HENSOMASTIK® WUM

Effective Support Measure (WUM) for cable systems with a requirement for functional retention

The HENSOMASTIK® WUM provides innovative fire protection solutions for secure cable systems, meeting the requirements of DIN 4102-12 and ensuring functional retention in the event of a fire for functional retention classes E30 to E90 in accordance with MLAR.

With a HENSOMASTIK® WUM, cable systems that require functional retention can be installed vertically on profile rails using clip-on hangers, cable trays, or individual clips without the need for strain relief loops—which can be entirely eliminated. This effective support measure safeguards critical infrastructure and minimises the risk of system failures during a fire, making it ideal for industry, tunnels, hospitals, and more.

The HENSOMASTIK® WUM is available as a well-conceived kit made of robust materials with high temperature resistance in standard sizes, allowing for a flexible, rapid, and secure installation.

Advantages:

• No additional cable coating required
• Available in various sizes up to a width of 900 mm (custom dimensions available on request)
• No strain relief loops required – saving time and costs during installation
• Suitable for functional retention classes E30 to E90 as specified by MLAR
• Complies with the requirements of DIN 4102-12
• Fit for all cable types, diameter and cross-sectional area
• Flexible mounting on profile rails, on ladder rungs, or on walls
• Annular gap filled with HENSOMASTIK® 5 KS SP (Spachtel)

Particularly suitable for:

• Industrial and office buildings
• Hospitals and public facilities
• Tunnels and infrastructure installations
• Escape routes and emergency exits
• Fire detection systems
• Systems for smoke and heat extraction control (RWA)

Environment:

• Free from solvents, silicones, halogens, and plasticisers
• Green Product, VOC emissions class A+
• Meets the requirements of eco-bau 1 and Minergie-eco
• PFAS-free (free from per- and polyfluorinated chemicals)
• Components are reusable after deconstruction
• Environmental Product Declaration (EPD-RHG-20240374-IBA3-DE)

Would you like to learn more about HENSOMASTIK® WUM or require a quotation? Our experts are available to help you find the optimal fire protection solution for your construction project or specific requirements.

HENSOMASTIK® WUM – Your solution for safe and efficient cable installations in the event of a fire.

Why fire protection for cable systems is important

Fire protection for cable systems is a crucial factor in ensuring the safety of buildings and infrastructure. In the event of a fire, conventional cable fixings are at risk of failing due to high temperatures and mechanical stresses. If cables break, the functional retention of critical systems—such as emergency lighting, fire alarm systems or smoke and heat extraction systems (RWA)—may be compromised. This poses significant risks to human lives and property.

The legal requirements for the functional retention of cable systems are clearly defined in the Muster-Leitungsanlagen-Richtlinie (MLAR) and DIN 4102 Part 12. According to MLAR Section 5.1.1, electrical cable systems for safety-critical installations required by building regulations must be designed or separated by structural elements so that these systems remain operational for a sufficient period during a fire (functional retention). This functional retention must be maintained even when there is interaction with other systems, installations or their components.

Furthermore, MLAR Section 5.3, “Duration of Functional Retention”, stipulates that electrical cable systems must remain operational for a defined period in the event of a fire. This includes the functional retention classes E30 (at least 30 minutes of functional retention, e.g. for fire alarm or emergency lighting systems) and E90 (at least 90 minutes of functional retention, e.g. for automatic fire-fighting systems or fire water supply).

To ensure the power supply—and thereby the operational capability—of these technical installations during a fire, the associated installations must be implemented with specially designed cables and laying systems for functional retention. MLAR, in Section 5.2 “Functional Retention of Cables and Distribution Systems”, refers among other things to the test requirements of DIN 4102-12; thus, in conjunction with DIN 4102 Part 12, MLAR also imposes additional technical requirements on functional retention.

Paragraph 8.3 of DIN 4102 Part 12 specifies that, particularly for vertical cable installations, an effective support measure (WUM) is necessary. Such measures prevent cables from breaking due to heat or their own weight, thereby ensuring functional retention over the prescribed period. For continuous vertical installation of cables with functional retention, a WUM must be provided at a maximum spacing of 3.5 metres.

The WUM can be implemented as a fire protection seal system in the floor slab with the appropriate classification (see also our firestop seals for cables), as a strain relief loop that takes into account the permissible bending radii of the cables, as specialised fire-rated fastening systems, or by reinforcing conventional fixings and support systems that would fail under high temperatures and fire exposure.

Through the correct selection and installation of the fixing systems, the functional retention of the cables can be ensured even in the event of a fire. Reinforcing the cable support systems with a HENSOMASTIK® WUM provides a reliable, fire-safe fixing that mitigates these risks and meets the requirements of both MLAR and DIN 4102-12.