ISO 14531-4:2006 プラスチックパイプおよび継手—ガス状燃料を輸送するための架橋ポリエチレン（PE-X）パイプシステム—メトリックシリーズ—仕様—パート4：システム設計および設置ガイドライン | ページ 6

3.1

nominal outside diameter

d_n

numerical designation of size which is common to all components in a thermoplastics piping system other than flanges and components designated by thread size

Note 1 to entry: It is a convenient round number for reference purposes.

Note 2 to entry: The nominal outside diameter expressed in millimetres is the minimum mean outside diameter d_e,min of pipe produced in accordance with ISO 14531-1.

3.2

nominal wall thickness

e_n

nominal designation of wall thickness of a pipe in millimetres in accordance with ISO 4065

3.3

standard dimension ratio

SDR

Note 1 to entry: The value of the SDR is selected from Table 5 in ISO 14531-1:2002.

3.4

gaseous fuel

fuel which is in a gaseous state at a temperature of +15 °C and a pressure of 1 bar

3.5

category D gaseous fuel

natural gas

Note 1 to entry: Categories of gaseous and liquid fuels are defined in detail in ISO 13623.

3.6

category E gaseous fuel

LPG vapour or natural gas conveyed in association with liquid condensate

Note 1 to entry: Categories of gaseous and liquid fuels are defined in detail in ISO 13623.

3.7

design pressure

DP

pressure on which design calculations are based

Note 1 to entry: The design pressure for pipes is designated DP_P and for fittings DP_F.

3.8

design stress

σ_S

pipe wall circumferential stress calculated from the design pressure DP_P and pipe SDR with a maximum limiting value determined by the quotient of MRS _{θ, t} and the overall service (design) coefficient C

3.9

maximum operating pressure

MOP

highest effective pressure, in bars, of the gas in the piping system which is allowed in continuous use

Note 1 to entry: The MOP takes into account the physical and the mechanical characteristics of the components of a piping system.

3.10

temporary operating pressure

TOP

maximum pressure that can be generated on a temporary basis under the control of the regulating devices

3.11

maximum incidental pressure

MIP

maximum pressure generated for example by surges or failure of pressure control equipment and limited by the activation of overpressure protection devices

3.12

pipeline operator

private or public organization authorized to design, construct and/or operate and maintain the gas supply system

3.13

minimum required strength

MRS _{θ, t}

value of σ_lpl for the pipe material, in megapascals, calculated using ISO 9080 for a specific design temperature θ and lifetime t and then categorized in accordance with Table 3

Note 1 to entry: At 20 °C and 50 years, MRS _{θ, t} = MRS.

3.14

overall service (design) coefficient

C

overall coefficient, with a value greater than 1,0, which takes into consideration service conditions as well as properties of the components of a piping system other than those represented in the lower prediction limit (3.15)

3.15

lower prediction limit

σ_lpl

quantity, expressed in megapascals, which can be considered as a property of the material and which represents the 97,5 % lower prediction limit of the long-term hydrostatic strength at a temperature of 20 °C and a time of 50 years in water

3.16

heat-fusion fitting

fitting designed to connect PE-X pipes to form an assembly for subsequent jointing by heat fusion and the creation of an integral pipe-to-fitting connection

3.17

operating-temperature range

assumed range of temperatures experienced by a PE-X pipeline at the intended service location, for use in the process of designing the pipeline for operation at MOP

3.18

minimum operating temperature

T_min

minimum operating temperature (above and/or below ground) expected during the service life of the pipeline

3.19

maximum operating temperature

T_max

maximum operating temperature (above and/or below ground) expected during the service life of the pipeline

3.20

design temperature

θ

temperature used to determine MRS _{θ, t}