Natural Bend Radius in Pexgol Pipes
To create turns with Pexgol pipes laid inside trenches, above the ground or over pipe bridges, the pipe can be bent according to table 78.1.
The values in table 78.1. are relevant for installations at all ambient temperatures from low subzero temperatures and up to 40°C.
For pipe diameters lower than 110 mm use the values of the 110 mm pipes at all pressure classes.
Field bending involves excavating the trench to the appropriate bend radius, then sweeping or pulling the pipe string into the required bend and placing it in the trench.
This kind of pipeline design, which takes advantage of the natural flexibility of the pipe, reduces the number of connections and lowers head losses.
Observe appropriate safety precautions during field bending. Considerable force might be required to field bend the pipe, and the pipe could spring back forcibly if the restraints slip or are inadvertently released while bending.
Designing Pexgol pipes with natural bends
When designing Pexgol pipes with natural bends, it is recommended to consult with our field service personnel. Take into consideration that to bend the pipe on site, suitable facilities are required. Take into consideration the space required to insert the pipe into the construction, as well as the possibility to exert bending moment of the pipe.
“NATURAL” bends of Pexgol pipes
Table 78.1 shows bending radii for Pexgol pipes. If possible, design the pipeline with larger bending radii to facilitate pipe bending on site.
The pipe bends must be fixed with fixpoint clamps before and after each elbow. For pipe diameters of 280 mm and larger, the pipe bends must be supported in the centre in addition to the two fix points noted. For additional details please contact the Golan’s application engineer.
Route change of Pexgol pipes inside trenches
For a route change in buried pipes, it is recommended to dig the trench with the minimum natural bending radius listed in table 78.1.
Table No. 78.1: Natural bending radius
Natural Bends in Pexgol Pipes
When designing and installing Pexgol pipes in natural bends, high bending moments might be exerted upon the end- connectors. In case of self- restrained fittings no special care should be taken. In case of non-restrained fittings to special care should be taken to prevent excessive bending moment on the end-connectors due to forced installation.
See page 56 (Non-Restrained Fittings and Pullout Prevention Techniques).
Bending the Pipes
Use a suitable device, such as a winch or a lever, to bend the pipes. Remember that the pipe is rigid and considerable force is required for bending and fixing it – for example, 2 tons for a 110 mm pipe and 5 tons for a 280 mm pipe. Please exercise caution!
Bend the pipe carefully to avoid kinking. For best results, it is recommended to prepare a continuous support (with the radius of the pipe to be bent) for the pipe. Then bend the pipe against it.
The installation is complicated since it is difficult to calculate in advance the exact length of the pipe. As a result, on-site adaptation (field welding) is necessary.
Proper installation procedure:
The longer arm of the natural bend is more flexible than the shorter arm; therefore, always choose the longer arm as the pipe end whose length is adjusted.
Install the fitting onto the end of the shorter arm.
Connect the shorter arm to the existing counter-flange.
If necessary, install a fixpoint clamp before the fitting to protect it during bending.
4.1 If the fitting is an electrofusion fitting, wait three cooling times (3x) before continuing with the next step.
Adjust the length of the longer arm.
Cut the length and install the fitting.
6.1 If the fitting is an electrofusion fitting with a stub-end (flared end) connection, perform the welding when the flared end is free (not connected to the counter-flange). Connect the flared end & flange to the counter-flange only after waiting three cooling times (3x).
6.2 If the fitting is an electrofusion fitting which connects the longer arm to another Pexgol or PE pipe, install a temporary fixpoint bridge before welding in order to protect the electrofusion fitting during welding. Disassemble the temporary fixpoint bridge only after waiting three cooling times (3x).
6.3 See Non-restrained fittings page 56.
Natural Bends in Pexgol Pipes
1. Defining the design temperature.
The design temperature of the Pexgol pipe is chosen according to data from the RFI questionnaire.
1.1 Buried pipes: according to the temperature of the liquid flowing through the pipe.
1.2 Exposed pipes: design temperature calculated by adding 20°C to the maximum ambient temperature (for example, a design temperature of 60°C for maximum ambient temperature of 40°C).
1.3 Alternatively, according to the temperature of the liquid flowing through the pipe (if higher than 60°C).
2. Water and Newtonian fluids
2.1 The pipe class is selected according to the following data from the RFI questionnaire:
2.2 Pressure head losses in the line expressed in bars (taking into account the specific gravity of the transported material).
2.3 Design temperature (see first paragraph above).
2.4 Basic safety factor (design coefficient):
- 1.25 for water and fluids with the classification A in the chemical resistance list.
- For materials with classification B, C, D in the chemical resistance list, please consult Golan.
- 1.5 for air supply lines.
2.5 Static pressure according to the altitude difference in the line and the specific gravity of the transported material.
2.6 If the pipeline is horizontal and the static pressure is low, select class 6 and verify its suitability.
2.7 Choose a higher class with the same OD in order in to increase the transportable section lengths.
2.8 The hydraulic calculation usually results in the same OD.
2.9 If the altitude difference in the line is significant, select a Pexgol pipe class that has in the design temperature higher pressure rating than the static pressure. The additional pressure margin is used for the pressure head losses; this will determine the ID of the pipe.
2.10 The OD is determined by the Pexgol pipe class the customer chooses and the availability of this specific pipe diameter.
3. Replacing waterline steel pipes
When replacing steel pipes (Hazen - Williams C = 110) with Pexgol pipes (Hazen - Williams C = 155) with the same pressure head losses, the ID of the Pexgol pipe can be 88% of the ID of the existing steel pipe.
When replacing steel pipes with Pexgol pipes with the same ID, the head losses are expected to be lower by 50%.
4. Influence of temperature changes on Pexgol pipes
4.1 Pexgol pipes placed above the ground or over bridges tend to get longer (to expand) when temperature rises (snaking phenomenon) or to get shorter (contract) as the temperature decreases. Expansion or contraction does not affect the Pexgol pipe, even in extremely low temperatures.
4.2 There is no need to protect the pipe against thermal stresses, as they are absorbed by the pipe.
4.3 Fixpoints or guiding clamps are used for restraining the elongation of the pipe (mainly for aesthetic considerations).
4.4 There is no need for installation of “expansion joints” or omegas.
4.5 Special fixpoint clamps should be used before and after the fittings (as recommended) to prevent the pipe from pulling out.
5. Pexgol pipes above ground
Pexgol pipes withstand exposure to sunlight for unlimited periods—that is, the lifetime of the pipe.
Pexgol pipes can be placed directly on ground.
Special bedding is not required.
For further information see: Above ground installation guidelines.
6. Pipes under full vacuum conditions
It is recommended to use a minimum pipe class 15. For more information see page 36 "Vacuum/Suction Pipelines".
7. Pexgol pipes at low temperatures
Pexgol pipes are used at temperatures as low as -50°C and even lower. Since the Pexgol material does not become fragile at these temperatures, it tolerates bending and dragging at low temperatures during installation. Pexgol pipes tolerate complete ”homogeneous” freezing of the transported liquid. Homogeneous freezing takes place if the pipe is evenly exposed to low temperatures along the pipeline.
However, if freezing starts at localized freezing points, the pressure of the fluid which is trapped between two adjacent freezing points increases until the pipe bursts. This happens to any pipe material. Localized freezing points might be metal fittings (including Pex-lined steel fittings), fixpoint clamps or any point where the metal touches the pipe. Consequently, localized freezing points should be avoided or properly insulated.
Please note that this applies to both above-ground or shallow underground installations.
Slurry Design Considerations
1. The pipe class is determined based on the following data from the RFI Application Questionnaire:
- Working pressure
- Design temperature
- Chemical resistance of the pipe material to the slurry
2. The pipe diameter is chosen based on the ID of existing steel pipe or on the value of the minimum critical slurry velocity.
3. Replacing carbon steel slurry pipes with Pexgol pipes with the same ID: A slurry pipeline is designed according to the minimum critical velocity of the slurry material. Carbon steel slurry pipes can be replaced with Pexgol pipes of the same or slightly smaller nominal ID, maintaining the same slurry velocity.
Table No. 81.1: Replacing Carbon steel slurry pipes with Pexgol pipes
Table 81.1 can be used as guidelines for choosing the suitable Pexgol pipes for replacing carbon steel slurry pipes according to the ID and flanges of existing steel pipe. The values of the ID of the Pexgol pipes in Table 81.1 are nominal ID values which were calculated based on the value of the nominal wall thickness of the pipe. The Pexgol pipes were chosen assuming that the working conditions of the existing steel pipes are appropriate for the Pexgol pipe classes listed here. Pexgol special reducers should be used for matching ID of Pexgol pipes to existing steel pipes.
4. Abrasion allowance:
Pexgol pipes have an “abrasion allowance“ of 20% of the nominal wall thickness of the pipe. This means that the pipe can withstand the design working pressure until the remaining wall thickness of the pipe is reduced to 80% of the nominal value. The real lifetime of the pipe depends on the actual abrasion rate in the line. The 80% rule applies for all working pressures and all temperatures in all classes.
5. Increasing the ID of the Pexgol pipes due to abrasion results in decreasing the velocity of the slurry. In order to make sure that the value of the minimum critical slurry velocity is maintained after 20% abrasion, the ID of the Pexgol pipe can be calculated by multiplying the Nominal Pexgol pipe ID by the correction factors in Table 91.2.
Table No. 81.2: Correction factors for abrasion
Inclined and Dewatering Pipes, High-Gradient Supply Lines
- All these type of pipes should be axially restrained at the top and bottom of the line.
- The pump rests on the ground. The weight of the pump and water column is not supported by the pipe.
Defining the design temperature
The design temperature of the Pexgol pipe is chosen according to data from the RFI questionnaire.
- Buried pipes: according to the temperature of the liquid flowing through the pipe.
- Exposed pipes: design temperature calculated by adding 20°C to the maximum occurring ambient temperature (e.g. a design temperature of 60°C for an ambient temperature of up to 40°C).
Selecting the Pexgol pipe for dewatering/uphill pipes
Required flow rate – 150 cubic meters per hour Pipeline goes from an altitude of 2100 m to an altitude of 2235 m.
Line length – 500 m ambient temperature 40°C
The pipe can be installed above ground or covered by 0.9 m of soil.
Calculate the line pressure by grade line calculation or according to any other applicable method.
Calculate the static pressure at the lowest point of the pipeline taking into account the fluid density. For water, divide the altitude difference (in meters) in the line by 10. The result is in bar. Please note that the lowest point is not necessarily at the bottom of the pipeline! In this example: 2235 - 1100 = 135 / m = 13.5 bar
Choose the appropriate Pexgol pipe class from table 11.2 by looking at the design temperature. Select the Pexgol pipe class which has a higher working pressure than the calculated value in section 3.1. The additional pressure margin will be used for the head losses.
Design temp for above ground installation is 40 + 20 = 60°C.
Selected pipe class for buried pipes installation: Class 19. Working pressure - 14.9 bar at 40°C.
Selected pipe class for above ground installation:
A. Class 24: Working pressure -15 bar at 60°C.
B. Alternative pipe - class 30. Working pressure – 18.9 bar at 60°C. Design temperature for buried pipes is 40°C.
Design example with alternative pipe class 24. Working pressure 18.7
- Calculate the pressure margin and the allowable Head losses coefficient J;
- Pressure margin for above ground installation is 15-13.5=1.5bar=15m/J=15x100/500=3%
- Pressure margin for the alternative pipe for above ground installation is: 18.9-13.5 = 5.4 bar = 54 m/J = 54 x 100/500 = 10.8%
- Pressure margin for buried pipes installation 14.9-13.5=1.4bar=14m/J=14x100/500=2.8%
- Pressure margin for the alternative pipe for buried pipes installation: 18.7 - 13.5 = 5.2 bar = 52 m/J = 52 x 100/500 = 10.4%
- Select the pipe diameter according to the calculated J and the flow rate.
The selected pipe diameter for above ground installation is 200 class 24.
The alternative pipe diameter for above ground installation is 180 class 30.
The selected pipe diameter for buried pipe installation is 200 class 19.
The alternative pipe diameter for buried pipe installation is 160 class 24.
Advantages of the alternative pipes:
Smaller diameter – allows transportation of longer pipe sections = cheaper transportation.
Cheaper pipe per meter length.
Disadvantage: higher head losses.
The line designer should include in the line the all the required accessories including air relief valves and drain valves.
If the overall altitude difference in the line is much higher that the max. allowable altitude difference H of the highest Pexgol class available, the line should be designed using booster pumps.
Selecting the Pexgol pipe for a downhill pipeline using a full cross-section flow design. In a full cross-section flow design the pipe has to support the full static pressure (liquid column) of the line.
The Pipeline pipeline goes down a slope from an altitude of 2250 m to an altitude of 2100 m.
Required flow rate – 150 cubic meters per hour Line length – 1500 m Ambient temperature 40°C.
The pipe can be installed above ground or covered by 0.9 m of soil.
Calculate the line pressure by grade line calculation or according to any other method. Calculate the static pressure at the lowest point of the pipeline taking into account the fluid density. For water – divide the altitude difference (in meters) in the line by 10. The result is in bar. Please note that the lowest point is not necessarily at the bottom of the pipeline.In this example the lowest point in the line is located at the end of the line: 2250 - 1100 = 150 m = 15.0 bar.
Choose the suitable Pexgol pipe class from table 11.2 by looking at the design temperature. Select the Pexgol pipe class which has the same or slightly higher working pressure than the calculated value in section.
Design temp for above ground installation is 40 + 20 = 60°C. Selected pipe class for above ground installation:
For a full cross-section flow design the pipe should be Pexgol Class 24 in order to allow a working pressure of 15 bar at 60°C.
Calculate the allowable head losses coefficient J based on the altitude difference in the line and the line length: Altitude difference is: 150 m J = 150 x 100/1500 = 10%
For a full cross-section flow design, select the suitable pipe that can transport the required flow with the calculated value of J. Selected pipe class for above ground installation is 160 class 24. Selected pipe class for buried pipe installation is 160 class 19.
Check the value of the expected surge pressure (water hammer) against the maximum permissible. Total occasional pressure, which is 2.5 the working pressure in the design temperature.
For the 160 class 24, the Line velocity V = 4 m/sec.
According to the table 32.1 the surge pressure for class 24 is 3 bar for V = 1 m/sec. for V = 4 m/sec. the surge pressure value will be 4 x 3 = 12 bar.
The total occasional pressure will be 15 + 12 = 27 bar. The maximum permissible total occasional pressure in Class 24 at 60°C is 15 x 2.5 = 37.5 bar.
Conclusion – the 160 class 24 is O.K. or the 160 class 19, the line velocity V = 3.44 m/sec.
According to the table 32.1, the surge pressure for class24is3.2barforV=1m/secsoforV=3.44m/sec the surge pressure value will be 3.44 x 3.2 = 11 bar. The total occasional pressure will be 15 + 11 = 26 bar. The maximum permissible total occasional
pressure in Class 19 at 40°C is 14.9 x 2.5 = 37.25 bar. Conclusion – the 160 class 19 is O.K.
Air relief valves
Air relief valves are required in any pipeline material including Pexgol.
The line designer should include in the line the all the required accessories including air relief valves and drain valves.
As a service to our customers, Pexgol application engineers can perform the analysis of the line in cooperation with A.R.I. Israel and supply a drawing with the location of the air relief valves. Golan supplies the air relief valves and the saddles/fittings required for connecting the line accessories to the Pexgol pipes.
The following data is required for the analysis:
A: List of key points along the line in Excel file or PDF/ DWG drawing of the line with the following details:
Name of the point.
Location of the point – distance from the beginning of the line and height above a reference point.
Type and functionality of each fitting: drain, cut- off valve, pressure reducer, outlet connection to consumer (indicate flow rate), etc.
B: Working conditions:
- Flow direction
- Discharge rate
- Inlet/outlet pressures
Selecting the Pexgol pipe for downhill single slope pipeline using a partially filled cross-section flow design.
Please note that this type of design requires a skilled designer so the following information should be considered as guidelines only.
In case of a partially filled cross-section flow design, the pipe is to be designed so that it will be in a low pressure (close to an atmospheric pressure) in all or most of its length. This design allows the use of a lower pipe class of with a larger OD and this might be problematic for transportation.
Calculate the allowable head losses coefficient J based on the altitude difference in the line and the line length.
Calculate the ID of the pipeline (according to Hazen – Williams C = 155 or any other formula).
• In order to make sure that flow regime will be a partially filled cross-section, the selected actual ID of the line should be at least 25% higher than the calculated pipe ID according to previous design example.
• Selecting the Pexgol pipe class: It is a good practice to design Class 15 in order to allow full vacuum resistance and possibility of transporting long pipe sections. Lower pipe classes should be avoided in this case. Higher pipe classes can be designed for transporting longer sections while maintaining the required minimum ID for the partially filled crosssection low design.
Pexgol pipe for downhill single slope pipeline can be designed using a partially filled cross-section flow design.
Each top point in the line should be vented so that the pressure there is atmospheric pressure.
Each valley is actually a siphon so that the height of the fluid column above the bottom of the valley is calculated from the previous top point in the line.
In some cases, the pipe class might have to be higher than class 15, depending on the local static pressure.
Installing the Pexgol pipe
Pexgol pipes can be towed upwards from the bottom of the line or it is possible to slide the pipe down from a high point.
Empty pexgol pipes can be towed up to the top of the line in very long sections. Table 84.1 presents the maximum allowable length of an empty Pexgolpipe that is allowed to be towed or slid to its final location, depending on the design temperature.
The maximum allowable length is the same for all Pexgol pipe classes.
The required towing force can be calculated by multiplying the weight of the pipe by the friction coefficient of 0.5.
If the pipe consissts of more than one sections, the sections can be connected temporarily during towing.
Table No. 84.1: Towing of empty Pexgol pipe - maximum allowable length (meters)
If the pipe sections are already connected by fittings, they should be secured and protected by fixpoint bridges.
Securing inclined Pexgol pipes
The top and bottom ends of the Pexgol pipeline should be anchored by a fixpoint. see drawing.
The Pexgol pipeline can be laid uphill or downhill in a long continuous section, without any fixpoint between the top and bottom ends.
There is no limitation on the total pipe length.
It is recommended to design the pipe with an additional 1 - 2% slack in order to reduce potential axial contraction forces.
The weight of the pipe might increase due to accumulation of soil or snow on top of it. This additional weight will be balanced by the increasing friction between the pipe and the ground.
Restraining of fittings along the pipeline
- In slopes of less than 40°, all mechanical couplers (flared ends, flanged couplers etc.) should be restrained by floating fixpoint devices like Golan’s fixpoint bridge (page 75). Electrofusion couplers can be installed without a floating fixpoint device.
- In slopes above 40°, all type of fittings (including electrofusion couplers) should be restrained by floating fixpoint devices.
- When installing a repair fitting, the pipe can be secured by a fixpoint bridge prior to cutting the pipe (page 75).
Design Guidelines for Complete Systems
*See design example on page 7
Designing a complete solution by Golan:
For every application received from a customer, we must have the Application RFI Questionnaire and the relevant assembly drawings of the pipeline. We design the pipe class and recommend the complete solution.
The detailed assembly drawing of the proposed solution is sent to the client for approval. We transform the approved version into parts drawings and prepare a price quotation.
1.1 If possible, use Pexgol straight pipes with a natural bend. (see page 75). Pexgol pipes come in straight sections in maximum length of 11.8 meters. They are available with one or two flared ends and flanges. If you have to bend a pipe with a longer length, order two sections and make a longer pipe by connecting it with a reinforced electrofusion coupler. Always select the length of the two sections so that the electrofusion coupler is not in the exact location of the bend.
1.2 When straight pipe sections with the natural bend is not an option, use Prefabricated Pexgol elbows 3 x D or 1.5 x D.
1.3 Please note that our 1.5 x D elbows are significantly longer than the carbon steel 1.5 x D elbows.
1.4 3 x D elbows are recommended rather than 1.5 x D since 3 x D elbows reduce head losses and abrasion rate.
1.5 Other non-standard angles are available by special order.
1.6 Elbows and natural pipe bends must be fixed with fixpoint clamps before andafter each elbow. For pipe diameters of 280 mm and larger, thenatural pipe bends should be supported in the centre, in additionto the two fixpoints.
1.7 If there is not enough space for Pexgol elbows, you can specify Pex-lined steel elbows, (Pex-lined fittings, see page 61).
2. Other fittings
2.1 The following items, in addition to straight pipe sections and elbows, can be supplied from Pexgol material: concentric or eccentric reducers and instrumentation Tees.
3. Pex-lined steel fittings
3.1 Components in the line which are not straight pipes or elbows including steel Tees, laterals, and others can be designed as Pex-lined steel fittings. Choose standard items from our Fittings Catalog, page 137.
3.2 However, if you find that you need to make a non-standard item with longer or shorter legs, make your selection and ask Golan for approval.
3.3 The maximum length of any item is approx 2000 mm x 2000 mm.
3.4 The standard items come with fixed flanges.
3.5 When Pex-lined steel fittings are connected to Pexgol pipes or elbows, the ID of the Pex-lined steel fittings can be larger than the ID of the Pexgol pipe with the same flange size .In order to match up their ID , smaller –size fittings with the same flange sizes as the flanges of the pipes can be used. Please consult us.
4. Expansion joints & Omega loops:
4.1 Expansion joints and Omega loops are not necessary in a Pexgol system. However, expansion joints might be needed when connecting a few Pex-lined steel fittings.
5. Influence of temperature changes on pipeline length
5.1 The length of Pexgol pipes can be changed by 0.3% due to a temperature change of 20°C, meaning 3 mm for every 1 meter.
5.2 When installing a straight Pexgol pipe section between two steel flanges, take into consideration the thermal expansion of the Pexgol pipe.
6. Field welding
6.1 The actual length of the pipe can be different than the designed length due to production tolerances and temperature changes.
6.2 Field welds” should be included in the design in order to compensate for the deviation of the actual length of the pipe during the installation from the designed length.
6.3 This is very important in case of pipes and elbows with flared ends . It is a good practice to design some pipe ends with mechanical couplers.
6.4 When using only mechanical connectors, design some of them so that the final pipe length can be adjusted on site.
7. Protecting the fittings
7.1 When designing Pexgol pipes and fittings, the designer can utilize the flexibility of the Pexgol pipes & elbows. However, electrofusion and mechanical fittings should be regarded as rigid items.
7.2 Special care should be exercised in order to prevent excessive bending moment from being exerted on the fittings due to forced installation
8.1 Fixpoints must be designed before and after each fitting (for example, flared end connection) as specified in our engineering guide.
9. Specifying the length of the Pexgol straight sections and elbows as separate items is acceptable after the design has been completed and approved by the designers and by Golan.
9.1 It is a good practice to specify a longer section to allow for measuring inaccuracies other possible errors.
Design Considerations for Pexgol Fittings
1. General considerations
1.1 Use only fittings approved by Pexgol and listed in the Engineering Guide.
1.2 Service limitations (as relevant) for each type of fitting are specified in the Engineering Guide. When designing Pexgol pipes and fittings, the designer can utilize the flexibility of the Pexgol pipes & elbows. However, electrofusion and mechanical fittings should be regarded as rigid items.
1.3 Special care should be exercised in order to prevent excessive bending moment from being exerted on the fittings due to forced installation.
1.4 Use special fixpoint clamps before and after the fittings where required (see Non-restrained fittings).
1.5 Mechanical fittings might cause local reduction of the inner diameter at pipe ends.
1.6 Drawings of the fittings are supplied on request.
1.7 For further questions, please consult Golan’s application engineer.
2. Pre-fabricated Pexgol elbows
2.1 Prefabricated elbows are available in all pipe
classes with diameters up to 630 mm.
2.2 The standard bending radius of the elbows is approximately R = 3D or R = 1.5D for 450 or 900 elbows.
2.3 The working pressures and temperatures are the same as the Pexgol pipe class from which the elbow is made.
2.4 Order elbows with plain ends for either flanged couplings or electrofusion fittings.
2.5 Elbows with flared ends with or without flanges are available.
2.6 Flared end connectors can be used throughout the entire range of allowable working temperatures and pressures.
2.7 Install special fixpoint clamps before and after each flared end.
3. Pexgol spigot reducers
3.1 Pexgol spigot reducers of all sizes and all pipe classes are available on request; (see page 60 for more details).
3.2 The working pressures and temperatures are the same as for the Pexgol pipe class.
3.3 The Pexgol reducers are supplied with flared ends, with or without flanges.
4. Pexgol spacers and special reducers
4.1 Pexgol instrument tees of all sizes are available on request; (see page 68 for more details).
5. Pexgol instrument tees
6. PEX-lined steel fittings
6.1 Pex-lined steel fittings can be used as a part of any Pexgol pipe system. Their working pressures and temperatures are usually higher than working pressures and temperatures of the Pexgol pipes.
6.2 The Pex-lined steel fittings are available in nearly any size and shape; see product page 61 for more details.
6.3 The minimum length of each fitting is indicated in the Fittings Catalog, pages 137, 146 & 61. This length can be reduced after consulting Golan Plastic Products.
6.4 It is possible to order a non-standard fitting which is a combination of standard fittings, or a standard fitting with longer legs.
6.5 The maximum allowable length for any such fitting is 2200 mm x 2200 mm.
6.6 Pex-lined steel fittings can be used in the following cases:
- A fitting that is not available as an all-Pexgol fitting is required.
- The all-Pexgol fitting is too long.
- A special shape is required.
6.7 All the Pex-lined steel fittings can be connected to the flared ends of the Pexgol pipes without an additional gasket.
6.8 All the Pex-lined steel fittings must be fully supported when installed on pipe bridges.
7. Pexgol Pipes with flared ends
7.1 Pexgol pipes up to 160 mm, in lengths according to the tables for transportation in coils in Transportation, are available with flared end and metal flanges.
7.2 Larger diameter Pexgol pipes (up to 630 mm) can be ordered in any length up to 11.5 meters (to fit into 40 ft. containers) with one or two flared ends.
7.3 Flared ends connect two Pexgol pipes or a Pexgol pipe to a fitting.
7.4 The sections with flared ends are produced with a tolerance of +/- 10 mm in length.
7.5 No additional gaskets are needed.
7.6 Tightening the flanges of the flared end connectors does not require specific torque values. Simply tighten the bolts evenly around the flange until all bolts are tight.
7.7 The flanges are supplied according to industrial standard ASA 150. Other flanges are available by special order.
7.8 A flared end connection can be used throughout the range of allowable working temperatures and pressures.
7.9 Prefabricated Pexgol elbows with flared ends are also available.
7.10 Use special fixpoint clamps before and after the flared.
8. PE100 electrofusion fittings
- PE100 couplers can be used up to 45°-50°C.
- Regarding working pressures and temperature of PN16 and PN25 couplers, please refer to the recommendations of the approved manufacturers.
- The PE100 electrofusion fittings must be protected in the following cases:
- Above ground installations in extremely low temperatures.
- Underground installations without sand embedding.
9. Pex2Pex electrofusion couplers
9.1 Pex2Pex electrofusion couplers are used for the same pressure rating as Pexgol pipes SDR 11 up to 60°C. For 70°C the maximum allowable pressure is 6 bar for 50 years.
9.2 The couplers are not UV resistant and must be protected from UV light.
10. Special high temperature electrofusion couplers
10.1 Special high temperature and pressure couplers for all pipe sizes can be specified on request. Please consult Golan’s application engineer.
11. Brass fittings
- GP bolt connectors are self-restraint type fittings.
- For full details, see Fittings Catalog, page 132.
- It is recommended to install brass fittings above the ground. If you must install them anyway, make sure they are protected from corrosion.
- Do not connect brass fittings to steel or galvanized pipes or fittings.
12. GP flanged couplings
12.1 Available from 63 mm (with 2” flange) to 630 mm (with 24” flange).
12.2 All couplings comply with ASA 150 flange standard and some of them comply with other international standards; see table 69.1.
12.3 GP flanged couplings are suitable for the full range of allowable working temperatures and pressures of Pexgol pipes.
12.4 In above ground applications, use special fixpoint clamps before and after the fittings
12.5 In some cases, the ID of the Pexgol pipes might be reduced locally by the GP flanged coupling.
13. Brass saddles
13.1 Available for Pexgol pipes from 32 mm to 160 mm.
13.2 British Standard Pipe Tapered Threaded (BSPT) threaded outlets.
13.3 Suitable for the full temperature and pressure ranges of Pexgol pipes.
13.4 See the instruction for the installation of saddles (page 98).
14. Stainless Steel Saddles
14.1 Available for Pexgol pipes from 110 mm to 630 mm.
14.2 Flanged or threaded outlets (internal thread).
14.3 Maximum outlet diameter – up to half of the pipe’s outer diameter.
14.4 The saddles are available with a special rubber coating over the flange and neck to protect from corrosive liquids to which stainless steel is not resistant.
14.5 Stainless steel saddles can be used throughout the range of allowable working temperatures and pressures for Pexgol pipes.
14.6 In above ground applications, use special fixpoint clamps before and after the fittings.
14.7 Stainless steel saddles working pressure it up to 150 psi (10.3 bar).
15. Victaulic, Bruno and Aquafast fittings for HDPE pipes are approved for use with Pexgol pipe classes 10 and higher pressure classes.
15.1 In above ground applications, use special fixpoint clamps before and after the fittings.