DESIGN GUIDELINES FOR COMPLETE SYSTEMS
Designing a Complete Solution by GPP:
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 an electrofusion coupler.
1.2 When straight pipe sections with the natural bend is not an option, use Pexgol elbows.
1.3 Please note that our elbows are significantly longer than the carbon steel 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 If there is not enough space for Pexgol elbows, you can specify Pex-lined steel elbows.
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 instrument Tees.
3. PE-X 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 PE-X lined steel fittings. Choose standard items from our Fittings Catalog.
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 GPP for approval.
3.3 The maximum length of any item is approximately 2200 mm x 2200 mm.
3.4 The standard items come with fixed flanges.
3.5 When PE-X lined steel fittings are connected to Pexgol pipes or elbows, the ID of the PE-X 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. However, expansion joints might be needed to protect other fittings such as carbon steel lined 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 metre.
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 connections, such as GP Flanged 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 consider the flexibility of the Pexgol pipes & elbows. In order to reduce the number of fix points, 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 mechanical fittings due to forced installation.
8.1 In case of fittings that should be protected by fix points (as specified on our Engineering Guide), the fix points must be located before and after each fitting. For further details see table on page 101.
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