous in the following cases:
- Slurry lines which are frequently relocated.
- Installation through marshes or areas with difficult access.
- Quick installation of temporary pipelines.
Pexgol pipes withstand exposure to sunlight for pipe lifetime.
The coefficient of expansion of Pexgol pipes is high compared to steel pipes, but the forces generated by thermal stresses are much lower. The reason is the low modulus of elasticity and the fact that the Pexgol pipes feature stress relaxation.
Pexgol pipes installed above ground might increase in length as a result of temperature increases and tend to undergo “snaking”. Longitudinal elongation and contraction of the pipe is not uniform due to the coefficient of friction between the pipe and the ground varies. However, the toughness and the exceptional abrasion resistance of Pexgol pipes enable the pipes to move across the soil without affecting strength or service life.
Above ground installation instructions for Pexgol pipes laid on the ground
When the design temperature is lower than the installation temperature. The pipe tends to contract. The contraction creates axial stresses in the pipes which tend to pullout the pipes from the fittings.
Installing Pexgol pipes above the ground with a calculated slack rather than in a straight line, is a way to reduce thermal stresses.
This procedure reduces the tendency of the pipe to pull out of its fittings.
The slack (calculated according to the Pexgol coefficient of thermal contraction) is 0.2% or 2 mm for every meter per 10°C.
The actual value depends on the temperature difference between the installation temperature and the lowest temperature.
The slack can be maintained by pushing the mid span of the pipe slightly sidewise during the installation.
Axially unrestrained fittings should be secured and protected from pull out, (see page 56).
Maintaining Pexgol pipeline in a straight line, on the ground or on pipe racks
If a straight pipeline is required, guiding the pipeline at intervals is a good method of limiting and controlling thermal expansion and contraction of the pipeline.
The smaller the distance between the guides, the smaller the theoretic increase in pipe length. As a result, lateral deflections decrease and the pipeline remains straight.
Determining the maximum distance between two guides
The distance between two adjacent guides is calculated according to the following formula:
L = F x D where:
L is the distance (in m) between the guides.
D = outside pipe diameter (in mm).
F is a coefficient which depends on the temperature increase ΔT between the installation temperature and the design temperature (See table 70.1)
The formula allows for a maximum sidewise deflection of 50 mm between two adjacent guides.
Example: Pipe diameter 200 mm, installation temperature 20°C, maximum ambient temperature 40°C, design temperature is 20 + 40 = 60°C. ΔT=60°-20°=40° I F=0.064 I L=0.064x200=12.8m
Table No. 102.1: Coefficients F
Pexgol Horizontally Supported Pipeline
The distance between two adjacent supports can be found in the following table:
Figure 103.1: Maximum supports distance
The values shown in Figure 103.1 must be multiplied by the following correction factors in Table 103.2.
Table No. 103.2: Correction factors for figure 103.1