ISO 8779:2020 プラスチック配管システム—灌漑用ポリエチレン（PE）パイプ—仕様 | ページ 6

3.1

main

main supply line within an irrigation system, including sub-mains

3.2

lateral

branch supply line within an irrigation system on which water distribution devices are mounted directly or by means of fittings, risers or tubes

Note 1 to entry: Examples of water distribution devices are sprinklers, emitters and drippers.

3.3

melt mass-flow rate

MFR

value relating to the viscosity of the molten material at a specified temperature and load measured in accordance with ISO 1133-1

Note 1 to entry: MFR is expressed in units of grams per 10 min (g/10 min).

3.4

nominal outside diameter

d_n

specified outside diameter, assigned to a nominal size DN/OD

Note 1 to entry: Expressed in millimetres.

3.5

mean outside diameter

d_em

value of the measurement of the outer circumference of the pipe or spigot end of a fitting in any cross-section divided by π (= 3,142), rounded to the next greater 0,1 mm

3.6

minimum mean outside diameter

d_{em, min}

minimum value of the outside diameter as specified for a given nominal size

3.7

maximum mean outside diameter

d_{em, max}

maximum value of the outside diameter as specified for a given nominal size

3.8

out-of-roundness

ovality

difference between the measured maximum outside diameter and the measured minimum outside diameter in the same cross-section of the pipe or spigot end of a fitting

3.9

nominal wall thickness

e_n

numerical designation of the wall thickness of a component, which is a convenient round number approximately equal to the manufacturing dimension

Note 1 to entry: Expressed in millimetres.

3.10

wall thickness at any point

e

value of the measurement of the wall thickness at any point around the circumference of a component

3.11

minimum wall thickness at any point

e_min

minimum value of the wall thickness at any point (3.10) around the circumference of a component as specified

3.12

maximum wall thickness at any point

e_max

maximum value of the wall thickness at any point (3.10) around the circumference of a component as specified

3.13

standard dimension ratio

SDR

numerical designation of a pipe series, which is a convenient round number, approximately equal to the ratio of the nominal outside diameter (3.4) , d_n, of a pipe to its nominal wall thickness (3.9) , e_n

3.14

tolerance

permissible variation of the specified value of a quantity expressed as the difference between the permissible maximum and permissible minimum values

3.15

pressure class

PC

the maximum allowable working pressure (3.16) of the pipe at a temperature of 20 °C

3.16

maximum allowable working pressure

MAWP

highest water pressure in the pipe which is allowed in continuous use

Note 1 to entry: Maximum allowable working pressure is expressed in bar.