Underfloor systems

DIN EN 50085-2-2 specifies the load requirements for underfloor systems in electrical installations. According to this standard, cassettes/service outlets may only bend by a maximum of 6 mm when subjected to a load. However, with harder floor coverings, such as stone or tiles, bending will lead to breakage. For this reason, OBO has increased its internal quality criteria and goes a step further with the OBO testing standard. The test results from the OBO BET Test Centre formed the basis for the development of the internal classification of heavy-duty classes SL1 and SL2. Products of heavy-duty class SL1 are suitable for loads of up to 10 kN, whilst products of heavy-duty class SL2 are even suitable for loads of up to 20 kN. This can prevent the breaking of hard and sensitive floor coverings such as stone or tiles.

All the device installation units for wet-care floors have a protection rating of at least IPX4 when closed to fulfil the requirements of EN 50085-2-2 without restriction. Device installation units with tube body also protect the electrical installation against the ingress of water when used. The tube body extends 10 mm beyond the top edge of the floor covering, offering protection against the ingress of water into the internal electrical installation.

The underfloor systems from OBO are intended for installation in floating screeds. Normally, there are requirements for the transmission of air and footfall sound, both for vertical sound transmission, i.e. from storey to storey, and for horizontal sound transmission (from adjacent rooms). As the underfloor systems are also run under partitions, the question of the influence of the system on noise transmission is of high relevance. For this reason, the air and noise transmission for the EÜK duct and OKA and OKB trunking systems and UDHOME floor boxes were evaluated in qualified tests with the MÜLLER-BBM testing institute in Planegg, Munich.

The following floor structure requirements must be considered:

• Installation requirements
• Requirements from architectural construction planning
• Organisational requirements and user specifications
• Safety requirements

Accordingly, the correct selection of the duct or trunking system is of key significance for technical planning. Besides personal project advice, the OBO service also includes the OBO Construct software, offering a fast, targeted planning tool for underfloor systems (www.obo-construct.com).

These can be divided into two categories: installation specifications and product standards. The installation engineer is primarily responsible for compliance with the erection specifications.
The product standard EN 50085-2-2 specifies the testing criteria for underfloor systems. The OBO Bettermann underfloor systems meet this standard and are VDE-certified.

In Germany, the Master Cable Installation Guideline (MLAR) is significant for fire protection measures in cable systems and for underfloor systems. The Master System Floors Directive (MSys-BöR) applies additionally. According to the requirements in these standards, OBO Bettermann underfloor systems can be run in escape and rescue routes and through fire walls. In so doing, special requirements need to be taken into account in the installation and system selection.