Nominal bore pipes

Applied gauge pressure bar Nominal standard pipe size (nominal bore) (mm) ... 

Maximum recommended airflow (l/s free air) through medium series steel pipe for branch mains not exceeding 15 meters in length (see BS 1387). The flow values are based on maximum recommended peak flows. Normal steady air consumption should not exceed 80 per cent of these figures in pipe sizes 20 mm nominal bore and above. 

Bulk hydrate is discharged pneumatically from a vehicle into a reception silo, via a filling pipe (typically 100 mm nominal bore), which may be up to 40 m long. Bends should have a radius of at least 1 m. 

In Eqs. (10.1)-(10.3) Dl denotes the diameter of the leak in mm (a circular leak geometry is assumed) and DN is the nominal diameter (occasionally called nominal bore) of the pipe (approximately equal to the internal diameter in mm). Equation (10.3) is the only one to estabhsh a relationship between leak size and its expected annual frequency of occurrence h. The latter refers to a length of 1 m and must therefore be multiplied by the length of the pipe under consideration. Equation (10.3) is based on evaluations for steel pipes in the process and petrochemical industries. 

As a simple example, consider a pipe of nominal bore 250 mm, containing a fluid with mean flow velocity 2 m/s (which as we remarked is towards the upper end of commonly applied in-plant flow velocities for clear fluids). The velocity head... 

Carbon steel seamless piping with welded-on flanges is recommended for the construction of liquor mains. Pipelines, normally 2" nominal bore, should be self-draining, but if this is impracticable, drain cocks should be installed at the lowest points. Where there is a risk of liquor freezing, pipelines should be steam-traced and lagged. 

Table 4.1 Pipe diameters and wall thicknesses for 4 inch nominal bore pipeline.

The pipeline was manufactured from carbon steel schedule 40 electrical-resistance-welded seamed pipe. This is virtually the industry-standard for a large proportion of pneumatic conveying pipelines. 50mm nominal bore was used as previous experience indicated this to be the smallest size from which scaling-up to substantially larger sizes gave acceptable accuracy. 

Screwed plugs in pipes, only permissible on air, water, nitrogen under iOO psi, one and a half inch nominal bore and below ... 

In fig, 4 local corrosion by erosion is shown in a pipe with a bore of 100 mm behind a welding. In this case only the nominal wall thickness of the pipe is known (6.3 mm). To calibrate the obtained density changes into wall thickness changes a step wedge exposure with a nominal wall thickness of 13 mm (double wall penetration in the pipe exposure) and the same source / film system combination was used. From this a pcff = 1-30 1/cm can be expected which is used for the wall thickness estimation of the pipe image according to equation (4). 

Standard pipe size, in Nominal dimensions, in (mm) Cross-sectional area of bore, in (cm ) Nominal weight, Ih/ft (kg/m) Tolerances, in (mm) ... 

Nominal pipe bore (mm (in)) Equivalent length of fitting ... 

Nominal Pipe Flange Class Size Outside Diameter of Flange, O Thickness of Flange, tf Diameter of Hub, X Diameter Beginning of Chamfer, A Length Through Hub,Y Bore, B... 

Much pipe, especially in the larger sizes (for which compatibility with traditionally sized plastic piping components such as valves and fittings is not necessary), is made to fit into special diameter-sizing systems determined by the specific product standard or by the pipe manufacturer. Most of these systems have established diameter dimensions of such proportions that the resultant size of the inside bore is close to the pipe nominal diameter. 

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