BS 8561:2021 pdf download.Specification for mechanical fittings for use in the repair, connection and renovation of pressurized water supply pipelines — Requirements and test methods
3.7wide tolerance coupling
mechanical fitting capable of connecting a range of pipe materials and/or pipe dimensions providingconnection between two pipe spigot ends
3.8wide tolerance step coupling
mechanical fitting capable of connecting a range of pipe materials and /or pipe dimensions providingconnection between two pipe spigot ends of different outside diameter
3.9dedicated flange adaptor
mechanical fitting providing connection between a spigot and a flange
NOTE For repair of existing water supply pipes, flange adapters are designed such that they can slide over thepipe spigot or have a setting gap to facilitate assembly.
3.10wide tolerance flange adaptor
mechanical fitting capable of connecting a range of pipe materials and/or pipe dimensions providingconnection between a spigot and a flange
NOTE For repair of existing water supply pipes, flange adapters are designed such that they can slide over thepipe spigot or have a setting gap to facilitate assembly.
3.11repair clamp
mechanical fitting installed around a leaking pipe barrel to affect a seal on both local andcircumferential pipe defects
3.12joint encapsulation unit
mechanical fitting installed around a leaking pipe joint that seals to both sections of pipe barrel eitherside of the joint forming a pressure-tight container to contain the leakage
3.13under pressure tee
mechanical fitting installed on/around a pipe to create a branch connection usually terminating in aflange outlet
NOTE1 The fitting, along with other equipment and fittings, facilitates a live connection to the pipe withoutinterruption to the supply flowing through it.
NOTE 2 Under pressure tees may have full pipe surface contact sealing to accommodate the branch connection andalso any circumferential cracking which might occur.
3.14barrier pipe
multi-layer pipe consisting of two polyethylene layers with an intervening aluminium barrier layerthat together provide the necessary strength and resistance to permeation
3.15nominal pressure (PN)
numerical designation which is a convenient rounded number for reference purposes
NOTEFor plastic piping systems conveying water, it corresponds to the maximum continuous operating pressure,expressed in bar, which can be sustained with water as 20 °C, based on the minimum design coefficient.
3.16pipe nominal size (DN)
nominal size,related to the outside diameter3.17standard dimension ratio (SDR)
numerical designation of a pipe series, which is a convenient round number, approximately equal tothe dimension ratio of the nominal outside diameter, DN, and the nominal wall thickness,EN
3.18end load resistance
resistance to end load transmitted via the connecting pipe and generated by internal pressure,pipeline external interference and thermally induced pipe stresses in any combination
3.19fastener
device that serves to secure one part to another
NOTE These include but are not limited to nuts,bolts and washers.
3.20depth of engagement
when jointed, the distance between the end of the spigot and the face of the socket on a couplings,stepped/reducing couplings and flange adaptors
3.21joint angular deflection
angle between the axis of two connected pipeline components which a flexible joint can accommodate
3.22setting gap
when jointed, the distance between the ends of the spigots in a coupling orthe end of the spigot andthe flange face for a flange adaptor
3.23allowable operating pressure PFA
maximum hydrostatic pressure that a fitting is capable of withstanding continuously in service3.24spigot
male end of a pipe or fitting
4 Material characteristics
4.1 Effect on water quality
All fittings for potable water applications shall ensure the constructional materials, coatings, sealsor gaskets in contact with potable water present no risk to human health with regard to affecting thequality.appearance, smell or taste.
The effect on water quality of fittings for PE barrier pipe shall meet the requirements ofBS 8588:2017,7.7.
4.2Materials
All fittings shall be made from thermoplastics or materials which conform to the relevant standardlisted in Table 1.BS 8561 pdf download.