What is ISO 4427-3 - Polyethylene (PE) fittings about?  
The ISO 4427 series of standards are a set of system standards that specify the requirements for a piping system and its components when made from PE.
ISO 4427-3 is the third part in the multi-series that is applicable to the plastics piping systems for water supply and for drainage and sewerage under pressure. It details best practices for ensuring safe, reliable, and high-performance plastic piping systems.
ISO 4427-3 specifies the fittings made from polyethylene (PE) for buried or above ground applications, intended for the conveyance of water for human consumption, raw water prior to treatment, drainage and sewerage under pressure, vacuum sewer systems, and water for other purposes.
ISO 4427-3 is applicable to fittings of the following types:
- Fusion fittings
- Electrofusion fittings
- Spigot end fittings (for butt fusion using heated tools and electrofusion socket fusion)
- Socket fusion fittings (see Annex A)
- Mechanical fittings
- Compression fittings
- Flanged fittings
- Fabricated fittings (see Annex B)
Note: The intended uses include sea outfalls, laid in water, and pipes suspended below bridges.
Note: It is the responsibility of the purchaser or specifier to make the appropriate selections from these aspects, taking into account their particular requirements and installation practices or codes.
Who is ISO 4427-3 – PE fittings for? 
ISO 4427-3 on PE fittings is useful for: 
- Manufacturers and suppliers of PE
- Manufacturers and suppliers of PE fittings
- Construction industry
- Contractors
- Civil engineers
- Specifiers and installers
- Local bodies
Why should you use ISO 4427-3 – PE fittings?
PE is a flexible, lightweight and corrosion-resistant piping product. These benefits make it an ideal piping material for a broad variety of applications such as potable water service or distribution lines, natural gas distribution, lawn sprinklers, sewers, waste disposal, and drainage lines.
For assembling PE pipe to another PE pipe or any other element of the piping system, ISO 4427-3- compliant mechanical fitting ensure that the compression provides optimal pressure integrity, leak-tightness, and resistance to end loads.
ISO 4427-3 specifies requirements for material and compound, along with geometrical, electrical, mechanical, and physical properties of PE fittings. Requirements, test parameters and standard references for the test methods are also provided. As a result, you can ensure characteristics such as tensile strength, resistance to slow crack growth, and resistance to weathering, amongst others, are exhibited by the PE fittings.
By selecting the right materials for PE fittings in compliance with ISO 4427-3, you can ensure that product failure is avoided and overall structural integrity of the external water conveyance systems is maintained.
What’s changed since the last update?
BS ISO 4427-3:2019 supersedes BS ISO 4427‑3:2007, which is withdrawn. BS ISO 4427-3:2019 includes some technical changes with respect to BS ISO 4427‑3:2007. These include: 
- Update of the normative references
- Technical consistency with ISO 4437-3
