Project R1041: Dubai Parks Access from Sheikh Zayed Road Dubai Sewerage and Drainage Master Plan Standard Specifications Volume 2 Part III

March 2015 Tender Documents Page 4/13

All thermoplastic pipes shall be shaded/protected from direct sunlight during handling, transportation, storage and laying. The Contractor shall ensure that thermoplastic pipes do not come into contact with bituminous or other hydrocarbon based materials. Determination of Ring Stiffness of Thermoplastic Pipes shall be tested at Dubai Central Laboratory in accordance with BS EN ISO 9969:2007 (Mechanical Testing)

4.3 GRANULAR MATERIAL FOR PIPE BEDDING

Granular material for pipe bedding shall be free-draining, hard, clean, chemically stable gravel or crushed stone to BS EN 12620 and shall be graded in accordance with BS EN 12620 as shown in the following table:-

Table 4-3. Grading of Granular Material for Pipe Bedding

Test Sieve Percentage by Weight Passing Sieve

( mm) For Pipe For Pipe Diameters Diameters upto 600 mm 400 mm and above

63 - - 37.5 - - 20 - 100 14 100 85 - 100 10 85 - 100 0 - 50 5 0 - 25 0 - 10

2.36 0 - 5 -

Notes: 1) For pipes 400 mm to 600 mm diameter, either grading is acceptable. 2) Total acid soluble content of the material when tested in accordance

with BS1377 shall not exceed 0.3 percent by weight of sulphate expressed as SO3 (sulphur trioxide).

3) The material shall have a Compaction Fraction value not exceeding

0.15. 4) For uPVC pipes only rounded aggregates will be permitted but for all

other pipe materials crushed aggregates may also be used.

4.3.1 Stone for Land Drains Stone for land drains shall be nominal single size 20 mm in accordance with the following table or the manufacturer’s recommendations if different, and placed as shown on the drawings. The stone shall also comply with the general requirements of Clause 4.3.

Project R1041: Dubai Parks Access from Sheikh Zayed Road Dubai Sewerage and Drainage Master Plan Standard Specifications Volume 2 Part III

March 2015 Tender Documents Page 4/14

Table 4-4. Grading of Stone for Land Drains

Test Sieve Percentage by Weight Passing Sieve

(mm) 75 - 63 -

37.5 100 20 85-100 14 - 10 0 - 25 5 0 - 5

2.36 -

4.3.2 Compaction Fraction Test For testing pipe bedding material, a representative sample of about 40 kg shall be heaped onto a clean surface and quartered to obtain approximately 10 kg. The moisture content of the sample should not differ materially from that of the main body of material, at the time of use in the trench. A 150 mm internal diameter open ended cylinder 250 mm high, shall be placed on a firm flat surface and loosely filled, without tamping, from the 10 kg sample. Any surplus material shall be struck off level with the top of the cylinder. The area around the filled cylinder shall be cleared of all surplus material and the cylinder then lifted clear of its contents and placed alongside the material. Approximately one quarter of the material shall then be replaced into the cylinder and compacted by tamping vigorously with a 40 mm diameter metal rammer weighing about 1 kg until no further compaction can be obtained. This operation shall then be repeated for each of the remaining quarters, tamping the final surface as level as possible. The distance from the top of the cylinder to the surface of final layer shall then be measured and this value, divided by the height of the cylinder, shall be taken as the Compaction Fraction.

4.4 CONVENTIONAL (OPEN TRENCH) PIPELINE CONSTRUCTION

4.4.1 General This section applies to conventional open-trench pipe works. Non-conventional pipeworks have been detailed in Sections 14 and 16.

4.4.2 Nominal Trench Widths Nominal trench widths for single pipelines shall be defined as 1.50 times the diameter plus 500 mm, subject to a minimum trench width of 750 mm. Nominal trench widths for two or more pipes in the same trench (laid in parallel with similar invert levels) shall be defined as the sum of the internal diameters plus 450 mm between the pipes, plus 750 mm.