ISO 4132:1979

Overview

ISO 4132:1979 specifies the metric series of diameters, laying lengths and thread sizes used for unplasticized polyvinyl chloride (PVC/uPVC) and metal adaptor fittings for pipes under pressure. The purpose of the Standard is to provide common dimensions that allow adaptor fittings to connect reliably to existing metal pipes, fittings, valves and apparatus with pipe threads.

Key points from the Standard include:

• The PVC components (plain sockets or spigots) shall correspond to the dimensions in ISO 727 or ISO 264.
• Threaded parts conform to pipe thread standards where pressure-tight joints are made on the threads (ISO 7/1) and where pressure-tight joints are not made on the threads (ISO 228/1).
• Metal components should conform to ISO/R 49 or equivalent national practice.
• The Standard covers common adaptor types and provides tables of laying lengths and connections for metric sizes (examples in the document include sizes in the range shown in the tables, e.g. DN 16 to DN 90).

Key Topics

• Laying lengths: Defined distances required between pipe ends for assembly. The Standard distinguishes "pipe to pipe" and "pipe to axis" conditions and gives laying lengths in clauses with permissible deviations.
• Thread designation and fit: Nominal thread sizes for joint threads (ISO 7/1) and parallel connecting nut threads (ISO 228/1) are specified to ensure pressure-tight or non-pressure-tight assembly as intended.
• Component compatibility: The document prescribes which PVC socket/spigot and metal component dimensions are common to adaptor fittings so they can be used interchangeably with metal pipework and valves.
• Types of adaptor fittings: Includes adaptor unions and adaptor connections in several configurations (examples: unions with metal female/male threads, PVC union ends, spigot/socket combinations and special sleeve designs).

Applications

ISO 4132:1979 is valuable for manufacturers, specifiers and engineers involved in:

• Designing and specifying adaptor fittings that join uPVC systems to existing metal pipe systems.
• Ensuring interchangeability between plastic and metal components where metric threads are used.
• Verifying dimensional conformity for pressure-bearing piping systems in building services, utilities and industrial fluid transport.

Benefits include reduced risk of mismatched fittings, predictable assembly clearances, and consistent pressure-tight joint performance when used with the referenced ISO thread and socket standards.

Related Standards

• ISO 7/1 - Pipe threads where pressure-tight joints are made on the threads: designation, dimensions and tolerances.
• ISO 228/1 - Pipe threads where pressure-tight joints are not made on the threads: designation, dimensions and tolerances.
• ISO 727 / ISO 264 - Dimensions and laying lengths for uPVC plain sockets and spigots for pipes under pressure.
• ISO/R 49 - Malleable cast iron (and related metal) pipe fittings screwed in accordance with ISO thread forms.

Use ISO 4132 in conjunction with these referenced documents to specify, manufacture and inspect adaptor fittings that reliably connect uPVC pipe systems to metal pipework under pressure.