Basic PPR Knowledge

Time:2014-09-11 11:57

PPR Pipes Specification Identifiers

PPR pipes are represented by Series S, with a nominal outside diameter of dn times the nominal wall thickness en

For example, if there is a PPR S5 series pipe, with a nominal outside diameter of dn 25mm, and a nominal wall thickness of en 2.5mm,

it should be represented by S5, dn25×en2.5mm.

The S means the non-dimensional numerical series of PPR pipes, with following relation: S=

(dn-en)/ 2 en,

where, dn represents the nominal outside diameter of PPR, the unit is mm,

en represents PPR nominal wall thickness, the unit is mm.

Normally, regular PP-R pipes are one of the following five series: 5, 4, 3.2, 2.5, and 2.

PPR pipes with PPR specifications, in accordance with the value of standard dimension rate SDR, are divided into following five series: 11, 9, 7.4, 6, and 5.

The standard dimension rate SDR of PPR specification pipes: the ratio of nominal outside diameter dn and nominal wall thickness en.

The relation between SDR and series S of PPR is as follows: SDR=2S+1.

Representation method of PPR pipe specifications:

The nominal outside diameter dn of PPR pipe represents the nominal outside diameter of PPR piping connected with the PPR pipe. Thickness of PPR pipes

shall not be less than that of the same series S PPR piping.

For most enterprises, PPR pipes have only one series S2 with the highest standard, suitable for both cold and hot water

PPR specification pipes, S5 series--------------1.25 MPa (12.5 kg)

PPR specification pipes, S4 series--------------1.6 MPa (16kg)

PPR specification pipes, S3.2 series--------------2.0 MPa (20kg)

PPR specification pipes, S2 series--------------2.5 MPa (25kg)

The way to connect PP-R and steel pipes

Connecting PP-R and steel pipes have two methods: screwed connection and flanged connection.

PP-R :DN20 connecting with steel pipes via 4' threads or flange

PP-R: DN25 connecting with steel pipes via 6' threads or flange

PP-R: DN32 connecting with steel pipes via 1' threads or flange

PP-R: DN40 connecting with steel pipes via 1 1/2' threads or flange

PP-R: DN50 connecting with steel pipes via 1 3/4' threads or flange

PP-R: DN63 connecting with steel pipes via 2' threads or flange

PP-R: DN75 connecting with steel pipes via 21/2' threads or flange

PP-R: DN90 connecting with steel pipes via 23/4' threads or flange

PP-R: DN110 connecting with steel pipes via 3' threads or flange

Nominal diameter of steel pipe

Nominal diameter is a numerical value indicating the size for all the pipeline fittings of a piping system, and it is for reference only.

A round number is for convenience, and is not strictly related to the finish size. Nominal diameter is represented by DN, immediately followed by a number sign.

The nominal diameter is also known as the mean outside diameter.

This results from the very thin wall of metal pipes, with the outside and inside diameters almost the same, thus the mean value of them is taken as the pipe diameter.

DN is the nominal diameter, representing the general diameter of various pipes and fittings. The pipes and fittings with the same nominal diameter can be connected to each other, which are exchangeable. The nominal diameter is meaningless,

representing neither the outside nor the inside diameter, even though its numerical value is close to or equal to the inside diameter;

To make the pipes and fittings connect with uniform dimensions, the nominal diameter is used.

For example, the welded steel pipes include thin-wall steel pipes, common steel pipes and thickened steel pipes. The nominal diameter is neither the outside diameter, nor the inside diameter, but a nominal size approximate to the inside diameter of steel pipes. Each of the nominal diameters corresponds to an outside diameter, while the value of the inside diameter varies with the change of thickness. The nominal diameter can be denoted by either metric mm, or the imperial in. Pipeline fittings are also represented by a nominal diameter, with the same meaning as seamed pipes.

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