BRL K536-L: Assessment guideline for multilayer plastic piping systems with metal inner layer
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What is BRL K536-L?
BRL K536-L defines the certification requirements for plastic piping systems with a metal inner layer for transporting hot and cold drinking water within buildings. This guideline was declared binding by Kiwa on 27 February 2026. It specifies requirements for multilayer systems that combine plastic and metal, focusing on:
- Safety and reliability of the piping system
- Hygienic suitability for drinking water
- Performance under long-term pressure and temperature stress
Pipes, fittings, and joints are all covered by the certification scope.
Scope of application
The guideline applies to piping systems for:
- Distribution of hot and cold drinking water within buildings
- Applications with a design pressure of 8 or 10 bar
The systems must comply with a temperature profile according to class 2 of ISO 10508:
- 70 °C for 49 years
- 80 °C for 1 year
- 95 °C for 100 hours
This corresponds to an expected service life of 50 years.
Key requirements
- Reliable connections
- Leak-tight under pressure and vacuum
- Resistant to temperature and pressure cycles
- Resistant to tensile stress and loosening
- Pipe performance
- Long-term pressure strength
- Strength of the metal inner layer and weld seam
- Adhesion between layers (delamination)
- Thermal durability of the outer layer
- Fittings and components
- Material and strength requirements for plastic and metal
- Pressure and corrosion resistance
- Compatibility with the piping system
- Hygiene and materials
- Compliance with Kiwa requirements for drinking water contact
- Use of recycled material is not allowed
- Use of rework material is permitted under conditions
Certification under BRL K536-L
Certification according to BRL K536-L results in a Kiwa technical approval or product certificate. The certification process includes:
- Initial product assessment and type approval
- Evaluation of materials and system construction
- Periodic inspections and testing
- Assessment of the internal quality control system (IQC)
This ensures the ongoing compliance of your product.
Benefits of certification
A BRL K536-L certificate:
- Demonstrates that your product is suitable for drinking water applications
- Provides assurance of performance and service life
- Supports market access and acceptance
- Builds trust with clients and regulators
BRL K536-A Plastics piping systems of PVC-C for hot and cold drinking water
The products are intended to be applied in piping systems for hot and cold water distribution at a design pressure (= maximum operating pressure) of 8 or 10 bar (9 or 11 bar absolute or 8 or 10 bar overpressure), under the conditions mentioned in table 1.
BRL K536 B Plastic piping systems of PP-R for hot and cold drinking water
The products according BRL K536 B are applicable for piping systems distribution systems for hot and cold drinking water at a design (working) overpressure of 8 or 10 bar according the temperature profile table 1.
BRL K536 C Plastic Piping Systems of PB for hot and cold drinking water
The products according BRL K536 C are applicable for piping systems distribution systems for hot and cold drinking water at a design (working) overpressure of 8 or 10 bar according the temperature profile table 1.
BRL K536 E Plastic piping systems of PE-X/Al for hot and cold drinking water
The products according BRL K536 E are applicable for piping systems distribution systems for hot and cold drinking water at a design (working) overpressure of 8 or 10 bar according the temperature profile table 1.
BRL K536-F Plastic piping systems of PP-R/Al for hot and cold drinking water
The products according BRL K536 F are applicable for piping systems distribution systems for hot and cold drinking water at a design (working) overpressure of 8 or 10 bar according the temperature profile table 1.
BRL K536-G Plastic piping systems of PE-RT/Al for hot and cold drinking water
The products according BRL K536 G are applicable for piping systems distribution systems for hot and cold drinking water at a design (working) overpressure of 8 or 10 bar according the temperature profile table 1.
BRL K536-H Plastic piping systems of PE-RT Type II for hot and cold drinking water
The products according BRL K536 H are applicable for piping systems distribution systems for hot and cold drinking water at a design (working) overpressure of 8 or 10 bar according the temperature profile table 1.