Properties
Download as PDFChemical Resistance
Saudi Vitrified Clay Pipes and Fittings are immune to attack by all alkalis or acids contained in waste water, ground water and in the earth.
Physical Properties
The most important properties which might be required for calculating purposes are listed in the following table:
| Specific weight (kN/m3) | 22 |
| Bending tensile strength (N/mm2) | 15 - 40 |
| Crushing strength (N/mm2) | 100 - 200 |
| Tensile strength (N/mm2) | 10 - 20 |
| Mohr's hardness | ≈ 7 |
| Modulus of elasticity (N/mm2) | ≈ 50,000 |
| Coefficient of thermal expansion (1/k) | ≈ 5.10-6 |
| Thermal conductivity (W/m.k) | ≈ 1.2 |
Wall Roughness
The degree of roughness has a decisive influence on the hydraulic behaviour.
Natural roughness k Values varied between:
k = 0.02 mm in the case of straight pipeline and k = 0.15 mm in the case of a pipeline with a close succession of branches.
Pipes with internal glazing shall be deemed to meet these requirements.
Abrasion Resistance
The abrasion resistance of pipe depends on the strength of the pipe material, the smoothness of its internal surface and the wall thickness. Special attention is paid to these factors in the manufacture of Saudi Vitrified Clay Pipes which ensures a very high resistance to abrasion.
According to EN 295, vetrified clay pipes and fittings are resistant to abrasion.
Ring Bending Tensile Strength
Operating as gravity lines, pipelines are exposed only to an insignificant internal pressure, if at all Nevertheless, they do have to withstand loads arising from backfilling or surcharge and traffic loads. This results in bending moments in the pipe wall and is known as "ring bending tensile strength". The ring bending tensile strength can be calculated from the ultimate crushing load.
Impermeability to Water
The impermeability to water is tested on individual vitrified clay pipes and fittings according to standards. The permissible water addition during the test period of 15 minutes is 0.07 ltr/m2. EN 295 calls for vitrified clay pipes and fittings to withstand an internal pressure of 5 N/cm2 (5m head of water). In addition to the pressure level called for by standard specification, Saudi Vitrified Clay Pipes are guaranteed to withstand an internal and external pressure of 10 N/cm2 (10m head of water).
Dimensional Accuracy
Dimensions and unavoidable permissible manufacturing tolerances are given in tables in products section. Beyond this, the deviation from straightness of the barrel of a pipe must not exceed the values stated in the following table:
Deviation from straighness of pipe barrel
| Nominal Size | Deviation mm / meter of pipe length |
| DN < 150 | 5 |
| 150 ≤ DN < 200 | 4.5 |
| 200 ≤ DN ≤ 300 | 4 |
| DN > 300 | 3 |